Construction of 3D metal–organic frameworks bearing heteropolyoxometalate units and multi-azole molecules and exploration of their photocatalytic activities

• Published in: RSC advances Vol. 7; no. 59; pp. 36860 - 36866
• Main Authors: Gong, Chunhua, Zeng, Xianghua, Xin, Li, Zhang, Junyong, Xie, Jingli
• Format: Journal Article
• Language: English
• Published: 2017
• DOI: 10.1039/C7RA05210C
• ISSN: 2046-2069

Taking advantage of multi-azole molecules as organic linkers, two novel 3D metal–organic frameworks consisting of heteropolyoxometalate building blocks, i.e. , [Cu 5 (1,4-ttb) 4 (CrMo 6 (OH) 6 O 18 )(H 2 O) 8 ]·10H 2 O ( 1 ) and [Cu 4 (1,4-ttb) 4 (SiW 12 O 40 )(H 2 O) 8 ]·4H 2 O ( 2 ) (1,4-ttb = 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene) have been fabricated and characterized via X-ray single-crystal diffraction, FT-IR spectroscopy, powder X-ray diffraction (PXRD) and TG analyses. Compounds 1 and 2 both possess pillared-layer 3D frameworks which were based on POM units and different Cu–tetrazolate motifs. Compound 1 is a (2,6,6)-connected 3D framework constructed from the 2D networks {Cu 5 (1,4-ttb) 4 (H 2 O) 8 } n through connected CrMo 6 polyoxoanions with (3 2 .4 2 .5 2 .6 8 .8)(3 4 .4 4 .5 4 .6 3 ) topology. Compound 2 is a (2,3,5)-connected 3D framework constructed from the 2D wave layers {Cu 4 (1,4-ttb) 4 (H 2 O) 8 } through connected SiW 12 polyoxoanions with (4.8 2 ) 2 (4 2 .6 4 .8 2 .10 2 )(8) topology. Magnetism studies of compound 1 reveal the dominant antiferromagnetic coupling between the Cu( ii ) ions. The electrochemistry properties of compound 2 were studied. Intriguingly, compounds 1 and 2 display considerable photocatalytic activities for the degradation of several organic dyes.