Syntheses, Structures, and Properties of Trinuclear Copper(I)/Titanium(IV) Thiolate Complexes

Abstract

AbstractThe thiolato‐bridged copper(I)/titanium(IV) complexes [Li(15‐crown‐5)thf]2[Cu2Ti(SPh)8] (thf = tetrahydrofuran) and [Cu2Ti(SPh)6(PPh3)2] have both been prepared in yields of at least 83 % by reaction of CuCl and TiCl4·2thf with LiSPh in THF in the presence of 15‐crown‐5 or PPh3, respectively. The crystal structures of the trinuclear compounds were determined by X‐ray analysis of single crystals. The dark colored compounds display absorption bands over a wide energy range with absorption onsets lying in the near infrared region at approximately 1350 nm for [Li(15‐crown‐5)thf]2[Cu2Ti(SPh)8] and 1050 nm for [Cu2Ti(SPh)6(PPh3)2]. Density functional calculations reproduce and explain the energy difference of the lowest energy transitions. Thermal treatment of [Cu2Ti(SPh)6(PPh3)2] up to 500 °C resulted in the cleavage of SPh2 and PPh3 and the formation of a mixture of ternary copper titanium sulfides, namely Cu4TiS4 and the defect thiospinel Cu0.33TiS2. In contrast, reflections of the powder diffraction patterns of the residues from the thermal analysis of [Li(15‐crown‐5)thf]2[Cu2Ti(SPh)8] could only be assigned to the known phases Cu1.8S (Digenite) and Cu1.96S (Djurleit).