title: Thermal Chemistry of Cp*W(NO)(CH2CMe3)(H)(L) Complexes (L = Lewis Base).
abstract: The complexes trans-Cp*W(NO)(CH2CMe3)(H)(L) (Cp* = η5-C5Me5) result from the treatment of Cp*W(NO)(CH2CMe3)2in n-pentane with H2(∼1 atm) in the presence of a Lewis base, L. The designation of a particular geometrical isomer as cis or trans indicates the relative positions of the alkyl and hydrido ligands in the base of a four-legged piano-stool molecular structure. The thermal behavior of these complexes is markedly dependent on the nature of L. Some of them can be isolated at ambient temperatures [e.g., L = P(OMe)3, P(OPh)3, or P(OCH2)3CMe]. Others undergo reductive elimination of CMe4via trans to cis isomerization to generate the 16e reactive intermediates Cp*W(NO)(L). These intermediates can intramolecularly activate a C-H bond of L to form 18e cis complexes that may convert to the thermodynamically more stable trans isomers [e.g., Cp*W(NO)(PPh3) initially forms cis-Cp*W(NO)(H)(κ2-PPh2C6H4) that upon being warmed in n-pentane at 80 °C isomerizes to trans-Cp*W(NO)(H)(κ2-PPh2C6H4)]. Alternatively, the Cp*W(NO)(L) intermediates can effect the intermolecular activation of a substrate R-H to form trans-Cp*W(NO)(R)(H)(L) complexes [e.g., L = P(OMe)3or P(OCH2)3CMe; R-H = C6H6or Me4Si] probably via their cis isomers. These latter activations are also accompanied by the formation of some Cp*W(NO)(L)2disproportionation products. An added complication in the L = P(OMe)3system is that thermolysis of trans-Cp*W(NO)(CH2CMe3)(H)(P(OMe)3) results in it undergoing an Arbuzov-like rearrangement and being converted mainly into [Cp*W(NO)(Me)(PO(OMe)2)]2, which exists as a mixture of two isomers. All new complexes have been characterized by conventional and spectroscopic methods, and the solid-state molecular structures of most of them have been established by single-crystal X-ray crystallographic analyses.
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Diana
authors.initials: D
authors.lastname: Fabulyak
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Rex C
authors.identifier: http://orcid.org/0000-0002-3693-1697
authors.initials: RC
authors.lastname: Handford
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Holmes
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Taleah M
authors.initials: TM
authors.lastname: Levesque
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Wakeham
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Brian O
authors.initials: BO
authors.lastname: Patrick
authors.affiliation: Department of Chemistry, The University of British Columbia , Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Peter
authors.identifier: http://orcid.org/0000-0002-3914-3768
authors.initials: P
authors.lastname: Legzdins
authors.affiliation: The Dow Chemical Company , 2301 North Brazosport Boulevard, Freeport, Texas 77541, United States.
authors.forename: Devon C
authors.initials: DC
authors.lastname: Rosenfeld