A new carboxyl-copper-organic framework and its excellent selective absorbability for proteins

One-pot solvothermal treatments of CuCl2·2H2O, H2L (5-(3-methyl-5-(pyridin-4-yl)-4H-1, 2, 4-triazol-4-yl) isophthalic acid) and Sm(NO3)3·6H2O in water yielded a rare carboxyl-copper-organic framework, [Cu(HL)]n·nH2O (1). The existence of carboxyl groups in compound 1 may be due to the interference of Sm(NO3)3·6H2O at the relatively high temperature and autogenous pressure of the reaction. Compound 1 has been characterized by single-crystal X-ray diffraction, XRPD, IR, and elemental analysis. Compound 1 is a 3D coordination polymer, and an xfe-4-Fddd, (42.6.83) topology in 1 is created. In addition, the optical properties have been investigated. Rhodamine B dyeing experiments exhibited that there were residual carboxyl groups on the surface of compound 1. UV-vis results showed that more lysozyme was adsorbed onto the surface of compound 1 than that of BSA at pH 7.4. At the same time, XPS spectra were also investigated to verify the results.