Supramolecular arrays of the [Re₆([μ₃-Se) ₈]²⁺ core-containing clusters mediated by transition metal ions

Vapor diffusion of diethyl ether into a methanol/dichloromethane (v/v, 1:1) solution of M(NO₃)₂ (M = Cd²⁺, Co ²⁺, Zn²⁺) and the site-differentiated solvated cluster trans-[Re₆(μ₃-Se)₈(PEt₃) ₄(4,4′-dipyridyl)₂](SbF₆)₂ afforded supramolecular arrays featuring the [Re₆(μ ₃-Se)₈]²⁺ core-containing clusters mediated by the transition metal ions. The cluster complex with two 4,4′-dipyridyl moieties can be viewed as an expanded dipyridyl ligand, serving to coordinate the transition metal ions via a pair of N_pyridyl-M dative bonds. All compounds have been characterized by microanalysis (CHN) and their solid-state structures have been established by single crystal X-ray diffraction. Two polymorphous forms (1 and 2) of the crystal of M = Cd²⁺ have been obtained, one of which (1) exhibits a highly porous structure, whereas the other (2) displays a wavy one-dimensional arrangement. The latter form is isostructural with the complex with Co²⁺ (3). In the case of Zn ²⁺ (4), the cluster complex ligand and the mediating Zn²⁺ are arranged in a zigzag fashion, with an average N_pyridyl-M-N _pyridyl, angle bond of 88°.