Zeolitic Open-Framework Borates with Noncentrosymmetric Structures and Nonlinear Optical Properties

Abstract

Three zeolitic pentaborates (H2en)­[B5O8(OH)] (1, en = ethylenediamine), (Hen)2[Al­(B5O10)] (2), (H2en)­[NH­(CH3)2]­[Al­(B5O10)] (3) were solvothermally obtained by employing ethanediamine molecules as structure-directing agents (SDAs). The nonmetal borate of 1 features a noncentrosymmetric two-dimensional layered structure. Through introducing Al atoms as the linkers and regulating the reaction conditions of 1, two three-dimensional zeolitic open-framework aluminoborates, noncentrosymmetric (NCS) of 2 and centrosymmetric (CS) of 3, were achieved. Both 2 and 3 exhibit [Al­(B5O10)] n 2n– zeolitic frameworks based on the same fundamental building blocks (FBBs). However, the different arrangements between two FBBs result in 2 showing a NCS framework with dia topology, while 3 presents CS framework with cag topology. The flexibility of linkages modes of the FBBs as well as the unique structure-directing functions play crucial roles in the different formations. Powder second-harmonic generation (SHG) measurements revealed that acentric 1 and 2 possess nonlinear optical activity and 2 is type I phase-matchable with SHG responses of ∼1.0 time for KDP (KH2PO4). Infrared and UV–vis diffuse reflectance spectroscopy, along with electronic structure calculations, were also performed for the materials.

Sb6O7(SO4)2: A Promising Ultraviolet Nonlinear Optical Material with an Enhanced Second‐Harmonic‐Generation Response Activated by SbIII Lone‐Pair Stereoactivity

“…With the development and applications of laser science and techniques, exploiting new nonlinear optical (NLO) materials with high performance has been a topic of intensive study. Typically, the search for UV and deep‐UV NLO materials is mainly limited to borate systems [1–12] . Recently, it has become evident that introducing NLO‐active asymmetric structural units, such as π‐conjugated triangular groups, is an effective strategy to design noncentrosymmetric (NCS) materials.…”

“…Typically,t he search forU Va nd deep-UVN LO materials is mainly limited to borate systems. [1][2][3][4][5][6][7][8][9][10][11][12] Recently,i th as become evident that introducing NLO-active asymmetric structural units, such as p-conjugated triangular groups,i sa ne ffective strategyt od esign noncentrosymmetric (NCS) materials. For example,s imilar to the BO 3 3À unit, CO 3 2À and NO 3 À anions are also p-conjugatedg roups.…”

Li3[Al(PO4)2(H2O)1.5] and Na[AlP2O7]: from 2D layered polar to 3D centrosymmetric framework structures

“…, to form complex materials, e.g. borophosphates, 36 aluminophophates, 37 silicophosphates, 38 and germanophophates. 39 Among these, aluminophosphate (AlPO) molecular sieves have been extensively studied for their structural diversity as well as potential applications in magnetic, separation, catalysis, ion-exchange, and nonlinear optical (NLO) materials.…”

Two layered galloborates from centric to acentric structures: syntheses and NLO properties

“…[22][23][24][25] Since 2009, we firstly proposed the use of aluminium isopropoxide (Al(i-PrO) 3 ) as the Al source, replacing the traditional inorganic Al sources to synthesize ABOs under hydro(solvo)thermal conditions, 5 large amounts of ABOs were made, which not only expand the ABO open framework family with definite structures, but also increase the possibility of acentric structures through the synergistic effects of chiral AlO 4 group and acentric oxoboron clusters. [26][27][28][29] As part of our ongoing work, we continue to expand our research focus to GBOs with the similar Ga source of gallium isopropoxide (Ga(i-PrO) 3 ) and make a series of them with novel structures. [30][31][32][33][34][35] However, compared with ABOs (more than 100 cases reported), the development of GBOs is still in its infancy (35 cases reported), especially for those with novel structures and excellent NLO properties.…”