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[IO 2F 2][HF 2

Abstract

The salt, [N(CH 3) 4][IO 2F 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(CH 3) 4] 2[IO 2F 2][HF 2] were obtained by reduction of [N(CH 3) 4][ cis-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) Å, b = 8.60490(10) Å, c = 13.9572(2) Å, β = 120.2040(10)°, V = 1523.35(3) Å 3, Z = 4 and R = 0.0192 at 210 K. The crystal structure consists of two I O 2 F 2 − anions that are symmetrically bridged by two H F 2 − anions, forming a [F 2O 2I(FHF) 2IO 2F 2] 4− dimer. The symmetric bridging coordination for the H F 2 − anion in this structure represents a new bonding modality for the bifluoride anion.