The crystal structures of two isomers I and Ⅱ in [Co(aipamp)(amp)Cl][ZnCl₄] (aipamp=2-[(2-aminoisopropyl)aminomethyl]pyridine, amp=2-(aminomethyl)-pyridine) system and the crystal structure of one isomer Ⅲ in [Co(apamp)(amp)Cl][ZnCl₄] (apamp=2-[(2-aminopropyl)aminomethyl]pyridine, amp=2-(aminomethyl)pyridine) system have been determined by single crystal X-ray diffraction analysis.The crystal of I belongs to monoclinic system with space group P2₁/n, a=1.08028(10) nm, b=1.84843(18) nm, c=1.25582(12) nm, α=90.00°, β=97.150(2)°, γ=90.00°, V=2.4881(4) nm³, D_c=1.620 g·cm^-3, Z=6, F(000)=582, R=0.0361, wR=0.0974.There are four complex cations which are enantiomers with a ratio of 1:1 in a unit cell.The crystal of Ⅱ belongs to triclinic system with space group P1, a=0.9957(2) nm,b=1.0207(3) nm, c=1.1478(3) nm, α=102.584(5)°, β=91.559(5)°, γ=98.462(5)°, V=1.1240(5) nm³, D_c=1.699 g·cm^-3, Z=2, F(000)=580.00, R=0.0449, wR=0.0984.There are two complex cations which are enantiomers with a ratio of 1:1 in a unit cell.The crystal of Ⅲ belongs to monoclinic system with space group P1, a=0.82423(7) nm, b=1.7199(8) nm, c=1.36399(11) nm, α=86 6350(10)°, β=81.7140(10)°, γ=67 6230(10)°, V=1.10278(15) nm³, D_c=1.734 g·cm^-3, Z=2, F(000)=582.00, R=0.0332, wR=0.0823.There are four complex cations which are enantiomers with a ratio of 1:1 in a unit cell.1D and 2D NMR technique analysis reveals that the fourth isomer IV belongs to the [Co(apamp)(amp)Cl][ZnCl₄] system.It is common that a C—H…π interaction exists in all four complexes.

Key words: cobalt(Ⅲ)complex, geometric isomer, crystal structure, 1D and 2D NMR techniques, computational result, C—H…πinteraction