Synthesis, characterization and CO2 uptake of a chiral Co(ii) metal–organic framework containing a thiazolidine-based spacer
作者:Andrea Rossin、Barbara Di Credico、Giuliano Giambastiani、Maurizio Peruzzini、Gennaro Pescitelli、Gianna Reginato、Elisa Borfecchia、Diego Gianolio、Carlo Lamberti、Silvia Bordiga
DOI:10.1039/c2jm16236a
日期:——
The polytopic ligand thiazolidine-2,4-dicarboxylic acid (H2L) has been synthesised on a large scale starting from the naturally occurring amino acid L-cysteine. The (R,R)/(S,R)diastereomeric mixture has been separated into its constituents through selective precipitation of the pure (R,R) isomer from concentrated H2O/MeOH solutions. The enantiomerically pure ligand (H2L-RR) has been reacted with CoCl2·6H2O under hydrothermal conditions, with the final product being [Co(L-RR)(H2O)·H2O]â (1). The obtained coordination polymer is optically pure, and it maintains the chiral information that is present in its building block. Two different kinds of channels are present in the 3D structure of 1: one hydrophobic (with the sulfur atoms of the thiazolidine rings exposed) and the other hydrophilic [with the aquo ligand on Co(II) exposed, and hosting the crystallization water solvent]. 1 has been characterized through a combination of X-ray diffraction (single-crystal and powder) and spectroscopic (CD, IR, UV-Vis, XANES, EXAFS) techniques. Finally, CO2 adsorption tests conducted at 273 K and (pCO2)max = 920 torr have shown a good carbon dioxide uptake, equal to 4.7 wt%.
以天然存在的氨基酸L-半胱氨酸为起始原料,已大规模合成了多环配体噻唑烷-2,4-二羧酸(H2L)。通过从浓缩的H2O/MeOH溶液中选择性沉淀纯的(R,R)异构体,将(R,R)/(S,R)立体异构体混合物分离为其组分。在高温高压条件下,将光学纯的配体(H2L-RR)与CoCl2·6H2O反应,最终产物为[Co(L-RR)(H2O)·H2O]¨(1)。所获得的配合物聚合物具有光学纯度,并且保留了其构建单元中的手性信息。在1的三维结构中存在两种不同类型的通道:一种疏水性通道(暴露了噻唑烷环的硫原子)和另一种亲水性通道[暴露了Co(II)上的水配体,并容纳了结晶水溶剂]。通过X射线衍射(单晶和粉末)和光谱(CD、IR、UV-Vis、XANES、EXAFS)技术的组合对1进行了表征。最后,在273 K和(pCO2)max = 920 torr条件下进行的CO2吸附测试显示出良好的二氧化碳吸附量,达到4.7 wt%。