Chemical and electrochemical oxidation of group 6 cyclopentadienylmetal hydrides. First estimates of 17-electron metal hydride cation radical thermodynamic acidities and their decomposition to 17-electron neutral radicals

Journal Article · Wed Mar 28 04:00:00 EST 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00163a023· OSTI ID:6428774

Ryan, O B; Tilset, M ^[1]; Parker, V D ^[2]

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1. Univ. of Oslo (Norway)
2. Utah State Univ., Logan (USA)

The oxidation chemistry of the organometallic hydride complexes ({eta}{sup 5}C{sub 5}H{sub 5})M(CO){sub 3}H (M = Cr, 1; Mo, 2; W, 3), ({eta}{sup 5}-C{sub 5}Me{sub 5})Mo(CO){sub 3}H (4), and ({eta}{sup 5}-C{sub 5}H{sub 5})W(CO){sub 2}(PMe{sub 3})H (5) has been investigated in acetonitrile solution by electrochemical and other methods. The thermodynamic acidities of the cation radicals of 1-5 have been estimated by the use of a thermochemical cycle based on the oxidation potentials of 1-5 and their conjugate bases (anions) as well as the solution pK{sub a} values of 1-5. The metal hydride cation radical pK{sub a} estimates fall in the range {minus}10 to +5, which makes these complexes the most acidic hydrides for which pK{sub a} values have been determined. Coulometric measurements show that 1-5 undergo overall two-electron oxidations. Chemical oxidation of 5 gives a 1:1 mixture of dihydride ({eta}{sup 5}-C{sub 5}H{sub 5})W(CO){sub 2}(PMe{sub 3})H{sub 2}{sup +} (13) and ({eta}{sup 5}-C{sub 5}H{sub 5})W(CO){sub 2}(PMe{sub 3})(NCMe){sup +} (10), the latter as a mixture of cis and trans isomers in the thermodynamic 95:5 ratio.

• OSTI ID: 6428774
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:7; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTIONS
CHEMISTRY
CHROMIUM COMPOUNDS
CHROMIUM HYDRIDES
DATA
DATA ANALYSIS
ELECTROCHEMISTRY
EXPERIMENTAL DATA
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
MOLYBDENUM COMPOUNDS
MOLYBDENUM HYDRIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
OXIDATION
REFRACTORY METAL COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
TUNGSTEN HYDRIDES