Kinetics and mechanisms of ligand substitution reactions of the vanadium triad metals. Syntheses and reactivities of (. eta. sup 5 -C sub 5 H sub 5 )M(CO) sub 3 (C sub 4 H sub 8 E) (M = Nb, E = S, Se, Te; M = Ta, E = S)

Kinetic studies were performed for CO substitution reactions of CpM(CO){sub 4} (M = Nb, Ta) and for dialkylchalcogenide substitution reactions of CpM(CO){sub 3}(C{sub 4}H{sub 8}E) (M = V, E = S; M = Nb, E = O, S, Se, Te; M = Ta, E = O, S) with phosphines. The syntheses and characterization of the ne...

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Bibliographic Details
Published in:Organometallics 1991-01, Vol.10:1
Main Authors: Freeman, J.W., Basolo, F.
Format: Article
Language:English
Subjects:
400201 - Chemical & Physicochemical Properties
ALKENES
CARBONYLS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
CYCLOALKENES
CYCLOPENTADIENE
DECOMPOSITION
DIENES
DISSOCIATION HEAT
ELECTROMAGNETIC RADIATION
ELEMENTS
ENTHALPY
ENTROPY
FURANS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFRARED SPECTRA
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
KINETICS
LIGANDS
NIOBIUM COMPLEXES
NMR SPECTRA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHOSPHINES
PHOSPHORUS COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PHYSICAL PROPERTIES
POLYCYCLIC SULFUR HETEROCYCLES
POLYENES
RADIATIONS
REACTION HEAT
REACTION KINETICS
SELENIUM
SEMIMETALS
SPECTRA
TANTALUM COMPLEXES
TELLURIUM
TETRAHYDROFURAN
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPLEXES
ULTRAVIOLET RADIATION
VANADIUM COMPLEXES
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Summary:Kinetic studies were performed for CO substitution reactions of CpM(CO){sub 4} (M = Nb, Ta) and for dialkylchalcogenide substitution reactions of CpM(CO){sub 3}(C{sub 4}H{sub 8}E) (M = V, E = S; M = Nb, E = O, S, Se, Te; M = Ta, E = O, S) with phosphines. The syntheses and characterization of the new compounds CpM(CO){sub 3}(C{sub 4}H{sub 8}E) (M = Nb, E = S, Se, Te; M = Ta, E = S) are reported. Both CpM(CO){sub 4} and CpM(CO){sub 3}(C{sub 4}H{sub 8}E) were found to react by the same mechanism. For M = V, a dissociative mechanism was observed, while for M = Nb, Ta both dissociative and associative mechanisms were observed. This change in mechanism is attributed to the larger size of the Nb and Ta centers. The reactivity of the compounds was found to increase in the order V > Nb > Ta. The higher reactivity of the V compounds compared to the Nb compounds is unusual when compared to other triads, where the second-row metal usually forms the most reactive compound. The reactivity of the CpM(CO){sub 3}(C{sub 4}H{sub 8}E) compounds was found to increase in the order Te < Se < S < O, indicating that the heavier chalcogenides form more stable complexes than the higher chalcogenides.
ISSN:0276-7333
1520-6041
DOI:10.1021/om00047a058