2-[(Diisopropyl-thio-phosphor-yl)amino]-pyridinium tetra-fluoro-borate

The title compound, C(11)H(20)N(2)PS(+)·BF(4) (-), is a salt of 2-(diisopropyl-thio-phospho-ryl-amino)-pyridine, a chelating bidentate ligand that furnishes an S atom as a soft donor and a pyridine N atom as a hard atom for transition-metal complexation. The title salt crystallizes with two formula units in the asymmetric unit. The two independent cations are protonated at the pyridine N atoms and have the S atoms syn-oriented to them so as to form bent intra-molecular N-H⋯S hydrogen bonds, one of which one is bifurcated by involving also an N-H⋯F inter-action. The phospho-ryl-amino NH groups form near linear hydrogen bonds to proximal tetra-fluoro-borate anions. Five weak C-H⋯F and three weak C-H⋯S inter-actions link the constituents into a three-dimensional framework. As a result of the crystal packing, the two cations differ notably in conformation, as can be seen from the S-P-N-C torsion angles of -18.7 (1)° in the first and -35.1 (1)° in the second cation.