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Redox Activity in a Vanadium(V)– o ‐Dioxolene Complex Is Modulated by Protonation State As Indicated by 51 V Solid‐State NMR Spectroscopy and Density Functional Theory
Author(s) -
Chatterjee Pabitra B.,
GoncharovZapata Olga,
Hou Guangjin,
Dmitrenko Olga,
Polenova Tatyana,
Crans Debbie C.
Publication year - 2012
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.201200259
Subject(s) - chemistry , vanadium , redox , density functional theory , protonation , nuclear magnetic resonance spectroscopy , ligand (biochemistry) , crystallography , chemical shift , solid state nuclear magnetic resonance , computational chemistry , stereochemistry , inorganic chemistry , nuclear magnetic resonance , ion , organic chemistry , biochemistry , physics , receptor
Most known vanadium(V) complexes with redox‐active o ‐dioxolene ligands are non‐innocent. Since the vanadium(V) complex [VO(gsal)(HCat)] is innocent, its properties were investigated by 51 V solid‐state NMR spectroscopy and density functional theory (DFT). The innocent ligand behavior manifested itself by the upfield isotropic chemical shift and large negative chemical shift anisotropy observed in the solid state. The electronic structure and NMR spectroscopic parameters of this complex were addressed by DFT calculations and found to be consistent with the NMR spectroscopic observations indicating that the complex is redox‐inactive. The observed increase in the HOMO–LUMO gap for the innocent complex is concomitant with the 51 V NMR chemical shift of –460 ppm and consistent with the high redox stability of this molecule. The stabilization was traced to the overall charge of [VO(gsal)(HCat)] facilitated by the coordination of the minus‐one‐charged o ‐dioxolene ligand and rendering the overall complex neutral. These studies suggest that protonation may prove to be an effective way in which vanadium(V) complexes with redox‐active ligands can be stabilized.