Synthesis and reactivity of [OsH{C6H4(CHCHH) }(CO)(PPri3)2] and the formato compounds [Os{(E )-CHCHPh}(η2-O 2CH)(CO)(PPri3)2] and [OsH(η2-O2CH)(CO)(PPri3) 2]*

Abstract

Synthesis and reactivity of [OsH{C 6 H 4 (CH᎐ ᎐ CHH)}(CO)(PPr i 3) 2 ] and the formato compounds [Os{(E)-CH᎐ ᎐ CHPh}(2-O 2 CH)-(CO)(PPr i 3) 2 ] and [OsH(2-O 2 CH)(CO)(PPr i 3) 2 ]*

Five-Coordinate Complexes MHCl(CO)(PiPr3)2 (M = Os, Ru) as Precursors for the Preparation of New Hydrido− and Alkenyl−Metallothiol and Monothio−β-Diketonato Derivatives

“…The resonance of the hydrido ligand of 9 is observed at −9.16 (t, J H - P = 19.5 Hz) ppm, while the resonance of the hydrido ligand of 10 appears at −17.88 (t, J H - P = 20.1 Hz) ppm, thus shifted by 8.72 ppm to higher field. This difference in chemical shift is similar to that observed (8.78 ppm) between the chemical shifts of the complexes OsH(κ 2 -S 2 CH)(CO)(P i Pr 3 ) 2 (−12.80 ppm) 9c and OsH(κ 2 -O 2 CH)(CO)(P i Pr 3 ) 2 (−21.58 ppm) . The 31 P{ 1 H} NMR spectra of both isomers show singlets at 54.0 ( 9 ) and 47.5 ( 10 ) ppm, which are split into doublets under off-resonance conditions.…”

Hydrogen Migration and HCl Elimination Promoted by Metal-Centered Nucleophilic Attack on Osmium Hydrido−Carbynes

“…The subsequent elimination of styrene to produce 4 is readily explained (at least formally) by selective electrophilic attack of H + (produced in situ) on the vinyl ligand of 3 , followed by coordination of Cl - to the osmium center. In fact, 3 is observed to be stable in solution in the absence of excess CO and HCl for at least 48 h. This selectivity toward protonation at C α of the vinyl ligand is unusual since a number of recent reports , have established that C β is generally the preferred site of electrophilic attack in osmium vinyl complexes, to yield the corresponding carbene. Furthermore, selective electrophilic attack at C α of a vinyl ligand (to eliminate olefin) has only been reported in a few cases. 10b, Apparently, then, the selectivity toward protonation is quite sensitive to the ligands, and hence the electronic environment, about the osmium.…”

“…In fact, 3 is observed to be stable in solution in the absence of excess CO and HCl for at least 48 h. This selectivity toward protonation at C α of the vinyl ligand is unusual since a number of recent reports , have established that C β is generally the preferred site of electrophilic attack in osmium vinyl complexes, to yield the corresponding carbene. Furthermore, selective electrophilic attack at C α of a vinyl ligand (to eliminate olefin) has only been reported in a few cases. 10b, Apparently, then, the selectivity toward protonation is quite sensitive to the ligands, and hence the electronic environment, about the osmium. The slow production of 4 from 3 is presumably a function of the low concentration of HCl generated in the reaction.…”

Synthesis and Characterization of OsH2Cl[κN,κO-(ONCR2)](PiPr3)2 (CR2 = C(CH2)4CH2, R = CH3): Influence of the L2 Ligand on the Nature of the H2 Unit in OsH2ClL2(PiPr3)2 (L2 = ONCR2, NHC(Ph)C6H4) Complexes

“…In general, the M−H distances obtained from X-ray diffraction data are imprecise . However, ab initio calculations have been shown to provide useful accurate data for the hydrogen positions in both classical polyhydride and dihydrogen complexes . Therefore, to corroborate the dihydride nature of the H 2 unit of these compounds, a B3LYP geometry optimization was performed on the OsH 2 Cl{κ N ,κ O -(ONCH 2 )}(PH 3 ) 2 ( 4 ) model system.…”