Formation of PbS materials from lead xanthate precursors

摘要

Six lead xanthate adducts Pb(S_2COR)_2.L [R = Et, ~nBu, L = bipy, TMEDA (tetramethylethylenediamine), PMDETA (pentamethyldiethylenetriamine)] have been synthesised and the structures of all, save Pb(S_2COBu~n)_2.TMEDA (4) which is an oil, determined. Pb(S_2COEt)_2.TMEDA (3) is seven-coordinate at lead through three chelating ligands and one weak intermolecular PbS interaction. Both Pb(S_2COR)_2.bipy [R = Et (1), ~nBu (2)] are dimers in which one xanthate is terminal and the other μ_2 bridging at each sulphur, generating an eight-coordinate lead when the bipy donor is included. Both Pb(S_2COR)_2.PMDETA [R = Et (5), ~nBu (6)] are seven-coordinate at lead by virtue of two bidentate chelating xanthate ligands and a tridentate PMDETA; there are no intermolecular interactions. Trends in the ~(207)Pb NMR chemical shifts mirror the changes in the intramolecular coordination number across the series. Pb(S_2COEt)_2.TMEDA (3) has been used to deposit PbS films on glass, Mo-coated glass and Si by AACVD. Pb(S_2COEt)_2 also generated PbS nanocubes when decomposed under an autogenerated pressure.