Abstract
ZnX2, CdX2, CuX2, and NiX2 (X = Cl−, Br−, , or
) react with meta-aminophenyl benzimidazole in 1 : 2 mole ratio at reflux in methanol to give Zn2Cl4L3 · 2H2O, ZnBr2L2(OH2), [Zn(OClO3)L3]ClO4 · 3H2O, CdCl2L(OH2), Cd2Br4L3 · 2H2O, Cd(ONO2)2L2 · 2H2O, [Cu2Cl4L3] · 2H2O, Cu2Br4L3, [Cu(OClO3)L2]2(ClO4)2, [NiCl2L(OH2)] · 2H2O, [NiBrL3]Br · 3H2O, and [Ni(OClO3)L3]ClO4 · H2O. These complexes were characterized by elemental analysis, melting point, TGA, conductivity, magnetic moment measurements, IR, far-IR, NMR, electronic, and mass spectral studies. Based on these studies, Zn2Cl4L3 · 2H2O and Cd2Br4L3 · 2H2O were assigned binuclear structures while [Zn(OClO3)L3]ClO4 · 3H2O, CdCl2L(OH2), Cd(ONO2)2L2 · 2H2O, [NiCl2L(OH2)] · 2H2O, and [NiBrL3]Br · 3H2O were mononuclear with tetrahedral geometry. The copper complexes were binuclear and exhibit strong antiferromagnetic coupling at room temperature. Square pyramidal geometry was proposed for halo complexes of copper and ZnBr2L2(OH2) and square-planar geometry for perchlorato complexes of copper and nickel. All the synthesized compounds were screened for antimicrobial activities.
Acknowledgements
Authors wish to thank “CESEM” award project under Vision Group on Science and Technology, Government of Karnataka, India. SAIF, CDRI, Lucknow, for elemental analyses and mass spectra. SAIF, IIT, Bombay, and STIC, Cochin University for TGA. SAIF, NMR Research Centre, Indian Institute of Science, Bangalore, for NMR spectra. Central Instrumentation Facility, Pondicherry University, for far-IR spectra. Dr Vasanthacharya, SSCU, Indian Institute of Science, Bangalore, for magnetic susceptibility measurements and SAIF, IIT, Madras, for variable temperature magnetic susceptibility measurement. Spectroscopy/Analytical Test Facility, IISc, Bangalore, for ESI-MS. B. Roopashree thanks JSSATE, Bangalore, and JSSMVP, Mysore, for encouraging doctoral studies.