Even the normal is abnormal: N-heterocyclic carbene C(2) binding to a phosphaalkene without breaking the P=C π-bond.
Chem Commun (Camb)
; 52(5): 998-1001, 2016 Jan 18.
Article
em En
| MEDLINE
| ID: mdl-26592925
ABSTRACT
The reaction of MesP=CPh2 with the least sterically demanding N-heterocyclic carbene (NHC = IMe) results in formation of the 'abnormal' (C(4)-substituted) 4-phosphino-NHC (1). In contrast, reaction with Me2IMe gives the unprecedented 'normal' C(2) adduct, Me2IMe â P(Mes)=CPh2 (2). Particularly striking is the asymmetric and weak bonding of the NHC to the P=C moiety in 2. DFT calculations indicate that the P=C natural bond order in 2 (1.54) still reflects significant π-character to the bond (cf. MesP=CPh2 NBO = 1.98). Further computational analysis suggests that π-delocalization into the remote C-phenyl substituents is key to stabilizing the NHC adduct.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2016
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Article