title: Synthesis and Characterization of the Chromium(III) complexes of Ethylene Cross-Bridged Cyclam and Cyclen Ligands.
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 tetraazamacrocycle. Aquation of these complexes proved difficult, but Chlorohydroxo(4,11-dimethyl-1,4,8,11-tetraazabicyclo[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) = 583nm (epsilon = 65.8 L/cm.mol), 431nm (epsilon = 34.8 L/cm.mol) and 369nm (epsilon = 17 L/cm.mol).
authors.affiliation: Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA.
authors.forename: Danny L
authors.initials: DL
authors.lastname: Maples
authors.forename: Randall D
authors.initials: RD
authors.lastname: Maples
authors.forename: Wesley A
authors.initials: WA
authors.lastname: Hoffert
authors.forename: Trenton H
authors.initials: TH
authors.lastname: Parsell
authors.forename: Alan
authors.initials: A
authors.lastname: van Asselt
authors.forename: Jon D
authors.initials: JD
authors.lastname: Silversides
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Archibald
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Hubin