Three new Cu(Ⅱ)-Ln(Ⅲ) heterometallic coordination polymers based on two N-heterocyclic carboxylic ligands, {[LnCu(L1)2(L2)(H2O)2]·mH2O}n (Ln = La(1), Nd(2), Gd(3), m = 2 (for 1), 1 (for 2, 3), H2L1 = quinolinic acid, HL2 = nicotinic acid), have been synthesized and characterized. 1 has a two-dimensional (2D) layer structure with a Schlfli symbol of (44.62), while complexes 2 and 3 are isostructural and have three-dimensional (3D) structures with a Schlfli symbol of (3.4.5)2(32.42.52.614.74.83.9)(32.63.7) of 3-nodal net. Magnetic investigations suggest that antiferromagnetic coupling exists between NdIII and CuII in 2, while weak ferromagnetic coupling between GdIII and CuII in 3. The difference of magnetic properties between 2 and 3 has been discussed.
LIU SuiJun SONG WeiChao XUE Li HAN SongDe ZENG YongFei WANG LiFu BU XianHe
Four new Cu(II) complexes with two benzotriazole-based ligands, [Cu2(L1)2(NO3)2]· 2H2O (1), [Cu2(L1)2]·2ClO4·2H2O (2), [Cu2(HL2)2(NO3)4]·2CH3COCH3 (3) and [Cu(HL2)2(Cl)]·Cl·2CH2Cl2 (4), where HL1 = 1,3-bis(benzotriazol-2-yl)-2-propanol and HL2 = 1,3-bis(benzotriazol-1-yl)-2-pro- panol, were synthesized and structurally characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. It is revealed that complexes 1～3 have dinuclear structures, while 4 possesses a one-dimensional (1-D) chain structure, which extends in two orthogonal orientations. In 1～4, the coordination numbers of Cu(II) centers range from four to six, which may be attributed to the different geometries and coordination abilities of the ligands and anions. The L1 ligand in complexes 1 and 2 adopts a tridentate di-chelating coordination mode, whereas ligand HL2 in complexes 3 and 4 has a bidentate bridging coordination mode. The different coordination modes of these two ligands may be explained by the different charges of nitrogen donor atoms in the benzotriazole ring, which has been investigated by density functional theory (DFT) calculations.
