Abstract
The crystal and molecular
structure of LCo2Br2,CH3OH (where LH2
represents the macrocycle obtained by condensation of two molecules each of
propane-1,3-diamine and 2-hydroxy-5-methyl-isophthalaldehyde) has been
determined by single-crystal X-ray diffraction techniques. The compound
crystallizes in the monoclinic space group P21/c with two molecules
in a cell of dimensions a 9.8723(5), b 16.891(1), c 8.0745(5)Ǻ and
102.06(1)�. Counter methods were used to collect the 2004 independent
reflections above background and the structure was refined by least-squares
methods to a conventional R-factor of 0.049. The structure is molecular, consisting
of discrete binuclear units LCo2Br2,CH3OH,
containing two cobalt(II) atoms separated by 3.158(2) Ǻ. Each cobalt atom
is in an identical pseudo-square-pyramidal environment, in agreement with the
conclusion drawn from the electronic spectrum of the complex, with an N2O2
basal plane and a bromine atom coordinated at the apex. The methanol molecule
is disordered and partially occupies the sixth coordination site of each cobalt,
with a long bond of 2.503(9) Ǻ between the cobalt and the methanol oxygen
atom. The central carbon atom of the propane-1,3-diamine residue is also
disordered, occupying partially each of two positions.