*Article* **Synthesis, Spectroscopic Studies for Five New Mg (II), Fe (III), Cu (II), Zn (II) and Se (IV) Ceftriaxone Antibiotic Drug Complexes and Their Possible Hepatoprotective and Antioxidant Capacities**

**Samy M. El-Megharbel 1,2,\*, Safa H. Qahl <sup>3</sup> , Fatima S. Alaryani <sup>3</sup> and Reham Z. Hamza 4,5,\***


**Abstract:** Magnesium, copper, zinc, iron and selenium complexes of ceftriaxone were prepared in a 1:1 ligand to metal ratio to investigate the ligational character of the antibiotic ceftriaxone drug (CFX). The complexes were found to have coordinated and hydrated water molecules, except for the Se (IV) complex, which had only hydrated water molecules. The modes of chelation were explained depending on IR, <sup>1</sup>HNMR and UV–Vis spectroscopies. The electronic absorption spectra and the magnetic moment values indicated that Mg (II), Cu (II), Zn (II), Fe (III) and Se (VI) complexes form a six-coordinate shape with a distorted octahedral geometry. Ceftriaxone has four donation sites through nitrogen from NH<sup>2</sup> amino, oxygen from triazine, β-lactam carbonyl and carboxylate with the molecular formulas [Mg(CFX)(H2O)<sup>2</sup> ]·4H2O, [Cu(CFX)(H2O)<sup>2</sup> ]·3H2O, [Fe(CFX)(H2O)(Cl)]·5H2O, [Zn(CFX)(H2O)<sup>2</sup> ]·6H2O and [Se(CFX)(Cl)<sup>2</sup> ]·4H2O and acts as a tetradentate ligand towards the five metal ions. The morphological surface and particle size of ceftriaxone metal complexes were determined using SEM, TEM and X-ray diffraction. The thermal behaviors of the complexes were studied by the TGA(DTG) technique. This study investigated the effect of CFX and CFX metal complexes on oxidative stress and severe tissue injury in the hepatic tissues of male rats. Fifty-six male rats were tested: the first group received normal saline (1 mg/kg), the second group received CFX orally at a dose of 180 mg/kg, and the other treated groups received other CFX metal complexes at the same dose as the CFX-treated group. For antibacterial activity, CFX/Zn complex was highly effective against *Streptococcus pneumoniae*, while CFX/Se was highly effective against *Staphylococcus aureus* and *Escherichia coli*. In conclusion, successive exposure to CFX elevated hepatic reactive oxygen species (ROS) levels and lipid peroxidation final marker (MDA) and decreased antioxidant enzyme levels. CFX metal complex administration prevented liver injury, mainly suppressing excessive ROS generation and enhancing antioxidant defense enzymes and in male rats.

**Keywords:** ceftriaxone; hepatotoxicity; metal complexes; oxidative stress

## **1. Introduction**

The antibiotic ceftriaxone drug (CFX) (Figure 1) is the third generation of antibiotic cephalosporin drugs. It is a parenteral cephalosporin that shows a high antibacterial activity [1]. This effect decreases urinary tract and respiratory infections, skin infections and skin structure, infections of bones and joints, pelvic inflammatory disease, non-enlarged gonorrhea, intra-abdominal infections and acute otitis media due to its surgical prophylaxis [2]. The drug shows high antibacterial activity and rare side effects, a long half-life of serum

**Citation:** El-Megharbel, S.M.; Qahl, S.H.; Alaryani, F.S.; Hamza, R.Z. Synthesis, Spectroscopic Studies for Five New Mg (II), Fe (III), Cu (II), Zn (II) and Se (IV) Ceftriaxone Antibiotic Drug Complexes and Their Possible Hepatoprotective and Antioxidant Capacities. *Antibiotics* **2022**, *11*, 547. https://doi.org/10.3390/ antibiotics11050547

Academic Editors: Yaojun Tong, Linquan Bai and Zixin Deng

Received: 28 March 2022 Accepted: 14 April 2022 Published: 20 April 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

bacteria [21].

and is currently recommended for newborns that have Neisseria gonorrhea during childbirth [3]. CFX can be used as a stable mediator for acyl enzyme, preventing peptidoglycan cross-linking and thus disrupting the cell wall's structural integrity [4]. activity of the Ca (II) complex was screened against *Staphylococcus aureus, Escherichia coli* and *Pseudomonas aeruginosa*, and the results were compared with the activity of ceftriaxone disodium salt.

*Antibiotics* **2022**, *11*, x FOR PEER REVIEW 3 of 22

diseases and enhance antioxidant defense systems [18].

patic tissues in COVID-19 patients, which is of great importance to alleviate pandemic

plexes were prepared with Ca (II), Zn (II), Fe (III), Au (III) and Pd (II) [20].

HepG-2 cell line is 8.53 μg higher than that of HCT-116 cell line, at 20.5 μg [20].

A CFX complex of lead (II) was prepared and characterized, and the antibacterial activity (Gram-positive and Gram-negative bacteria) was evaluated [19]. Five CFX com-

CFX metal complexes of Ca (II), Zn (II), Fe (III), Au (III) and Pd (II) metal ions were prepared, and all chemical characterizations were performed. Calcium (II), zinc (II), and iron (III) complexes have a distorted octahedral geometry, while Au (III) and Pd (II) are in the four-coordinate mode. The CFX ligand acts as a tetradentate towards the five metal ions through N (NH2) and O (triazine, β-lactam carbonyl, and COO groups). The assessment of the cytotoxicity of the Au (III) complex against HCT-116 and HepG-2, known as colon and hepatocellular carcinoma cells, showed that the IC50 of CFX/Au against

Reactions of CFX with transition metal (II) ions with the general formula of [M(CFX)] (M = Mn, Co, Cu and Cd) and [Fe (CFX)Cl] were characterized using physicochemical and spectroscopic methods, where ceftriaxone acted as a dianionic pentadentate chelating agent through N2O3. The antibacterial activity was screened against several

A CFX/Ca (II) complex was prepared and characterized [22] using elemental, TGA, IR spectroscopy and density functional theory calculations. The antibacterial and luminescence of ceftriaxone and the calcium complex were studied. The Ca (II) complex has a crystalline form. Cell parameters of the compound were determined. Ceftriaxone was chelated with calcium ion through oxygen (triazine cycle, lactam carbonyl and carboxylate groups) and nitrogen from the amino group of the thiazole ring. The antibacterial

**Figure 1.** Chemical structure of sodium salt from the antibiotic ceftriaxone drug. **Figure 1.** Chemical structure of sodium salt from the antibiotic ceftriaxone drug.

**2. Experimental**  *2.1. Chemicals*  All chemicals used were pure, and no further purifications were performed. Sodium salt of ceftriaxone ligand (Figure 1), MgCl2, CuCl2, FeCl3·6H2O, ZnCl2 and SeCl4 were from Sigma-Aldrich Chemical Company, Saint Louis, MO, USA. CFX is also stable in relation to beta lactamases, which are formed using two bacterial types—Gram-positive and Gram-negative—and so can be used in the treatment of neonates [5]. Cefotaxime complexes with the general formula of MLCl (where L = cefotaxime drug; M = manganese (II)<sup>+</sup> , cobalt (II), nickel (II), cobber (II) and cadmium (II)) were prepared, and the ratio of metal to cefotaxime was 1:2, where cefotaxime was chelated via atoms of oxygen and nitrogen from groups of carboxylates, beta-lactam and aminothiazole. The antimicrobial activity of Cu (II) complexes is greater than free cefotaxime ligand [6].

*2.2. Synthesis*  CFX complexes were prepared by adding 1.0 mmol of MgCl2, CuCl2, FeCl3·6H2O, ZnCl2 and SeCl4 in CH3OH (40 mL solvent) with sodium salt to ceftriaxone (1.0 mmol) in CH3OH (40 mL). Then, refluxing was performed for about 4 h until colored precipitates were produced. After that, cooling, filtration for the solid complexity and washing using with hot methanol were performed; finally, the complexes were dried in a desiccator CFX is an antibiotic that is commonly used for the treatment of bacterial infections such as abdominal and joint infection, skin and pelvic inflammatory diseases and bone and middle ear infection [7]. CFX vials are among the most prevalent types of antibiotics [8]. However, CFX produces a great deal of side effects, such as elevated liver enzymes and urea levels and diarrhea, and sometimes it induces thrombocytosis. Given the side effects of using this antibiotic drug in today's health care system, it is essential to develop new drug complexes to elevate its wide activity and reduce any possible side effects [7].

Recently, some studies revealed that a novel nano-formula of the CFX drug had higher antibacterial activity against *E. coli* Gram-negative bacteria compared to the CFX drug alone. The greater antibacterial effect of the CFX nano-formula at a lower dose is another important finding with regard to the reduction of the antibiotic dose and to the cost-effective treatment of resistant microbes [9].

CFX complexes of Mn (II), Co (II), Cu (II), and Cd (II) were prepared in a molar ratio of 1:1 (M: CFX) and acted as pentadentate chelator with metal ions [10]. The antimicrobial activity of cadmium (II) complexes is more than free ceftriaxone ligand, while other complexes have almost the same effect as ceftriaxone. Ceftriaxone complexes of Fe (III), Co (II), Ni (II) and Cu (II) were prepared with octahedral geometry and molar ratios of 1:3 (CFX:M) [11]. Cefixime complexes with Mn (II), Co (II), Ni (II) and Cd (II) were prepared with a 1:1 molar ratio [12,13]. In addition, Fe (III) ceftriaxone complex was prepared with an octahedral geometry and was found to have high activity against bacterial species such as *Pseudomonas aeruginosa* [14].

Recently, there has been a great correlation between SARS-CoV-2 severity and hepatotoxicity especially induced by antibiotics. The severity of COVID-19 may be related with the risk of liver injury development [15]. There is increasing evidence that indicates that hepatotoxicity has been associated with the use of some medications in the treatment of patients infected with SARS-CoV-2 during the COVID-19 pandemic [15]. Recent epidemiological studies indicate different degrees of elevated liver hepatic enzymes with an incidence of 24.4%, particularly in liver transaminases, AST and ALT in COVID-19 patients. Liver injury associated with COVID-19 is defined as any damage that occurred in about 20–46.9% of COVID-19 patients to the liver due to either the treatment or pathogenesis of COVID-19 [16].

It has now been concluded that the severity of COVID-19 is correlated with the risk of liver injury. Additionally, it has been suggested that SARS-CoV-2 is greatly associated with liver injury and infection, which is still a matter of debate [17]. Meanwhile, in most cases, some treatments with antibiotics can cause liver damage during infection and can potentially cause some adverse effects, from severe bleeding to liver failure and even death. Hence, it is essential to find out novel antibiotic drug complexes with high antioxidant efficacy and low hepatic dysfunction to prevent such adverse effects on the hepatic tissues in COVID-19 patients, which is of great importance to alleviate pandemic diseases and enhance antioxidant defense systems [18].

A CFX complex of lead (II) was prepared and characterized, and the antibacterial activity (Gram-positive and Gram-negative bacteria) was evaluated [19]. Five CFX complexes were prepared with Ca (II), Zn (II), Fe (III), Au (III) and Pd (II) [20].

CFX metal complexes of Ca (II), Zn (II), Fe (III), Au (III) and Pd (II) metal ions were prepared, and all chemical characterizations were performed. Calcium (II), zinc (II), and iron (III) complexes have a distorted octahedral geometry, while Au (III) and Pd (II) are in the four-coordinate mode. The CFX ligand acts as a tetradentate towards the five metal ions through N (NH2) and O (triazine, β-lactam carbonyl, and COO groups). The assessment of the cytotoxicity of the Au (III) complex against HCT-116 and HepG-2, known as colon and hepatocellular carcinoma cells, showed that the IC<sup>50</sup> of CFX/Au against HepG-2 cell line is 8.53 µg higher than that of HCT-116 cell line, at 20.5 µg [20].

Reactions of CFX with transition metal (II) ions with the general formula of [M(CFX)] (M = Mn, Co, Cu and Cd) and [Fe (CFX)Cl] were characterized using physicochemical and spectroscopic methods, where ceftriaxone acted as a dianionic pentadentate chelating agent through N2O3. The antibacterial activity was screened against several bacteria [21].

A CFX/Ca (II) complex was prepared and characterized [22] using elemental, TGA, IR spectroscopy and density functional theory calculations. The antibacterial and luminescence of ceftriaxone and the calcium complex were studied. The Ca (II) complex has a crystalline form. Cell parameters of the compound were determined. Ceftriaxone was chelated with calcium ion through oxygen (triazine cycle, lactam carbonyl and carboxylate groups) and nitrogen from the amino group of the thiazole ring. The antibacterial activity of the Ca (II) complex was screened against *Staphylococcus aureus*, *Escherichia coli* and *Pseudomonas aeruginosa*, and the results were compared with the activity of ceftriaxone disodium salt.

#### **2. Experimental**

#### *2.1. Chemicals*

All chemicals used were pure, and no further purifications were performed. Sodium salt of ceftriaxone ligand (Figure 1), MgCl2, CuCl2, FeCl3·6H2O, ZnCl<sup>2</sup> and SeCl<sup>4</sup> were from Sigma-Aldrich Chemical Company, Saint Louis, MO, USA.

#### *2.2. Synthesis*

CFX complexes were prepared by adding 1.0 mmol of MgCl2, CuCl2, FeCl3·6H2O, ZnCl<sup>2</sup> and SeCl<sup>4</sup> in CH3OH (40 mL solvent) with sodium salt to ceftriaxone (1.0 mmol) in CH3OH (40 mL). Then, refluxing was performed for about 4 h until colored precipitates were produced. After that, cooling, filtration for the solid complexity and washing using with hot methanol were performed; finally, the complexes were dried in a desiccator using dry CaCl2. All synthesized complexes were fully characterized as shown in (Table 1).


**Table 1.** Instrumentations and experimental analyses.

#### *2.3. Experimental Animals*

Fifty-six two-month-old male rats were used in this study. They were housed under standard conditions of temperature and supplied food ad libitum, and the study was ethically approved following all the international ethics guidelines for animal care. The treated groups were then divided into seven treated groups (eight rats in each group): Group 1 received 1 mL/kg saline solution (control group); Group 2 received CFX (180 mg/Kg) [23] orally for 30 consecutive days; Group 3, 4, 5, 6 and 7 received 180 mg/kg of Mg (II), Fe (III), Cu (II), Zn (II) and Se (IV) dissolved in saline solution for the same period of time.

Blood samples were collected, and serum samples were obtained after centrifugation at 10,000 rpm for approximately 25 min for biochemical tests. The male rats were gently dissected after light anesthesia by xylene/ketamine, and hepatic tissues were collected. Tissue samples were fixed in approximately 6% of neutral buffered formalin for the examination of histopathological sections.

#### *2.4. Hepatic Functions and Antioxidant Assay*

ALT and AST were evaluated in serum using a kit (Spinreact, Sant Esteve de Bas, Spain). Malondialdehyde, a final lipid peroxidation marker (MDA), was assayed in the hepatic tissues [24]. Superoxide dismutase (SOD) [25] and catalase (CAT) antioxidant enzymes were assessed in the homogenates of the liver tissues [26].

### *2.5. Histopathological Study*

Liver tissue pieces were fixed in 6% neutral buffered formalin for 48 h, further processed for examination by hematoxylin and eosin (H&E) staining [27] and examined under a microscope (Leica Microsystems, New York, NY, USA).

#### *2.6. Antibacterial Activities of CFX and Its Metal Complexes*

The antimicrobial activity of the tested samples was determined by a modification of the Kirby–Bauer disc diffusion method. Antibacterial activity was tested in triplicate, and then the mean was calculated. In brief, 100 µL of the best bacteria was grown in 10 mL of fresh media until reaching an amount of approximately 108 cells/mL [28]. Then, 100 µL of the microbial suspension was spread into agar plates corresponding to the broth in which they were maintained. Isolated colonies of each organism that may play a pathogenic role were selected from the primary agar plates and tested for susceptibility by the disc diffusion method [29]. The Gram-positive bacteria *Bacillus subtilis* (Ehrenberg 23857™), *Streptococcus pneumonia* (Klein) Chester (6303™) and *Staphylococcus aureus* (23235™) and the Gram-negative bacteria *Escherichia coli* (BAA-2471™) and *Pseudomonas aeruginosa* (BAA-1744™) were incubated at 35–37 ◦C for 24–48 h. Afterwards, the inhibition zones' diameters were measured in millimeters [30]. Standard discs of tetracycline drug served as positive

controls for the antimicrobial activity, and a filter disc impregnated with 10 µL solvent (dist. H2O, DMSO) was used as a negative control.

The agar used was the Mueller–Hinton agar, which was tested continuously in terms of its pH. Furthermore, the depth of the agar in the plates was considered in the disc diffusion method [30].

#### *2.7. Statistical Analysis*

The results were presented as mean ± standard error. Comparisons within groups were conducted with a one-way ANOVA followed by post hoc analysis using SPSS version 17 (IBM® SPSS®, Armonk, NY, USA).

#### **3. Results and Discussions**

#### *3.1. Microanalytical and Conductance Measurements*

Equal molar ratios for the metal ions (MgCl2, CuCl2, FeCl3·6H2O, ZnCl<sup>2</sup> and SeCl4) and ligand ceftriaxone sodium salt (Na2CFX) produced colored metal complexes. C, H and N analysis data, magnetic susceptibility values and molar conductance (Λm = 15–25 Ω−<sup>1</sup> ·cm<sup>2</sup> ·mol−<sup>1</sup> ) for ceftriaxone metal complexes are in Table 2. White, black, brown, white and yellowish white colors of the Mg (II), Cu (II), Fe (III), Zn (II) and Se (VI) complexes were shown, respectively. The data of the conductivity measurements prove the non-electrolytic character of Mg (II), Cu (II), Fe (III), Zn (II) and selenium (IV) complexes. Hence, CFX metal complex structures can be written as [Mg(CFX)(H2O)2]·4H2O, [Cu(CFX)(H2O)2]·3H2O, [Fe(CFX)(H2O)(Cl)]·5H2O, [Zn(CFX)(H2O)2]·6H2O and [Se(CFX)Cl2]·4H2O. The ceftriaxone complexes are insoluble in most organic and inorganic solvents, such as H2O, CH3OH, C2H5OH, CHCl3, CH2Cl<sup>2</sup> and CCl4, but they are soluble in DMSO and DMF. The contents of metal were measured gravimetrically [31]. The produced complexes were elucidated using different tools of analysis such as C, H and N, molar conductance, IR, <sup>1</sup>HNMR, electronic spectra, magnetic, SEM, TEM and XRD analyses.


**Table 2.** Elemental analysis and conductivity measurements for ceftriaxone complexes.

#### *3.2. FTIR Spectral Studies*

Infrared spectroscopy is an essential tool for identifying the main functional groups of organic molecules. The CFX free ligand has more than one donor atom, such as the O atom from the thiazole cycle, N atom of the NH<sup>2</sup> group and atoms of O from carboxylate, lactam and amide carbonyl groups. The mode of chelation for free ceftriaxone drug ligand towards metal ions Mg (II), Cu (II), Fe (III), Zn (II) and Se (VI) was studied. The IR for ceftriaxone and its metal complex are similar and are recorded in Table 3 and Figure 2. Generally, the absorption frequency for carbonyl ring groups for free ceftriaxone ligands will be shifted to lower wave numbers after complexation.


**Table 3.** Infrared frequencies (cm–1) for ceftriaxone and its complexes.

**Figure 2.** *Cont*.

**Figure 2.** FT-IR of (**A**) CFX, (**B**) CFX/Mg, (**C**) CFX/Cu, (**D**) CFX/Fe, (**E**) CFX/Se and (**F**) CFX/Zn. **Figure 2.** FT-IR of (**A**) CFX, (**B**) CFX/Mg, (**C**) CFX/Cu, (**D**) CFX/Fe, (**E**) CFX/Se and (**F**) CFX/Zn.

After the reaction of CFX with metal ions, there are shifts in the stretching vibrations of ν(C=O) βlactam and ν(C=O) triazine to 1766–1621 cm−<sup>1</sup> and 1552–1536 cm−<sup>1</sup> , respectively [32]. These shifts can be attributed to the contribution of oxygen atoms to the chelation with metal ions. The frequencies of symmetric stretching for the carboxylate group vs. (COO−) shift to 1399–1309 cm−<sup>1</sup> [10,28]. Based on frequencies of the FTIR spectra of Na2CFX and its metal complexity, a shift in the band appeared at 3410 cm−<sup>1</sup> assigned to a stretching vibration ν(N–H) of the amino group to wavenumbers 3380–3395 cm−<sup>1</sup> , confirming the participation of N atoms of the NH<sup>2</sup> group in the coordination with metal ions. For the monodentate coordination of the COO- group, according to the explanations of Deacon and Phillips [31,32], a difference larger than >200 cm−<sup>1</sup> disproves this, whereas one smaller than 200 cm−<sup>1</sup> indicates that coordination is monodentate. These shifts confirm the involvement of the oxygen from the (COO)carboxylate group, the oxygen from the (C=O) carbonyl group of β-lactam, nitrogen from the amine group and the oxo group of the triazine ring in the coordination. All these data are in agreement with previous studies showing a tetradentate behavior of ceftriaxone ligand [10,31]. The spectral band, which is broad in all ctx complexes that appear at 3264–3290 cm−<sup>1</sup> , is due to the ν(OH) of hydrated and coordinated water molecules [33]. There are new bands that appear at the range of 513–461 cm−<sup>1</sup> corresponding to stretching vibration bands ν(M–N) for the metal complexes (with no free ligand), confirming that the -NH<sup>2</sup> group of the thiazole moiety is chelated with metal ions. The chelation of the group of -NH<sup>2</sup> with metal ions is not the only explanation for these absorption bands. For CONH and C=N-OCH<sup>3</sup> groups, nitrogen atoms could react with metal ions in solid complexes; however, coordination through nitrogen atoms and COO and lactam CO groups is prevented due to steric constraints. In addition, the stretching vibration for CONH moiety and C=N of C=N-OCH<sup>3</sup> appeared in free ligands of ceftriaxone at 1178 and 1551 cm−<sup>1</sup> , respectively, and did not shift for all ceftriaxone metal chelates, confirming that these groups did not participate in coordination. The new bands appear in the range of 541–678 cm−<sup>1</sup> for ceftriaxone complexes and are absent for free ceftriaxone; these are assigned to stretching vibrations of ν(M–O). At the range of 1700–1600 cm−<sup>1</sup> in ceftriaxone metal complexesm there are broad bands that have high intensity and low resolution regarding the overlap between several vibrational modes, such as ν(C=O)-amide, ν(C=O)-triazine, νas(COO– ), ν(C=C) and ν(C=N). This is in an agreement with previous data for polydentate ceftriaxone ligands [34,35]. *Antibiotics* **2022**, *11*, x FOR PEER REVIEW 9 of 22 *3.3. Electronic Spectra*  The u.v-vis. spectra for sodium salt of the CFX free ligand and its metal complexes measured within 200–800 nm using DMSO as a solvent are shown in Figure 3. The u.v.–vis. spectra for ceftriaxone and its complexes give an absorption maximum at 250–270 nm assigned to the π→π\* transition due to orbital molecular energy levels of the nitrogen–carbon–sulfur moiety [36] at 285–300 nm, due to transitions of the π→π\* band of intraligands in moieties of triazole and 1,3-thiazole. The appearance of bands in the region of 350–390 nm is related to the n→π\* type of transition in intraligands, and this is in agreement with literature data for sulfur atom transitions [37]. The bands related to sulfur atoms are not shifted, confirming that S atoms do not participate in chelation with metal ions. The Fe(III) complex gives very weak absorption bands, and this may be attributed to spin-orbit forbidden transitions. The selenium(VI) complex gives a weak band at around 500 nm, while the Cu(II) complex exhibits a transition of d–d, which appears as

#### *3.3. Electronic Spectra* a weak band around at 400 nm, suggesting that copper(II) and Se(IV) complexes form six coordinate chelates [37]. The difference in wavelength values in CFX complexes is more

The u.v.-vis. spectra for sodium salt of the CFX free ligand and its metal complexes measured within 200–800 nm using DMSO as a solvent are shown in Figure 3. than that for free ceftriaxone ligand, confirming the participation of Mg (II), Cu (II), iron (III), Zn(II) and Se (VI) with CFX complexes [38].

magnetic moments is located within the high spin octahedral geometry. The magnetic moment value for copper(II) ceftriaxone complex at room temperature is 2.31 B.M., confirming that Cu metal ions are present in an excess amount inside the chelation sphere. The lowered values for magnetic moments are related to antiferromagnetic interactions between the ions, while the higher values for magnetic moments show that ferromagnetic interactions rarely occurred. The value of magnetic moment μeff for the Se (VI) complex is 5.98 B.M.—this value of effective magnetic moments is located within the high spin

For free ceftriaxone Na2CFX, the 1HNMR spectrum data obtained can be summa-

At 3.368 [CH2 of thiazine, 2H] at δ 3.489, [N-CH3 of triazine, 3H] at 3.889, [=N-O-CH3,

**Figure 3.** U.v.-vis spectra of CFX metal complexes. 3H] at 3.960 [S-methylen, 2H], at 5.069 [β-lactam, 1H] and 6.910 [thiazol ring, 1H]. The **Figure 3.** U.v.-vis. spectra of CFX metal complexes.

*3.4. Magnetic Measurements* 

octahedral geometry.

*3.5. 1H-NMR Study* 

rized as follows.

The u.v.-vis. spectra for ceftriaxone and its complexes give an absorption maximum at 250–270 nm assigned to the π→π\* transition due to orbital molecular energy levels of the nitrogen–carbon–sulfur moiety [36] at 285–300 nm, due to transitions of the π→π\* band of intraligands in moieties of triazole and 1,3-thiazole. The appearance of bands in the region of 350–390 nm is related to the n→π\* type of transition in intraligands, and this is in agreement with literature data for sulfur atom transitions [37]. The bands related to sulfur atoms are not shifted, confirming that S atoms do not participate in chelation with metal ions. The Fe(III) complex gives very weak absorption bands, and this may be attributed to spin-orbit forbidden transitions. The selenium(VI) complex gives a weak band at around 500 nm, while the Cu(II) complex exhibits a transition of d–d, which appears as a weak band around at 400 nm, suggesting that copper(II) and Se(IV) complexes form six coordinate chelates [37]. The difference in wavelength values in CFX complexes is more than that for free ceftriaxone ligand, confirming the participation of Mg (II), Cu (II), iron (III), Zn(II) and Se (VI) with CFX complexes [38].

#### *3.4. Magnetic Measurements*

The value of magnetic moment µeff for the Fe (III) complex is 5.92 B.M., which is consistent with d<sup>5</sup> high spin systems with five electrons unpaired. This value of effective magnetic moments is located within the high spin octahedral geometry. The magnetic moment value for copper(II) ceftriaxone complex at room temperature is 2.31 B.M., confirming that Cu metal ions are present in an excess amount inside the chelation sphere. The lowered values for magnetic moments are related to antiferromagnetic interactions between the ions, while the higher values for magnetic moments show that ferromagnetic interactions rarely occurred. The value of magnetic moment µeff for the Se (VI) complex is 5.98 B.M.—this value of effective magnetic moments is located within the high spin octahedral geometry.
