Esperanza Galarza

Two complexes derived from the reaction of M3(CO)12 clusters (M = Ru, Os) with the 9-(triphenylphosphonio)fluorenide ylide: tricarbonyl[9-(triphenylphosphonio)fluorenylidene]ruthenium and nonacarbonyl-μ3-fluorenylidene-μ2-hydrido-triangulo-triosmium(III).

Tricarbonyl[9-(triphenylphosphonio)fluorenylidene]ruthenium, [Ru(C31H21P)(CO)3], (I), is mononuclear, consisting of a single Ru centre, to which three carbonyl units and a chelating μ3-9-(triphenylphosphonio)fluorenide ylide bind to generate a distorted octahedral RuC6 core. Nonacarbonyl-μ3-fluorenylidene-μ2-hydrido-triangulo-triosmium(III), [Os3H(C13H7)(CO)9], (II), is trinuclear and presents a triangular triosmium core, nine carbonyl ligands and one fluorenylidene ligand. Two of the Os(III) centres present a highly distorted hexacoordinated Os(Os2C4) core and are in turn bridged by a hydride ligand. The remaining Os(III) cation is octacoordinated, with an Os(Os2C6) nucleus. The crystal structures of both compounds are the result of nondirectional forces, much resembling the packing of weakly interacting quasi-spherical units, viz. the molecules themselves in (I) and centrosymmetric π-π-bonded dimers in (II).

ADICION OXIDATIVA DE SUSTRATOS TIPO PhZ-ZPh (Z = S, Se, Te) AL COMPLEJO HETEROTRINUCLEAR Au2Pt [CH2P(S)Ph2] 4

Nuevos derivados del sistema Au2Pt[MTP]4 (MTP=CH2(S)P(C6H5)2-) con formula general Au2Pt[MTP]4(PhZ)2(Z=S, Se, Te) se han sintetizado y caracterizado por espectroscopia1Hy 31P-RMN, IR, UV-VIS y analisis elemental. Se observa una adicion simetrica transanular de las moleculas tipo PhZ-ZPh al complejo trinuclear Au2Pt[MTP]4.

Synthesis, spectroscopic characterization and DFT study of dinuclear ruthenium sawhorse-type complexes derived from the reaction of trinuclear aggregates and (Z)-5-arylidenerhodanines

Abstract The synthesis of dinuclear ruthenium sawhorse-type complexes [Ru2(μ-ArCH:Rhod)2(CO)4]n 12a–e and [Ru2(ArCH:Rhod)2(μ-ArCH:Rhod)2(CO)4] 13a–e through reaction of [Ru3(CO)10(NCMe)2] and [Ru3(CO)12] and the corresponding (Z)-5-arylidenerhodanines (ArCH:Rhod) 10a–e, respectively, are reported. These complexes are arranged in a sawhorse structure in which two bridged (Z)-5-arylidenerhodanines coordinate to the metals using sulfur and nitrogen of the rhodanine ring. A Density Functional Theory method was used to gain insight into the polymerization process by calculating dimerization Gibbs energies (ΔGdim). Values between −10.7 and −5.3 kcal mol−1 indicate that dimerization is a spontaneous process. A reaction pathway for formation of the sawhorse compounds [Ru2(μ-ArCH:Rhod)2(CO)4] was calculated and the rate-determining step for the mechanism is coordination of a second (Z)-5-arylidenerhodanine ligand with activation energies between 41.1 and 47.8 kcal mol−1. In order to understand the apparent thermodynamic favorability of the fragmentation step, we calculated the fragmentation energy (ΔEFrag) for the key intermediate and its energetic contributors, the interaction energy, ΔEint and the reorganization energy, ΔEreorg. Low values of ΔEFrag imply that the fragmentation is thermodynamically facile. Large values of ΔEint are countered by opposite and large values of ΔEreorg which indicate that the cleavage of the trimetallic intermediate aggregate is determined by the nature of the ligand and the balance between its interaction with the metal and the extent of structural reorganization.