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Is the R 3 Si Moiety in Metal–Silyl Complexes a Z ligand? An Answer from the Interaction Energy
Author(s) -
Binh Dang Ho,
Milovanović Milan,
PuertesMico Julia,
Hamdaoui Mustapha,
Zarić Snežana D.,
Djukic JeanPierre
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.201703373
Subject(s) - silylation , moiety , ligand (biochemistry) , metal , chemistry , stereochemistry , crystallography , organic chemistry , biochemistry , receptor , catalysis
The computation of metal–silyl interaction energies indicates the existence of situations in which the silyl group behaves as a Z‐type ligand according to the Green method of covalent‐bond classification. There is a scale of relative intrinsic silylicity Π , defined as the ratio of the intrinsic silyl‐to‐triflate interaction energy of a silyltriflate as a reference compound relative to the silyl‐to‐metal interaction of given complex, that can reveal in a straightforward manner the propensity of SiR 3 groups to behave chemically as metal‐bound “silylium” ions, namely, [SiR 3 ] + . Emblematic cases, either taken from the Cambridge Structural Database (CSD) or constructed for the purpose of this study, were also investigated from the viewpoints of extended transition‐state natural orbitals for chemical valence (ETS‐NOCV) and quantum theory of atoms in molecules (QTAIM) analyses. It is shown in the case of POBMUP—which is the iridium 1,3‐bis[(di‐ tert ‐butylphosphino)oxy]benzene (POCOP) complex isolated by Brookhart et al.—how slight variations of molecular charge and structure can drastically affect the relative intrinsic silylicity of the SiEt 3 group that is weakly bonded to the hydrido–iridium motif.