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Reactivity‐Tuning in Frustrated Lewis Pairs: Nucleophilicity and Lewis Basicity of Sterically Hindered Phosphines
Author(s) -
Follet Elsa,
Mayer Peter,
Stephenson David S.,
Ofial Armin R.,
Berionni Guillaume
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701080
Subject(s) - frustrated lewis pair , lewis acids and bases , steric effects , chemistry , nucleophile , reactivity (psychology) , adduct , affinities , computational chemistry , medicinal chemistry , catalysis , stereochemistry , organic chemistry , medicine , alternative medicine , pathology
The nucleophilicity and Lewis basicity of sterically hindered phosphines, widely used in catalysis and in frustrated Lewis pair (FLP) chemistry, have been quantified by determining the rates and equilibrium constants of their associations with reference systems (benzhydrylium and tritylium ions) of calibrated electrophilicities and Lewis acidities. These structure–reactivity investigations allow a rationalization of the Lewis acid–base interactions all along the way from covalent Lewis adducts to FLPs. Comparisons of the association of phosphines of increasing sizes (Ph 3 P, ( o ‐tolyl) 3 P, and t Bu 3 P) with the triarylborane B(C 6 F 5 ) 3 and with the isoelectronic tritylium ions Ar 3 C + provide detailed insights for the future fine‐tuning of the reactivities of FLPs. As a proof of concept, tritylium‐ion‐derived FLPs were shown to react with alkynes, as reported for the FLPs derived from the benchmark triarylborane B(C 6 F 5 ) 3 .