The high yield synthesis of an unsaturated osmium cluster; the X-ray crystal structure of [Os3(CO)8(H){Ph2PCH2P(Ph)C6H4}]

Abstract

Thermolysis of [O~~(CO),~(dpprn)] (dppm = Ph2PCH2PPh2) in refluxing toluene affords a high yield of the unsaturated cluster [OS~(CO)~(H){ Ph2PCH2P(Ph)C6H4}] which has been characterised by X-ray crystallography, and which undergoes a facile reversible reaction with CO.

Cyclometallation of bis(diphenylphos-phino)methane ligands on a binuclear ruthenium(0) carbonyl complex

“…In previous studies, thermolysis of binuclear dppm complexes has led to P-C bond cleavage, either alone or along with cyclometallation (2). There are a few precedents in cluster chemistry for cyclometallation of a coordinated dppm ligand (3,6) but most such reactions also lead to P-C bond cleavage (4). There is obviously a competition between these possible reactions and the formation of 2 represents the first high-yield example of Can.…”

“…However, under forcing conditions, these ligands can be involved in C-P and (or) C-H bond cleavage reactions, thus forming phosphido (1,2) and cyclometallated (3)(4)(5) complexes, respectively. Phosphido complexes may be formed by cleavage of either P-CH, or P-Ph bonds and cyclometallated complexes by activation of a C-H bond of either the CH, group or a phenyl group of a dppm ligand (1)(2)(3)(4)(5). Cyclometallation by activation of an ortho C-H bond of a phenyl substituent of a phenylphosphorus group constitutes an important example of orthometallation, a reaction that is very useful in metalkarbon bond-forming I '~u t h o r to whom correspondence may be addressed.…”

“…Similar reactions with dppm are not known. There appears to be only one example of simple orthometallation of a dppm ligand, which occurs in the thermolysis of [Os3(CO),,(dppm)] to give [Os,(CO),(p-H)(Ph2PCH2PPhC6H,)I containing the functional group D (3). It is likely that similar reactions occur in other cluster complexes of dppm but the metal hydride formed combines with a phenyl substituent to eliminate benzene and so yield orthometallated phosphido ligands (4).…”

“…E-mail: rpuddeph@uwovax reactions with applications in both organometallic and organic synthesis (6). There are many examples of orthometallation of monodentate tertiary phosphine ligands such as PPh3 (6,7), but a much smaller number with diphosphine ligands (3)(4)(5)8).…”

Reversible C-H bond activation at a triosmium centre: A comparative study of the reactivity of unsaturated triosmium clusters Os 3 (CO) 8 (μ-dppm)(μ-H) 2 and Os 3 (CO) 8 (μ-dppf)(μ-H) 2 with activated alkynes

“…Control experiments confirm that 5a and 5b decarbonylate at 80 °C to give 6a and 6b, respectively. Both 5a and 5b exist as a pair of isomers in solution, as demonstrated by 1 H NMR and 31 P{ 1 H} NMR spectroscopy. DFT calculations on cluster 5a (as the dppf-Me 4 derivative) indicate that the isomeric mixture derives from a torsional motion that promotes the conformational flipping of the cyclopentadienyl groups of the dppf-Me 4 ligand relative to the metallic plane.…”