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., Archibald, S. J., & 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