New Ruthenium-Tin Clusters With Bulky Ligands. Crystal And Molecular Structures Of [Ru-2(Co)(6)(Mu-Snr(2))(Mu-Ph(2)Pch(2)Pph(2))], [Ru-3(Co)(9)(Mu-Snr'(2))(3)], [Ru-3(Co)(9)(Mu-Snr(2))(Mu-Snr'(2))(2)] And [Ru-3(Co)(9)(Mu-Snr(2))(2)(Mu-Snr'(2))] [R=Ch(Sime(3))(2), R'=C6h2pr3i-2,4,6]

The first heterometallic clusters containing the SnR'(2) (R' = 2,4,6-triisopropylphenyl) moiety have been prepared. Triruthenium dodecacarbonyl reacted at low temperatures with SnR', or, at higher temperatures, with its trimer (SnR'(2))(3) to give both [Ru-3(CO)(10)(mu-SnR'(2))(2)] 1 and [Ru-3(CO)(9)(mu-SnR'(2))(3)] 2. Reaction of the pentametallic species [Ru-3(CO)(10)(mu-SnL(2))(2)][L = R = CH(SiMe(3))(2) 3 or R'] with SnR'(2) or SnR(2) respectively afforded the hexametallic clusters [Ru-3(CO)(9)(mu-SnR(2))(mu-SnR'(2))(2)] 4 and [Ru-3(CO)(9)(mu-SnR(2))(2)(mu-SnR'(2))] 5. In the reaction of [Ru-3(CO)(12)] with SnR(2) the hexametallic cluster [Ru-3(CO)(9)(mu-SnR(2))(3)] 6 has now been isolated in addition to the previously reported Ru3Sn2 cluster. The trimer (SnR'(2))(3) also reacted with [Ru-3(CO)(10)(dppm)](dppm = Ph(2)PCH(2)PPh(2)) to give [Ru-3(CO)(8)(mu-SnR'(2))(2)(dppm)] 7, whereas with SnR(2) the product was [Ru-2(CO)(6)(mu-SnR(2))(mu-dppm)] 8. Compound 7 can also be obtained by the reaction of 2 with dppm, using sodium-benzophenone to activate the cluster. Reaction of the dodecacarbonyl with Sn[CH(PPh(2))(2)](2) or its lead analogue surprisingly did not yield a mixed cluster, but afforded a rapid and quantitative route to [Ru-3(CO)(10)(dppm)]. Compound 2 behaves similarly, yielding 7 again in high yield. The crystal and molecular structures of 2, 4, 5 and 8 have been determined. In compounds 2, 4 and 5, the ruthenium triangle and the three tin atoms form a planar array. A detailed comparison of ligand steric effects is made. In 8 the metal atoms and the two P atoms are coplanar, with a long Ru-Ru vector bridged by the R(2)Sn group and the diphosphine [2.954(2) Angstrom]. The structure of 4 is unusual, the characteristic aryltin twist on only two of the three tin atoms generating chirality, resulting in a spiral packing in space group P6(5). This structure was determined both diffractometrically and using two different image-plate systems, and the results are remarkably consistent in all three cases.