Hameed A. Mirza

Alkyne diruthenium chemistry

Abstract The reaction of [Ru2(CO)4(μ-CO)(μ-dppm)2] (1) with alkynes RCCR′ gives the alkyne complexes [Ru2(CO)4(μ-RCCR′)(μ-dppm)2] [2, R′=H; 3, R′=CO2Me or COMe; 4, R′=CCR], [Ru2(CO)4H(CCR)(μ-dppm)2] (5) or [Ru2(CO)2(μ-CO)H(μ-CCR)(μ-dppm)2] (6), when R=Ph. Complex 6 reacts with chlorinated solvent to give [Ru2(CO)2(μ-CO)Cl(μ-CCR)(μ-dppm)2] (7), R=Ph. Complex 1 reacts with excess alkyne RCCH to give [Ru2(CO)2(μ-CO){C(CH2)R}(μ-CCR)(μ-dppm)2] (8), when R=Ph, Bu or CH2CH2CCH, and, when R=Ph, 8 reacts with more PhCCH to give [Ru2(CO)2(μ-CCHPh){C(CH2)Ph}(μ-CCPh)(μ-dppm)2] (9), a complex containing three different organic ligands (alkenyl, alkynyl and vinylidene).

Rapid phosphorus–carbon bond cleavage in bis(diphenylphosphino)methane under very mild conditions: a one-step synthesis of µ-PPh2, µ-Ph2PCH2PPh2 binuclear CoI and NiI carbonyls directly from CoII and NiII salts

CoII and NiII react rapidly with NaBH4 in the presence of bis(diphenylphosphino)methane (dppm) under CO at or below (0 °C) room temperature to yield complexes of the types Co2(µ-H)(µ-PPh2)(µ-dppm)(CO)4, Co2(µ-H)(µ-PPh2)(µ-dppm)2(CO)2, and [Ni2(µ-PPh2)(µ-dppm)2(CO)2]X (X = Cl, BPh4).

Diruthenium alkyne chemistry: stepwise formation of an alkenyl(alkynyl)vinylidene complex

Abstract A new form of reactivity, in which up to three terminal alkyne molecules may react with the binuclear compound [Ru2(CO4)(μ-CO)(μ-dppm)2] without alkyne coupling, is described.

A BINUCLEAR ALKYNE COMPLEX OF RUTHENIUM

Abstract The reaction of [Ru2(CO)4(μ-CO)(μ-dppm)2], dppm = Ph2PCH2PPh2, with the alkyne MeO2CC═O2Me gives only the dimetallacyclobutene derivative [Ru2(CO)4(μ-MeO2CC = CCO2Me)(μ-dppm)2], 5b, which has been characterized spectroscopically and by an X-ray structure determination [C60H72O8P4Ru2, monoclinic, P21/c, a = 12.534(2), b = 16.236(3), c = 27.094(6) A, β = 99.93(1)°, Z = 4, R f , R w = 0.054, 0.046]. The reaction is particularly simple compared to the complex reaction of [Ru2(CO)4(μ-CO)(μ-dmpm)2], dmpm = Me2PCH2PMe2, and possible reasons for this are discussed.

Synthesis and characterization of dinuclear complexes of 3,3′,4,4′-tetraminobiphenyl with tetramminoruthenium and bis(bipyridine)ruthenium residues and their two- and four-electron oxidized products including a ZINDO study of orbital mixing as a function of ligand oxidation state†

This paper reports the synthesis, characterisation and reactivity of new complexes of ruthenium, the symmetric dinuclear complex of ruthenium tetrammine [(Ru(NH3)4)2(catH4·catH4)](PF6)4 and the asymmetric dinuclear complex of ruthenium bis(bipyridine) and ruthenium tetrammine [Ru(NH3)4(catH4·catH4)Ru(bpy)2](PF6)4 where (catH4·catH4) represents the bridging ligand 3,3′,4,4′-tetraminobiphenyl. These complexes can be oxidized to the two-electron oxidized ligand mixed valence (qH2·catH4) species and the four-electron oxidized ligand (qH2·qH2) species. Further oxidation yields a range of Ru(III) species. These complexes were studied by proton NMR, UV–VIS spectra, cyclic voltammetry and ZINDO/1 and ZINDO/S calculations.

An unusual heptanuclear Co4Cu3 cluster complex : a copper(III) cluster derivative ?

The new cluster cation [Co4Cu3(CO)8(Me2PCH2PMe2)4]+ contains a central copper atom bridging two Co2Cu triangles; on the basis of, (i) its approximately square-planar stereochemistry, and (ii) electron counting considerations, it is suggested that the central copper atom has the d8 CuIII electron configuration, which is unique in copper clusters.