Qian Zhen, Wu Hongping, Yu Hongwei, Hu Zhanggui, Wang Jiyang, Wu Yicheng
Tianjin Key Laboratory of Functional Crystal Materials, Institute of Functional Crystal, Tianjin University of Technology, Tianjin 300384, China.
Inorg Chem. 2020 Oct 19;59(20):15430-15437. doi: 10.1021/acs.inorgchem.0c02426. Epub 2020 Oct 4.
A new noncentrosymmetric (NCS) transition-metal (TM) iodate BaTi(IO)·0.5HO has been successfully synthesized by the typical hydrothermal method. The single-crystal X-ray diffraction shows that BaTi(IO)·0.5HO crystallizes in the polar trigonal space group 3 (no. 146) with = = 11.1920(12) Å, = 24.006(3) Å. The reported compound features zero-dimensional (0D) [Ti(IO)] clusters that are separated by Ba cations and bound water in the structure. By comparing BaTi(IO)·0.5HO with the centrosymmetric (CS) α- and β-BaTi(IO) that were reported before, it can be found that the bound water plays an important role for the formation of NCS structure for BaTi(IO)·0.5HO. In addition, based on the powder second harmonic (SHG) measurement, BaTi(IO)·0.5HO can achieve type-I phase matching with a moderate SHG effect (∼1 × KDP). The source of SHG effect was analyzed by dipole moment calculation and structure comparison. UV-vis-NIR diffuse reflectance spectroscopy, infrared spectroscopy, and thermogravimetric measurements are also presented.
通过典型的水热法成功合成了一种新型非中心对称（NCS）过渡金属（TM）碘酸盐BaTi(IO₃)₃·0.5H₂O。单晶X射线衍射表明，BaTi(IO₃)₃·0.5H₂O结晶于极性三角空间群R3（编号146），a = b = 11.1920(12) Å，c = 24.006(3) Å。所报道的化合物具有零维（0D）[Ti(IO₃)₆]簇，这些簇在结构中被Ba阳离子和结合水隔开。通过将BaTi(IO₃)₃·0.5H₂O与之前报道的中心对称（CS）α-和β-BaTi(IO₃)₃进行比较，可以发现结合水对BaTi(IO₃)₃·0.5H₂O的NCS结构形成起着重要作用。此外，基于粉末二次谐波（SHG）测量，BaTi(IO₃)₃·0.5H₂O可以实现I型相位匹配，具有中等的SHG效应（~1×KDP）。通过偶极矩计算和结构比较分析了SHG效应的来源。还展示了紫外-可见-近红外漫反射光谱、红外光谱和热重测量结果。
