Syntheses,Structure and Thermal Analysis of a Cobalt Coordination Polymer with Multiform Helical Features Based on Flexible Iododicarboxylate Ligand and N-donor Ancillary Ligand

A new 3D complex,[Co(L)(bpe)0.5(H2O)2]n(1,H2 L = 5-iodo-benzene-1,3-dioxyacetic acid,bpe = 1,2-bis(4-pyridyl)ethylene),has been hydrothermally synthesized and structurally characterized by elemental analysis,IR and X-ray diffraction.It is formulated as C16H16 Co INO8,crystallizes in monoclinic,space group P21/c,with a = 9.806(2),b = 6.5492(13),c = 28.187(8) ?,β = 100.12(3)°,V = 1782.0(7) ?3,Z = 4,Dc = 1.998 g/m3,F(000) = 1052,Μr = 536.13,the final R = 0.0393 and w R = 0.0858 for 3134 observed reflections with I > 2σ(I).Complex 1 displays a 3D framework with multiform helical features,left-and right-handed triple helical braids and single helical chains,which can be simplified as a new type of(3,4)-connected lattice with a(6·102)(62·104) Schl?fli symbol.Moreover,the thermal analysis of complex 1 has also been investigated.