Hydrogen Bonding Ring Patterns of Chiral Dibenzoyltartrate in a Series of Hydrated Ammonium Carboxylate Salts with Chiral 1-Phenylethylammonium

Abstract

A number of ammonium carboxylate salts using the cations (R)-1-phenylethylammonium (R–C) and (S)-1-phenylethylammonium (S–C), and the anions (2R,3R)-(-)-2,3-di-p-toluoyloxybutanedioate (RR-A) and (2S,3S)-(+)-2,3-di-p-toluoyloxybutanedioate (SS-A) were prepared by using different ratios of the R and S cations to the two anions. In particular, the crystal structures of the ammonium carboxylate salts (R-A)2 ·(RR-A)·(H2O)·(MeOH) (1), (R–C)3 ·(S–C)·(RR-A)2 ·(H2O)5 (2), (R–C)·(S–C)·(RR-A)·(H2O)8 (3), (R–C)·(S–C)3 ·(RR-A)2 ·(H2O)6 ·(MeOH) (4), (S–C)2 ·(RR-A)·(H2O)2 (5), (R–C)2 ·(SS-A)·(H2O)2 (6) and (S–C)2 ·(SS-A)·(H2O)·(MeOH) (7) were synthesized and their solid state structures determined by low temperature single crystal X-ray diffraction. The molecular salts were prepared by solution crystallization of the carboxylic acids with the respective amines in a 1:2 stoichiometric ratio, and crystallized out as hydrated and solvated salts. The salts 1–5 all have the same anion species, but with the cation chiral ratio varying from R to S, and the salts 6 and 7 feature the SS-A anion. The crystal structure of 1 belongs to the orthorhombic space group P212121 with a = 7.9812(1), b = 10.3781(2), c = 41.1897(6) A. The crystal structure of 2 belongs to the monoclinic space group P21 with a = 12.7316(2), b = 18.0107(3), c = 15.0977(2) A and β = 101.755(1)°. The crystal structure of 3 belongs to the monoclinic space group P21 with a = 13.9615(2), b = 18.0549(2), c = 15.1335(2) A and β = 111.397(1)°. The crystal structure of 4 belongs to the monoclinic space group P21 with a = 10.3381(5), b = 25.6109(12), c = 13.3450(4) A and β = 91.504(3)°. The crystal structure of 5 belongs to the orthorhombic space group P212121 with a = 10.3104(2), b = 13.4412(2), c = 24.6998(6) A. The crystal structure of 6 belongs to the orthorhombic space group P212121 with a = 10.3149(3), b = 13.4377(7), c = 24.7113(13) A. The crystal structure of 7 belongs to the orthorhombic space group P212121 with a = 7.9755(6), b = 10.3946(7), c = 41.186(3) A. The changes in cation and anion species produces 1-D ribbons in 1 and 7, and 2-D layers in 2–6, with corresponding changes in the hydrogen bonded ring patterns linking the ionic species together using charge-assisted N+–H···O−, O–H···O− and N+–H···O hydrogen bonds. Hydrogen bonding ring patterns of chiral dibenzoyltartrate in a series of hydrated ammonium carboxylate salts with chiral 1-phenylethylammonium. The three most commonly observed ring patterns in hydrated chiral ammonium carboxylate salts.