Three Alumino/Galloborate Frameworks Templated by Organic Amines: Syntheses, Structures, and Nonlinear Optical Properties.

A series of alumino/galloborates, including (H3APEA)6[Al-B5O10]9·12H2O (1, APEA = N, N'-bis(3-aminopropyl)ethylenedi-amine), (HDETA)2(H2DETA)2[AlB5O10]3 (2, DETA = diethylenetriamine), and (H2EDAP)[GaB5O10]·H2O (3, EDAP = N-ethyl-diaminopropane), was solvothermally synthesized and characterized in solid-state by powder X-ray diffraction, Fourier transform infrared spectroscopy, UV-vis spectroscopy, and single-crystal X-ray diffraction. All of them feature the [MB5O10] n2 n- (M = Al or Ga) frameworks, charge-balanced by the long chain-like amine cations. Three frameworks exhibit different interlinkage modes of {MB5O10} layers, resulting in channels varying in size and shape. The flexibility of long chain-like amine cations as well as their significant structure-directing functions in forming these crystalline products is also discussed in detail. Powder second-harmonic generation measurements showed that all three compounds present a nonlinear optical property, and compound 2 exhibits type I phase-matchable optical nonlinearity.