Abstract: Through the reaction of Co₂(CO)₈with four thiuram [R₂NC(S)S]₂, four new sulfur capped trinuclear cobalt carbonyl clusters Co₃(CO)₇(μ₃-S)(μ,η²-S ^*C^*NR₂)(Ⅰ: R=Me; Ⅱ: R=Et; Ⅲ: R= i-Pr; Ⅳ: NR=, were prepared and characterized by elementary analysis, IR, ¹HNMR and MS spectroscopy. The crystal structure of the cluster Co₃(CO)₇(μ₃-S)[μ,η²-S^*C^*N(i-Pr)₂] (Ⅲ) was determined by X-ray single crystal diffraction method. The crystal of Ⅲ is monoclinic, belonging to space group P2₁/n, and the cell parameters are as follows: a =1.1452(2) nm, b =1.5028(3)nm, c =1.2144(2) nm; α=90°, β=92.15(3)°, γ=90°; V=2.0885(7) nm³, Z =4, F(000)=1096, D_c=1.747 mg·m^-3, μ=2.588 mm^-1, R =0.0407, R_w=0.0624. The structural analysis shows that cluster Ⅲ has a pyrimidal Co₃S framework and contains a heterocylic bridging bidentate ligand[μ,η²-S^*C^*N(i-Pr)₂] linked to the Co2 and Co3 atoms of the cluster by a cobalt-carbon and a cobalt-sulfur bond respectively.

Key words: Sulfo-trinuclear cobalt cluster, Thiuram ligand, Synthesis, Crystal structure