Two new 3-D vanadoborates incorporating rare polymeric K-O-K chain or network with photocatalytic properties

Abstract

The discovery of novel high-dimensional vanadorates with important photocatalytic properties is of great importance in structural chemistry and materials science. Herein, new types of three-dimensional (3-D) vanadoborates (H3O)2{[K6(H2O)10][Ni(H2O)4][V12B18O54(OH)6]}·13H2O (1) and (H3O)2{[K12(H2O)10][Zn4(B2O4H2)(B4O14H10)(V10B28O74H8)]}·2H2O (2) were synthesized by a facile and feasible hydrothermal technique and structurally characterized. 1 comprises cage-like vanadoborate cluster [V12B18O54(OH)6]10- based on the combination of one puckered [B18O36(OH)6] ring and two hexa-meric oxo-vanadate [V6O9] units, while 2 contains a rare vanadoborate cluster {[Zn4(B2O4H2)(B4O14H10)(V10B28O74H8)]}14- built up from two [B14O28(OH)4] rings, one [Zn4(B2O4H2)(B4O14H10)] unit and one ellipse-like [V10O30] ring. The 3-D framework of 1 is constructed by the linkage of rare [K6(H2O)10]n chains and {[Ni(H2O)4][V12B18O54(OH)6]}n chains, while 3-D architecture of 2 is built from the interconnection of infrequent [K12(H2O)10]n layers and vanadoborate {[Zn4(B2O4H2)(B4O14H10)- (V10B28O74H8)]}14- clusters. The documented polymeric vanadoborates are usually based on low nuclearity metal complexes as bridging groups, however, 1 and 2 present new types of the 3-D vanadoborates based on K-O-K polymeric chain or layer as bridging group. The photocatalytic results revealed 1 and 2 displayed the efficient photo-catalytic properties for degradation of methylene blue under visible light. This study offers a facile synthetic method for the preparation of new high-dimensional vanadorates as the potential photo-catalysts to eliminate the harmful methylene blue dyes in industrial wastewaters.