Syntheses and characterizations of three-dimensional channel-like polymeric lanthanide complexes constructed by 1,2,4,5-benzenetetracarboxylic acid

The hydrothermal reaction of YbCl(3)(.)6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride resulted in [{Yb((b)btec)(1.4)((d)btec)(3.6)(H2O)(2)}(4)(.)6H(2)O}(n) (1) (H(4)btec = 1,2,4,5-benzenetetracarboxylic acid), and the solvothermal reaction of Er(NO3)(3)(.)6H(2)O or TbCl(3)(.)6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride in H2O/acetic acid gave rise to [{Er-2((o)btec)(2/4)((e)btec)(2/4)((f)btec)(2/4)(H2O)(4)}(.)4H(2)O](n) (2) and [{Tb(H(2)btec)(2/4)((f)btec)(3/6)(H2O)}(.)2H(2)O](n) (3), respectively. Complex 1 crystallizes in monoclinic space group C2/m with a = 20.8119(5) Angstrom, b = 17.6174(1) Angstrom, c = 5.7252(2) Angstrom, beta = 92.324(1)degrees, and Z = 1. 1 possesses a three-dimensional framework consisting of eight-coordinate ytterbium centers and two kinds of channels along the c axis. Complex 2 crystallizes in triclinic space group P (1) over bar with a = 9.6739(5) Angstrom, b = 11.0039(5) Angstrom, c = 11.5523 Angstrom, alpha = 104.8330(10)degrees, beta = 91.0000(10)degrees, gamma = 114.2570(10)degrees, and Z= 2. 2 has a three-dimensional framework comprising both eight- and nine-coordinate erbium centers and channels along the a axis, Complex 3 crystallizes in monoclinic space group P2(1)/n with a = 10.7246(12) Angstrom, b = 7.1693(9) Angstrom, c = 17.158(2) Angstrom, beta = 97.109(2)degrees, and Z = 4. 3 shows a three-dimensional framework containing nine-coordinate terbium centers and channels along the b axis. Uncoordinated water molecules occupy the channels in the three complexes. TGA and XRPD were determined for the three complexes, and the results illustrate that the framework of 1 is retained upon removal of uncoordinated and coordinated water molecules.