Synthesis of a new relay four photosensitized hydrogen production in basic aqueous SiO 2 media

Abstract

In this paper we describe the synthesis of a new viologen with zwitter-ionic character [(7,8-dihydro-6 H-dipyrido[1,2,- a:2,1- c][1,4]diazepinium)-2,12-]di-4,4′-phenethylsulphonate, which belongs to the series of bridged 2,2′-bipyridinium compounds. Its E 1 2 value has been measured using cyclic voltammetry and it has been used in investigations of the sacrificial photo-reduction of water, either in a homogeneous phase or in the presence of colloidal SiO 2 as a support. This viologen has proved to be four times more efficient than those previously employed to generate hydrogen at the basic pHs needed for the use of SiO 2.