Two-dimensional metal-organic framework constructed from 4,4′-bipydine and 1,2,4-benzenetricarboxylate: Synthesis, structure and magnetic properties

Two new copper coordination polymers generated from mixed organic ligands 4,4′-bipydine and 1,2,4-benzenetricarboxylate [Cu3(1,2,4-BTC)2(4,4′-bipy)(H2O)4] 1 and [Cu(1,2,4-HBTC)(4,4′-bipy)] 2 (1,2,4-BTC=1,2,4-benzenetricarboxylate) have been prepared hydrothermally and characterized by single crystal X-ray diffraction. Compound 1 crystallizes in the noncentrosymmetric space group Fdd2Fdd2, with a=19.004(3)Å, b=26.711(4)Å, c=11.0770(15)Å, V=5622.8(14)Å3, and Z=8Z=8. Its structure contains two different one-dimensional (1-D) chains for the Cu ions, namely [Cu2(1,2,4-BTC)2]n2n- and [Cu(4,4′-bipy)]n2n+; the carboxylate of 1,2,4-BTC ligands links the two different 1-D chains into an interesting steplike neutral framework. Compound 2 crystallizes in the monoclinic space group P21/nP21/n, with a=9.9806(8)a=9.9806(8), b=16.5512(16)b=16.5512(16), c=11.3109(7)Å, β=99.375(5)°β=99.375(5)°, V=1843.5(3)Å3, Z=4Z=4. Its structure contains novel paddle-wheel clusters Cu2(CO2)4(4,4′-bipy)2 as SBUs which are further linked by monoprotonated 1,2,4-BTC ligands into a 2-D neutral framework. The magnetic behaviors of both compounds have been studied.

View of the structure of 2 along the c-axis.Figure optionsDownload as PowerPoint slide