Crystal structures of a pair of diastereomeric 3-(N,N-dimethylammonium)-1,1-diphenyl-1-butanol O,O′-di-p-toloyl hydrogen tartrates

The crystal structures of a pair of diastereomeric salts of (−)-(2R, 3R)-O, O′-di-p-toloyl tartaric acid and (−)- and ( + )-3-N,N-dimethylamino-1,1-diphenyl-1-butanol have been determined. Crystal data: 3: (-)-(R)-C18HC24NO+(-)-(2R,3R)-C20H17O-8 orthorhombic, P212121, a = 7.873(2), b = 15.343(3), c = 28.76(1) Å, V = 3474(2) Å3, Z = 4, and Dcalc = 1.254 g cm−3. 4: (+)- (S)-C18H24NO+, (-)-(2R,3R)-C20H17O-8orthorhombic, P212121, a = 7.504(1), b = 17.215(2), c = 26.490(4) Å, V = 3422.0(8) Å3,Z = 4, and Dcalc = 1.273 g cm−3. The geometries and the conformational energies of the solid state conformations of the cations have been compared with global and local energy minimum conformations determined by molecular mechanics calculations. In the solid state, one conformation with and one without an intramolecular hydrogen bond are observed. The calculated global energy minimum conformation in aqueous solution contains the intramolecular hydrogen bond.