Syntheses, characterization and electrical property of a new silver diphosphonate with zeolite-like framework and three-dimensional silver interactions: [Ag4(O3PCH2CH2PO3)]

A new silver organodiphosphonate, Ag₄(O₃PCH₂CH₂PO₃)] (1), has been synthesized and characterized by X-ray diffraction, IR, TGA-DSC, electricity measurement and element analysis. 1 crystallizes in the monoclinic space group P2(1)/n (a=6.0115(16) Å, b=8.630(2) Å, c=8.462(2) Å, β=97.693(4)°, Z=2, R₁=0.0604, wR₂=0.1450). 1 contains one-dimensional channels and a three-dimensional Ag?Ag interacted substructural net. TGA and XRD indicate little weight loss up to 300 °C and little structure change after heated at 170 °C for 2 h, respectively. The grain interior conductivity of 1 increases continuously from 50 to 170 °C. Results of EHT calculations show that under thermal or optical excitation the conductivity of 1 is mainly due to transfer of π antibonding electrons of -PO₃ group through O atom to Ag 5s orbital, which also leads to enhancement of Ag?Ag interactions and promotes formation of Ag?Ag substructural net.