Synthesis, Structure, and Catecholase Reaction of a Vanadate Ester System Incorporating Monoionized Catechol Chelation

Abstract

An example of the title system is VO(Hdbcat)(A1), 1a, where the tridentate coligand (A1)2- is a diionized salicylhydrazone. The reaction of 1a with O2 in solution forms the basis of the depicted cycle where 1a is the reactive intermediate and V2O3(A1)2, 3a is the catalyst. The net result is the catecholase reaction H2dbcat +1/2 O2 → dbq + H2O. The phenolic proton of 1a is proposed to have a crucial role in anchoring O2 thus making it O2-sensitive.

Mixed‐Ligand Oxidovanadium(V) Complexes with N′‐Salicylidenehydrazides: Synthesis, Structure, and 51V Solid‐State MAS NMR Investigation

“…Fiveand a six-membered-chelate rings are established by the hydrazone ligand with bite angles of 75°(O13-V1-N11, O23-V2-N21) and 84°(O12-V1-N11, O22-V2-N21), respectively. The V=O moiety in both molecules shows a bond length of about 159 pm, which is at the lower end of the typically observed range for VO 3+ complexes, [9][10][11][12] but consistent with other complexes containing hydrazone ligands together with appropriate coligands such as 8-hydroxyquinoline, [36] catechol, [37] hydroxamate, [38,39] and polyols. [40] The trans influence of the oxido group leads to a rather long V-N bond to the nitrogen atom of the 8-hydroxyquinoline coligand (235 pm), and consequently to a displacement of the vanadium atom towards the oxido group out of the tetragonal basal plane by about 30 pm.…”

Redox Activity in a Vanadium(V)–o‐Dioxolene Complex Is Modulated by Protonation State As Indicated by 51V Solid‐State NMR Spectroscopy and Density Functional Theory

“…[3,5,23] Previously, complex charge has been reported as one of the factors affecting the electronic properties of complexes. Considering that this compound is one of the three structurally known examples of vanadium(V)-catechol complexes, [27,44] a better understanding of the electronic structure of this complex is desirable by using the combination of solid-state 51 V NMR spectroscopy and DFT calculations. Considering that this compound is one of the three structurally known examples of vanadium(V)-catechol complexes, [27,44] a better understanding of the electronic structure of this complex is desirable by using the combination of solid-state 51 V NMR spectroscopy and DFT calculations.…”

The Chemistry and Biochemistry of Vanadium and the Biological Activities Exerted by Vanadium Compounds

“…98,99,[355][356][357][358][359][360][361][362][365][366][367] This testifies as to how critical the supporting ligand is to the properties of these systems and how such a ligand provides structural precedence for biologically relevant chemistry.…”