Antiferromagnetic complexes with metalmetal bonds: XXV. Synthesis, molecular structure and magnetic properties of the triangular cluster Cp 2Cr 2(μ-SCMe 3)(μ 3-S) 2IR(CO)(PPh 3) and the octanuclear cluster Cp 2Cr 2(μ 3-S) 2(μ 4-S)Rh 2[Cp 2Cr 2(μ-SCMe 3)(μ 3-S) 2] 2 with an unusual triangular heterometalloornament framework

Abstract

The antiferromagnetic cluster Cp 2Cr 2)(μ-SCMe 3)(μ 3-S) 2Ir(CO)(PPh 3) (II) (−2 J = 324 cm −1) has been The antiferromagnetic cluster Cp 2Cr 2(μ-SCMe 3)(μ 3-S) 2Ir(CO)(PPh 3) (II) (-2 j=324 cm −1) has been obtained by prolonged refluxing of Cp 2Cr 2(μ-SCMe 3) 2(μ-S) (I) with equimolar (Ph 3P) 2Ir(CO)Cl in toluene. According to X-ray structural analysis (space group P2 1/ n, a = 12.226(1), b = 12.086(1), c = 22.528(2) Å, β = 98.975(8)°, V = 3288.1 Å 3, Z = 4) II has a Cr 2Ir triangular metal core with loosened IrCr bonds (3.229(2) and 3.0341(1) Å) and an ordinary CrCr bond (2.714(a) Å). The analogous reaction of I with (Ph 3P) 2Rh(CO)Cl results in formation of a cluster Cp 2Cr 2(μ-SCMe 3)(μ-S) 2Rh(CO)(PPh 3) (IV) (-2 J = 418 cm −1, which is presumably isostructural to the cluster II. Interaction of I with [(C 2H 4) 2RhCl] 2 the (CR/Rh ration of 2:1) in benzene resultsin formation of an octanuclear antiferromagnetic cluster Cp 2Cr 2(μ 3-S) 2(μ 4-S)Rh 2[Cp 2Cr 2(μ-SCMe 3)(μ 3-S)(μ 3-S) 2] 2 (V) (μ eff 1.59 (296 K)-1.29 (77 K) μ B). According to X-ray structural data (space group P 1 , a = 1-.470(6), b = 14.253(7), c = 18.340(1) Å, α = 81.09(1), β = 86.28(1), γ = 85.91(1)°, V = 2692.9 Å 3, Z = 2) III has a central fragment Rh 2Cr 2 in the form of a butterfly with RhCr 2 wings (RhCr 2.766(2)-2.754(2) rA, and the angle between RhCr 2 planes 129.8°) and short CrCr bond distance(2.560(3) Å). One ofthe sulphur atoms is located between the wings (RhS av 2.369(4); CrS av 2.268(4) Å), while the other two sulphur atoms are located under the RhCr 2 wings of the butterfly (RhS av 2.253(4), CrS av 2.265(4) Å). Besides, each Rh atom is connected with the Cp 2Cr 2 (μ-SCMe 3)(μ 3-S) 2 fragment (CrCr 2.646(3) and 2.651(4) Å) by two RhCr bonds (2.794(2)-2.826(2) Å) and two RhS bonds (2.323(4) Å).