metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
and 4-¯uoro-, (I), 3-¯uoro-4-methyl-, (II), 3,5-bis(tri¯uoro-
methyl)-, (III), and 4-tri¯uoromethoxyanilines, (IV), and the
bis-ligand oxovanadium(IV) complex of the Schiff base
derived from salicylaldehyde and 4-tri¯uoromethoxyaniline,
(V).
ISSN 0108-2701
Fluoro derivatives of bis(salicylidene-
aminato-N,O)copper(II) and -oxovan-
adium(IV)
John Burgess, John Fawcett,* Vitor Palma² and Syeda R.
Gilani
Department of Chemistry, University of Leicester, Leicester LE1 7RH, England
Correspondence e-mail: jxf@leicester.ac.uk
Received 26 October 2000
Accepted 11 December 2000
For the copper complexes (I), (II) and (IV), the Cu atom
and the four ligand donor atoms are coplanar, as expected.
However, the 3,5-CF3-substituted complex (III) has a
distorted coordination at the Cu atom, intermediate between
square-planar and tetrahedral, with an interplanar angle
(Cu1ÐO1ÐN1 to Cu1ÐO10ÐN10) of 37.8 (1)ꢀ. Such distor-
tion may be compared with that engendered by the attach-
ment of relatively bulky groups to the N-donor atoms. This
distortion has been of considerable interest to kineticists (Voss
et al., 1979). It has been tracked through X-ray diffraction
structure determination of, for example, the N-tert-butyl
derivative, where the angle between the mean planes of the
chelate rings is 61.9ꢀ (Cheeseman et al., 1966a) and through
electronic spectroscopy (Cheeseman et al., 1966b; Voss et al.,
1974). For all the Cu complexes, the substituted amine ring of
each ligand is rotated about the N1ÐC8 bond from the
The structures of ®ve complexes of ¯uorine-containing
bidentate salicylideneamine Schiff base ligands are reported.
These are the bis-ligand copper(II) complexes of the Schiff
bases derived from salicylaldehyde and 4-¯uoro-,
[Cu(C13H9FNO)2], 3-¯uoro-4-methyl-, [Cu(C14H11FNO)2],
3,5-bis(tri¯uoromethyl)-, [Cu(C15H8F6NO)2], and 4-tri¯uoro-
methoxyanilines, [Cu(C14H9F3NO2)2], and the bis-ligand
oxovanadium(IV) complex of the Schiff base derived from
salicylaldehyde and 4-tri¯uoromethoxyaniline, [VO(C14H9-
F3NO2)2]. Three of the copper complexes have square-planar
coordination at the metal, imposed by the virtue of symmetry,
but the immediate coordination environment of the copper in
the 3,5-bis(tri¯uoromethyl) complex is intermediate between
square planar and tetrahedral. The coordination environment
at the metal of the vanadium complex can be described as
distorted square pyramidal.
Comment
Bidentate Schiff base ligands of various types and their metal
complexes have been extensively studied for many decades.
Of the various classes of Schiff base which can be generated by
condensation of different types of amines and carbonyl
compounds, one of the most popular has been that of the
salicylideneamines, potential O,N-donors derived from
(substituted) salicylaldehydes and primary amines. If the
amine is aromatic, then a great variety of ligands can be
prepared from the great range of substituted anilines which
are available. We are interested in the synthesis of ¯uoro-
substituted ligands and metal complexes, in particular in
relation to the consequences of ¯uorine-for-hydrogen repla-
cement on solvation and on reactivity. Here we combine our
speci®c interest in ¯uoro-derivatized complexes with our
general interest in Schiff base complexes, reporting the
preparations and structures of bis-ligand copper(II)
complexes of the Schiff bases derived from salicylaldehyde
Figure 1
The molecular structure of one of the unique molecules of (I) showing the
atom-numbering scheme and 30% probability displacement ellipsoids. H
atoms are drawn as spheres of arbitary radii. [Symmetry code: (i) x, y,
z.]
² Erasmus student visitor from CEQUP, Faculdade de Ciencias, Porto 4150,
Portugal.
ꢁ
Acta Cryst. (2001). C57, 277±280
# 2001 International Union of Crystallography
Printed in Great Britain ± all rights reserved 277
Burgess, John
