**Appendix A**

**Figure A1.** The COSY spectrum of C0 with 1.939 equivalent of Q[7] in D2O (400 MHz).

**Table A1.** Data from the 1H NMR spectra for the interaction of C0 and di fferent proportions of Q[7].



**Table A2.** Data from the 1H NMR spectra for the interaction of C2 and different proportions of Q[7].

**Figure A2.** The COSY spectrum of C4 with 1.653 equivalent of Q[7] in D2O (400 MHz).

**Table A3.** Data from the 1H NMR spectra for the interaction of C4 and different proportions of Q[7].



**Table A4.** Data from the 1H NMR spectra for the interaction of C6 and di fferent proportions of Q[7].

**Figure A3.** (Color online) ( **A**) Electronic absorption of C0 (2 × 10−<sup>5</sup> mol <sup>L</sup>−1) upon addition of increasing amounts (0, 0.2, 0.4······2.6, 2.8, 3.0 equiv.) of Q[7]; (**B**) the concentrations and absorbance *vs.* NQ[7]/NC0 plots; ( **C**) the corresponding ΔA–NQ[7]/(NQ[7] + NC0) curves.

**Figure A4.** (Color online) ( **A**) Electronic absorption of C4 (2 × 10−<sup>5</sup> mol <sup>L</sup>−1) upon addition of increasing amounts (0, 0.2, 0.4······2.6, 2.8, 3.0 equiv.) of Q[7]; (**B**) the concentrations and absorbance *vs.* NQ[7]/NC4 plots; ( **C**) the corresponding ΔA–NQ[7]/(NQ[7] + NC4) curves.

**Figure A5.** (Color online) ( **A**) Electronic absorption of C6 (2 × 10−<sup>5</sup> mol <sup>L</sup>−1) upon addition of increasing amounts (0, 0.2, 0.4······2.6, 2.8, 3.0 equiv.) of Q[7]; (**B**) the concentrations and absorbance *vs.* NQ[7]/NC6 plots; ( **C**) the corresponding ΔA–NQ[7]/(NQ[7] + NC6) curves.

Guests C0, C2, C4, C6 were synthesized by previously reported methods. [23].

Synthesis of gues<sup>t</sup> C0: 4-pyrrolidinopyridine (296 mg, 0.002 mol) and HCl (10 mL) were stirred under an inert nitrogen atmosphere and heated to 80 ◦C and refluxed for 12 h. The resulting solution was filtered and then the white precipitate was washed with diethyl ether and dried in vacuum to give C0 (331 mg, 90%). 1H NMR (D2O, 400 MHz) δ: 7.79 (d, J = 7.5 Hz, 2H), 6.58 (d, J = 7.5 Hz, 2H), 3.35 (t, J = 6.8 Hz, 4H), 1.94–1.89 (m, 4H). 13C NMR (101 MHz) δ: 154.65, 137.82, 107.26, 48.09, 24.65. Anal. Calcd. for C9H13N2Cl: C, 58.54; H, 7.10; N, 15.17; found C, 57.92; H, 7.18; N, 15.93. The 1H NMR (top) (400 MHz) and 13C NMR (below) (100 MHz) spectra of C0 in D2O are presented in Figure A6.

Synthesis of gues<sup>t</sup> C2: 4-pyrrolidinopyridine (296 mg, 0.002 mol) and bromoethane (1.308 g, 0.012 mol) were dissolved in acetonitrile (40 mL). The solution was stirred under an inert nitrogen atmosphere and heated to 80 ◦C and refluxed for 12 h. The resulting solution was filtered and then the yellow precipitate was washed with diethyl ether and then dried in vacuum to give C2 (437 mg, 85%). 1H NMR (D2O, 400 MHz) δ: 7.78 (d, J = 7.6 Hz, 2H), 6.54 (d, J = 7.5 Hz, 2H), 3.94 (q, J = 7.3 Hz, 2H), 3.30 (m, J = 8.0 Hz, 4H), 1.90–1.84 (m, 4H), 1.25 (t, J = 7.3 Hz, 3H). 13C NMR (101 MHz) δ 153.50, 140.95, 108.23, 52.98, 48.15, 24.82, 15.42. Anal. Calcd. for C11H17N2Br: C, 51.37; H, 6.66; N, 10.89; found C, 51.29; H, 6.71; N, 10.92. The 1H NMR (top) (400 MHz) and 13C NMR (below) (100 MHz) spectra of C2 in D2O are presented in Figure A7.

Synthesis of gues<sup>t</sup> C4: The same method as for C2 was employed, but using 4-pyrrolidinopyridine (296 mg, 0.002 mol) and bromobutane (1.644 g, 0.012 mol) to give C4 (496 mg, 87%). 1H NMR (D2O, 400 MHz) δ: 7.79 (d, J = 7.6 Hz, 2H), 6.57 (d, J = 7.5 Hz, 2H), 3.94 (t, J = 7.1 Hz, 2H), 3.34 (t, J = 6.7 Hz, 4H), 1.93–1.88 (m, 4H), 1.66 (m, J = 14.8 Hz, 2H), 1.14 (m, J = 14.8 Hz, 2H), 0.75 (t, J = 7.4 Hz, 3H). 13C NMR (D2O, 101 MHz) δ: 153.52, 141.23, 107.82, 57.46, 48.24, 32.12, 24.78, 18.73, 12.69. Anal. Calcd. for C13H21N2Br: C, 54.74; H, 7.42; N, 9.82; found C, 54.82; H, 7.47; N, 9.75. The 1H NMR (top) (400 MHz) and 13C NMR (below) (100 MHz) spectra of C4 in D2O are as presented in Figure A8.

Synthesis of gues<sup>t</sup> C6: The same method as for C2 was employed, but using 4-pyrrolidinopyridine (296 mg, 0.002 mol) and bromohexane (1.981 g, 0.012 mol) to give C6 (551 mg, 88%). 1H NMR (D2O, 400 MHz) δ: 7.79 (d, J = 7.0 Hz, 2H), 6.57 (d, J = 7.1 Hz, 2H), 3.94 (q, J = 7.0 Hz, 2H), 3.35 (d, J = 6.1 Hz, 4H), 1.91 (m, 4H), 1.68 (m, J = 6.6 Hz, 2H), 1.12 (m, 6H), 0.69 (t, J = 6.4 Hz, 3H). 13C NMR (400 MHz) δ: 153.52, 141.23, 108.22, 57.42, 48.24, 30.42, 29.94, 24.90, 24.77, 21.80, 13.21. Anal. Calcd. for C15H25N2Br: C, 57.51; H, 8.04; N, 8.94; found C, 57.48; H, 8.11; N, 8.99. The 1H NMR (top) (400 MHz) and 13C NMR (below) (100 MHz) spectra of C6 in D2O are as presented in Figure A9.

**Figure A6.** 1H NMR (**top**) (400 MHz) and 13C NMR (**below**) (100 MHz) spectra of C0 in D2O.

**Figure A7.** 1H NMR (**top**) (400 MHz) and 13C NMR (**below**) (100 MHz) spectra of C2 in D2O.

**Figure A8.** 1H NMR (**top**) (400 MHz) and 13C NMR (**below**) (100 MHz) spectra of C4 in D2O.

**Figure A9.** 1H NMR (**top**) (400 MHz) and 13C NMR (**below**) (100 MHz) spectra of C6 in D2O.
