**1. Introduction**

Transition metal-catalyzed cross-coupling reactions between aryl halides and primary/secondary amines to obtain aminated aryl compounds has been an area of interest due to the wide applications of arylamines in the synthetics and pharmaceutical industries [1–5]. In this direction, the Buchwald– Hartwig cross-coupling reaction was performed by using transition metal catalysts, ligands and bases

with substrates to obtain the desired arylamine products [6–8]. The disadvantage of this reaction is the use of expensive catalysts, which offers the chemist the opportunity to discover cheaper, reusable catalysts to drive the arylamination reactions. Inspired by major developments in cobalt-catalyzed arylamination reactions, we developed a complementary method to perform an arylamination reaction using cobalt as a metal catalyst [9–11] disadvantage of this reaction is the use of expensive catalysts, which offers the chemist the opportunity to discover cheaper, reusable catalysts to drive the arylamination reactions. Inspired by major developments in cobalt-catalyzed arylamination reactions, we developed a complementary method to perform an arylamination reaction using cobalt as a metal catalyst [9–11]

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In addition, benzimidazole ligand coordinated metal complexes are widely used as catalysts in arylamination reactions [12]. Since these catalysts were found to be less hydrophobic, immobilization of such metal complexes with polymer support was observed to be stable, selective, and recyclable, attributed to the steric, electrostatic, hydrophobic and conformational effects of the polymer support [13]. Hence, several reports pertaining to the synthesis of arylamines using polymer-supported transition metal complexes are found [14–16]. Specifically, chloromethylated polystyrene cross-linked with divinyl-benzene was employed as a macromolecular support to perform the arylamination reactions [17–22]. In addition, benzimidazole ligand coordinated metal complexes are widely used as catalysts in arylamination reactions [12]. Since these catalysts were found to be less hydrophobic, immobilization of such metal complexes with polymer support was observed to be stable, selective, and recyclable, attributed to the steric, electrostatic, hydrophobic and conformational effects of the polymer support [13]. Hence, several reports pertaining to the synthesis of arylamines using polymer-supported transition metal complexes are found [14–16]. Specifically, chloromethylated polystyrene cross-linked with divinyl-benzene was employed as a macromolecular support to perform the arylamination reactions [17–22].

In medicinal chemistry, an adamantane-coupled bicyclical core structure was used as an important pharmacophore, which was inserted in many drugs [23]. Hence, the adamantane structure was recognized as a readily available "liphophilic bullet" for providing critical liphophilicity to known pharmacophoric units. Given the remarkable importance of adamantane chemistry, we recently reported the synthesis and biology of adamantyl-tethered biphenylic compounds as potent anticancer agents [24]. In our continued efforts to synthesize newer bioactive agents [25–31], we herein report a practical, economically feasible and efficient arylamination reaction using polymer-supported 1,3-bis(benzimidazolyl)benzeneCo(II) complex (PS-Co(BBZN)Cl2) as a catalyst. Interestingly, the recovered (PS-Co(BBZN)Cl2) could be reused three times without a significant loss of activity. In medicinal chemistry, an adamantane-coupled bicyclical core structure was used as an important pharmacophore, which was inserted in many drugs [23]. Hence, the adamantane structure was recognized as a readily available "liphophilic bullet" for providing critical liphophilicity to known pharmacophoric units. Given the remarkable importance of adamantane chemistry, we recently reported the synthesis and biology of adamantyl-tethered biphenylic compounds as potent anticancer agents [24]. In our continued efforts to synthesize newer bioactive agents [25–31], we herein report a practical, economically feasible and efficient arylamination reaction using polymer-supported 1,3-bis(benzimidazolyl)benzeneCo(II) complex (PS-Co(BBZN)Cl2) as a catalyst. Interestingly, the recovered (PS-Co(BBZN)Cl2) could be reused three times without a significant loss of activity.

#### **2. Results 2. Results**

#### *2.1. Chemistry of Catalyst Design and Method Development 2.1. Chemistry of Catalyst Design and Method Development*

We initially synthesized polymer-supported 1,3-bis(benzimidazolyl)benzeneCo(II) complex [PS-Co(BBZN)Cl2] as shown in Scheme 1. We initially synthesized polymer-supported 1,3-bis(benzimidazolyl)benzeneCo(II) complex [PS-Co(BBZN)Cl2] as shown in Scheme 1.

**Scheme 1.** Schematic representation to show synthesis of PS-Co(BBZN)Cl2. **Scheme 1.** Schematic representation to show synthesis of PS-Co(BBZN)Cl<sup>2</sup> .

For this, 1, 3-bis(benzimidazolyl)benzene was treated with chloromethylated polystyrene divinylbenzene and followed by the addition of cobalt chloride. The obtained PS-Co (BBZN)Cl2 was characterized by analytical techniques including CHNS, UV-Vis, FT-IR, SEM-EDX and TGA as presented in supporting information (Figure 1, Supplementary SI-02). Based on N% and Co% obtained through elemental and metal ion analysis, the complex formed on the polymer support was about 0.0053 moles per 1 g of the polymer support which corresponded to 7.16% of Co intake. This further confirmed the formation of the complex on the polymer support. For this, 1, 3-bis(benzimidazolyl)benzene was treated with chloromethylated polystyrene divinylbenzene and followed by the addition of cobalt chloride. The obtained PS-Co (BBZN)Cl<sup>2</sup> was characterized by analytical techniques including CHNS, UV-Vis, FT-IR, SEM-EDX and TGA as presented in supporting information (Figure 1, Supplementary SI-02). Based on N% and Co% obtained through elemental and metal ion analysis, the complex formed on the polymer support was about 0.0053 moles per 1 g of the polymer support which corresponded to 7.16% of Co intake. This further confirmed the formation of the complex on the polymer support.

2).

2).

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**Figure 1.** Structure of (**A**) PS-Co (BBZN)Cl2 and (**B**) unbound Co(BBZN)Cl2. **Figure 1.** Structure of (**A**) PS-Co (BBZN)Cl<sup>2</sup> and (**B**) unbound Co(BBZN)Cl2. **Figure 1.** Structure of (**A**) PS-Co (BBZN)Cl2 and (**B**) unbound Co(BBZN)Cl2.

Motivated by the increased understanding of the Co-catalyzed amination reaction, we next investigated the applicability of (PS-Co (BBZN)Cl2) in the arylamination reaction. To examine this hypothesis, 1-(5-bromo-2-methoxyphenyl)adamantine (**1a**) and 4-chloro aniline (**2a**) were selected as model substrates and reagents for the reaction in 1,4-dioxane media and Cs2CO3 as a base (Scheme Motivated by the increased understanding of the Co-catalyzed amination reaction, we next investigated the applicability of (PS-Co (BBZN)Cl2) in the arylamination reaction. To examine this hypothesis, 1-(5-bromo-2-methoxyphenyl)adamantine (**1a**) and 4-chloro aniline (**2a**) were selected as model substrates and reagents for the reaction in 1,4-dioxane media and Cs2CO<sup>3</sup> as a base (Scheme 2). Motivated by the increased understanding of the Co-catalyzed amination reaction, we next investigated the applicability of (PS-Co (BBZN)Cl2) in the arylamination reaction. To examine this hypothesis, 1-(5-bromo-2-methoxyphenyl)adamantine (**1a**) and 4-chloro aniline (**2a**) were selected as model substrates and reagents for the reaction in 1,4-dioxane media and Cs2CO3 as a base (Scheme

**Scheme 2.** General scheme of arylamination reaction between adamantane bromide and various amines using PS-Co(BBZN)Cl2 as a catalyst. **Scheme 2.** General scheme of arylamination reaction between adamantane bromide and various amines using PS-Co(BBZN)Cl2 as a catalyst. **Scheme 2.** General scheme of arylamination reaction between adamantane bromide and various amines using PS-Co(BBZN)Cl<sup>2</sup> as a catalyst.

Control experiments established the importance of both PS-Co(BBZN)Cl2 and ligand, as no product was obtained (Table 1, entry **1**). Gratifyingly, the substrate was transformed into the desired product 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3a**) with 51% yield in the presence of catalyst (PS-Co(BBZN)Cl2) (10 mol%) and ligand **L3** (Table 2, entry **10**). Screening of various classes of ligands (Figure 2) to improve the yield revealed that the use of phosphine based ligand BINAP (**L3**) or Xphose (**L4**) gave improved yields at different catalyst concentrations (Table 1, entry **10**, **11**, **14**, **15**), whereas the other ligands such as bidentate ligands (**L1**, **L2**) and N-heterocyclic carbine ligands (**L5**, **L6**) yielded no products indicating the high role of selectivity of ligands in the forward reaction. The most robust reaction was achieved by the use of 12 mol% of PS-Co(BBZN)Cl2 in the presence of BINAP with an 86% yield at 10 h reaction condition (Table 1, entry **14**). Further investigation revealed that there was no considerable improvement in yield when the catalyst load was increased to 15 mol% (Table 1, entry **18**, **19**) whereas the yield dropped to 69% when the reaction time was reduced to 6 h with 15 mol% catalyst (Table 1, entry **20**). Using the above better protocol, we further synthesized ABTAs by reacting adamantine bromo compounds (**1a**) and various amines Control experiments established the importance of both PS-Co(BBZN)Cl2 and ligand, as no product was obtained (Table 1, entry **1**). Gratifyingly, the substrate was transformed into the desired product 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3a**) with 51% yield in the presence of catalyst (PS-Co(BBZN)Cl2) (10 mol%) and ligand **L3** (Table 2, entry **10**). Screening of various classes of ligands (Figure 2) to improve the yield revealed that the use of phosphine based ligand BINAP (**L3**) or Xphose (**L4**) gave improved yields at different catalyst concentrations (Table 1, entry **10**, **11**, **14**, **15**), whereas the other ligands such as bidentate ligands (**L1**, **L2**) and N-heterocyclic carbine ligands (**L5**, **L6**) yielded no products indicating the high role of selectivity of ligands in the forward reaction. The most robust reaction was achieved by the use of 12 mol% of PS-Co(BBZN)Cl2 in the presence of BINAP with an 86% yield at 10 h reaction condition (Table 1, entry **14**). Further investigation revealed that there was no considerable improvement in yield when the catalyst load was increased to 15 mol% (Table 1, entry **18**, **19**) whereas the yield dropped to 69% when the reaction time was reduced to 6 h with 15 mol% catalyst (Table 1, entry **20**). Using the above better protocol, we further synthesized ABTAs by reacting adamantine bromo compounds (**1a**) and various amines (Table 2). It was observed that all amine partners productively coupled with good yields of around Control experiments established the importance of both PS-Co(BBZN)Cl<sup>2</sup> and ligand, as no product was obtained (Table 1, entry **1**). Gratifyingly, the substrate was transformed into the desired product 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3a**) with 51% yield in the presence of catalyst (PS-Co(BBZN)Cl2) (10 mol%) and ligand **L3** (Table 2, entry **10**). Screening of various classes of ligands (Figure 2) to improve the yield revealed that the use of phosphine based ligand BINAP (**L3**) or Xphose (**L4**) gave improved yields at different catalyst concentrations (Table 1, entry **10**, **11**, **14**, **15**), whereas the other ligands such as bidentate ligands (**L1**, **L2**) and N-heterocyclic carbine ligands (**L5**, **L6**) yielded no products indicating the high role of selectivity of ligands in the forward reaction. The most robust reaction was achieved by the use of 12 mol% of PS-Co(BBZN)Cl<sup>2</sup> in the presence of BINAP with an 86% yield at 10 h reaction condition (Table 1, entry **14**). Further investigation revealed that there was no considerable improvement in yield when the catalyst load was increased to 15 mol% (Table 1, entry **18**, **19**) whereas the yield dropped to 69% when the reaction time was reduced to 6 h with 15 mol% catalyst (Table 1, entry **20**). Using the above better protocol, we further synthesized ABTAs by reacting adamantine bromo compounds (**1a**) and various amines (Table 2). It was observed that all amine partners productively coupled with good yields of around 70–86%.

(Table 2). It was observed that all amine partners productively coupled with good yields of around 70–86%. 70–86%. All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, <sup>1</sup>H and <sup>13</sup>C NMR analysis).

**Table 1.** PS-Co(BBZN)Cl2-catalyzed coupling of 1-(5-bromo-2-methoxyphenyl)adamantane with 4-Chloro aniline a. **Entry PS-Co(BBZN)Cl2 Ligand b Time Yield (%) c 1** 5 mol% --- 16 NR **Table 1.** PS-Co(BBZN)Cl2-catalyzed coupling of 1-(5-bromo-2-methoxyphenyl)adamantane with 4-Chloro aniline a. **Entry PS-Co(BBZN)Cl2 Ligand b Time Yield (%) c 1** 5 mol% --- 16 NR **2** 5 mol% L1 16 NR The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in

**2** 5 mol% L1 16 NR **3** 5 mol% L2 16 NR **4** 5 mol% L3 16 NR

**3** 5 mol% L2 16 NR **4** 5 mol% L3 16 NR good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2, entries **5**, **11**, **12**, **13**).


**Table 1.** PS-Co(BBZN)Cl<sup>2</sup> -catalyzed coupling of 1-(5-bromo-2-methoxyphenyl)adamantane with 4-Chloro aniline <sup>a</sup> .

<sup>a</sup> Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO<sup>3</sup> (3 eq); 1, 4 dioxane (10 mL); N<sup>2</sup> atmosphere: 100 ◦C. <sup>b</sup> ligands (15 mol%): L1 = 2, 20 -bipyridine, L2 = 1,10-phenanthroline; L3=2,20 -bis(diphenylphosphino)-1,10 -binaphthalene, L4=dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 = 2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium chloride; <sup>c</sup> isolated yield; NR = no reaction. **20** 15 mol% L3 6 69 a Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO3 (3 eq); 1, 4 dioxane (10 mL); N2 atmosphere: 100 °C. b ligands (15 mol%): L1 = 2, 2′-bipyridine, L2 = 1,10-phenanthroline; L3 = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, L4 = dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 = 2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium **20** 15 mol% L3 6 69 a Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO3 (3 eq); 1, 4 dioxane (10 mL); N2 atmosphere: 100 °C. b ligands (15 mol%): L1 = 2, 2′-bipyridine, L2 = 1,10-phenanthroline; L3 = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, L4 = dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 = 2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium **20** 15 mol% L3 6 69 a Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO3 (3 eq); 1, 4 dioxane (10 mL); N2 atmosphere: 100 °C. b ligands (15 mol%): L1 = 2, 2′-bipyridine, L2 = 1,10-phenanthroline; L3 = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, L4 = dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 = **20** 15 mol% L3 6 69 a Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO3 (3 eq); 1, 4 dioxane (10 mL); N2 atmosphere: 100 °C. b ligands (15 mol%): L1 = 2, 2′-bipyridine, L2 = 1,10-phenanthroline; L3 = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, L4 = dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 = 2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium **19** 15 mol% L4 12 79 **20** 15 mol% L3 6 69 a Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO3 (3 eq); 1, 4 dioxane (10 mL); N2 atmosphere: 100 °C. b ligands (15 mol%): L1 = 2, 2′-bipyridine, L2 = 1,10-phenanthroline; L3 = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, L4 = dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 = **20** 15 mol% L3 6 69 a Conditions: admantane-bromo compounds (1 mmol), 4-chloro aniline (1 mmol) (PS-Co (BBZN)Cl2) (12 mol%); Cs2CO3 (3 eq); 1, 4 dioxane (10 mL); N2 atmosphere: 100 °C. b ligands (15 mol%): L1 = 2, 2′-bipyridine, L2 = 1,10-phenanthroline; L3 = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, L4 = dicyclohexyl(2-(2,4,6-trisopropylphenyl)cycohexyl)phosphine, L5 =

**Table 2.** PS-Co(BBZN)Cl<sup>2</sup> composite-catalyzed coupling of various substituted halo aromatic compounds with various substituted aromatic amines <sup>a</sup> . chloride; c isolated yield; NR = no reaction. **Table 2.** PS-Co(BBZN)Cl2 composite-catalyzed coupling of various substituted halo aromatic chloride; c isolated yield; NR = no reaction. **Table 2.** PS-Co(BBZN)Cl2 composite-catalyzed coupling of various substituted halo aromatic chloride; c isolated yield; NR = no reaction. **Table 2.** PS-Co(BBZN)Cl2 composite-catalyzed coupling of various substituted halo aromatic chloride; c isolated yield; NR = no reaction. **Table 2.** PS-Co(BBZN)Cl2 composite-catalyzed coupling of various substituted halo aromatic 2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium chloride; c isolated yield; NR = no reaction. chloride; c isolated yield; NR = no reaction. **Table 2.** PS-Co(BBZN)Cl2 composite-catalyzed coupling of various substituted halo aromatic

2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium

2,6-bis(3-methylimidazoline-1yl)pyridine, L6 = 1,3-dimessityl-4,5-dihydro-1H-imidazole-3-ium



**Table 2.** *Cont.*

a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting

a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting

a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting

a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting

**Figure 2.** Various classes of ligands used in this study.

**Figure 2.** Various classes of ligands used in this study.

**Figure 2.** Various classes of ligands used in this study.

**Figure 2.** Various classes of ligands used in this study.

**3l(61)** 

**3l(61)** 

**3l(61)** 

**3l(61)** 

**3m (64)**

**3m (64)**

**3m (64)**

**3m (64)**

**2p** 

**2p** 

**2p** 

**2p** 

**2q** 

**2q** 

**2q** 

**2q** 

isolated yield.

isolated yield.

**12** 

**12** 

**12** 

**12** 

**13** 

**13** 

**13** 

**13** 

information; c

information; c

isolated yield.

isolated yield.

information; c

information; c

**10** 

**11** 

**12** 

**13** 

**10** 

**10** 

**10** 

**10** 

**2n** 

**2o** 

**11** 

**11** 

**2p** 

**11** 

**Table 2.** *Cont.*

**3j(76)** 

**3j(76)** 

**3j(76)** 

**3j(76)** 

**3j(76)** 

**3k(64)** 

**3l(61)** 

**3m (64)**

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**2n** 

**2n** 

**2n** 

**2n** 

a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting information; c isolated yield. mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting information; c isolated yield. a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting information; c isolated yield. a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl2 (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b All new compounds were characterized by their spectroscopic data shown in supporting information; c isolated yield. <sup>a</sup> Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15 mol%), PS-Co(BBZN)Cl<sup>2</sup> (12 mol%), CS2CO3(3 mmol), 1,4-dioxane (5 mL), N<sup>2</sup> atmosphere 10 h, 100 ◦C. <sup>b</sup> All new compounds were characterized by their spectroscopic data shown in supporting information; <sup>c</sup> isolated yield. °C. b All new compounds were characterized by their spectroscopic data shown in supporting information; c isolated yield.

a Reaction conditions—Aromatic halo compounds (1 mmol), aromatic amine (1 mmol), BINAP(15

**Figure 2. Figure 2.** Various classes of ligands used in this study. Various classes of ligands used in this study.

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted and electron-withdrawing group bearing aromatic bromo compounds observed a loss in yield (entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).

entries **5**, **11**, **12**, **13**).


**Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction. **Table 3.** Various substrates and reagents used to optimization of arylamination reaction.

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

to yields (entries **1**, **2**and ), with ortho-substituted

to excellent (Table 2, **1**–**12**). ortho-substituted and

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

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*Catalysts* **2020**, *10*, x FOR PEER REVIEW 7 of 16 All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and

electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

electron-withdrawing bearing were giving entries **5**, **11**, **12**, **13**). With the established to investigate scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give

With the reaction conditions established we tried to investigate the scope of the new protocol on different substituted aromatic bromo compounds by treating with various amines (Table 3). We found that electron donating para-substituted on aromatic halo partner was tolerated well to give

corresponding products in good to excellent yields (entries **1**, **2**, **3** and **5**), but with ortho-substituted

, **6** and ) with in the conversion reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

(entries **4**, **6** and **7**) with no improvement in the reaction conversion on prolonged reaction.

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*Catalysts* **2020**, *10*, x FOR PEER REVIEW 7 of 16

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis).

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

*10*, 7 of 16

All novel compounds exhibited spectral properties consistent with the assigned structures and

All novel compounds exhibited spectral properties consistent with the assigned structures and

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in aromatic amino-compounds. that electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

The majority of reactions were done by keeping time point for 16 h and when the concentration of the catalyst was increased to 12%, the reaction was completed in 12 h and in many cases pure product was produced with excellent yield. The above developed method tolerated the presence of substituent in the aromatic amino-compounds. Specifically, we observed that the electron-donating para-substituted aromatic amine partners were well-tolerated to produce corresponding products in good to excellent yields (Table 2, entries **1**–**12**). However, ortho-substituted and electron-withdrawing group bearing compounds were not productive giving lower yields (Table 2,

> a Reported compounds. a Reported a Reported compounds. a Reported compounds. <sup>a</sup> Reported compounds.

All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis). It was found that the use of a catalyst PS-Co(BBZN)Cl2, in combination with some ligands provided a robust catalytic system. On the basis of previous mechanistic studies in cobalt-catalyzed C−N bond formation reactions, it was possible to propose a mechanism for the conversion of 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3 a**) as shown in Figure 3 [32–34]. All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized their data (mass, elemental, 1H and analysis). It was the use of catalyst with some ligands provided a robust catalytic system. On the basis of previous mechanistic studies in cobalt-catalyzed C−N bond formation reactions, it was possible to propose mechanism for the conversion of 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3 a**) as shown in Figure 3 [32–34]. All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis). It was found that the use of a catalyst PS-Co(BBZN)Cl2, in combination with some ligands provided a robust catalytic system. On the basis of previous mechanistic studies in cobalt-catalyzed C−N bond formation reactions, it was possible to propose a mechanism for the conversion of 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3 a**) as shown in Figure 3 [32–34]. All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis). It was found that the use of a catalyst PS-Co(BBZN)Cl2, in combination with some ligands provided a robust catalytic system. On the basis of previous mechanistic studies in cobalt-catalyzed C−N bond formation reactions, it was possible to propose a mechanism for the conversion of 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3 a**) as shown in Figure 3 [32–34]. All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, <sup>1</sup>H and <sup>13</sup>C NMR analysis). It was found that the use of a catalyst PS-Co(BBZN)Cl2, in combination with some ligands provided a robust catalytic system. On the basis of previous mechanistic studies in cobalt-catalyzed C−N bond formation reactions, it was possible to propose a mechanism for the conversion of 3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3 a**) as shown in Figure 3 [32–34].

**Figure 3.** Plausible mechanism for the generation of arylamines using PS-Co(BBZN)Cl2 as a catalyst.

**Figure 3.** Plausible mechanism for the generation of arylamines using PS-Co(BBZN)Cl2 as a catalyst.

**Figure 3.** Plausible mechanism for the generation of arylamines using PS-Co(BBZN)Cl2 as a catalyst.

**Figure 3.** Plausible mechanism for the generation of arylamines using PS-Co(BBZN)Cl2 as a catalyst.

**6** 

**4 d**

**7 2 a**

**2 a**

a Reported compounds.

3-(adamantan-1-yl)-N-(4-chlorophenyl)-4-methoxyaniline (**3 a**) as shown in Figure 3 [32–34].

All novel compounds exhibited spectral properties consistent with the assigned structures and were fully characterized by their spectroscopic data (mass, elemental, 1H and 13C NMR analysis). It was found that the use of a catalyst PS-Co(BBZN)Cl2, in combination with some ligands provided a robust catalytic system. On the basis of previous mechanistic studies in cobalt-catalyzed C−N bond

**5 f a (59)**

**5 ga (58)**

**Figure 3. Figure 3.** Plausible mechanism for the generation of arylamines using PS-Co(BBZN)Cl Plausible mechanism for the generation of arylamines using PS-Co(BBZN)Cl<sup>2</sup> as a catalyst. 2 as a catalyst.

Initially, the catalyst makes a complex with amine to form a catalyst-amine complex **A**, which undergoes an oxidative addition reaction with 1-(5-bromo-2-methoxyphenyl)adamantane and complex **B** formation occurs. Complex **B** reacts with cesium carbonate base and undergoes metathesis step, which gave complex **C**. Finally, the reductive elimination reaction complex **C** takes place and thereby catalyst regeneration and the desired product formation occur in the last step (Figure 3).

Further, we performed density-functional theory calculations using dispersion corrected CAM-B3 LYP functional and 6–31+G method [35]. All electron basis set as implemented in the Gaussian 09 package [36]. The minima nature of the structures has been confirmed based on computed real harmonic vibrational analysis at the same level of theory. Gibbs free energy calculations for four intermediate cobalt complexes were chosen for our mechanistic elucidation. Initially CoCl<sup>2</sup> makes the coordination complex with the ligand and reacts with aromatic amine and forms Co-NH bond quickly [intermediate (**a**); ∆E = −6.03 kcal/mole], which in turn gets stabilized by releasing HCl and attains a lower energy intermediate with a ∆E of −9.62 kcal/mole. Alkyl bromide adds to the intermediate (**b**) quickly and attains still lower energy of ∆E of −17.18 kcal/mole where the bindentate ligand detachment takes place and immediate loss of HCl takes place and again attains lowest energy intermediate (**d**) of ∆E = −19.62 kcal/mole, which gives the product immediately. The optimized geometries and the energy profile diagram of intermediates (**a**–**d**) are shown in Figures 4 and 5, respectively. On the basis of lower Gibbs free energy of intermediates across (**a**) to (**d**), we can conclude that the reaction occurs naturally upon cobalt chloride coordination complex formation occurring with the bidentate ligands.

*Catalysts* **2020**, *10*, x FOR PEER REVIEW 10 of 16

**Figure 4.** Computed intermediate structures (**a**), (**b**), (**c**) and (**d**) and reaction path. Energy difference ΔE are given in kcal/mole. **Figure 4.** Computed intermediate structures (**a**–**d**) and reaction path. Energy difference ∆E are given in kcal/mole.

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*Catalysts* **2020**, *10*, x FOR PEER REVIEW 11 of 16

**Figure 5.** Energy profile diagram or arylamination reaction. C= catalyst; P = product. **Figure 5.** Energy profile diagram or arylamination reaction. C= catalyst; P = product. **Figure 5.** Energy profile diagram or arylamination reaction. C= catalyst; P = product.

#### *2.2. Recyclability of the Catalyst 2.2. Recyclability of the Catalyst 2.2. Recyclability of the Catalyst*

Further, the superiority of PS-Co(BBZN)Cl2 catalyst was its recyclability, which was investigated by using the compound **1 a** and **2 b** as a model reaction. After each run, the catalyst was filtered off and washed with water followed by methanol, it was then dried in an oven at 120 °C for 15 min and used directly for the next reaction. The results were summarized (Table 4). We recorded that the catalyst could be used thrice and isolated yields achieved were above 70%. Further, the superiority of PS-Co(BBZN)Cl<sup>2</sup> catalyst was its recyclability, which was investigated by using the compound **1 a** and **2 b** as a model reaction. After each run, the catalyst was filtered off and washed with water followed by methanol, it was then dried in an oven at 120 ◦C for 15 min and used directly for the next reaction. The results were summarized (Table 4). We recorded that the catalyst could be used thrice and isolated yields achieved were above 70%. Further, the superiority of PS-Co(BBZN)Cl2 catalyst was its recyclability, which was investigated by using the compound **1 a** and **2 b** as a model reaction. After each run, the catalyst was filtered off and washed with water followed by methanol, it was then dried in an oven at 120 °C for 15 min and used directly for the next reaction. The results were summarized (Table 4). We recorded that the catalyst could be used thrice and isolated yields achieved were above 70%.

> **Table 4.** The recycling of the catalyst a. **Table 4.** The recycling of the catalyst <sup>a</sup> . **Table 4.** The recycling of the catalyst a.


Yield b (%) 86 81 75 a Reaction conditions—1 a (1 mmol), 2 b (1 mmol), BINAP (15 mol%), (PS-Co (BBZN)Cl2) (12 mol%), a Reaction conditions—1 a (1 mmol), 2 b (1 mmol), BINAP (15 mol%), (PS-Co (BBZN)Cl2) (12 mol%), CS2 CO3 (3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b Isolated yield. <sup>a</sup> Reaction conditions—1 a (1 mmol), 2 b (1 mmol), BINAP (15 mol%), (PS-Co (BBZN)Cl2) (12 mol%), CS<sup>2</sup> CO<sup>3</sup> (3 mmol), 1,4-dioxane (5 mL), N<sup>2</sup> atmosphere 10 h, 100 ◦C. <sup>b</sup> Isolated yield.

CS2 CO3 (3 mmol), 1,4-dioxane (5 mL), N2 atmosphere 10 h, 100 °C. b Isolated yield.

#### **3. Materials and Methods 3. Materials and Methods 3. Materials and Methods**

#### *3.1. Procedure for the Synthesis of PS-Co(BBZN)Cl2 Complex 3.1. Procedure for the Synthesis of PS-Co(BBZN)Cl2 Complex 3.1. Procedure for the Synthesis of PS-Co(BBZN)Cl<sup>2</sup> Complex*

#### 3.1.1. Preparation of BBZN Functionalized Polymer Support 3.1.1. Preparation of BBZN Functionalized Polymer Support

3.1.1. Preparation of BBZN Functionalized Polymer Support The chloromethylated polystyrene beads cross-linked with 6.5% divinylbenzene were first washed with a mixture of THF and water in the ratio 4:1 using Soxhlet extractor for 48 h. The beads were then vacuum dried. The chloromethylated polystyrene beads (3 g) were allowed to swell in DMF solution of BBZN ligand (5.2 g) was added to the above suspension followed by the addition of triethylamine (12 mL) in ethylacetate (105 mL) and was heated at 60 °C for 45 h in a water bath. It was cooled to room temperature, filtered, and washed with DMF. The beads were then Soxhlet The chloromethylated polystyrene beads cross-linked with 6.5% divinylbenzene were first washed with a mixture of THF and water in the ratio 4:1 using Soxhlet extractor for 48 h. The beads were then vacuum dried. The chloromethylated polystyrene beads (3 g) were allowed to swell in DMF solution of BBZN ligand (5.2 g) was added to the above suspension followed by the addition of triethylamine (12 mL) in ethylacetate (105 mL) and was heated at 60 °C for 45 h in a water bath. It was cooled to room temperature, filtered, and washed with DMF. The beads were then Soxhlet extracted with ethanol to remove any unreacted BBZN and dried in an oven at 60 °C overnight. The chloromethylated polystyrene beads cross-linked with 6.5% divinylbenzene were first washed with a mixture of THF and water in the ratio 4:1 using Soxhlet extractor for 48 h. The beads were then vacuum dried. The chloromethylated polystyrene beads (3 g) were allowed to swell in DMF solution of BBZN ligand (5.2 g) was added to the above suspension followed by the addition of triethylamine (12 mL) in ethylacetate (105 mL) and was heated at 60 ◦C for 45 h in a water bath. It was cooled to room temperature, filtered, and washed with DMF. The beads were then Soxhlet extracted with ethanol to remove any unreacted BBZN and dried in an oven at 60 ◦C overnight.

extracted with ethanol to remove any unreacted BBZN and dried in an oven at 60 °C overnight.
