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

High Resolution Image Download MS PowerPoint Slide Three pentaborates were made by precise structural regulations under hydrothermal conditions, namely, K 2 Cs[B 5 O 8 (OH)]·0.5CO 3 ( 1 ), KNa 4 Cs[B 5 O 8 (OH)] 2 ·2OH ( 2 ), and NaBa[B 5 O 8.5 (OH)] ( 3 ). Compound 1 features the typical 2D layers constructed from the four-connected B 5 O 10 (OH) clusters. By adjustment of the reactants and pH values of the systems to remove interlayered CO 3 2– groups, the centric layers in 1 were transformed to the chiral layers of 2 . By further adjusting cationic templates based on host–guest charge matching, the B 5 O 10 (OH) cluster unit was transformed to B 5 O 11 (OH), which built the chiral porous layers of 3 . The chiral compounds 2 and 3 exhibit moderate second harmonic generation (SHG) responses of 1.1 and 1.7 times that of KDP (KH 2 PO 4 ). The structural regulations actualize the evolutions on both structural symmetries and dimensions.