Tuning the electronic structure of Mo-Mo quadruple bonds by N for O for S substitution

Jamie Hicks, Sam P. Ring, Nathan J. Patmore

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


A series of quadruply bonded dimolybdenum compounds of form Mo 2(EE′CCCPh) 4 (EE′ = {NPh} 2, Mo 2NN; {NPh}O, Mo 2NO;{NPh}S, Mo 2NS; OO, Mo 2OO) have been synthesised by ligand exchange reactions of Mo 2(O 2CCH 3) 4 with the acid or alkali metal salt of {PhCCCEE′} -. The compounds Mo 2NO, Mo 2NS and Mo 2OO were structurally characterised by single crystal X-ray crystallography. The structures show that Mo 2NO adopts a cis-2,2 arrangement of the ligands about the Mo 2 4+ core, whereas Mo 2NS adopts the trans-2,2 arrangement. The influence of heteroatom substitution on the electronic structure of the compounds was investigated using cyclic voltammetry and UV-Vis spectroscopy. Simple N for O for S substitution in the bridging ligands significantly alters the electronic structure, lowering the energy of the Mo 2-δ HOMO and reducing the Mo 2 4+/5+ oxidation potential by up to 0.9 V. A different trend is found in the optoelectronic properties, with the energy of the Mo 2-δ-to-ligand-π* transition following the order Mo 2OO > Mo 2NO > Mo 2NN > Mo 2NS. Electronic structure calculations employing density functional theory were used to rationalise these observations.

Original languageEnglish
Pages (from-to)6641-6650
Number of pages10
JournalDalton Transactions
Issue number22
Publication statusPublished - 14 Jun 2012
Externally publishedYes


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