Acta Cryst. (2009). E65, m158-m159 [ doi:10.1107/S1600536808042980 ]
Abstract: The title complex, [PdCl2(C25H22P2)], is a slightly distorted square-planar bis(diphenylphosphino)methane cis-complex of PdCl2. The structure of a polymorph of the title compound has been described earlier, but the arrangement of the molecules observed in the current structure is distinctively different from that previously reported [Steffen & Palenik (1976). Inorg. Chem. 15, 2432-2439]. The earlier report describes a structure with individual well separated molecules crystallizing in space group P21/n. The polymorph described here, which is isostructrural to its Pt analogue [Babai et al. (2006). Z. Anorg. Allg. Chem. 632, 639-644], crystallizes in C2/c with chains of C2-symmetric molecules stretching parallel to the b axis. The Pd atoms and the bisphosphinomethane units are located on two different positions created by a non-crystallographic mirror operation with an occupancy of 0.6677 (11) for the major (PCH2P)Pd moiety. The positions of the Cl atoms of the minor moiety do coincide perfectly with those of the next molecule along the chain parallel to b, and they are thus not included in the disorder. The phenyl rings also do not take part in the disorder and are common to both the major and minor moieties of the (PCH2P)PdCl2 units. Assuming no defects, molecules in each chain will thus have to be oriented the same way and the effect of the disorder of the (PCH2P)Pd unit is thus a reversal in direction of the chains parallel to b. The presence of light streaks of intensity between actual Bragg peaks indicates that a somehow ordered arrangement not resolved in the Bragg diffraction data may be present (i.e. an incommensurate superstructure) rather than a random or domain arrangement of the chains.
Online 8 January 2009
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