Selectively Measuring [pi]Back-Donation in Gold(I) Complexes by NMR Spectroscopy

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, th...

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Bibliographic Details
Published in:Chemistry : a European journal 2015-02, Vol.21 (6), p.2467
Main Authors: Ciancaleoni, Gianluca, Biasiolo, Luca, Bistoni, Giovanni, Macchioni, Alceo, Tarantelli, Francesco, Zuccaccia, Daniele, Belpassi, Leonardo
Format: Article
Language:English
Subjects:
Chemistry
Ligands
Online Access:Get full text
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Summary: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 πback-donation, can be effectively probed by NMR measurements aimed at determining the rotational barrier of a CN bond ([Delta]Hr≠) 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.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.201406049