Design and construction of one-dimensional coordination polymers based on the dispiro-dipyridyloxy-cyclotriphosphazene ligand

Abstract Three one-dimensional coordination polymers, namely {[Mn(L)(Cl) 2 (H 2 O)]·(CH 3 ) 2 CO)} n ( 1 ), {[Co(L)(Cl) 2 ]} n ( 2 ) and {[Zn(L)(Cl) 2 ]} n ( 3 ), were obtained from the self-assembly reactions of the dispiro-dipyridyloxy-cyclotriphosphazene ligand ( L ). All the isolated crystalline compounds were structurally characterized by elemental analysis, IR spectra, thermal analyses (TGA) and single crystal X-ray diffraction. X-ray crystallography revealed that all the complexes crystallized in the monoclinic crystal system with the P 2 1 / c space group and the ligand ( L ) exhibited the same κ 2 N coordination binding mode with the divalent metal ions (Mn(II), Co(II) and Zn(II)) to form one-dimensional chain structures. The central Mn(II) ion has a distorted octahedral coordination geometry, whereas the Co(II) and Zn(II) ions have a distorted tetrahedral coordination geometry in the complexes. Complexes 2 and 3 are isostructural. The IR spectra illustrated that the P N stretching frequencies of the complexes show some changes when compared to the free ligand L . The UV–Vis properties and thermal stabilities of L , 1 , 2 and 3 were also investigated. The ground state absorption spectra of maximum absorbance wavelength were recorded at 260 nm in acetonitrile solution for all the compounds. It was observed that the complexes give a stronger absorption band than the free ligand. According to TGA analysis, the coordination polymers exhibited thermal stability up to 300 °C.