Studies on crystal structures, optical and electrical properties of viologen cation salts of d10 metal halide anions

Construction of viologen cation salts of d10 metal halide anions (inorganic-organic hybrid materials) with semiconducting properties via supramolecular design and aggregate enable the hybrid materials multifunctionality. Our interest focused on the use of the viologen derivatives as the building units because they were redox-active units and more suited to yield new generation of multifunctional networks. In the present investigation, three new inorganic-organic hybrid semiconductors {[bbpyb]·[AgBr3]}n (1) [1, 3-PMBP][Zn2Cl5.1Br0.9] (2) and [1, 3-PMBP][Zn2Br6] (3) (bbpyb = 1,1″-(1,4-butanediyl)bis[4,4′-bipyridinium]bis[bromide], 1,3-PMBP = 1,1″-[1,3-phenylene-bis(methylene)]bis-4,4′-bipyridinium-bisbromide) were synthesized. More importantly, great efforts were devoted to investigate their properties, such as optical and electrical properties. 1-3 exhibited photochromism, which can be ascribed to the intermolecular charge transfer to yield radicals. Fabricating the appropriate inorganic and organic units controllably within photosensitive materials at a molecular level is critical for the development of new photochromic inorganic-organic hybrids.