| Pyridinemulticarboxylic acids are useful ligands because of their rich coordination modes, the ability to construct multidimentional complexes, and their coordination polymers have potentially useful ionexchange, adsorption, catalytic, fluorescence, and magnetic properties. This paper summarized the coordination modes and structure of 2,6–pyridinedicarboxylate (H2pdc) and 2,4,6–pyridinetricarboxylate (H3ptc) compounds, then, synthesis and crystal structures of seven new complexes were reported and some of them infra-red spectropic, thermal, magnetic and fluorescence spectrum were described.A 3D complex {[La(μ5–ptc)(H2O)2]·1.5H2O}n (1) was synthesized under hydrothermal conditions, and La3+ ions are bridged by the ptc3- anions formed 3D structure with nanometre channel, two uncoordinated waters are linked with coordinate waters by Hydrogen–bonds and fill in the hole of the net.Within the compound (Hbpy)2[Fe(Hptc)(ptc)]·3H2O (2), a Fe3+ ion is chelated by ptc3- anion and Hptc2- anion, two unilateral protonation 4,4'–bipyridine (Hbpy) ions supply Hydrogen–bonds to makeup a 3D structure and balance valence. Monochain [Co(bpy)(H2O)4]2+ and double chain [Co(ptc)(H2O)2]22- are involved in polymer (H2O)4][Co(ptc)(H2O)2]2·2H2O}n (3), between 1.8 and 300K, (3) obeys Curie–Weiss law and shows antiferromagnetic interactions. Cu2+ could be reduced to Cu+ by bpy under hydrothermal conditions , a novel mixed–valence copper complex {Cu(I)Cu(II)(ptc)-(bpy)·H2O}n (4) was synthesised, two–coordinated Cu+ and five–coordinated Cu2+ get a rail–sharing ladders.Two 2D coordinated polymer [Tb(pdc)(ox)0.5(H2O)]n (5) and [Nd2(pdc)(ox)2–(H2O)4]n·nH2O (6) with different crystal structures, in (5), pdc2- connect with Tb3+ ion to 2D ploymer, oxalate (ox2-) anion link with metal ions and make the plane stronger. Ox2- bridged Nd3+ to a chain which along c axis, and these chains construct 2D plane through pdc2- bridge in (6), fluorescence spectrum of (5) indicate pdc2- and ox2- make no difference of Tb3+ ion's fluorescence character. In complex (H3O)n·[KNd(ptc)-(ox)]n·2nH2O (7), two kinds of metal ion Nd3+ and K+ form a 2D plane through ptc3- bridge, and then planes are bridged to 3D structure by ox2- ligand.
|
PDF Full Text Request