Structural systematics of the isomeric di-μ-chlorobis( N, N-dialkylbenzylamine-2, C, N)dipalladium(II) complexes. The crystal structures of the ortho-, meta- and para-methoxy substituted complexes

Abstract

The crystal structures of three isomeric methoxy substituted bis-chloro bridged ( N, N-dimethylbenzylamine)palladium(II) dimers have been determined by X-ray diffraction. Both the ortho-isomer ( 1) and the meta-isomer ( 2) are monoclinic, spacegroup P2 1/ c with Z = 2 in cells of dimensions a 5.7391(7), b 17.794(4), c 10.907(2) Å, β 97.76(1)° ( 1), and a 9.897(1), b 11.178(2), c 10.660(2) Å, β 105.76(1)° ( 2). The four molecules of the para-isomer ( 3) crystallize with two molecules of toluene of solvation in a cell of dimensions a 8.403(1), b 20.056(3), c 15.521(2) Å, β = 90.54(1)°, space group P2 1/ n. All three complexes have the expected trans-related dimeric structures about square planar palladium(II) centres, although 3 does not have the centrosymmetry of 1 and 2. The PdC and PdN bond lengths show no significant variation across the series (range 1.967–1.986 Å; mean, 1.977 Å) and (range 2.068–2.075 Å; mean, 2.071 Å), respectively. The PdCl bridge bonds are asymmetric, consistent with the trans effect of the PdC bond (range, 2.466–2.488 Å; mean 2.476 Å and 2.334–2.341 Å; mean, 2.337 Å).