Versatile Reactivity of Bridged Pentelidene Complexes toward Secondary and Tertiary Phosphines
dataset
posted on 2013-06-24, 00:00 authored by Markus Stubenhofer, Christian Kuntz, Michael Bodensteiner, Alexey Y. Timoshkin, Manfred ScheerThe
reaction of the phosphinidene complex [Cp*P{W(CO)5}2] (1a) with secondary and tertiary phosphines,
respectively, proceeds via W(CO)5 elimination to form the
phosphoranylidene complexes [{W(CO)5}(Cp*)P-P(H)iPr2] (2), [{W(CO)5}(Cp*)P-PMeiPr2] (7), and [{W(CO)5}(Cp*)P-PEt3] (9). Other novel types of products, the phosphine-coordinated bridged
parent phosphinidene complexes [{W(CO)5}2(H)P-PMeiPr2] (6a) and [{W(CO)5}2(H)P-PEt3] (8a), are
obtained by elimination of 1,2,3,4-tetramethylfulvene. The latter
reaction path is predominantly found for the arsinidene complex [Cp*As{W(CO)5}2] (1b) to yield [{W(CO)5}2(H)As-PHiPr2]
(4) upon reaction with HPiPr2 and, with tertiary phosphines, the products [{W(CO)5}2(H)As-PMeiPr2] (6b) and [{W(CO)5}2(H)As-PEt3] (8b). If a secondary phosphine coordinates
to a bridged parent pentelidene complex, Cp*H elimination occurs to
form either HP[PiPr2{W(CO)5}]2 (3) or the phosphine-substituted
diarsene complex W(CO)5[AsPiPr2{W(CO)5}]2 (5).
Each of the new products has been characterized by X-ray structure
analysis, NMR, and mass spectroscopy. In each case as a first step
the Lewis acid/base adducts are formed, which was monitored by 31P NMR spectroscopy. The different reaction pathways of the
electrophilic pentelidene complexes [Cp*E{W(CO)5}2] (E = P, As) have been emphasized by extended DFT calculations.
