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).
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http://dx.doi.org/10.1016/j.ica.2008.09.034 | DOI Listing |
ACS Omega
April 2024
Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada.
Chromium(III) complexes bearing bidentate {NH(CH)PPh: PN, ()-[NH(CHPh)PPh]: P'N} and tridentate [PhP(CH)N(H)(CH)PPh: P-NH-P, ()-(Pr)PCHCHN(H)CH(Ph)CH(Ph)PPh: P-NH-P'] ligands have been synthesized using a mechanochemical approach. The complexes {-[Cr(PN)Cl]Cl (), -[Cr(P'N)Cl]Cl (), -Cr(P-NH-P)Cl (), and -Cr(P-NH-P')Cl ()} were obtained in high yield (95-97%) the grinding of the respective ligands andthe solid Cr(III) ion precursor [CrCl(THF)] with the aid of a pestle and mortar, followed by recrystallization in acetonitrile. The isolated complexes are high spin.
View Article and Find Full Text PDFInorg Chem
May 2024
Laboratorio en Química Inorgánica, Catálisis y Bioinorgánica, Departamento de Química, Facultad de Ciencias, Universidad de los Andes, Bogotá 111711, Colombia.
Cobalt(III) and chromium(III) salophen chloride complexes were synthesized and tested for the cycloaddition of carbon dioxide (CO) with epoxides to obtain cyclic carbonates. The , , , and complexes presented high catalytic activity without cocatalysts and are solvent-free at 100 °C, 8 bar, and 9 h. At these conditions, the terminal epoxides (-) were successfully converted into the corresponding cyclic carbonates with a maximum conversion of ∼99%.
View Article and Find Full Text PDFThe catalytic properties of a series of novel chromium(iii) salophen complexes having different pyridinium chloride units (pyridinium, 2,6-dimethylpyridinium or 4-(dimethylamino)pyridinium ones) have been studied in the reaction of carbon dioxide cycloaddition to phenyl glycidyl ether. The examined complexes were found to be capable of catalyzing cycloaddition under relatively mild reaction conditions without any additional nucleophilic co-catalyst. However, their catalytic activity depended strongly on the structure and number of pyridinium salt units in the ligand molecule.
View Article and Find Full Text PDFBioresour Technol
October 2023
Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India. Electronic address:
2,5-Furandicarboxylic acid (FDCA) is one of the platform chemicals and monomers used in plastic industries, currently synthesized by carcinogenic and toxic chemical processes with high pressure and temperature. The aim of this study was to develop a bioprocess for the production of FDCA. 5-(Hydroxymethyl)furfural (HMF) was synthesized (22.
View Article and Find Full Text PDFDalton Trans
November 2022
Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
Seven novel oxalate-based [CuCr] compounds: [Cu(terpy)Cl][Cr(CO)]·9HO (1; terpy = 2,2':6',2''-terpyridine), {[CrCu(HO)(terpy)(CO)]·10HO} (2), [CrCu(HO)(terpy)(CO)]·12HO (3), [Cu(HO)(terpy)][CrCu(HO)(terpy)(CO)]·9HO (4), [Cu(HO)(terpy)(NO)][CrCu(HO)(terpy)(CO)]·6HO (5), [CrCu(terpy)(CO)(NO)]·1.5HO·CHOH (6) and [CrCu(HO)(terpy)(CO)][CrCu(terpy)(CO)]·9HO·CHOH (7) were obtained from the reaction of an aqueous solution of the building block [Cr(CO)] and a methanol solution containing Cu ions and terpyridine ligand by the layering technique. Interestingly, changing only the anion of the starting salt of copper(II), NO instead of Cl, resulted in an unexpected modification in the bridge type, namely oxalate (compounds 2-7) chloride (compound 1).
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