A luminescent bis(pyridyl)-substituted benzimidazole platinum(II) complex exhibiting an intermolecular anagostic interaction

The photophysical properties of transition metal complexes of the 5,6-dimethyl2-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)-1H-benzimidazole ligand are of interest. Dichlorido[5,6-dimethyl-2-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)-1H-benzimidazole-kappa(2) N-2 ,N-3]platinum(II), [PtCl2(C20H18N4)], is luminescent in the solid state at room temperature. The compound displays a distorted square-planar coordination geometry. The Pt-N(imidazole) bond length is shorter than the PtN(pyridine) bond length. The extended structure reveals that symmetry-related molecules display weak C-H center dot center dot center dot N, C-H center dot center dot center dot Cl, and C-H center dot center dot center dot Pt hydrogenbonding interactions that are clearly discernable in the Hirshfeld surface and fingerprint plots. The intermolecular C-H center dot center dot center dot Pt and C-H center dot center dot center dot N interactions have been explored using density functional theory. The result of an analysis of the distance dependence of C-H center dot center dot center dot Pt yields a value consistent with that observed in the solid-state structure. The energy of interaction for the CH center dot center dot center dot Pt interaction is found to be about -11 kJ mol(-1).