The Design And Performance Studies Of The Functional Benzylphosphonate Complexes

Three series of novel organic–inorganic complexes based on phosphonic acidligands1,3-C6H4[CH2P(O)(OH)2]2(H4L1),1,4-HOOCC6H4CH2PO(OH)(OC2H5)(H2L2’)and metal nitrates have been obtained as single phases by regulating the pH underhydrothermal conditions.Complexes Ln(HL1)(H2O)2(Ln=La,1; Pr,2; Nd,3; Sm,4; Eu,5; Gd,6; and Tb,7) are isomorphous two-dimensional network in which {LnO7} polyhedra areinterconnected by bridging {CPO3} tetrahedra. These layers are further stacked with thebenzyl groups of ligands via C–H···π interaction. Luminescences indicate thatcomplexes4,5, and7show strong metal-centered emissions in yellow, red and greenlight region, respectively. Magnetic properties of complexes2and7indicate thatthere are antiferromagnetic interactions.Complexes Ln(HL2)(H2L2)(H2O)(H3L2=HOOCC6H4CH2PO(OH)2, Ln=La,8;Ce,9; Pr,10; Nd,11; Sm,12; Eu,13; Gd,14; Tb,15) are also two-dimensionalframework in which the {LnO7} polyhedra are interconnected by bridging {CPO3}tetrahedra. These layers are further cross-linked by hydrogen-bonds of the COOHgroups of ligands. Luminescences show that complexes13and15display Ln-centeredstrong red and green luminescence, respectively. The possible energy transferprocesses between ligands and metal ions have been elucidated and the energy levelsof the relevant electronic states have been estimated. Magnetic properties ofcomplexes14and15indicate that there are antiferromagnetic interactions above TCand ferromagnetic interactions under TCbetween Ln3+ions.In addition, Complexes M(H2L2)2(H2O)2(M=Co,16; Ni,17; Zn,18; Cd,19)feature a one-dimensional (1D) zigzag chain in which the {MO6} polyhedra areinterconnected by bridging {CPO3} tetrahedra. Luminescent measurements illustratethat complexes18and19are blue light emission bands and could be served aspotential luminescence materials.