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Contrasting E−H Bond Activation Pathways of a Phosphanyl‐Phosphagallene
Author(s) -
Feld Joey,
Wilson Daniel W. N.,
Goicoechea Jose M.
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202109334
Subject(s) - chemistry , phenylsilane , hydroamination , reagent , medicinal chemistry , reactivity (psychology) , bond cleavage , stereochemistry , organic chemistry , catalysis , intramolecular force , medicine , alternative medicine , pathology
The reactivity of the phosphanyl‐phosphagallene, [H 2 C{N(Dipp)}] 2 PP=Ga(Nacnac) (Nacnac=HC[C(Me)N(Dipp)] 2 ; Dipp=2,6‐ i Pr 2 C 6 H 3 ) towards a series of reagents possessing E−H bonds (primary amines, ammonia, water, phenylacetylene, phenylphosphine, and phenylsilane) is reported. Two contrasting reaction pathways are observed, determined by the polarity of the E−H bonds of the substrates. In the case of protic reagents ( δ− E−H δ+ ), a frustrated Lewis pair type of mechanism is operational at room temperature, in which the gallium metal centre acts as a Lewis acid and the pendant phosphanyl moiety deprotonates the substrates. Interestingly, at elevated temperatures both NH 2 i Pr and ammonia can react via a second, higher energy, pathway resulting in the hydroamination of the Ga=P bond. By contrast, with hydridic reagents ( δ+ E−H δ− ), such as phenylsilane, hydroelementation of the Ga=P bond is exclusively observed, in line with the polarisation of the Si−H and Ga=P bonds.