Hydride mobility in trinuclear sulfido clusters with the core [Rh3(µ-H)(µ3-S)2]: molecular models for hydrogen migration on metal sulfide hydrotreating catalysts.

The treatment of [{Rh(µ-SH){P(OPh)(3)}(2)}(2)] with [{M(µ-Cl)(diolef)}(2)] (diolef=diolefin) in the presence of NEt(3) affords the hydrido-sulfido clusters [Rh(3)(µ-H)(µ(3)-S)(2)(diolef){P(OPh)(3)}(4)] (diolef=1,5-cyclooctadiene (cod) for 1, 2,5-norbornadiene (nbd) for 2, and tetrafluorobenzo[5,6]bicyclo[2.2.2]octa-2,5,7-triene (tfb) for 3) and [Rh(2)Ir(µ-H)(µ(3)-S)(2)(cod){P(OPh)(3)}(4)] (4). Cluster 1 can be also obtained by treating [{Rh(µ-SH){P(OPh)(3)}(2)}(2)] with [{Rh(µ-OMe)(cod)}(2)], although the main product of the reaction with [{Ir(µ-OMe)(cod)}(2)] was [RhIr(2)(µ-H)(µ(3)-S)(2)(cod)(2){P(OPh)(3)}(2)] (5). The molecular structures of clusters 1 and 4 have been determined by X-ray diffraction methods. The deprotonation of a hydrosulfido ligand in [{Rh(µ-SH)(CO)(PPh(3))}(2)] by [M(acac)(diolef)] (acac=acetylacetonate) results in the formation of hydrido-sulfido clusters [Rh(3)(µ-H)(µ(3)-S)(2)(CO)(2) (diolef)(PPh(3))(2)] (diolef=cod for 6, nbd for 7) and [Rh(2)Ir(µ-H)(µ(3)-S)(2)(CO)(2)(cod)(PPh(3))(2)] (8). Clusters 1-3 and 5 exist in solution as two interconverting isomers with the bridging hydride ligand at different edges. Cluster 8 exists as three isomers that arise from the disposition of the PPh(3) ligands in the cluster (cis and trans) and the location of the hydride ligand. The dynamic behaviour of clusters with bulky triphenylphosphite ligands, which involves hydrogen migration from rhodium to sulfur with a switch from hydride to proton character, is significant to understand hydrogen diffusion on the surface of metal sulfide hydrotreating catalysts.

High tacticity control in organolanthanide polymerization catalysis: formation of isotactic poly(alpha-alkenes) with a chiral C3-symmetric thulium complex.

The thulium complexes [Tm((i)Pr-trisox)(CH(2)SiMe(2)R)(3)] (R = Me , Ph ) were synthesized from the thulium trialkyl precursors [Tm(CH(2)SiMe(2)R)(3)(thf)(2)]; reaction of with two equivalents of [Ph(3)C][B(C(6)F(5))(4)] gave a cationic complex 1c, which was found to polymerize 1-hexene, 1-heptene and 1-octene to give the corresponding polyolefins with moderate to good activities and with minimum isotacticity of 90%, 83% and 95%, respectively.