Directed Synthesis of Noncentrosymmetric Molybdates

The directed synthesis of two noncentrosymmetric sulfated molybdates has been achieved through the use of chiral organic amines. Reaction gels containing either (R)-2-methylpiperazine or (S)-2-methylpiperazine, MoO3, H2SO4, and H2O were subjected to mild hydrothermal conditions, resulting in the growth of single crystals of [(R)-C5H14N2][(MoO3)3(SO4)]·H2O and [(S)-C5H14N2][(MoO3)3(SO4)]·H2O. These materials crystallize in the noncentroysmmetric space group P212121 (No. 19), which exhibits the enantiomorphic crystal class 222 (D 2). The second harmonic generation activities were measured on sieved powders.