New isomers of [Os3(CO)10(PMe2Ph)2] and [Os3(CO)9(PMe2Ph)3]

Abstract

The com pou nds [ Os, ( CO ) ,,, ( q4 -scis-C, H J] ( C, H = b uta -1,3 -d iene) , [ Os, ( CO) ( p-s-trans-C, H J 3, and [Os,(CO),,( MeCN),] react with PMe,Ph at room temperature t o give [Os,(CO),,( PMe,Ph),] and [Os,(CO),( PMe,Ph),] as mixtures of isomers. The decacarbonyl compound separates on silica into a 1,land a 1,2-isomer, which d o not interconvert at room temperature, although the 1,2isomer exists as t w o rapidly interconverting isomers of C, and Czv symmetry respectively. Likewise

Synthesis and characterization of the substituted products from the reaction of a bulky phosphite with [Os3(CO)12]

“…In addition to the expected pattern for [Os 3 (CO) 10 L 2 ], some additional absorptions are observed in the IR spectrum measured in hexane, attributed to the presence of isomers in solution. Similar IR absorption bands were reported for the phosphine tri-osmium complex [Os 3 (CO) 10 (PMe 2 Ph) 2 ] and were corroborated by variable temperature NMR studies [18]. Similar to the pattern seen for the ligand, three sets of signals arising from phenyl protons and two signals due to methyl protons are seen in the proton NMR spectrum of 4.…”

“…Meijboom et al involves restricted turnstile rotation at one of the phosphorus bearing osmiums [18,21]. Satisfactory elemental analyses were obtained for this compound, which further supports formation of the bis-substituted product.…”

Two modes of C–H bond activation of tris(2-thienyl)phosphine in trinuclear osmium carbonyl clusters

“…The broad signal for 2 is indicative of fluxional behaviour, which has also been observed for the analogous disubstituted cluster [Os 3 (CO) 10 {Ph 2 P(C 4 H 3 S)} 2 ] [12]. We [12,15] and others [16] have demonstrated that [Os 3 (CO) 10 (phosphine) 2 ] clusters exist in solution as mixtures of trans-trans and cis-trans isomers of which the latter appears to be the thermodynamically favoured isomer that predominates at low temperatures while the two isomers are usually found to be in rapid equilibrium at room temperature. In the case of [Os 3 (CO) 10 {Ph 2 P(C 4 H 3 S)} 2 ] [12], the fluxionality could be frozen out at À60°C to reveal the existence of two isomers with the cis-trans isomer being favoured at low temperature, but the fluxionality was not investigated in detail in the present case.…”

W(η2-PhCCPh)3(η1-Ph2PCCPPh2) as a ligand to prepare homo- and hetero-nuclear cluster complexes

“…Thus, the major isomer of 4 likely has the configuration 1,2-B, which contains nonequivalent phosphorus nuclei, and the minor isomer has the configuration 1,2-C with equivalent phosphorus nuclei. The isomerism of phosphine-substituted triosmium clusters is well documented in the literature [11][12][13][14].…”