The structures of eleven (4-phen-yl)piperazinium salts containing organic anions.

Eleven (4-phen-yl)piperazinium salts containing organic anions have been prepared and structurally characterized, namely, 4-phenyl-piperazin-1-ium 4-fluoro-benzoate monohydrate, C 10 H 15 N 2 + ·C 7 H 4 FO 2 - ·H 2 O, 1 ; 4-phenyl-piperazin-1-ium 4-bromo-benzoate monohydrate, C 10 H 15 N 2 + ·C 7 H 4 BrO 2 - ·H 2 O, 3 ; 4-phenyl-piperazin-1-ium 4-iodo-benzoate, C 10 H 15 N 2 + ·C 7 H 4 IO 2 - , 4 ; 4-phenyl-piperazin-1-ium 4-nitro-benzoate, C 10 H 15 N 2 + ·C 7 H 4 NO 4 - , 5 ; 4-phenyl-piperazin-1-ium 3,5-di-nitro-salicylate, C 10 H 15 N 2 + ·C 7 H 3 N 2 O 7 - , 6 ; 4-phenyl-piperazin-1-ium 3,5-di-nitro-benzoate, C 10 H 15 N 2 + ·C 7 H 3 N 2 O 6 - , 7 ; 4-phenyl-piperazin-1-ium picrate, C 10 H 15 N 2 + ·C 6 H 2 N 3 O 7 - , 8 ; 4-phenyl-piperazin-1-ium benzoate monohydrate, C 10 H 15 N 2 + ·C 7 H 5 O 2 - ·H 2 O, 9 ; 4-phenyl-piperazin-1-ium p -toluene-sulfonate, C 10 H 15 N 2 + ·C 7 H 7 O 3 S - , 10 ; 4-phenyl-piperazin-1-ium tartarate monohydrate, C 10 H 15 N 2 + ·C 4 H 5 O 6 - ·H 2 O, 11 ; and 4-phenyl-piperazin-1-ium fumarate, C 10 H 15 N 2 + ·C 4 H 3 O 4 - , 12 . Compounds 1 and 3 - 12 are all 1:1 salts with the acid proton transferred to the phenyl-piperaizine basic N atom (the secondary amine) with the exception of 3 where there is disorder in the proton position with it being 68% attached to the base and 32% attached to the acid. Of the structures with similar stoichiometries only 3 and 9 are isomorphous. The 4-phenyl substituent in all cases occupies an equatorial position except for 12 where it is in an axial position. The crystal chosen for structure 7 was refined as a non-merohedral twin. There is disorder in 5 , 6 , 10 and 11 . For both 5 and 6 , a nitro group is disordered and was modeled with two equivalent orientations with occupancies of 0.62 (3)/0.38 (3) and 0.690 (11)/0.310 (11), respectively. For 6 , 10 and 11 , this disorder is associated with the phenyl ring of the phenyl-piperazinium cation with occupancies of 0.687 (10)/0.313 (10), 0.51 (7)/0.49 (7) and 0.611 (13)/389 (13), respectively. For all salts, the packing is dominated by the N-H⋯O hydrogen bonds formed by the cation and anion. In addition, several structures contain C-H⋯π ( 1 , 3 , 4 , 8 , 9 , 10 , and 12 ) and aromatic π-π stacking inter-actions ( 6 and 8 ) and one structure ( 5 ) contains a -NO 2 ⋯π inter-action. For all structures, the Hirshfeld surface fingerprint plots show the expected prominent spikes as a result of the N-H⋯O and O-H⋯O hydrogen bonds.