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Structural, Spectroscopic and Computational Examination of the Dative Interaction in Constrained Phosphine–Stibines and Phosphine–Stiboranes
Author(s) -
Chalmers Brian A.,
Bühl Michael,
Athukorala Arachchige Kasun S.,
Slawin Alexandra M. Z.,
Kilian Petr
Publication year - 2015
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.201500281
Subject(s) - phosphine , chemistry , crystallography , acceptor , bond length , crystal structure , organic chemistry , catalysis , physics , condensed matter physics
A series of phosphine–stibine and phosphine–stiborane peri ‐substituted acenaphthenes containing all permutations of pentavalent groups SbCl n Ph 4– n ( 5 – 9 ), as well as trivalent groups SbCl 2 , Sb(R)Cl, and SbPh 2 ( 2 – 4 , R=Ph, Mes), were synthesised and fully characterised by single crystal diffraction and multinuclear NMR spectroscopy. In addition, the bonding in these species was studied by DFT computational methods. The P–Sb dative interactions in both series range from strongly bonding to non‐bonding as the Lewis acidity of the Sb acceptor is decreased. In the pentavalent antimony series, a significant change in the P–Sb distance is observed between SbClPh 3 and SbCl 2 Ph 2 derivatives 6 and 7 , respectively, consistent with a change from a bonding to a non‐bonding interaction in response to relatively small modification in Lewis acidity of the acceptor. In the Sb III series, two geometric forms are observed. The P–Sb bond length in the SbCl 2 derivative 2 is as expected for a normal (rather than a dative) bond. Rather unexpectedly, the phosphine–stiborane complexes 5 – 9 represent the first examples of the σ 4 P→σ 6 Sb structural motif.