Supramolecular squares with Mo-2(4+) corners

Seven complexes obtained by reacting the quadruply bonded complex [Mo-2(cis -DAniF)(2)(CH3CN)(4)] (BF4)(2) (DAniF = N,N'-di-p-anisylformamidinate) and ((Bu4N+)-N-n)(2)(Carb(2-)), where Carb(2-) is a dicarboxylate anion, have b een found to have a ratio of dimetal unit to dicarboxylate of 1:1. As noted by the carboxylate linker, the compounds are oxalate, 1, fumarate, 2, ferr ocene dicarboxylate, 3, 4,4'-biphenyldicarboxylate, 4, acetylenedicarboxyla te, 5, tetrafluorophthalate, 6, and carborane dicarboxylate, 7. Structural characterization of 1-4 revealed a square of dimolybdenum units linked by t he dicarboxylate anions, each having an interstice capable of accommodating specific solvent molecules. Results of NMR studies of all seven compounds are consistent with the presence of a highly symmetrical structure. These c ompounds display a rich electrochemical behavior that is affected by the na ture of the carboxylate group.