Dinuclear Complexes Formed by Hydrogen Bonds: Synthesis, Structure and Magnetic and Electrochemical Properties.
The synthesis is reported of a series of homo- and hetero-dinuclear octahedral complexes of the ligand 1, 1,2-bis(1-methyl-benzimidazol-2-yl) ethanol, where the two metal centres are linked by hydrogen bonds between coordinated alcohols and coordinated alkoxides. Homonuclear divalent MIIMII, mixed-valent MIIMIIIand heteronuclear MIIM'IIIspecies are prepared. The complexes have been characterised by X-ray crystallography and show unusually short O⋅⋅⋅O distances for the hydrogen bonds. Magnetic measurements show the hydrogen-bond bridges can lead to ferromagnetic or antiferromagnetic coupling. The electrochemistry of the dinuclear species is significantly different from the mononuclear systems: the latter show irreversible waves in cyclic voltammograms as a result of the need to couple proton and electron transfer. The dinuclear species, in contrast, show reversible waves, which are attributed to rapid intramolecular proton transfer facilitated by the hydrogen-bonded structure.
Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva 4, Switzerland.
Matteo
M
Granelli
Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva 4, Switzerland.
Alan M
AM
Downward
Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva 4, Switzerland.
Robin
R
Huber
Laboratory for X-ray Crystallography, University of Geneva, 24 quai Ernest Ansermet, 1211, Geneva 4, Switzerland.
Laure
L
Guénée
Laboratory for X-ray Crystallography, University of Geneva, 24 quai Ernest Ansermet, 1211, Geneva 4, Switzerland.
Céline
C
Besnard
Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland.
Karl W
KW
Krämer
Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland.
Silvio
S
Decurtins
Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland.
Shi-Xia
SX
Liu
Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada.
Laurence K
LK
Thompson
Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva 4, Switzerland.
Alan F
http://orcid.org/0000-0002-3779-1593
AF
Williams
chirality; hydrogen bonding; magnetic exchange interactions; proton-coupled electron transfer; transition-metal complexes