title: CO2 fixation and transformation by a dinuclear copper cryptate under acidic conditions.
abstract: CO2 fixation and transformation by metal complexes continuously receive attention from the viewpoint of carbon resources and environmental concerns. We found that the dinuclear copper(II) cryptate [Cu2L1](ClO4)4 (1; L1 = N[(CH2)2NHCH2(m-C6H4)CH2NH-(CH2)2]3N) can easily take up atmospheric CO2 even under weakly acidic conditions at room temperature and convert it from bicarbonate into carbonate monoesters in alcohol solution. The compounds [Cu2L1(mu-O2COH)](ClO4)3 (2), [Cu2L1(mu-O2COR)](ClO4)3 (3: R = CH3; 4: R = C2H5; 5: R = C3H7; 6: R = C4H9; 7: R = C5H11; 8: R = CH2CH2OH), [Cu2L1(mu-O2CCH3)](ClO4)3 (9), and [Cu2L1(OH2)(NO3)](NO3)3 (10) were characterized by IR spectroscopy and ESI-MS. The crystal structures of 2-6 and 10 were studied by single-crystal X-ray diffraction analysis. On the basis of the crystal structures, solution studies, and DFT calculations, a possible mechanism for CO2 fixation and transformation is given.
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, and School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Jia-Mei
authors.initials: JM
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Xiao-Long
authors.initials: XL
authors.lastname: Feng
authors.forename: Tong-Bu
authors.initials: TB
authors.lastname: Lu