Synthesis,vibrational and NMR spectroscopic characterization of [N(CH_3)_4][IO_2F_2] and X-ray crystal structure of[N(CH_3)_4]_2[I0_2F_2][HF_2]

摘要

The salt,[N(CH_3)_4][IO2F_2],was prepared from [N(CH_3)_4][IO_3] and 49% aqueous HF,and characterized by Raman,infrared,and 19F NMR spectroscopy.Crystals of [N(CH3)4]2[IO2F2][HF2] were obtained by reduction of [N(CH_3)4][cw-IO_2F_4] in the presence of [N(CH_3)_4][F] in CH_3CN solvent and were characterized by Raman spectroscopy and single-crystal X-ray diffraction:C2/m,a = 14.6765(2) A,b = 8.60490(10) A,c = 13.9572(2) A,ft = 120.2040(10)°,V = 1523.35(3) A~3,Z = 4 and R = 0.0192 at 210 K.The crystal structure consists of two IO2F_2~- anions that are symmetrically bridged by two HFJ anions,forming a [F_2O_2l(FHF)_2IO_2F_2]~(4~) dimer.The symmetric bridging coordination for the HF_2 anion in this structure represents a new bonding modality for the bifluoride anion.