Synthesis and characterization of the chromium(III) complexes of ethylene cross-bridged cyclam and cyclen ligands

Maples, Danny L.; Maples, Randall D.; Hoffert, Wesley A.; Parsell, Trenton H.; Asselt, Allan van; Silversides, Jon D.; Archibald, Stephen J.; Hubin, Timothy J.

Abstract

Dichloro(4,10-dimethyl-1,4,7,10-tetraazabicyclo[5.5.2] tetradecane) chromium(III) chloride, Dichloro(4,10-dibenzyl-1,4,7,10-tetraazabicyclo[ 5.5.2] tetradecane) chromium(III) chloride, and Dichloro(4,11-dimethyl- 1,4,8,11-tetraazabicyclo[6.6.2] hexadecane) chromium)(III) chloride have been prepared by the reaction of anhydrous chromium(III) chloride with the appropriate cross-bridged tetra-azamacrocycle. Aquation of these complexes proved difficult, but Chlorohydroxo(4,11-dimethyl- 1,4,8,11tetraazabicyclo[6.6.2] hexadecane) chromium)(III) chloride was synthesized directly from chromium(II) chloride complexation followed by exposure or the reaction to air in the presence of water. The four complexes were characterized by X-ray crystal structure determination. All contain the chromium(III) ion in a distorted octahedral geometry and the macrocycle in the cis-V configuration, as dictated by the ethylene cross-bridge. Further characterization of the hydroxo complex reveals a magnetic moment of mu(eff) = 3.95 B.M. and electronic absorbtions in acetonitrile at lambda(max) = 583 nm (epsilon = 65.8 L/cm mol), 431 nm (epsilon = 34.8 L/cm mol) and 369 nm (epsilon = 17 L/cm mol). (C) 2008 Elsevier B.V. All rights reserved.

Citation

Maples, D. L., Maples, R. D., Hoffert, W. A., Parsell, T. H., Asselt, A. V., Silversides, J. D., …Hubin, T. J. (2009). Synthesis and characterization of the chromium(III) complexes of ethylene cross-bridged cyclam and cyclen ligands. Inorganica Chimica Acta, 362(6), 2084-2088. https://doi.org/10.1016/j.ica.2008.09.034

• Journal Article Type: Article
• Acceptance Date: Sep 12, 2008
• Online Publication Date: Sep 23, 2008
• Publication Date: Apr 20, 2009
• Journal: INORGANICA CHIMICA ACTA
• Print ISSN: 0020-1693
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 362
• Issue: 6
• Pages: 2084-2088
• DOI: https://doi.org/10.1016/j.ica.2008.09.034
• Keywords: Chromium(III); Bridged tetraazamacrocycle; Cyclam; Cyclen
• Public URL: https://hull-repository.worktribe.com/output/396181
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0020169308005987?via%3Dihub