Noncentrosymmetry in New Templated Gallium Fluorophosphates

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• 作者：Sarah J. Choyke ; Samuel M. Blau ; Abigail A. Larner ; Amy Narducci Sarjeant ; Jeongho Yeon ; P. Shiv Halasyamani ; Alexander J. Norquist
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：December 7, 2009
• 年：2009
• 卷：48
• 期：23
• 页码：11277-11282
• 全文大小：851K
• 年卷期：v.48,no.23(December 7, 2009)
• ISSN：1520-510X

文摘

Two new noncentrosymmetric polar gallium fluorophosphates have been synthesized under mild hydrothermal conditions through the use of enantiomorphically pure sources of either R-2-methylpiperazine or S-2-methylpiperazine. A centrosymmetric analogue was also prepared using a racemic source of the amine. Novel [Ga₃F(PO₄)₄]_n⁴ⁿ⁻ layers, constructed from [Ga₃O₃F(PO₄)₄] building units, are observed in all three compounds. 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 the amines. Second harmonic generation measurements were performed on [(R)-C₅H₁₄N₂]₂[Ga₃F(PO₄)₄]·5.5H₂O and [(S)-C₅H₁₄N₂]₂[Ga₃F(PO₄)₄]·4.75H₂O, both of which display type 1 phase-matching capabilities and exhibit activities of 50 × α-SiO₂. The structures of these compounds were determined using single crystal X-ray diffraction, infrared spectroscopy, and thermal analyses. [C₅H₁₄N₂]₂[Ga₃F(PO₄)₄]·5.25H₂O, a = 13.0863(5) Å, c = 9.9023(4) Å, trigonal, P-3 (No. 147), Z = 2; [(R)-C₅H₁₄N₂]₂[Ga₃F(PO₄)₄]·5.5H₂O, a = 13.0887(2) Å, c = 29.9439(4) Å, trigonal, P3₁ (No. 144), Z = 6; [(S)-C₅H₁₄N₂]₂[Ga₃F(PO₄)₄]·4.75H₂O, a = 13.0871(2) Å, c = 29.8350(6) Å, trigonal, P3₂ (No. 145), Z = 6.