Solvothermal synthesis of two 2-d Thioantimonates(III) with metal complexes as template ions, [M(dap)3]Sb4S7 (M= Ni2+ and Co2+)

Two new thioantimonates [M(dap)(3)]Sb4S7 (M = Ni2+ (1) and CO2+ (2)) were synthesized under solvothermal conditions by the reaction of NiS (or Co metal), Sb and S in an aqueous solution of 1,2-diaminopropane (dap). Compounds 1 and 2 are isostructural. The polymeric [Sb4S72-](n) anion is composed of two SbS3 trigonal pyramids and two SbS4 units. The SbS3 and SbS4 units are interconnected by corners and edges to build a 2-D puckered layer with Sb4S4 and Sb16S16 heterorings. The apertures of the large Sb16S16 hetero-rings are filled by two [M(dap)(3)](2+) complex cations which serve as template ions. The band gaps of 2.44 eV for 1 and 2.43 eV for 2 have been estimated from optical absorption spectra.