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 [Cu-3(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 Fdd2, with a = 19.004(3) angstrom, b = 26.711(4) angstrom, c = 11.0770(15) angstrom, V = 5622.8(14) angstrom(3), and Z = 8. Its structure contains two different one-dimensional (1-D) chains for the Cu ions, namely [Cu-2(1,2,4-BTC)(2)](n)(2n-) and [Cu(4,4'-bipy)](n)(2n)+; 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 P2(1)/n, with a = 9.9806(8), b = 16.5512(16), c = 11.3109(7) angstrom, beta = 99.375(5)degrees, V = 1843.5(3) angstrom(3), Z = 4. Its structure contains novel paddle-wheel clusters Cu-2(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. (c) 2005 Elsevier Inc. All rights reserved.