Hydride complexes osmium

A ruthenium porphyrin hydride complex was lirst prepared by protonation of the dianion, [Ru(TTP) in THF using benzoic acid or water as the proton source. The diamagnetic complex, formulated as the anionic Ru(If) hydride Ru(TTP)(H )(THF)l , showed by H NMR spectroscopy that the two faces of the porphyrin were not equivalent, and the hydride resonance appeared dramatically shifted upheld to —57.04 ppm. The hydride ligand in the osmium analogue resonates at —66.06 ppm. Reaction of [Ru(TTP)(H)(THF)j with excess benzoic-acid led to loss of the hydride ligand and formation of Ru(TTP)(THF)2. 

Treatment of OsT rf-T BT XCOXP Pr with ethanol under reflux does not lead to the formation of OsH2(CO)2(P Pr3)2 but instead gives the hydride-methyl osmium(II) compound OsHMe(CO)2(P Pr3)2 in good yield. 2-Methoxyethanol behaves in a manner similar to ethanol, and the reaction with the tetrahydridoborate complex yields OsH(CH2OMe)(CO)2(P Pr3)2 (Scheme 38).79... 

Allyl hydride complexes of osmium are isolated from treatment of phosphine-substituted osmacyclobutane complex 114 with a thallium salt (Scheme 21). The reaction initially provides a mixture of an unstable -benzyl hydride complex 115 and the rf -allyl hydride complex 116 the -benzyl intermediate ultimately isomerizes to the latter complex, a very rare instance of isolable allylic hydride products generated from a starting metallacyclobutane <2004OM4858>. 

A five-coordinate osmium hydride complex oxidatively adds HCl ... 

The osmium hydride (CO)ioOs3H2 reacts with isonitriles to give monosubstituted products (CO)io(RNC)Os3H(/2-H), which react further via insertion to give (CO)io(ju-ri -RNCH))(/i-H)Os3. In weak donor solvents, hydride attacks at the carbon whereas strong donor solvents result in hydride attack at nitrogen. The latter reaction results from deprotonation of the hydride complex, followed by reprotonation at nitrogen. 

Organometallic compounds with a 17-electron configuration are often labile toward associative ligand exchange. Radical chain mechanisms are well established for phosphine substitution on metal carbonyl hydrides (Scheme 23), the 17-electron chain carrier being in most cases non hydridic. This mechanism, however, was also shown to operate for OsH2(CO)4 via the 17-electron hydride complex OsH(CO)4 [137]. Thus, phosphine addition to the radical prevails over the dimerization, which indeed occurs in the absence of phosphine [33] (section 6.5.7), and over other possible decomposition pathways. The second step of the chain propagation process in Scheme 23, for this osmium system, is another example of atom transfer to a hydride radical (section 6.5.6). 

Formation of Ru ri3-CH2CHCHCH=C(CH3)2 Cl(CO)2(P Pr3) Formation of monothio-P-diketonato derivatives The hydride-chloro-osmium complex OsHCl(CO)(PTr3)2 as a precursor for carbon-carbon, carbon-oxygen, and carbon-sulfur coupling reactions... 

Complexes 126 are rare examples of hydride-azavinylidene osmium(IV) species. In these compounds, the hydride and azavinilydene ligands are mutually... 

H, Hydride, gold-osmium complex, 29 286 gold-ruthenium complex, 29 288 iridium complex, 26 117,119.120, 123-125,202,28 57-59 iron complex, 26 244 iron-tungsten, 26 336-340 manganese complex, 26 226 molybdenum and tungsten complexes, 26 98-105... 

One of the most promising applications of measuring y (H,H) is the prediction of several characteristics of molecules in the coordination chemistry framework. The high sensitivity of 7 (H,H) to many aspects of the hydride complexes makes it a powerful tool for their study. Kuhlman et employed the hypersensitivity of J (H,H) to several electronic effects for detecting the formation of hydrogen bonds and weak solvent coordination in several osmium trihydrides adducts. 

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