Pyridyl and pyrimidyl chalcogenolates of coinage metals and their utility as molecular precursors for the preparation of metal chalcogenides

Abstract

2-/4-Pyridyl chalcogenolates (S, Se and Te) and 2-(4,6-dimethyl)pyrimidyl selenolate complexes of coinage metals (Cu, Ag and Au), with and without phosphine ligands, such as [Cu(Epy)]₄ (E = Se or Te), [Cu(Sepym)]₆, [Ag₂(μ-Spy)₂(PPh₃)₄], [Ag₃(μ-Sepy)₃(PPh₃)₄] and [Ag(EAr)]₆, [Au(SeAr)(PR₃)], etc., have been synthesised and characterized unambiguously by single crystal X-ray diffraction analyses. The silver phosphine complexes undergo phosphine dissociation in solution to yield a variety of complexes, [Ag₂(μ-Spy)₂(PPh₃)₄], [Ag₃(μ-Sepy)₃(PPh₃)₄] and [Ag(Epy)]₆. These complexes, depending on the nature of the ligands, exhibit metallophilic interactions in the solid state. Thermolysis of copper and silver complexes in coordinating solvents yields metal selenide nano-crystals. AACVD of [Cu(EpyMe)]₄ (E = Se or Te) has been used to deposit continuous and uniform films of Cu₅Se₄ and Cu_1.85Te on a glass substrate. The copper complexes in combination with an appropriate indium or tin precursor have also been used for the preparation of phase pure ternary compounds like CuInSe₂ and Cu₂SnSe₃.