Water-Stable Zn(II) Coordination Polymers Regulated by Polysubstituted Benzenes and Their Photocatalytic Performance toward Methylene Blue Degradation Dominated by Ligand-Field Effects

• DOI: 10.1021/acs.cgd.0c01521
• Publication Date: 2021-01-15T05:02:03Z
• Authors: Yan Zhao; Lei Li; Zhong-Yi Liu; Bo Ding; Xiu-Guang Wang; Yan Luo; Xiao-Jun Zhao; En-Cui Yang
• Keywords: Photodegradation; Coordination polymer; Methylene blue

Photodegradation of organic dyes over coordination polymer (CP) photocatalysts has become one the effective strategies for prevention and control water pollution, in which energy band structures manipulated by ligand field catalytically active metal play extremely vital roles enhancing photocatalytic activity. To better rationalize ligand-field function on structure, a series six 2,4,6-tris(4-pyridyl)-1,3,5-triazine (tpt)-based Zn(II)-CPs have been hydrothermally prepared transforming types, numbers, locations coordinative substitutes attached benzene. All these fully structurally photophysically characterized used as methylene blue (MB) decontamination UV light illumination. Single-crystal structural analyses reveal that isomeric 1,2,4 (H3L1)- 1,3,5-benzenetricarboxylates (H3L2) assembled ternary system into gridlike framework {[Zn(tpt)(HL1)]·H2O}n (1), ribbon-to-connector aligned sheet [Zn3(H2O)(tpt)2(L1)2]n (2), hexagonal dimer based double layer [Zn3(H2O)2(tpt)(L2)2]n (3). 1,2,4,5-Tetrasubstituted phenyl diphenyl coligands assisted honeycomb-shaped, pillared-layer, cuboid-like frameworks via synergetic binding carboxylate, sulfonate hydroxyl moieties: {[Zn2(tpt)(H2L3)(L3)0.5]·0.5H2O}n (4, H4L3 = 2,5-dihydroxyltelephthalic acid), {[Zn2.5(tpt)(μ-OH)(L4)]·1.5H2O}n (5, H4L4 5-sulfobenzene-1,2,4-tricarboxylic {[Zn3(H2O)0.5(tpt)2(μ-OH)(L5)1.25]·5H2O}n (6, H4L5 3,3′-disulfonyl-4,4′-biphenyldicarboxylic acid). More significantly, changeable donor surroundings around Zn(II) ions optimized geometries, giving rise to variable gaps potentials. Resulting from isolation migration charge carriers much stronger oxidizing ability valence band, cuboid-shaped 6 exhibited best photodegradation activity toward MB pollutant, up 89% after 4 h These observations systematically revealed consequence CP dye photodecomposition.