A series of Anderson-type polyoxometalate-based metal–organic complexes: their pH-dependent electrochemical behaviour, and as electrocatalysts and photocatalysts. Issue 31 (19th July 2016)

• Record Type: Journal Article
• Authors: Wang, Xiuli; Sun, Junjun; Lin, Hongyan; Chang, Zhihan; Wang, Xiang; Liu, Guocheng
• Is Part Of: Dalton transactions. Volume 45:Issue 31(2016)
• Page Start: 12465
• Page End: 12478
• Publication Date: 2016-07-19
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt02216b
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Seven novel polyoxometalate-based metal–organic complexes are synthesized and structurally characterized, exhibiting high electrochemical sensitivity to pH and photocatalytic activities for the degradation of organic dyes under UV irradiation. Abstract : Seven polyoxometalate-based (POM) metal–organic complexes (MOCs) with different pyridyl–amide ligands were hydrothermally synthesized and structurally characterized. In1, the [CrMo6 (OH)5 O19 ] 4− (CrMo6 ) polyoxoanions bridge the Cu II ions to generate a 1D Cu-CrMo6 inorganic double chain, which is further consolidated by the μ2 -bridging 2-pdya ligands. Complex2 exhibits a 2D layer based on [γ-Mo8 O26 ] n 4 n − chains. In complex3, the β-Mo8 O26 anions link the metal–organic units [Cu(4-Hdpyp)2 ] 4+ to construct a 1D fishbone-like chain. Complex4 shows a 3D (6, 6)-connected framework constructed by the 2D inorganic network [Cu4 (μ3 -OH)2 (H2 O)4 (γ-Mo8 O27 )] and 3-dpyh bridging ligands. In2–4, all the [CoMo6 (OH)6 O18 ] 3− (CoMo6 ) anions were in situ transformed to Mo8 O26 4− or Mo8 O27 6− anions. Complexes5 and7 are isostructural, each [TeMo6 O24 ] 6− (TeMo6 ) polyoxoanion coordinates to two Cu II ions to generate a discrete copper complex [Cu2 (4-Hdpye)2 (TeMo6 O24 )(H2 O)6 ] and [Cu2 (4-Hdpyb)2 (TeMo6 O24 )(H2 O)6 ], respectively. In complex6, the TeMo6 polyoxoanions bridge the Cu II ions to generate a 2D [Cu3 (TeMo6 )] n inorganic layer, which is further linked by the μ2 -bridging 3-dpyb ligands to form a 3D metal–organic framework. The effects of POM types and their various coordination modes, as well as the pyridyl–amide ligands on the structures of the title complexes have been discussed. Their electrochemical behavior reveals characteristic multi-electron redox processes related to Mo VI centers. The electrocatalytic reduction performance toward hydrogen peroxide and bromate was fully measured and discussed; both complexes exhibit excellent electrocatalytic activity towards the reduction of bromate and hydrogen peroxide. In addition, the redox potentials of complexes5–7 are highly pH sensitive and may be used as a kind of potential pH sensor. The photocatalytic activities of the title complexes are also investigated in detail.