Yan Tian

A series of Keggin-based AgI-belt/cycle structures constructed from 5-phenyl-1H-tetrazole and its derivative through Ag–N and Ag–C bonds

Abstract Three Keggin-based compounds containing AgI belts and cycles constructed from 5-phenyl-1H-tetrazole (L1) and its derivative 5-m-tolyl-1H-tetrazole (L2), [Ag9L15(PWVWVI11O40)]·H2O (1), [Ag11L16(H2O)2(SiMoVMoVI11O40)] (2) and [Ag10L28(HPMo12O40)]·H2O (3), have been synthesized under hydrothermal conditions and characterized by IR spectra and single crystal X-ray diffraction. Compound 1 shows a channel-like 3-D metal-organic framework with Keggin anions in channels. Adjacent layers of 2 share the same anions to construct a 3-D framework. Compound 3 has a 2-D metal-organic layer containing AgI cycles. Adjacent layers link through sharing Ag–N bonds and a channel-like 3-D framework is formed. Electrochemical and photocatalytic properties of 1–3 have been studied. The experimental results show that 1–3 have excellent catalytic performance for reduction of nitrite and bromate and also have photocatalytic properties for degradation of MB and RhB.

Subtle difference of [SiMo12O40]4− and [PMo12O40]3− inducing two new distinct Keggin-Ag-(1H-Pyrazole) compounds

Abstract Two new inorganic-organic hybrid compounds based on α-Keggin clusters and Ag-(1H-Pyrazole) subunits, [AgL2]4[SiMo12O40] (1) and [AgL2]3[PMo12O40] (2) (L = pyrazole), have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. In 1, there are two kinds of chains, the chains linked by two [AgL2]+ clusters and the other linked only by one [AgL2]+, which further connect by sharing [SiMo12O40]4− anions to construct a 2-D layer. In 2, four-supporting [PMo12O40]3− anions are fused by [Ag(1)L2]+ subunits to form a 1-D chain. Through weak interactions of Ag⋯O (3.091 Å) a 2-D supramolecular layer is constructed. Additionally, the electrochemical properties of title compounds and the photocatalytic properties of 2 have been studied.

Two new organic-inorganic hybrid compounds induced by γ-[Mo8O26]4− and [PMo12O40]3−

Abstract Two new organic–inorganic hybrid compounds, [CuII(btb)1.5(γ-Mo8O26)0.5(H2O)]·2H2O (1) and [CuII2(btb)4(PMoVMoVI11O40)]·2H2O (2) (btb = 4-butyl-1,4-bis(1,2,4-triazole), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. In 1, there exists a ladder-like metal-organic chain with the bidentate [γ-Mo8O26]4− anions inserting into the grids. Adjacent chains share the same Cu-btb lines of the ladder to form a 2-D layer. Compound 2 also has a ladder-like metal-organic chain. The tetradentate [PMo12O40]3− anions embed in the grids. The same Cu-btb line is shared by adjacent chains to build a 2-D layer. The btb ligands link adjacent layers to form a 3-D framework. Moreover, we also have investigated the electrochemical and photocatalytic properties of 1 and 2.

Using a flexible bis(pyrazol) ligand to construct four new Keggin-based compounds: syntheses, structures and properties

Using a flexible bis(pyrazol) ligand, four new compounds based on Keggin anions, namely [Cu(H2bdpm)2(H2O)2(HPW12O40)] (1), [Cu(H2bdpm)2(H2PW12O40)]2·2H2O (2), [Cu2(H2bdpm)3(H2O)2(SiW12O40)]·2H2O (3), and [Cu2(H2bdpm)4(H2O) (SiW12O40)]·16H2O (4) (H2bdpm = bis(3,5-dimethyl-1H-pyrazol-4-yl)methane), have been synthesized under hydrothermal conditions. Compound 1 is a zero dimension (0D) structure, showing a [Cu(H2bdpm)2]2+ mono-supporting [PW12O40]3− anion. Compound 2 shows a 1D supramolecular chain, with bi-supporting anions lined by discrete [PW12O40]3− anions. Compound 3 contains bi-nuclear Cu2+ cycles, which are linked by O4W to form a cycle-connecting-cycle chain. The [SiW12O40]4− anions connect adjacent chains to construct a 2D structure. Compound 4 contains a nested cycle subunit [Cu4(H2bdpm)6]8+, with two bi-nuclear cycles [Cu2(H2bdpm)2]4+ linked by two H2bdpm ligands. The nested cycle subunits are connected by H2bdpm molecules to construct a 2D metal–organic layer. The Keggin anions link adjacent layers to form a 3D framework. The electrochemical and photocatalytic properties of compounds 1–4 are studied.

Two copper(II)-bbtz modified Keggin and β-octamolybdate compounds captured in one-pot under hydrothermal conditions

Abstract Under hydrothermal conditions two compounds based on Keggin and β-octamolybdate, respectively, [Cu2(bbtz)4(SiMo12O40)] (1) and [Cu2(bbtz)4(Mo8O26)]1/2·H2O (2) (bbtz = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene), were synthesized in one-pot and characterized by single-crystal X-ray diffraction, elemental analyses, and IR spectroscopy. In compound 1, two adjacent wave-like CuII-bbtz lines are connected by SiMo12 anions and bbtz to generate a ladder-like chain. Adjacent chains share the same CuII ions to build a three-dimensional (3-D) framework. In compound 2, the β-Mo8 anions link Cu3(bbtz)2 subunits alternately to form a one-dimensional (1-D) chain. These chains connect each other through sharing CuII ions and a 3-D network is constructed. Moreover, we studied the electrocatalytic and photocatalytic activities of these two compounds. The results indicate that 1 and 2 show good electrocatalytic performance for the reduction of nitrite and bromate; they also exhibit photocatalytic properties for degradation of MB and RhB.

Amperometric sensing and photocatalytic properties under sunlight irradiation of a series of Keggin–AgI compounds through tuning single and mixed ligands

By using a single conjugate ring-rich ligand La or Lb and mixed ligands La/Lb, eight Keggin–AgI-based compounds, namely [Ag4La5(SiW12O40)]·28H2O (1), [Ag3La4(PW12O40)] (2), [Ag3La2(H2O)(PW12O40)] (3), [Ag4Lb4(SiW12O40)] (4), [Ag3KLb4(SiW12O40)]·H2O (5), [Ag6Lb6(PMo12O40)2] (6), [Ag4LaLb3(C14H10O2)(SiW12O40)]·8H2O (7) and [Ag4La2Lb4(GeMo12O40)] (8) (La = 2,3-diphenylpyrazine, Lb = 2,3-diphenylquinoxaline, C14H10O2 = 1,2-diphenyl-ethane-1,2-dione), were successfully synthesized by controlling the reaction parameters and well established by single-crystal X-ray diffraction, elemental analyses, and IR spectra. Compounds 1–3 are based on the La ligand, while 4–6 are based on Lb. The mixed La/Lb ligands induce the formation of 7 and 8. In compound 1, the linear [Ag4La4]4+ subunits link SiW12 anions to form a chain. Two adjacent chains connect each other through POM anion bonds and a screw-like double track is built. Compound 2 is composed of 1D leaf-like AgI-La chains, which are further linked by anions to build a 2D grid-like layer. Compound 3 was obtained under the same conditions as 2 except at a different temperature. In 3, the inorganic double chains are connected by linear metal–organic clusters [Ag3La2]3+ and a 2D layer is formed. Compounds 4 and 5 were also obtained at different temperatures. In 4, the adjacent grid-like layers share the same Ag ions to construct a 3D framework. Compound 5 is composed of 1D cycle-connecting-cycle chains, which are further linked by anions and Ag ions to build a 3D structure. Compound 6 is a 3D framework, with dissociative anions accommodated in it. Compounds 7 and 8 are composed of mixed organic ligands La and Lb. Compound 7 has two kinds of chains, which are linked by anions to form a “ladder”. Compound 8 contains discrete anions and [Ag2LaLb2]2+ units. The title compound modified CPEs can act as amperometric sensors for detecting hydrogen peroxide, potassium bromate and potassium nitrite. Compounds 1–8 have excellent photocatalytic capacity for degradation of organic dyes MB and RhB under the sunlight irradiation.

Four New Coordination Polymers Constructed by 2-(4-Thiazolyl)benzimidazole and 1,3,5-Benzenetricarboxylic Acid

Through using mixed N/S-containing ligand 2-(4-thiazolyl)benzimidazole (L), four new metal–organic coordination polymers, namely, [Co2L4(HBTC)(H2O)2] (1), [Cu2L2(HBTC)2]·H2O (2), [NiL3]·(HBTC)·H2O (3) and [NiL3]·H2O (4), have been synthesized under hydrothermal conditions, further assisted by a second organic ligand, benzenetricarboxylic (H3BTC). The structures of 1–4 have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses and IR spectra. Compound 1 contains two {CoL2(H2O)} fragments, which are connected by a BTC molecule to form a discrete “V”-type subunit. The hydrogen bonding interactions between N3⋯O1 atoms induce a 1D chain of 1. Complex 2 includes bi-nuclear CuII subunits, which are linked by BTC ligands to form a 2D layer. Each bi-nuclear Cu subunit is linked by four BTC molecules. Both complexes 3 and 4 are based on [NiL3] subunits. In complex 3, when NiCl2·6H2O was used as reactant, a discrete BTC molecule is captured as a counter anion. In contrast, when using reactant NiSO4·6H2O, [NiL3]·H2O (4) is formed. Both complexes 3 and 4 contain abundant hydrogen bonding interactions. In these complexes, the N donors in L ligand coordinate with transition metals and the S atoms participate in hydrogen bonding interactions.Graphical AbstractThrough using mixed N/S-containing ligand 2-(4-thiazolyl)benzimidazole (L), four new metal-organic coordination polymers, namely, [Co2L4(HBTC)(H2O)2] (1), [CuL(HBTC)] (2), [NiL3]·(HBTC)·H2O (3) and [Ni(L)3]·H2O (4), have been synthesized under hydrothermal conditions further assisted by the second organic ligand benzentricaboxylate (H3BTC).

Temperature-controlled formation of Anderson-type compounds and their conversion to [γ-Mo8O26]4−-based variants using pendent ligands

Abstract By tuning the reaction temperature, two Anderson- and two [γ-Mo8O26]4−-based compounds decorated by pendent organic ligands, [CuII9(bpz)2(pz)2(H2O)24][H2(Cr(OH)5Mo6O19)4]·11H2O (1), [CuII(bpz)2(H2O)2(γ-H4Mo8O26)]·2H2O (2), [CuII2(tea)2(H2O)6(HCr(OH)6Mo6O18)2]· 6H2O (3) and [AgI(bpz)(H2O)(γ-H4Mo8O26)0.5] (4) (bpz=4-butyl-1H-pyrazole, pz=1H-pyrazole, tea=2-[1,2,4]triazol-4-yl-ethylamine), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. In compound 1, there are two kinds of tri-nuclear CuII clusters induced by bpz and pz ligands, respectively. Four Anderson-type anions are linked by these tri-nuclear clusters to form a “W”-type subunit. In compound 2, the [Cu(bpz)2(H2O)2]2+ subunits connect the γ-Mo8 anions to construct a chain. The remaining two non-coordinated N donors in [Cu(bpz)2(H2O)2]2+ further link two adjacent γ-Mo8 anions through Mo–N bonds. In compound 3, there exists a bi-nuclear CuII cluster [Cu2(tea)2(H2O)6]4+. The discrete bi-nuclear CuII clusters and the CrMo6 anions link each other through abundant hydrogen bonding interactions. In compound 4, the [Ag(bpz)(H2O)]+ subunits connect γ-Mo8 anions to build a zigzag chain. The chains are further fused by other [Ag(bpz)(H2O)]+ cations to form a grid-like layer. There still exist Mo–N bonds in 4. We also have investigated the electrochemical and photocatalytic properties of 1–4.

Influence of pendant 2-[1,2,4]triazol-4-yl-ethylamine and symmetrical bis(pyrazol) ligands on dimensional extension of POM-based compounds

Through utilizing pendant 2-[1,2,4]triazol-4-yl-ethylamine (tea) and two kinds of bis(pyrazol) ligand, five new polyoxometalate (POM)-based compounds [Cu3K2(tea)2(OH)4(H2Mo8O27)] (1), [Ag(tea)(β-H2Mo8O26)0.5] (2), [Ag(tea)(H2O)(γ-H2Mo8O26)0.5] (3), [Cu(H2bdpm)(β-Mo8O26)0.5] (4) and [Ag2(Hbhpe)(θ-Mo8O26)0.5] (5) (H2bdpm = 1,1′-bis(3,5-dimethyl-1H-pyrazol-4-yl)methane, H2bhpe = 1,2-bis(1H-pyrazolate)ethane) were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. In compound 1, three CuII are fused by two tea and two OH− moieties to form a tri-nuclear cluster [Cu3(tea)2(OH)2]4+. The Mo8 anions link each other through sharing terminal O atoms to build an Mo-chain. The tri-nuclear clusters are further connected by an Mo-chain and K+ ions to form a 3D framework. In compound 2, two Ag+ ions are fused by two tea ligands to construct a bi-nuclear subunit, which are linked by β-Mo8 anions alternately to form a 1D chain. In compound 3, there exists a bi-nuclear Ag+ cluster [Ag2(tea)2]2+. The γ-Mo8 anions link bi-nuclear Ag+ clusters alternately and a 1D chain is constructed. Furthermore, each [Ag2(tea)2]2+ offers two additional N donors to connect two anions through Mo–N bonds. In compound 4, two 1D zigzag Cu–H2bdpm chains cover one 1D inorganic Mo-chain up and down to build a “hamburger-like” chain. The adjacent hamburger chains share the same Cu atoms to build a 2D structure. In compound 5, there exists a bi-nuclear [Ag2(Hbhpe)2]2+ cycle and a tetra-nuclear [Ag4(Hbhpe)4]4+ cycle. The bi-nuclear cycles and tetra-nuclear cycles alternately connect to form 1D metal–organic chains, which are further linked by θ-Mo8 anions to construct a 2D layer. The electrochemical and photocatalytic properties of compounds 1–5 are studied.