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Stabilization of a Diphosphagermylene through pπ–pπ Interactions with a Trigonal‐Planar Phosphorus Center
Author(s) -
Izod Keith,
Rayner Daniel G.,
ElHamruni Salima M.,
Harrington Ross W.,
Baisch Ulrich
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201308002
Subject(s) - lone pair , delocalized electron , natural bond orbital , center (category theory) , chemistry , crystallography , germanium , phosphorus , stereochemistry , computational chemistry , molecule , density functional theory , organic chemistry , silicon
Abstract N‐Heterocyclic carbenes and their heavier homologues are, in part, stabilized by delocalization of the N lone pairs into the vacant p‐orbital at carbon (or a heavier Group 14 element center). These interactions are usually absent in the corresponding P‐substituted species, owing to the large barrier to planarization of phosphorus. However, judicious selection of the substituents at phosphorus has enabled the synthesis of a diphosphagermylene, [(Dipp) 2 P] 2 Ge, in which one of the P centers is planar (Dipp=2,6‐diisopropylphenyl). The planar nature of this P center and the correspondingly short PGe distance suggest a significant degree of PGe multiple bond character that is due to delocalization of the phosphorus lone pair into the vacant p‐orbital at germanium. DFT calculations support this proposition and NBO and AIM analyses are consistent with a GeP bond order greater than unity.