The effect of electron deficit on the geometry of sulphide bridged methylcyclopentadienylmetal tetrahedra. Synthesis, physicochemical characteristics, and molecular structures of Cp′3Cr3(μ3-S)4Co(CO), Cp′4Cr4(μ3-O)(μ3-S)3+ ZnCl3·C4H8O−, and Cp′4V4S4 (Cp′ = π-CH3C5H4)

Organometallic Oxides: Preparation and Properties of the Clusters [(η-C5Me5)V(μ3-O)]4and [(η-C5Me5)V]4(μ-O)6by Reductive Aggregation of (η-C5Me5)VCl2(O)

“…The cluster [Cp*V(μ 3 -O)] 4 was paramagnetic with μ eff = 2.35 μ B at 300 K. A plot of T vs 1/χ showed a slight curvature, and the magnetic moment was much lower than the spin-only value of 2.83 μ B , indicating that the magnetic behavior was more complicated than that of a simple paramagnet. Rauchfuss and co-workers found that [(CpMe)V(μ 3 -S)] 4 was paramagnetic with μ eff = 2.68 μ B at 300 K and a linear T vs 1/χ plot. ,, The energy level ordering for the cluster orbitals of [CpV(μ 3 -O)] 4 was calculated by the extended Hückel method to be e < a 1 < 1t 2 < t 1 < 2t 2 , using a V−V distance of 2.65 Å and a V−O distance of 1.86 Å (Figure ). For [CpM(μ 3 -S)] 4 cubanes the order is e < a 1 < 1t 2 < t 1 < 2t 2 or a 1 < e < 1t 2 < t 1 < 2t 2 . ,− Thus [Cp‘V(μ 3 -A)] 4 (A = O, S), with eight cluster electrons, would be predicted to have the configuration e 4 a 1 2 1t 2 2 t 1 0 2t 2 0 and be paramagnetic, with an S = 1 ground state and a spin-only magnetic moment of 2.83 μ B .…”

“…We have been preparing organometallic clusters that exhibit exchange interactions between the metal atoms. , Of particular interest were the cubanes of general formula [Cp‘M(μ 3 -A)] 4 (Cp‘ = η-C 5 R 5 ; M = d-block metal; A = p-block element, 1 ) − and the adamantanes [Cp‘M] 4 (μ 2 -O) 6 ( 2 ) 21-23 containing tetrahedra of metal atoms. The many [Cp‘M(μ 3 -A)] 4 (A = S, Se) cubanes either were diamagnetic or exhibited simple paramagnetic behavior with no evidence for significant exchange interactions. ,− However [Cp‘Cr(μ 3 -O)] 4 (Cp‘ = η-C 5 H 5 (Cp), η-C 5 H 4 Me (CpMe), or η-C 5 Me 5 (Cp*) 4 ) were antiferromagnetic. The adamantane [Cp*Ti] 4 (μ-O) 6 was diamagnetic, , and the magnetic behavior of [Cp*V] 4 (μ-O) 6 was uncertain. , …”

A Vanadium Chalcogenide Dicubane

“…Less studied are electron deficient early transition metal cubane clusters like Cp 4 V 4 S 4 (56e – or 14e – /V)9 and (MeCp) 4 Ti 4 S 4 (52e – or 13e – /Ti) 10. They feature highly distorted M 4 S 4 cores,11 even shorter intermetallic distances and significant metal–metal bonding.…”

Synthesis of the New, Cubane-like W3S4Co Cluster Core. Completion of the Homologous Series [(η5-Cp‘)3M3S4Co(CO)] (M = Cr, Mo, W)

“…[(η 5 -Cp′) 3 Cr 3 S 4 Co(CO)] ([1]) was, for example, prepared by heating a trinuclear Cr 2 Co sulfide cluster in heptane in the presence of diphenylacetylene. 10 Our investigations on the reactivity of the [(η 5 -Cp′) 3 -Mo 3 S 4 ] + cluster cation toward dicobalt octacarbonyl have now established a new, high yield synthesis of [(η 5 -Cp′) 3 -Mo 3 S 4 Co(CO)] ( [2]). Previously [2] had been obtained by self-assembly reactions of methylcyclopentadienyl-substituted Mo 2 Co 2 S x clusters (x ) 3, 4) at high temperatures in an autoclave (see Scheme 1).…”

“…Monometallic [(H 2 O) 9 Cr 3 S 4 ] 4+ or [(η 5 -Cp‘) 3 Cr 3 S 4 ] + cluster cations have not been prepared to date, and a rational synthesis of Cr 3 S 4 M‘ clusters by heterometal insertion into the Cr 3 S 4 cluster core has therefore not been possible. The few known bimetallic Cr 3 S 4 M‘ clusters (M‘ = V, Nb, Fe, , Co) have all been obtained by self-assembly reactions from precursor complexes of lower nuclearity. [(η 5 -Cp‘) 3 Cr 3 S 4 Co(CO)] ([ 1 ]) was, for example, prepared by heating a trinuclear Cr 2 Co sulfide cluster in heptane in the presence of diphenylacetylene …”