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A Quantitative Description of the σ‐Donor and π‐Acceptor Properties of Substituted Phenanthrolines
Author(s) -
Ardizzoia G. Attilio,
Bea Michela,
Brenna Stefano,
Therrien Bruno
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201600647
Subject(s) - chemistry , valence (chemistry) , phenanthroline , ligand (biochemistry) , atomic orbital , computational chemistry , acceptor , thiazole , transition metal , metal , density functional theory , coordination complex , crystallography , stereochemistry , catalysis , organic chemistry , quantum mechanics , biochemistry , physics , receptor , electron
The bond between molybdenum and substituted 1,10‐phenanthroline ligands in a series of [Mo(CO) 4 (phen*)] complexes has been studied by combining experimental data ( ν CO ) with DFT calculations. First, natural orbitals for chemical valence (NOCV) were calculated: The resulting charge‐transfer magnitudes (Δ q i ) associated with the deformation density channels (Δ ϱ i ) were related to σ‐donation and π‐back‐donation. Then, energy decomposition analysis was performed by applying the extended transition state (ETS) scheme. The outcomes of the ETS‐NOCV approach has allowed us to quantify the energetic contribution of both ligand‐to‐metal ( E σ ) and metal‐to‐ligand ( E π ) interactions. A new parameter ( T phen ) has been introduced comprising both E σ and E π and thus providing a descriptor for the overall electronic contribution given by phenanthrolines to the metal–ligand bond. This was corroborated by the linear correlation found between T phen and the ν CO vibration modes of [Mo(CO) 4 (phen*)] complexes, at least for those containing a 2,9‐unsubstituted phenanthroline. The case of [Mo(CO) 4 (phen*)] derivatives with a 2,9‐substituted phen* is also discussed.