Structural Regulations of Layered Borates: From Centric Layers to Chiral Porous Layers.

Three pentaborates were made by precise structural regulations under hydrothermal conditions, namely, KCs[BO(OH)]·0.5CO (), KNaCs[BO(OH)]·2OH (), and NaBa[BO(OH)] (). Compound features the typical 2D layers constructed from the four-connected BO(OH) clusters. By adjustment of the reactants and pH values of the systems to remove interlayered CO groups, the centric layers in were transformed to the chiral layers of . By further adjusting cationic templates based on host-guest charge matching, the BO(OH) cluster unit was transformed to BO(OH), which built the chiral porous layers of . The chiral compounds and exhibit moderate second harmonic generation (SHG) responses of 1.1 and 1.7 times that of KDP (KHPO). The structural regulations actualize the evolutions on both structural symmetries and dimensions.