Semiconducting lead-sulfur-organic network solids

The reactions of Pb(OAc)(2) with 1,2,4,5-benzenetetrathiol,1,4-benzenedithiol, and benzenehexathiol in ethylenediamine yield bright yellow [Pb-2(S2C6H2S2)(en)](n), orange-red [Pb-3(SC6H4S)(3)(en)(2)](n), and brown [Pb3C6S6](n), respectively. The structures of [Pb-2(S2C6H2S2)(en)](n) and [Pb3C6S6](n) were solved by synchrotron X-ray powder diffraction, while the structure of [Pb-3(SC6H4S)(3)(en)(2)]n was solved by single-crystal X-ray diffraction. The bonding in [Pb-2(S2C6H2S2)(en)](n) indicates the presence of 'molecular' units, while in [Pb3C6S6](n), the bonding most resembles that in an inorganic solid such as PbS. The differences in bonding are reflected in the optical and electrical properties of the materials; [Pb3C6S6](n) is a semiconductor.