Design and synthesis of new biomimetic materials by sol-gel: A Cu-II(histidine)(2) complex covalently bonded on a silica matrix

The synthesis of a new histidine-silane derivative, Boc-His(Boc)-CONH-(CH2) (3)Si(OEt)(3), is reported. Hydrolysis and co-condensation of this monomer with tetraethoxysilane, via the sol-gel procedure, results in a hybrid inor ganic-organic material that bears histidine molecules covalently bonded on a silica matrix. 1D-ESEEM and 2D-HYSCORE studies of its Cu(II) complex show that the copper atom is coordinated by two inequivalent histidine imidazol es. The new Cu(II) material exhibits catalytic activity for DTBQ formation in the presence of dioxygen, with considerable turnover rates and yields. I n addition it is highly recyclable and shows high specific surface area.