Biphenyl derived oxovanadium(IV) and copper(II) salen-type complexes--structure and redox tuning.
A series of vanadyl(IV) salen (N,N'-bis(salicylidene)ethylenediaminato)-type complexes (1-4) bearing phenyl or 2-hydroxyphenyl moieties have been prepared and characterized by means of mass spectrometry, infra-red, electron paramagnetic resonance (EPR), UV/Vis spectroscopy, cyclovoltammetry and X-ray crystallography. Their structures have been compared to their copper(II) analogs 5-8. Hydrogen intralinkages have been observed in the crystal structure of 5. The pendant hydroxy groups fine-tune the redox properties of the complexes. The catalytic activity in the oxygenation of ethyl phenyl sulfide to the corresponding sulfoxide was investigated. Results indicate that complex 1 bearing hydroxyphenyl subunits and a phenylene bridge is the most selective under these reaction conditions, with the smallest amount of the over-oxidized product, sulfone.
Plitt
Patrick
P
Anorganisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany. patrick.plitt@urz.uni-heidelberg.de
Pritzkow
Hans
H
Oeser
Thomas
T
Kraemer
Roland
R