Interaction of tantalum pentafluoride with imidotetraphenyldiphosphinic acid in noncoordinated solvents: Low-temperature cation-anion associates

An interaction of tantalum pentafluoride (I) with imidotetraphenyldiphosphinic acid (LH) at I: LH ratios from 2 to 0.5 has been studied using 1 9 F and 3 1 P NMR. During this interaction, one or two phosphoryl groups of the three donor sites of the LH ligand take part in complex formation. When I: LH = 2: 1 mol/mol, the reaction produces the binuclear molecular complex (TaF 5 ) 2 LH (II), where LH acts as a bridging ligand. The increasing ligand concentration in the solution provokes the deprotonation of the LH ligand coordinated in II with the formation of the [(TaF 5 ) 2 L] - binuclear anion, LH + 2 cation, and chelate tetrafluoro complex TaF 4 L. At LH excess binuclear anions are destroyed and mononuclear complex species [TaF 5 L] - and TaF 3 L 2 appear in addition to TaF 4 L. In TaF 3 L 2 , which is a product of further substitution for fluorine atoms, the L - anions act as chelating ligands. At temperatures lower than 223 K, the binuclear anion and LH + 2 cation are hydrogen-bonded to form ionic associates {[(TaF 5 ) 2 L] - [LH 2 ] + } and {[2(TaF 5 ) 2 L] - [LH 2 ] + ]}.