SYNTHESIS, CRYSTAL-STRUCTURE, AND PROPERTIES OF THE HEXA(MU-BENZENETHIOLATO)TETRA(BENZENETHIOLATOCOBALTATE(II)) DIANION, THE PROTOTYPE COBALT(II)-THIOLATE MOLECULAR CLUSTER

The complexes [(μ-SPh)6(CoSPh)4]2-, [(μ-SPh)6(CoSPh)2(CoCl)2]2-, and [Co(SPh)4]2- have been synthesized with Me4N+ and other cations, and the crystal structure of (Me4N)2[(μ-SPh)6(CoSPh)4] has been determined. Crystal data follow: a = 13.031 (2) Å, b = 23.590 (4) Å, c = 12.806 (2) Å, α = 92.28 (1)°, β = 115.04 (1)°, γ = 79.12 (1)°, Pl, Z = 2, 5121 observed reflections (Mo Kα), R = 0.034. The [(μ-SPh)6(CoSPh)4]2- molecular cluster contains a tetrahedron of cobalt(II) atoms (Co-Co 3.87 ± 0.02 Å) within an approximate octahedron of benzenethiolate ligands which bridge the edges of the Co4 tetrahedron. One terminal benzenethiolate ligand completes the pseudotetrahedral (μ-SPh)3(SPh) coordination of each cobalt atom. Principal features of the structure and bonding follow: (a) the bridging thiolate groups maintain the cluster structure, but without angular rigidity such that the Td symmetry possible for the Co4Sio core is only approximate; (b) there is no evidence of direct Co-Co bonding, but indirect electronic coupling between cobalt atoms influences the magnetic susceptibility and the S→Co charge-transfer absorption; (c) charge-transfer spectral regions indicative of bridging benzenethiolate are described; (d) Co-Sterminal = 2.258 ± 0.004 Å, Co-Sbridging = 2.322 ± 0.011 Å. Spectrophotometry data are presented on the equilibrium sequence of species: [Co(SPh)2]n (molecular structure) ⇌ [(μ-SPh)6(CoSPh)4]2- ⇌ [(μ- SPh)2(Co(SPh)2)2]2- ⇌ [Co(SPh)4]2-. The benzenethiolate bridges of the {(μ-SPh)6Co4} cluster core are relatively stable (thermodynamically) to bridge-opening reactions, including hydrolysis. © 1979, American Chemical Society. All rights reserved.