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Selectively Measuring π Back‐Donation in Gold(I) Complexes by NMR Spectroscopy
Author(s) -
Ciancaleoni Gianluca,
Biasiolo Luca,
Bistoni Giovanni,
Macchioni Alceo,
Tarantelli Francesco,
Zuccaccia Daniele,
Belpassi Leonardo
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.201406049
Subject(s) - nuclear magnetic resonance spectroscopy , spectroscopy , materials science , nuclear magnetic resonance , chemistry , crystallography , stereochemistry , physics , astronomy
Even though the Dewar–Chatt–Duncanson model has been successfully used by chemists since the 1950s, no experimental methodology is yet known to unambiguously estimate the constituents (donation and back‐donation) of a metal–ligand interaction. It is demonstrated here that one of these components, the metal‐to‐ligand π back‐donation, can be effectively probed by NMR measurements aimed at determining the rotational barrier of a CN bond (Δ H r ≠ ) of a nitrogen acyclic carbene ligand. A large series of gold(I) complexes have been synthesized and analyzed, and it was found that the above experimental observables show an accurate correlation with back‐donation, as defined theoretically by the appropriate charge displacement originated upon bond formation. The proposed method is potentially of wide applicability for analyzing the ligand effect in metal catalysts and guiding their design.