Antiferromagnetic complexes with a metal-metal bond

Abstract The antiferromagnetic cluster [Cp 2 Cr 2 (SCMe 3 )(μ 3 -S) 2 ] 2Mn (II) was obtained by reaction of (CpCrSCMe 3 ) 2 S with CpMn(CO) 3 (reagent ratio 2:1) under UV irradiation in boiling toluene. The structure of II was established by an X-ray structural study. Crystals of II are orthorhombic, space group F dd 2, a = 39.715(13), b = 21.127(7), c = 7.808(3) A, V = 6551.4 A 3 , Z = 8. The molecule of II has a symmetrical bow-tie metal framework Cr 4 Mn with short CrCr bonds (2.690(4) A) and elongated CrMn bonds (2.936(3) and 2.947(3) A). The angle between the planes of Cr 2 Mn triangles is equal to 90°. The central Mn II atom ( d 5 electron configuration) is situated on a crystallographic two-fold axis and, besides Cr atoms, is surrounded by four μ 3 -bridging sulphur atoms (MnS, 2.393(5) and 2.389(5) A). Both CrCr bonds are bridged by a tert-butylthiolate group (av. CrS 2.347(5) A).