Structure of cobalt (II) perchlorate adsorbed on silica gel surface chemically modified with benzimidazole molecule

• Autor(a) principal: Dias Filho, Newton L. [UNESP]
• Data de Publicação: 1997
• Outros Autores: Rodrigues, Edson, Gushikem, Yoshitaka
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S0103-50531997000400015; http://hdl.handle.net/11449/65297
• topic: Benzimidazole; Cobalt electron spin resonance; Cobalt-benzimidazole surface complex; Silica gel; Silica gel modified with benzimidazole

Covalently attached benzimidazole molecules on silica gel surface, ≡SiL (where L = N-propyl-benzimidazole), adsorbs Co(ClO4)2 from non-aqueous solvent by forming a surface complex according to the reaction: m ≡SiL + Co(ClO4)2 → (≡SiL)mCo(ClO4)2. The equilibrium constant and the adsorption capacity, determined by applying the Langmuir equation were b = 3.0 × 103 L mol-1 and Ns= 0.098 × 10-3 mol g-1, respectively. The metal is bonded through the nitrogen atom and the perchlorate ion is not coordinated. The ESR study indicated that the complex has essentially an octahedral geometry with tetragonal distortion, with the electrons of the four nitrogen atoms interacting with the cobalt central metal ion in the equatorial plane. Only one complex species was detected on the surface.