Second sphere coordination complex via hydrogen bonding: Synthesis, spectroscopic studies of [(C6H5)3RP][trans-Co(NH3)2(NO2)4] where R = benzyl, phenyl or ethyl and X-ray crystal structure of [(C6H5)4P][trans-Co(NH3)2(NO2)4]

Yellow colored precipitates of [(C6H5)3RP][trans-Co(NH3)2(NO2)4], where R = benzyl, phenyl or ethyl were obtained by reacting equimolar quantities of K[trans-Co(NH3)2(NO2)4] and [(C6H5)3RP]Br, where R = benzyl, phenyl or ethyl in aqueous medium at room temperature. The salt [(C6H5)4P][trans-Co(NH3)2(NO2)4] crystallized from acetone–methanol mixture in monoclinic space group P21/n having cell dimensions a = 7.013(1) Å, b = 17.111(1) Å, c = 22.958(3) Å, β = 98.06(1)°, V = 2727.7(6) Å3, Z = 4, R1 = 0.0485 and wR2 = 0.1263. X-ray structure determination revealed the presence of discrete ions, [(C6H5)4P]+ and [trans-Co(NH3)2(NO2)4]−. The constituent ions are held together by hydrogen bonding interactions involving second sphere coordination besides electrostatic forces of interaction.