Elsevier

Polyhedron

Volume 12, Issue 2, January 1993, Pages 133-140
Polyhedron

Nuclear magnetic resonance studies of multinuclear chromium assemblies

https://doi.org/10.1016/S0277-5387(00)81619-8Get rights and content

Abstract

1H NMR and 2H NMR resonance of a series of oxo-centred trinuclear chromium complexes of the form [Cr3O(O2CR)6(L)3]+ (R = —CH3, —CH2CH3, —Ph, -4-MePh; L = H2O, py, 2-Mepy, 3-Mepy, 4-Mepy) have been observed and assigned. The role of π- and σ-bonding frameworks in the delocalization of unpaired electron density onto the ligand protons is examined. The π-delocalization mechanism dominates where ligands contain aromatic substituents or carboxylate functionalities, consistent with the presence of a metal centre where unpaired electrons reside solely in t2g orbitals. A comparison of the importance of these mechanisms with that in trinuclear manganese and iron complexes is reported. These results suggest that 1H and 2H NMR studies could be useful probes of proteins containing coupled multinuclear chromium assemblies.

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