Preparation and crystal structure of dimolybdenum(ii) complexes with the 4-biphenylcarboxylate ligand and its bispyridine adduct

Abstract

The crystalline compound [Mo 2(4-biphCO 2) 4] · THF ( I) and its bispyridine adduct [Mo 2(4-biphCO 2)4(py) 2] ( II), where 4-biphCO 2H is 4-biphenylcarboxylic acid, have been prepared and structurally characterized. Compound ( I) has a pattern of catenation due to bridging by oxygen atoms that is different from the usual one. The Mo-Mo bond distances are 2.0955(12)and 2.112(7)for complexes ( I) and ( II), respectively. The molecules in compound ( I) are arranged to form a typical extended polymeric chain with an average MoO intermolecular contact of 2.85 . Compound ( II) has two axial pyridine molecules weakly coordinated to dimolybdenum unit. The Mo-N distance is 2.653(4) . Compound ( I) smoothly loses THF (50–100°) and at ca 325° begins to decompose. No discotic liquid phase was observed.