Tetrakis(benzylamino)phosphonium chloride

The title salt, [P(NHCH2C6H5)4]+·Cl−, crystallizes with the P atom and Cl− anion lying on a twofold rotation axis. The P atom has a slightly distorted tetrahedral geometry with two classes of N—P—N angles [101.15 (10) and 100.55 (11)° and 113.07 (9) and 114.83 (8)°] and the environments of sp 2-hybridized N atoms are essentially planar (sum of angles = 359.9 and 360.1°). In the crystal, the phosphonium ion interacts with each neighboring chloride ion via two approximately equal N—H⋯Cl interactions, forming parallel chains along the c axis.

The title salt, [P(NHCH 2 C 6 H 5 ) 4 ] + ÁCl À , crystallizes with the P atom and Cl À anion lying on a twofold rotation axis. The P atom has a slightly distorted tetrahedral geometry with two classes of N-P-N angles [101.15 (10) and 100.55 (11) and 113.07 (9) and 114.83 (8) ] and the environments of sp 2hybridized N atoms are essentially planar (sum of angles = 359.9 and 360.1 ). In the crystal, the phosphonium ion interacts with each neighboring chloride ion via two approximately equal N-HÁ Á ÁCl interactions, forming parallel chains along the c axis.

Data collection
The title salt, [P(NHCH 2 C 6 H 5 ) 4 ] + .Cl -, crystallizes with the P atom and Clanion lying on a two-fold rotation axis in the space group P2 1 2 1 2. The supramolecular structure of compound exhibits a polymeric chain of alternating phosphonium and chloride ions in the solid state ( Fig. 2) with P···P distances of 7.923 Å. The phosphonium ion interacts with each neighboring chloride ion via two equal N-H···Cl interactions and six-membered rings around each phosphorus atom are formed. The centroid-centroid distance between adjacent phenyl rings is 4.009 Å, indicating no strong π-π stacking interactions exist in compound.
The four P-N bonds are of almost equal lengths 1.6166 (14) and 1.6184 (14) Å and are similar to those found in [P(NHPh) 4 ]Cl (Bickley et al., 2004) and P(NH 2 ) 4 Cl (Horstmann & Schnick, 1996). These P-N bonds are shorter than the typical P-N single bond length (1.77 Å) . As observed in [P(NHPh) 4 ]Cl, there are two classes of N-P-N angles resulting in a distorted tetrahedral environment for P1. More acute angles of 101.15 (10) and 100.55° are observed within the hydrogen bonding chelates of the N1-P1-N1 i and N2-P1-N2 i (i: -x, -y, z) units respectively, whereas the remaining four N-P-N angles are 113.07 (9) and 114.83 (8)°. Although the main cause for the distortion from the ideal tetrahedral geometry is unclear, it seems to be partly controlled by hydrogen bonding. The sum of angles around nitrogen atoms are exactly 360°a nd these atoms are sp 2 hybridized.

Experimental
All the reagents and solvents were used as obtained without further purification. Phosphorus pentachloride (2 mmol) was added drop wise with constant stirring to a toluene solution (30 ml) of benzylamine (8 mmol) at 0°C. After an hour stirring, the reaction mixture was refluxed for 3 h. The solid formed during the reaction was filtered and then washed with distilled water, toluene, chloroform and dried. Single crystals suitable for single-crystal X-ray diffraction analysis were obtained from the mixture of MeOH and CH 3 CN solution.

Refinement
The hydrogen atoms of NH groups were found in difference Fourier synthesis, the H(C) atom positions were calculated.
All hydrogen atoms were refined in isotropic approximatiom in riding model with with the U iso (H) parameters equal to 1.2 U eq (X), where U(X) are the equivalent thermal parameters of the atoms to which corresponding H atoms are bonded. The absolute structure parameter (Flack, 1983) is refined based on 1321 Friedel pairs. Fig. 1. The structure of the title compound with 50% displacement ellipsoids and C-bound H atoms omitted. Unlabeled atoms are related to labeled atoms by a two-fold rotation.