Electronically coupled MM quadruply-bonded complexes (M = Mo or W) employing functionalized terephthalate bridges: Toward molecular rheostats and switches

Malcolm H. Chisholm, Florian Feil, Christopher M. Hadad, Nathan J. Patmore

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Toluene solutions of M2(O2CtBu) 4 (M = Mo, W; 2 equiv) react with a range of functionalized terephthalic acids, HO2CArCO2H (Ar = C6H 4, C6F4, C6Cl4, C 6H2-2,5-Cl2, C6H2-2,5- (OH)2, C6H3-2-F), to give [( tBuCO2)3M2]2[μ-O 2CArCO2]. These compounds show intense ML(bridge)CT absorptions in the visible region of the electronic spectrum, and the terephthalate bridge serves to electronically couple the two M2 units via interactions between the M2 δ and bridge π orbitals. Electronic structure calculations reveal how the degree of electronic coupling is controlled by the dihedral angles between the terephthalate C6 ring and the two CO2 units and the degree of interaction between the M4 δ MOs and the LUMO of the bridge. Both of these factors are controlled by the aryl substituents, and collectively these determine the thermochromism displayed by these complexes in solution together with the physical properties of the oxidized radical cations as determined by electrochemical studies (CV, DPV), UV-vis-NIR and EPR spectroscopic methods.

Original languageEnglish
Pages (from-to)18150-18158
Number of pages9
JournalJournal of the American Chemical Society
Volume127
Issue number51
Early online date30 Nov 2005
DOIs
Publication statusPublished - 28 Dec 2005
Externally publishedYes

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