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Carbodiphosphorane Analogues E(PPh 3 ) 2 with E=C–Pb: A Theoretical Study with Implications for Ligand Design
Author(s) -
Takagi Nozomi,
Tonner Ralf,
Frenking Gernot
Publication year - 2012
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.201100494
Subject(s) - lone pair , chemistry , molecule , divalent , ligand (biochemistry) , stereochemistry , bond dissociation energy , crystallography , valence electron , carbene , electron pair , reactivity (psychology) , valence (chemistry) , dissociation (chemistry) , atom (system on chip) , carbon group , acceptor , electron , group (periodic table) , organic chemistry , medicine , biochemistry , physics , receptor , alternative medicine , pathology , quantum mechanics , computer science , catalysis , embedded system , condensed matter physics
Quantum‐chemical calculations at the BP86/TZVPP level have been carried out for the heavy Group 14 homologues of carbodiphosphorane E(PPh 3 ) 2 , where E=Si, Ge, Sn, Pb, which are experimentally unknown so far. The results of the theoretical investigation suggest that the tetrelediphosphoranes E(PPh 3 ) 2 ( 1 E ) are stable compounds that could become isolated in a condensed phase. The molecules possess donor–acceptor bonds Ph 3 P→E←PPh 3 to a bare tetrele atom E, which retains its four valence electrons as two electron lone pairs. The analysis of the bonding situation and the calculation of the chemical reactivity indicate that the molecules 1 E belong to the class of divalent E(0) compounds (ylidones). All molecules 1 C–1 Pb have very large first but also very large second proton affinities, which distinguishes them from the N‐heterocyclic carbene homologues, in which the donor atom is a divalent E(II) species that possesses only one electron lone pair. Compounds 1 E are powerful double donors that strongly bind Lewis acids such as BH 3 and AuCl in the complexes 1 E(BH 3 ) n and 1 E(AuCl) n ( n =1, 2). The bond dissociation energies (BDEs) of the second BH 3 and AuCl molecules are only slightly less than the BDE of the first BH 3 and AuCl. The results of this work are a challenge for experimentalists.