Dinuclear Platinum(II) Terpyridyl Complexes with a para-Diselenobenzoquinone Organometallic Linker: Synthesis, Structures, and Room-Temperature Phosphorescence

Abstract

We report the synthesis of a unique class of luminescent heterotrinuclear complexes of the general formulas [Pt(terpy){Cp*Ir-p-(η4-C6H4Se2)}Pt(terpy)][X]4 (X = OTf, 3a; PF6, 3b; BF4, 3c; ClO4, 3d; BPh4, 3e). In these coordination assemblies two Pt(terpy) moieties are held by a stable η4-diseleno-p-benzoquinone complex [Cp*Ir-p-(η4-C6H4Se2)]. The molecular structures of solvates of 3a and 3b were ascertained by single-crystal X-ray diffraction study and confirmed the formation of the target molecules. The solid-state packing of two of these complexes confirms the presence of π–π and Pt···Pt interactions among individual units providing a 1D supramolecular chain for 3a, while a dimer species is obtained for 3b, illustrating the effect of the counterion on directing the crystal packing of the individual molecules. All compounds show phosphorescence in the red region (685–705 nm) in fluid solution and in the solid state at room temperature, unlike the analogous compound Pt(terpy){Cp*Ir-p-(η4-C6H4S2)}Pt(terpy)][CF3SO3]4 obtained with a dithiobenzoquinone organometallic linker, which is only luminescent at low temperature.