Formation, reactions, and solution dynamics of [M(η¹-C₅H₄R)(C₆H₄-2-X)(PEt₃)₂] (M = Pd, Pt)

Anderson, G. K., Black, D. M., Cross, R. J., Robertson, F. J., Rycroft, D. S. and Wat, R. K.M. (1990) Formation, reactions, and solution dynamics of [M(η¹-C₅H₄R)(C₆H₄-2-X)(PEt₃)₂] (M = Pd, Pt). Organometallics, 9(9), pp. 2568-2574. (doi: 10.1021/om00159a027)

Abstract

Reactions of [M(η⁵-C₅H₄R)(C₆H₄-2-X)] (M = Pd, R = H, Me, SiMe₃, X = N=NPh or R = H, X = CH=NMe, 2-C₅H₄N; M = Pt, R = H, SiMe₃, X = N=NPh) with PEt₃ in toluene solution produce the adducts [Pd(η⁵-C₅H₄R)(C₆H₄-2-X)(PEt₃)] and trans-[M(η¹-C₅H₄R)(C₆H₄-2-X)(PEt₃)₂] but none of the ionic [M(C₆H₄-2-X)(PEt₃)₃]⁺C₅H₄R⁻ found in halogenated solvents. Instead, the reactive intermediates cis-[M(η¹-C₅H₄R)(C₆H₄-2-X)(PEt₃)₂] are detected at −80 ºC, but these isomerize as the temperature is raised. The fluxional η¹-C₅H₄R groups of trans-[M(η¹-C₅H₄R)(C₆H₄-2-X)(PEt₃)₂] undergo rapid rotation about the M–C bonds at ambient temperature, resulting in apparent magnetic equivalence of the PEt₃ groups. At temperatures around −90 ºC bond rotation is slowed sufficiently to allow detection of the nonequivalent P atoms by NMR spectroscopy. The palladium complexes decompose slowly at 25 ºC, but the platinum species isomerize readily to sp²-carbon-bonded vinylic cyclopentadienyl derivatives. At low temperatures the effects of restricted rotation about the Pt–C bonds of the vinylic cyclopentadienyl compounds can be deduced from the detection of syn and anti rotational isomers in solution.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rycroft, Dr David
• Authors: Anderson, G. K., Black, D. M., Cross, R. J., Robertson, F. J., Rycroft, D. S., and Wat, R. K.M.
• Subjects: Q Science > QD Chemistry
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Organometallics
• Publisher: American Chemical Society
• ISSN: 0276-7333
• ISSN (Online): 1520-6041