Controllable synthesis of four series of lanthanide coordination polymers: synthesis, structures, luminescent and magnetic properties

Four series of new lanthanide coordination polymers, namely [LnL(glu)](n).2nH(2)O (Ln = Nd (1), Sm (2), Gd (3)), [YbL(glu)](n) (4), [LnL(glu)(H2O)] n (Ln = Pr (5), Sm (6), Gd (7), Dy (8), Ho (9), Er (10), Y (11)) and [PrL(glu)(H2O)](n) (12) [HL = 2-(2-sulfophenyl) imidazo.4,5-f).1,10)-phenanthroline, H(2)glu = glutaric acid] have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The isostructural compounds 1-3 exhibit 6-connected 3D networks with the topological type of pcu, containing left-and right-handed helical chains. Compound 4 is a 6-connected 3D network with bsn topology, which contains unique meso-helical chains. Because of the lanthanide contraction, compounds 1-3 and 4 show different structures, which were all synthesized at pH = 4.0 and with the molar ratio of Ln(III): HL: H2glu = 2 : 1 : 1. When only the pH value was changed, to 6.0, the resulting isostructural compounds 5-11 show 4-connected 2D sql topology with the point symbol of (4(4).6(2)). By changing the molar ratio of 2 : 1 : 1 (LnIII: HL: H2glu) to 2 : 1 : 2 at pH = 4.0, compound 12 shows an 8-connected 3D network with bcu topology, which has left-and right-handed helical chains. Photoluminescence spectra of compounds 1-12 have been investigated upon excitation at 370 nm. Magnetic susceptibility measurements exhibited typical paramagnetic behavior for compounds 3 and 7, and weak antiferromagnetic interactions for compounds 8-10.