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O , N ‐Chelated Vanadium(IV) Oxo Aminophenolate Complexes: the Effect of Steric Bulk on the Vanadium Coordination Geometry. Can this Influence be detected Spectroscopically?
Author(s) -
Hagen Henk,
Reinoso Santiago,
Reijerse Ed J.,
van Faassen Ernst E.,
Lutz Martin,
Spek Anthony L.,
van Koten Gerard
Publication year - 2004
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200400337
Subject(s) - vanadium , steric effects , electron paramagnetic resonance , chemistry , chelation , crystallography , coordination geometry , inorganic chemistry , geometry , stereochemistry , molecule , organic chemistry , nuclear magnetic resonance , hydrogen bond , physics , mathematics
In order to study the effect of steric bulk on the vanadium coordination geometry in O , N ‐chelated vanadium oxo (bis)phenolates, six different ortho ‐aminophenolate ligands have been used. The ortho ‐aminophenolate system was changed at three different places, i.e. 1) the second ortho position (C 6 ) of the arene ring (R), 2) the substituents at the amino nitrogen (R′ and R″), and 3) the benzylic carbon atom (R*). The phenols were used in the preparation of the vanadium oxo (bis)phenolate complexes. In order to study whether it is possible to predict geometrical features of these vanadium complexes, UV/Vis, solution and frozen state EPR and 14 N ESEEM spectroscopic data was measured and compared to the structural features of four structurally characterized vanadium oxo (bis)phenolates. Unfortunately, it turned out that is was not possible to correlate the EPR parameters, the UV/Vis HOMO‐LUMO transitions or 14 N hyperfine couplings to the structural parameters.