BOND - VALENCE STUDY OF COPPER(II) NIFLUMATES
Fedor Valach, Miroslav Tokarcik
Department of Chemical Physics, Faculty of Chemical Technology, Slovak University of Technology, SK-812 37 Bratislava, Slovak Republic, E-mail: valach@cvtstu.cvt.stuba.sk
Keywods: fenamate, copper(II) niflumate, 3-pyridylmethanol, bond-valence, crystal structure
Bond - valence sums distribution of niflumic acid anion in the
structures of niflumic acid, C13H9F3N2O2
1 and 1:1 complex of (2 - 3 - (Trifluoromethyl)phenylamino - 3 -
pyridine-carboxylic acid (niflumic acid) with ethanolamine, C19H20F3N3O3
2, was calculated by program VALMAP 2.0 3. The preferred
coordination of niflumate ligand to the copper cation through one
carboxylic oxygen atom was predicted. The crystal and molecular
structure of copper(II) complex of niflumate ligand with
3-pyridylmethanol as neutral ligand confirmed the predicted
bonding. Almost square-planar trans coordination of the Cu
atom is formed by two carboxylic atoms from two niflumic ligands
(nif) and two nitrogen atoms from two 3-pyridylmethanol ligands
(3-pyMe). Cu-O and Cu-N bonds are 1.946(3) (2) and 2.038(3)A (2)
long. Using the earlier developed formulae 4 for bond valence
calculation the calculated Cu(II)-O bond length connecting the Cu
(nif)2(3-pyMe)2 units into infinit chains
is 2.61 (2)A . Observed values of these bond lengths are
2.573(3) (2)A [5].