Noncentrosymmetry in new 2-methylpiperazinediium hexaaquazinc(II) bis(sulfate)

Two new noncentrosymmetric polar zinc sulfates have been synthesized by slow evaporation through the use of enantiomorphically pure sources of either (R)-2-methylpiperazine or (S)-2-methylpiperazine. A centrosymmetric analog was also prepared using a racemic source of the amine. The 3-D structure networks for these compounds consist of isolated [Zn(H2O)(6)](2+), [C5H14N2](2+), and SO42- linked by hydrogen bonds. The use of racemic 2-methylpiperazine results in crystallographic disorder of the amines and creation of inversion centers, while using a single enantiomer destroys the inversion symmetry and orders of the amines. These structures were determined using single-crystal X-ray diffraction, infrared spectroscopy, and thermal analyses. Crystal data are as follows: [C5H14N2][Zn(H2O)(6)](SO4)(2) (1), a = 6.5988(1) angstrom, b = 10.9613(2) angstrom, c = 12.5479(2) angstrom, beta = 101.385(1)degrees, V = 889.75(3) angstrom(3), P2(1)/n (No. 14), Z = 2; [(R)-C5H14N2][Zn(H2O)(6)](SO4)(2) (2), a = 10.8665(2) angstrom, b = 7.8600(1) angstrom, c = 11.7029(2) angstrom, beta = 116.283(1)degrees, V = 896.22(3) angstrom(3), P2(1) (No. 4), Z = 2; [(S)-C5H14N2][Zn(H2O)(6)](SO4)(2) (3), a = 6.5819(2) angstrom, b = 11.0014(2) angstrom, c = 12.5229(3) angstrom, beta = 101.489(1)degrees, V = 888.62(4) angstrom(3), P2(1) (No. 14), Z = 2.