Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 17, 2014
Previous Article Next Article

Long range charge transfer in trimetallic mixed-valence iron complexes mediated by redox non-innocent cyanoacetylide ligands

Author affiliations

Abstract

The reaction of Fe(C[triple bond, length as m-dash]CC[triple bond, length as m-dash]N)(dppe)Cp (1) with one-half equivalent of [trans-Fe(N[triple bond, length as m-dash]CMe)2(dppx)2][BF4]2 (dppx = dppe ([2][BF4]2) or dppm ([3][BF4]2)) affords trimetallic [trans-Fe{N[triple bond, length as m-dash]CC[triple bond, length as m-dash]CFe(dppe)Cp}2(dppx)2][BF4]2 (dppx = dppe [4][BF4]2; dppx = dppm [5][BF4]2). Both [4][BF4]2 and [5][BF4]2 undergo three, one-electron oxidation processes, arising from sequential oxidation of the two terminal Fe(C[triple bond, length as m-dash]CR)(dppe)Cp moieties and finally the central Fe(N[triple bond, length as m-dash]CR)2(dppx)2 fragment. The redox products [4]n+ and [5]n+ (n = 3, 4) have been characterised by UV-vis-NIR and IR spectroelectrochemistry. The shifts in the characteristic ν(C[triple bond, length as m-dash]CC[triple bond, length as m-dash]N) bands upon oxidation demonstrate not only the localised electronic structure of the trications, but also the redox non-innocence of the cyanoacetylide ligands. The trimetallic [formally Fe(II/II/III) mixed-valence] complexes [4]3+ and [5]3+ feature two distinct IVCT transitions, one associated with charge transfer from the central 18-electron {Fe(N[triple bond, length as m-dash]CR)2(dppx)2}2+ to terminal {Fe(C[triple bond, length as m-dash]CR)(dppe)Cp}+ moiety, and a lower energy transition involving charge transfer between the terminal Fe fragments which are separated by the redox active 9-atom, 10-bond –C[triple bond, length as m-dash]C–C[triple bond, length as m-dash]N{Fe(dppx)2}N[triple bond, length as m-dash]C–C[triple bond, length as m-dash]C– bridge. The tetracationic complexes [4]4+ and [5]4+ generated by a further stepwise oxidation exhibit a single {Fe(N[triple bond, length as m-dash]CR)2(dppx)2}2+→{Fe(C[triple bond, length as m-dash]CR)(dppe)Cp}+ IVCT transition.

Graphical abstract: Long range charge transfer in trimetallic mixed-valence iron complexes mediated by redox non-innocent cyanoacetylide ligands

Back to tab navigation

Supplementary files

Article information


Submitted
28 Feb 2014
Accepted
04 Mar 2014
First published
04 Mar 2014

Dalton Trans., 2014,43, 6291-6294
Article type
Communication
Author version available

Long range charge transfer in trimetallic mixed-valence iron complexes mediated by redox non-innocent cyanoacetylide ligands

J. B. G. Gluyas, A. J. Boden, S. G. Eaves, H. Yu and P. J. Low, Dalton Trans., 2014, 43, 6291
DOI: 10.1039/C4DT00614C

Social activity

Search articles by author

Spotlight

Advertisements