Synthesis and crystal and molecular structure of a tetranuclear cluster based on the rhenium(III)-bisorganohydrazino core: [Re(HNNC4H3N2)(NNC4H3N2)(OCH3)2]4

Reaction of NH4ReO4 with excess 2-hydrazinopyrimidine in methanol yields [Re(η1-NNC4H3N2H)(η2-HNNC4H3N2)Cl3] (1). Attempts to recrystallize 1 by slow diffusion of methanol into DMF after 8 months produced black crystals of [Re(HNNC4H3N2)(NNC4H3N2)(OCH3)2]4 (2). The structure of 2 consists of isolated tetranuclear clusters, constructed from {Re(η2-HNNC4H3N2)(η1-NNC4H3N2)(OCH3)2} units linked through the β-nitrogen of the chelating organodiazene ligand of adjacent units into a box-like aggregate.