Carbonyls, metal Infrared spectra

The mixed-metal tetranuclear derivatives that have been prepared are H2Re2Ru2(CO)i6, CReRu3(CO)16] , HMnOs3(CO)16, and HReOs3(CO)18 (238). All the complexes result from the reaction of the carbonyl, M3(CO)i2, with the related anion, [Mn(CO)5]- or [Re(CO)s]. The ruthenium anion [ReRu3(CO)16] was isolated as its tetramethylammo-nium salt. The infrared spectrum was complex, but consistent with... 

A kinetic trace for a particular metal carbonyl intermediate is recorded at a specific wavelength obtained from the time-resolved infrared absorption spectrum. Suitable data analysis allows determination of the kinetics of the decay of the intermediate. 

Pentacarbonyl(diphenylmethylene)tungsten(0) is a moderately air-stable soild that is readily soluble in most organic solvents. The resulting solutions are air and light sensitive and decomposed thermally at about 50°. The infrared spectrum of a heptane solution shows bands in the metal carbonyl region at 2070 (m), 1971 (s), and 1963 (s) cm"1, characteristic of a group VI pentacar-bonyl species. The proton NMR spectrum in CS2 or acetone-d6 shows a complex multiplet at 5 7.2 relative to internal tetramethylsilane. 

The intermediate cyclooctene complex appears to be more reactive with respect to CS coordination and more sensitive to oxidation when the arene ring bears electron-withdrawing groups (e.g., C02CH3). Dicarbonyl(methyl rj6-benzoate)-thiocarbonyl)chromium is air stable in the solid state and reasonably stable in solution.9 The infrared spectrum exhibits metal carbonyl absorptions at 1980 and 1935 cm"1 and a metal thiocarbonyl stretch at 1215 cm"1 (Nujol) (these occur at 1978, 1932, and 1912 cm"1 in CH2C12 solution).10 Irradiation of the compound in the presence of phosphite or phosphine leads to slow substitution of CO by these ligands, whereas the CS ligand remains inert to substitution. The crystal structure has been published."... 

Factors affecting the CO stretching frequency in the infrared spectrum of metal carbonyl derivatives... 

The infrared spectrum of Rh6(CO)i6 has sharp bands at 2075 (s), 2025 (m), and 1800 (s) cm i in Nujol due to v (CO). The crystal-structure determination has established that there are twelve terminal carbonyl groups and four bridging carbonyl groups, each of which bridges three metal atoms. These four bridging carbonyl groups are bonded to alternate faces of the octahedron of rhodium atoms and give rise to v(CO) at 1800 cm-. ... 

Benzylideneacetone)tricarbonyliron is stable indefinitely when stored under nitrogen and is soluble in most common organic solvents. The infrared spectrum exhibits three metal carbonyl frequencies at 2065, 2005, and 1985 cm i (cyclohexane). The nmr spectrum (Hor, t3.98, doublet H/9, t6.90, doublet ... 

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