Ordered mesoporous hybrid materials containing cobalt(II) Schiff base complex

Immobilisation of Co-salen and Co-fluomine onto ordered mesoporous silica has been achieved through coordination of the cobalt to pyridine or imidazole groups covalently attached to the silica matrix. Two routes have been investigated to obtain mesoporous hybrid materials containing coordinating ligands: post synthesis grafting of 4-[2-(trimethoxysilyl)ethyl] pyridine 1 and N-trimethoxysilylpropylimidazole 2 on hexagonally ordered mesoporous silica via SiOH groups or direct synthesis method i.e. co-hydrolysis and polycondensation of the same functionalised organotrimethoxysilane with a number of equivalents of TEOS in the presence of n-hexadecylamine as structure directing agent. The first method gave rise to hexagonally ordered mesoporous hybrid materials. The second afforded mesoporous hybrid materials with a typically disordered wormhole-like framework structure in which the organic groups are probably regularly distributed. The O-2-binding capacity of Co-fluomine immobilized on these materials via the imidazole group was investigated.