Dimolybdenum bis-2,4,6-triisopropyl-benzoate bis-4-isonicotinate: a redox active analogue of 4,4'-bipyridine with ambivalent properties.

The reaction between Mo2(TiPB)4 and 4-iso-nicotinic acid (2 equiv) in ethanol leads to the formation of trans-Mo2(TiPB)2(nic)2, I, where TiPB = 2,4,6-triisopropylbenzoate and nic = 4-isonicotinate. The molecular structures of I and I x 2DMSO were determined in the solid state by a single-crystal X-ray study, and its electronic structure was determined by DFT calculations on a model compound, where formate ligands were substituted for the bulky TiPB. The physicochemical properties of I are reported, and its potential as a redox active building block, a quasi-metalloorganic analogue of 4,4'-bipyridine, is described in the synthesis of molecular and solid-state assemblies. The molecular structure of I in the solid state consists of a 3-dimensional network in which each unit of Mo2(TiPB)2(nic)2 acts as a donor and acceptor via N to Mo coordination. In the structure of I x 2DMSO, the DMSO ligands coordinate axially with the Mo-Mo bond via oxygen. The reaction between I and Rh2(O2CMe)4 is shown to give a 1-D polymeric chain in the solid state: [{Rh2(O2CMe)4}{Mo2(TiPB)2(nic)2}] infinity, II. A similar structure was found for the product involving Rh2(O2CCMe3)4. Evidence is also reported for the formation of [(1,5-COD)MePt]2[mu-Mo2(TiPB)2(nic)2](PF6)2, III, and [(1,5-COD)Pt(mu-I)(PF6)2]n.