Negative charge on hydrogen atoms in carbonylmetal hydrides and their acid properties. Induced electrophilicity of hydrogen as a result of reversal of the direction of polarization of a bond under the action of a nucleophile

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Sov. J. Coordinat. Chem.; (United States)

OSTI ID:6322251

Imyanitov, N S

The contradiction between the negative charge on hydrogen atoms in carbonylmetal hydrides and their clearly expressed acid properties has been examined. The inconsistency of the interpretation which states that carbonyl hydrides acquire acid properties under the effects of water and similar solvents, while they remain hydrides (e.e., compounds with a nucleophilic hydrogen atom) in nonpolar media and in the gaseous phase, has been demonstrated. A mechanism for the realization of the acid properties of carbonyl hydrides has been proposed. According to this mechanism, the negative charge is displaced from the hydrogen atom to the metal carbonyl group under the action of a base, this results in a change in the direction of polarization of the hydrogen-transition-metal bond (polarization reversal), and the hydrogen atom acquires a positive charge (induced electrophilicity). It has been shown that in the case of the carbonyl-metal hydrides HFe(CO)/sub 4//sup -/, NMn(CO)/sub 5/, HCo(CO)/sub 4/, HCo(CO)/sub 3/P(C/sub 6/H/sub 5/)/sub 3/, HCo(COP)/sub 3/P(OC/sub 6/H/sub 5/)/sub 3/, and HCo(CO)(PF/sub 3/)/sub 3/, the logarithms of the acid dissociation constants are linearly dependent on the electron-acceptor properties of the metal carbonyl group. The key role of the acid properties of carbonylmetal hydrides in the catalysts of carbonylation reactions has been considered. It has been noted that the negative charge on the hydrogen atom is the cause of the reduced dynamic acidity of carbonyl hydrides and their poor solubility in water.

• Research Organization: All-Union Scientific-Research Institute of Petrochemical Processes, Leningrad, USSR
• OSTI ID: 6322251
• Journal Information: Sov. J. Coordinat. Chem.; (United States), Journal Name: Sov. J. Coordinat. Chem.; (United States) Vol. 12:3; ISSN SJCCD
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
BINDING ENERGY
CARBONYLATION
CARBONYLS
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL BONDS
CHEMICAL REACTIONS
COBALT COMPLEXES
COBALT COMPOUNDS
COBALT HYDRIDES
COMPLEXES
DISSOCIATION ENERGY
DISTANCE
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY
FERMIONS
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
HYDROGENATION
INTERATOMIC DISTANCES
IRON COMPLEXES
IRON COMPOUNDS
IRON HYDRIDES
LEPTONS
MANGANESE COMPLEXES
MANGANESE COMPOUNDS
MANGANESE HYDRIDES
NONMETALS
PH VALUE
POLARIZATION
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
VALENCE