Synthesis And Characterizations Of Borates Based On Single And Mixed Oxoboron Clusters

Borates have been one of the hot topics around the world for several decades due to their rich structure diversities and excellent optical properties.Over the past years,chemists have more interests in transition metal borates,rare earth borates,and alkaili/alkailine-earth borates.The synthetic method is limited to solid state reactions,and the compounds obtained are usually dense phases.Recently,researchers find that introducing main group metals into borate frameworks will enrich their structure diversities,generate structures with larger voids,and produce more potential materials with excellent phsio-chemical peroperties.In addition,with the development of hydro?sovo?thermal techniques,various structure templates and structure-directing agents,such as inorganic cations,organic amines and metal-organic complexes,can be added to the reaction system to control the formation of open framework structures effectively.We have been focusing on the the hydro?solvl?thermal synthesis of borates and metal borates for many years and lots of structures have been successfully obtained.Based on the previous work,the author designed and synthesized a series of main group metal borates,inorganic-organic hybrid borates and alkaili metal borates under hydro?solvo?thermal conditions at midium temperature.The products are characterized by X-ray single crystal and powder diffraction,IR,UV-Vis,fluorescence and TGA.Second-order nonlinear optical?NLO?peroperties are measured on the noncentrosymetric structures.60 new borates are synthesized and listed in appendix,25 of which are selected and categorized into 3 groups as following:1.Main group metal borates,including 9 aluminoborates and 6 galloborates.The template agents for these compounds are metal-organic complexes,alkaili metal cations,and co-templates of alkaili cations and organic amines.There are a series of structures consisting of both aluminoborate framework and metal-organic complex layer/chain,which form a rare interpenetrating structure.The NLO properties of these 4 compounds are 2.1,3.2,1.5 and 3 times that of KDP?KH₂PO₄?,respectively.MnAlB₁₇O₃₀·4H₃O⁺represents the first example of introducing transition metal into the aluminoborate framework.Metal-centered cluster[Mn@B₁₂O₂₄]and oxoboron cluster[B₅O₁₀]connect with each other to construct a 1D chain,which are further interconnected by AlO₄ tetrahedra into an open framework with volume voids of 56.3%.The NLO property is 1.75 times of KDP.There are also a series of galloborates constructed from different oxoboron clusters.Especially,the NLO of GaNa₄B₁₄O₂₄?OH?₂?2.5H₂O is 5times that of KDP.2.Inorganic-organic hybrid borates.9 hybrid borates have been obtained by using organic amines and metal-organic complexes as templates or supporting groups.B₉O₁₅?H₂ppz?NH₄ has 3D open framework consisting of[B₃O₇]and[B₆O₁₃]clusters.[?1,3-dap?CdB₅O₈?OH?]?H₂O is a hybrid borate with a 3D structure constructed from inorganic framework and organic components.The inorganic framework are built up by metal-centered wheel cluster[Cd@B₂₀O₃₆?OH?₄]and the organic part is 1,3-dap molecules.There is also a neutral layer[Cd@B₂₀O₃₆?OH?₄]?in this structure.We find for the first time in this structure that the inorganic framework and the organic componemt can be joined by M?Cd?-N-C bonds.There are also a series of hybrid borates supported by organic amines,exhibiting from 1D chains from 3D framework structures.3.Alkaili metal borates.Four alkaili metal borates are obtained successfully by using single or mixed alkaili metal cations as templates.They are based on single or mixed oxoboron clusters,exhibiting chain or layer structures.