Adsorption of copper(II) and cobalt(II) complexes on a silica gel surface chemically modified with 3-amino-1,2,4-triazole

Abstract

The isotherms of adsorption of MX 2 (M=Cu 2+, Co 2+; X=Cl −, Br −, ClO − 4) by silica gel chemically modified with 3-amino-1,2,4-triazole (SiATR) were studied in acetone and ethanol solutions, at 25°C. The 3-amino-1,2,4-triazole molecule, covalently bound to the silica gel surface, adsorbs MX 2 from solvent by forming a surface complex. At low loading, the electronic and electron spin resonance spectral parameters indicated that the Cu 2+ complexes have a distorted tetragonal symmetry. The CoX 2 (X=Cl −, Br −) analogues exhibit a distorted-tetrahedral geometry, whilst the (SiATR) m Co(ClO 4) 2 complex has a tetragonally distorted octahedral geometry, with four equatorial nitrogen atoms around the cobalt.