Electrochemical dehydrodimerisation of a vinylenylamide ligand: formation of the binuclear group {Mo[triple bond, length half m-dash]N⁺CH[double bond, length half m-dash]CHCH[double bond, length half m-dash]CHCH[double bond, length half m-dash]CHN⁺[triple bond, length half m-dash]Mo} which displays very strong electronic coupling in the {(Mo^III)–(Mo^IV)} mixed-valence state

Abstract

Electrochemical dehydrodimerisation of an {Mo–N[double bond, length half m-dash]CHCH[double bond, length half m-dash]CH₂} group gives an all-trans-{[triple bond, length half m-dash]N⁺CH[double bond, length half m-dash]CHCH[double bond, length half m-dash]CHCH[double bond, length half m-dash]CHN⁺[triple bond, length half m-dash]} ligand, bridging two Mo^IV centres; the {(Mo^III)–bridge–(Mo^IV)} mixed-valence state is accessible by electrochemical reduction and exhibits very strong electronic coupling over the 11.7 Å which separates the two metal centres; this accords with EHMO calculations which show that the SOMO has substantial (30%) bridging-ligand character; in its capacity to function as a molecular wire linking two metal centres, the eight-atom hexatriene di(imide) chain {N(CH)₆N} compares favourably with C₈ chains of acetylenic carbons bridging other metal centres.

References

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