Two New Alkaline Metal Borates with Supramolecular Framework Constructed from 1D {B5}/{B6} Helical Chains

Two new alkaline metal borates containing 1D {B₅}/{B₆} oxoboron helical chains, namely Na_0.5B₅O₈(OH)₂]_0.5B₅O₆(OH)₂]_0.5·0.5H₃O(1) and NaKCsB₆O₉(OH)₃](2) were synthesized under solvothermal conditions. Compound 1 contains the interesting alternative left- and right-handed helical {B₅O₈(OH)₂] B₅O₆(OH)₂]}^2- ({B₅}-1 and {B₅}-2) 1D chains and compound 2 possesses the similarB₆O₁₁(OH)₃]^7-({B₆}) chains. Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds. In addition, the UV cutoff edge of compounds 1 and 2 is both below 190 nm.