CRYSTAL-STRUCTURE OF (S)-1-PHENYLETHYLAMMONIUM (R)-MANDELATE AND A COMPARISON OF DIASTEREOMERIC MANDELATE SALTS OF 1-PHENYLETHYLAMINE

The crystal structure of (S)-1-phenylethylammonium (R)-mandelate has b een investigated, C8H12N+C8H7O3-, M(r) = 273.33, triclinic, P1, T = 12 2.0(5) K, a = 6.398(1), b = 14.807(3), c = 16.109(2) angstrom, alpha = 75.33(1), beta = 82.974(2), gamma = 81.03(2)-degrees, V = 1452.9 (5) angstrom3, Z = 4, D(x) = 1.250 g cm-3, lambda(CuKalpha) = 1.54184 angs trom, mu = 6.98 cm-1, F(000) = 584. The structure was refined against \F\2 including all 6518 unique reflections to a final residual of R(w) = 0.1178. The corresponding final residual based on F for 5663 observ ed reflections with \F(o)\2 > 2sigma(\F(o)\2) was R = 0.0449. Each of the four cations are hydrogen-bonded to two crystallographically equiv alent anions related by translation symmetry in the direction of the c rystallographic a-axis forming hydrogen-bonded chain's. These chains a re connected by hydrogen bonds forming sheets defined by the a-axis an d the diagonal of the bc-plane. Similar hydrogen bonded layers are fou nd in the diastereomeric salt (R)-1-phenylethylammonium (R)-mandelate. but the conformations of the ions differ in the two diastereomeric sa lts.