Antiferromagnetic complexes with a metal-metal bond. XI. Synthesis and structure of the pentanuclear cyclopentadienyl-t-butylthiolate-sulphidechromium cluster [Cp2Cr2(μ2-SCME3)(μ3-S)2]2Cr with a "bow-tie" frame

Abstract The reaction of the binuclear complex Cp 2 Cr 2 (SCMe 3 ) 2 S (I) with C 6 H 6 Cr(CO) 3 in a benzene/heptane ( 1 2 ) mixture under UV irradiation yields black crystals of the cluster [Cp 2 Cr 2 (SCMe 3 )S 2 ] 2 Cr (II), which, according to X-ray data, contains a pentanuclear “bow-tie” frame with a central Cr II atom, the angle between the Cr 3 triangle planes being 90°. The bonds between the central and peripheral chromium atoms are oridinary (2.933(1) and 2.889(1) A), while two pairs of Cr II atoms are double-bonded (CrCr 2.655(1) A). Above and below each Cr 3 triangle is a μ 3 -sulphide bridge (average Cr (centr.) S 2.333(3), average Cr (periph.) S 2.305(3) A). Moreover, the peripheral Cr III atoms are bonded in pairs with a μ 2 -SCMe 3 bridge (average CrS 2.358(4) A), and every Cr III atom is coordinated by a π-cyclopentadienyl ligand (average CrC 2.26(1) A, average CC 1.43(2) A).