Octahedral metal carbonyls. 63. Chelate ring displacement of DTHp from cis-(DTHp)W(CO)/sub 4/ by Lewis Bases (DTHp = 2,2,6,6-tetramethyl-3,5-dithiaheptane, Lewis Base = L (phosphine, phosphite))
Reactions of cis-(DTHp)W(CO)/sub 4/, in which DTHp forms a four-membered chelate ring, with L (DTHp = 2,2,6,6-tetramethyl-3,5-dithiaheptane; L = P(OMe)/sub 3/, P(O-i-Pr)/sub 3/, P(OCH/sub 2/)/sub 3/CCH/sub 3/, P(n-Bu)/sub 3/) in chlorobenzene (CB) proceed via displacement of DTHp according to cis-(DTHp)W(CO)/sub 4/ + 2L ..-->.. cis- and trans-(L)/sub 2/W(CO)/sub 4/ + DTHp. Kinetics data in CB indicate the reaction to be biphasic, with cis-(L)(/eta//sup 1/-DTHp)W(CO)/sub 4/ present as a predominant species during the reaction's course; this intermediate has been characterized for L = P(COH/sub 2/)/sub 3/ CCH/sub 3/. Evidence here suggests that significant L-W bond making takes place in the transition states leading to chelate ring opening and closing. The cis-(L)(/eta//sup 1/-DTHp)W(CO)/sub 4/ products produced via the first phase of the biphasic thermal process undergo unimolecular W-S bond fission. Rate constants for this process vary significantly and are largely influenced by the steric properties of coordinated L, increasing in the order of larger Tolan cone angles. This W-S bond dissociation is followed by solvation to afford cis-((CB)(L)W(CO)/sub 4/) intermediates, previously characterized, which then react via rapid reversible desolvation and attack at the five-coordinate, square-pyramidal ((L)W(CO)/sub 4/) intermediates by L, to afford cis-(L)/sub 2/W(CO)/sub 4/. Subsequent nondissociative isomerization of this species forms the equilibrium mixture of cis- and trans-(L)/sub 2/W(CO)/sub 4/ products ultimately obtained. These several steps involved in the overall chelate displacement process are discussed in detail. 25 references, 4 figures, 2 tables.
- Research Organization:
- Univ. of North Texas, Denton (USA)
- OSTI ID:
- 6181236
- Journal Information:
- Inorg. Chem.; (United States), Vol. 27:19
- Country of Publication:
- United States
- Language:
- English
Similar Records
Insertion products from photolysis of Tp{prime}(CO){sub 3}WH and alkynes
Octahedral metal carbonyls. 67. Rates of reaction of olefins with cis((chlorobenzene)(triphenylphosphine tetracarbonyltungsten(O))) produced via pulsed laser flash photolysis
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKANES
CHEMICAL REACTIONS
CARBONYLS
ORGANIC PHOSPHORUS COMPOUNDS
TUNGSTEN COMPLEXES
CARBON 13
DEUTERIUM
EXPERIMENTAL DATA
ISOTOPE EFFECTS
LABELLED COMPOUNDS
NMR SPECTRA
CARBON ISOTOPES
COMPLEXES
DATA
EVEN-ODD NUCLEI
HYDROCARBONS
HYDROGEN ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
SPECTRA
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
400202 - Isotope Effects
Isotope Exchange
& Isotope Separation