Synthesis and X-ray crystal structures of iron(II) and manganese(II) complexes of unsubstituted and benzyl substituted cross-bridged tetraazamacrocycles

Hubin, Timothy J.; McCormick, James M.; Collinson, Simon R.; Alcock, Nathaniel W.; Clase, Howard J. and Busch, Daryle H. (2003). Synthesis and X-ray crystal structures of iron(II) and manganese(II) complexes of unsubstituted and benzyl substituted cross-bridged tetraazamacrocycles. Inorganica Chimica Acta, 346 pp. 76–86.

DOI: https://doi.org/10.1016/S0020-1693(02)01427-5

Abstract

The Mn²⁺ and Fe²⁺ complexes of the cross-bridged tetraazamacrocyclic ligands, 4,11-dibenzyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane, 4,10-dibenzyl-1,4,7,10-tetraazabicyclo[5.5.2]tetradecane, 1,4,8,11-tetraazabicyclo[6.6.2]hexadecane, and 1,4,7,10-tetraazabicyclo[5.5.2]tetradecane provide new compounds of these elements for fundamental studies and applications. These unsubstituted and benzyl substituted derivatives were prepared for comparison of their structures and properties with the known catalytically active dimethyl cross-bridged ligand complexes, which are especially notable for their exceptional kinetic stabilities and redox activity. The X-ray crystal structures of five complexes demonstrate that the ligands enforce a distorted octahedral geometry on the metals with two cis sites occupied by labile ligands. The Fe²⁺ complexes of the unsubstitued ligands form mu-oxo dimers upon exposure to air, which have also been structurally characterized. Cyclic voltammetry of the monomeric complexes shows reversible redox processes for the M³⁺/M^2+M couples, which are sensitive to solvent, ring size, and ring substitution.

Viewing alternatives

Metrics

Item Actions

Export

You can export this page using these formats Digital Object Identifier - DOI