A study of crystal packing in a series of closely related square-planar palladium(II) and platinum(II) complexes

Abstract

The crystal structures of the series of four-coordinate complexes [PdL1Cl) · CH2Cl2 (1·CH2Cl2), [PtL1Cl]·CH2Cl2 (2·CH2Cl2), [PdL3Cl][PF6 · CH2Cl2 (3 · CH2Cl2) and [PdL4Cl][PF6 (4) [HL1 = 6-(2-hydroxyphenyl)-2,2′-bipyridine; L3 = 6-(2-dimethylaminophenyl)-2,2′-bipyridine; L4 = 2-(2-dimethylaminophenyl)-1,10-phenanthroline] are compared and contrasted to examine the extent to which aromatic π-stacking interactions contribute to crystal packing. Complexes 1 and 2 have very similar planar molecular structures but stack in different ways; molecules of 1 form a linear stack in which overlap of the aromatic ligands is maximized between adjacent molecules and there is no PdPd interaction, whereas in 2 there are axial PtPt interactions within the linear stack but less overlap between adjacent aromatic ligands.