Introduction of secondary pyridyl-1H-tetrazole derivatives into Keggin–Ag–(1,10-phenanthroline) system for tuning dimensionalities and architectures: assembly and properties

By introducing three pyridyl-1H-tetrazole derivatives to Keggin–Ag-(1,10-phenanthroline) system, five new polyoxometalate-based inorganic–organic hybrid compounds with different dimensionalities and structures, [Ag₃(4-ptz)₂Na(phen)(HPMo₁₂O₄₀)]·2H₂O (1), [Ag₄(3-ptz)₂(phen)₂(HPMo₁₂O₄₀)] (2), [Ag₄(3-ptz)₂(phen)₂(HVW₁₂O₄₀)] (3), [Ag₃(3-bptzb)(phen)₂(PMo₁₂O₄₀)] (4) and [Ag₃(3-bptzb)(phen)₂(VW₁₂O₄₀)] (5) (phen = 1,10-phenanthroline, x-ptzH = 5-(x-pyridyl)-1H-tetrazole (x = 3, 4), 3-bptzb = 1,4-bis(5-(3-pyridyl)-tetrazolyl)butane), have been synthesized under hydrothermal conditions. Compound 1 is a 1-D belt architecture constructed from an Ag-4-ptz metal–organic chain and two Ag–PMo₁₂O₄₀–Na–phen inorganic–organic chains. When 3-ptzH was introduced as secondary ligand in 2 and 3 instead of 4-ptzH, two isostructural architectures were obtained, which contain a 1-D zigzag Ag-3-ptz chain with phen ligands hanging on both sides of the chain. The Keggin anions connect adjacent Ag-3-ptz chains to construct 2-D networks. When the flexible 3-bptzb was selected, isostructural 4 and 5 with 2-D networks were obtained, which were constructed from binuclear subunits and Keggin–Ag inorganic chains. The influence of three pyridyl-1H-tetrazole derivatives as secondary ligands on the dimensionalities and architectures of 1–5 was discussed. The electrochemical and photocatalytic properties of the compounds were investigated.     

三个基于Wells-Dawson型多酸的三核铜簇的合成、结构及性能

在水热条件下,通过Wells-Dawson型多酸[As_2W_(18)O_(62)]6-、氯化铜(CuCl_2·2H_2O)和5-(4-吡啶基)-1H-四氮唑(4-ptz)的反应,在同一反应釜中合成出2个结构完全不同的、都包含三核铜簇的多酸基化合物[Cu3(4-ptz)4(H_2O)7(As_2W_(18)O_(62))]·42H_2O(1)和[Cu3(4-ptz)5(H_2O)5(As_2W_(18)O_(62))]·47H_2O(2);当我们以另一种Wells-Dawson型多酸[P_2W_(18)O_(62)]6-、氯化铜(CuCl_2·2H_2O)和5-(3-吡啶基)-1H-四氮唑(3-ptz)反应,获得了另一种多酸基三核铜簇化合物[Cu3(3-ptz)4(H_2O)8(P_2W_(18)O_(62))]·33H_2O(3)。X射线单晶衍射结果表明,化合物1为多酸单支撑三核铜簇的悬臂式结构,化合物2的多阴离子被三核铜簇交替连接形成一维链式结构,而化合物3为多阴离子和三核铜簇形成的孤立结构。吡啶-四氮唑类配体(3-ptz和4-ptz)是形成化合物1~3中三核铜簇的重要结构因素。同时,研究了3个化合物的电化学以及光催化性能。     

Assembly of two new polyoxometalate-templated supramolecular compounds by utilizing flexible 1,4-bis(pyrazol-1-ylmethyl)benzene ligand

Two new polyoxometalate-templated supramolecular compounds, [Cu^I₄(bpmb)₄][PMo^VI₁₁Mo^VO₄₀] (1) and [Cu^I₄(bpmb)₄SiW₁₂O₄₀] (2) (bpmb = 1,4-bis(pyrazol-1-ylmethyl)benzene), have been synthesized under hydrothermal conditions and characterized by routine methods. Structural analysis shows that in 1, there exist crown-like [Cu^I₄(bpmb)₄] coordination macrocycles, and the Keggin polyanions [PMo ^VI₁₁Mo^VO₄₀]^4? (abbr. as PMo₁₂), which direct the crown-like macrocycle to form a 3-D supramolecular framework. In 2, there exist unusual meso-helix chains, and these chains are mutually interlaced in a wave–trough pattern, but without intersection resulting in a multi-cavity layer, in which the [SiW₁₂O₄₀]^4? (abbr. as SiW₁₂) clusters as guest molecules occupy the cavities of the layers. The distinct structural features of the two compounds suggest that Keggin polyanions should play a significant role in the process of assembly. Electrocatalytic properties of 1 and 2 were investigated.     

Polyoxometalates–Directed Assembly of Inorganic–Organic Hybrid Compounds with Copper Multinuclear Nano-cluster Based on Flexible Double Tetrazole-based Thioether

Two new inorganic–organic hybrid compounds constructed from different polyoxometalates (POMs) and copper multinuclear clusters, [Cu(bmte)(H₂Mo₈O₂₆)_0.5]·3H₂O (1) and [Cu₃(bmte)₃(HSiMo₁₂O₄₀)]·H₂O (2) (bmte = 1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane), have been synthesized under hydrothermal conditions with a flexible double tetrazole-based thioether and characterized by IR, TG and single-crystal X-ray diffraction analyses. In compound 1, two bmte ligands chelate two Cu^I ions with three N atoms to form a binuclear nano-scale subunit [Cu₂(bmte)₂]²⁺, then the binuclear Cu^I subunits are connected by [Mo₈O₂₆]⁴⁻ anions to build a one dimensional (1D) chain. In compound 2, a trinuclear nano-scale subunit [Cu₃(bmte)₃]³⁺ constructed from three Cu^I ions and three bmte ligands has been obtained, and the adjacent trinuclear subunits are linked by [SiMo₁₂O₄₀]⁴⁻ anions to form a “zipper” 1D chain. The adjacent chains of the title compounds are ultimately extended into 2D layers by hydrogen bonds between bmte and POMs. The structural difference of the two compounds indicates that the POMs play an important structure-directed role on the final networks. In addition, the electrochemical behavior of 2-modified carbon paste electrode (2-CPE) and its electrocatalytic reduction of nitrite have been discussed.     

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

Two new organic–inorganic hybrid compounds, [Cu^II(btb)_1.5(γ-Mo₈O₂₆)_0.5(H₂O)]·2H₂O (1) and [Cu^II₂(btb)₄(PMo^VMo^VI₁₁O₄₀)]·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.     

1-(2-Hydroxyethyl)-5-mercapto-1H-tetrazole as ligand in Cu(I) complexes with or without X-ions (X = Cl,Br, I): synthesis,crystal structures and properties

Four Cu(I) complexes with 1-(2-hydroxyethyl)-5-mercapto-1H-tetrazole (Hhmt) as a ligand, [Cu(hmt)]_n (1), [Cu₂Cl(hmt)]_n (2), [Cu₄Br(hmt)₃]_n (3), and [Cu₄I(hmt)₃]_n (4), have been synthesized. In 1–4, hmt adopts a μ₄-η^1?:^? η^1?:^? ηS² coordinate mode to join the adjacent Cu(I) ions, which form different two-dimensional (2-D) structures. In 1, the neighboring four Cu(I) atoms are connected by μ₄-hmt to form a 2-D structure. In 2, the Cu(I) ions are firstly connected with Cl ions to form a 1-D [Cu₄Cl₂] subunit chain, which then have been bridged by hmt to form a 2-D structure. However, the inorganic [Cu₄Br] and [Cu₄I] motifs are respectively connected by hmt to form 2-D structures in isostructural 3 and 4. In addition, the fluorescent properties and the thermal stability properties of 1–4 have been investigated.     

The assembly of POM-induced inorganic–organic hybrids based on copper ions and mixed ligands

Three inorganic–organic hybrid materials based on Keggin-type polyoxometalates (POMs), [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂][PMo₁₂O₄₀]₂·2H₂O (1), [Cu^II(phen)₂(H4,4′bipy)][PW₁₂O₄₀]·H₂O (2), and [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂](H₂4,4′-bipy)_0.5·3H₂O (3) (phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine), were synthesized using different POMs in the hydrothermal conditions. Compounds 1–3 were characterized by single-crystal X-ray diffraction, IR spectra, elemental analyses, powder X-ray diffraction analyses, and thermogravimetric analyses. Compound 1 presents a two-dimensional (2-D) network containing the Keggin-type [PMo₁₂O₄₀]^3? anion and dinuclear metal–organic units [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂]³⁺. Compound 2 is a 2-D architecture constructed from a [PW₁₂O₄₀]^3? and mononuclear metal–organic units [Cu^II(phen)₂(H4,4′-bipy)]³⁺. In 3, the [BW₁₂O₄₀]^5? anions link [Cu^II₂(phen)₂(4,4′-bipy)] units to form a one-dimensional (1-D) chain [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂]; the 1-D chain connects with protonated 4,4′-bipy ligands and lattice waters, yielding a 2-D layer. Fluorescence spectra, UV–vis spectra, and electrochemical properties of 1–3 have been investigated.     

U(VI) and Zn(II) coordination complexes with 5-[N-acetato(4-pyridyl)]tetrazolate anions

A U(VI) mononuclear coordination complex [UO₂(a4-ptz)₂·(H₂O)₃] (1) and a Zn(II) 1-D coordination polymer [Zn(a4-ptz)₂·(H₂O)₂]·2H₂O (2) have been synthesized with 5-[N-acetato(4-pyridyl)]tetrazolate (a4-ptz) as ligand. Complex 1 has a slightly distorted pentagonal bipyramid around each U center. Complex 2 is octahedral with four a4-ptz and two water ligands. Each Zn center is linked by carboxylate-O(1) and tetrazolate-N(2) of a4-ptz forming a 1-D polymeric chain. Complexes 1 and 2 are self-assembled to form 3-D supramolecular structures through hydrogen bonds. The luminescence properties of 1 and 2 were investigated at room temperature in the solid state. The results suggest that 1 and 2 may be useful as photoactive materials.     

Hydrothermal synthesis and structural characterization of two new reduced phosphomolybdates based on an organoamine template and copper ion

Two new compounds, (H₂en)₃(H₂enMe)₄(H₃O){Cu^I[Mo^V ₆O₁₂(OH)₃(HPO₄)(PO₄)₃]₂}?·?6H₂O (1) and (H₂enMe)₄{Cu^ICu^II[Mo^V ₆O₁₂(OH)₃(PO₄)(HPO₄)₂(H₂PO₄)]₂}?·?3H₂O (2), were hydrothermally synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray diffraction analysis. Crystallographic analysis reveals that 1 is constructed from cluster anions {Cu^I[Mo^V ₆O₁₂(OH)₃(HPO₄)(PO₄)₃]₂}^15?, protonated organic amines, and water molecules. Each cluster is bridged through hydrogen bonds to form a 3-D supermolecular structure. For 2, {Cu^I[Mo^V ₆O₁₂(OH)₃(PO₄)(HPO₄)₂(H₂PO₄)]₂}^11? are connected by Cu^II cations to form an infinite chain. The formation of 1 and 2 reveals that organoamines influence the structures of the crystals.     

Three 2-(4-thiazolyl)benzimidazole-based supramolecular assemblies oriented by Keggin and Wells–Dawson anions

Three polyoxometalate supramolecular assemblies based on rigid 2-(4-thiazolyl)benzimidazole (L) and two types of polytungstate anions, [Cu^II₂Cl(L)₄(PW₁₂O₄₀)]·3H₂O (1), [Cu^II(L)₂(H₂O)]₂[P₂W₁₈O₆₂]·(HL)₂·6H₂O (2), and [Zn^II(L)₃]₄[H(KPW₁₂O₄₀)₃] (3), have been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, and IR spectra. Compound 1 contains binuclear copper clusters {Cu₂L₄Cl}³⁺ with Cl^– as bridges. These binuclear clusters and [PW₁₂O₄₀]^3– anions construct a supramolecular 2-D layer through hydrogen-bonding interactions. In 2, the [CuL₂(H₂O)]²⁺ subunits and Wells–Dawson anions build a 1-D supramolecular chain. In 3, the [PW₁₂O₄₀]^3– anions are covalently linked by K⁺ to form an inorganic chain. These chains and discrete [Zn^II(L)₃]²⁺ subunits construct a 3-D supramolecular structure. The electrochemical and photocatalytic properties of 1–3 have been studied.     

Two yttrium(III) coordination compounds containing a3-ptz or atza [a3-ptz = 5-[N-acetato(3-pyridyl)]tetrazole; atza = 5-aminotetrazole-1-acetato]

Two yttrium(III) coordination compounds, [Y(a3-ptz)₂(H₂O)₅]Cl?·?4H₂O (1) and [Y(atza)₂(H₂O)₂(CH₃OH)]Cl (2) [a3-ptz?=?5-[N-acetato(3-pyridyl)]tetrazole; atza?=?5-aminotetrazole-1-acetato], have been synthesized. Single-crystal X-ray diffraction analysis reveals that 1 has a distorted monocapped square-antiprism coordination geometry around Y^III. Complex 2 is a distorted pentagonal bipyramid with coordination from four atza ligands, two waters, and one methanol; the coordination of atza in 2 leads to its 1-D polymeric chain structure. 1 and 2 are self-assembled to form 3-D supramolecular structures through hydrogen bonds. The luminescence properties of 1 and Ka3-ptz were investigated at room temperature in the solid state.     

Synthesis,structures, and magnetic properties of two pyrazolato-bridged trinuclear copper(II) complexes

One nonlinear and one linear trinuclear copper(II) complex [Cu₃(dien)₂(pdc)₂CH₃OH]₂?·?6CH₃OH (1) and [Cu₃(pdc)₂(CH₃OH)₆(H₂O)₄] (2) were prepared and characterized structurally, where dien is diethylenetriamine and pdc^3? the trianion of 3,5-pyrazoledicarboxylic acid. Both complexes consist of 3,5-pyrazoledicarboxylato-bridged trinuclear copper(II) centers. In 1, copper(II) ions are five-coordinate in distorted square pyramids with bond angles 164.78° for Cu(1)–Cu(2)–Cu(3) and 164.51° for Cu(4)–Cu(5)–Cu(6). In 2, the three copper(II) ions are six-coordinate with elongated octahedral geometry. The trinuclear units of 1 and 2 interact through hydrogen bonds to form 3-D and 2-D supramolecular networks, respectively. Variable temperature magnetic susceptibility measurements show that 1 and 2 are antiferromagnetically coupled with J values of ?11.2 and ?13.3?cm^?1.     

Two organic–inorganic hybrid compounds constructed from [PMoV1MoVI7VIV2VV4O42]4− and different transition metal fragments

Two new organic–inorganic hybrid compounds, [Cu(phen)(prz)]₂[PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂]·4H₂O (1) and [Ag₂(phen)₄]₂[PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂] (2) (phen = 1,10-phenanthroline, prz = pyrazine), have been synthesized and characterized by IR, XPS, XRD, UV–vis, fluorescent spectra analyses, elemental analyses, X-ray diffraction analyses, TG analyses, and cyclic voltammetric measurements. Both compounds are formed by Keggin POM cores and transition metal fragments. Compound 1 exhibits an unprecedented 1-D chain structure constructed from [PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂]^4? and [Cu(phen)(prz)]²⁺ in the –A–B↑–C–B↓– linking mode. Compound 2 shows a supramolecular structure formed by [PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂]^4? and [Ag₂(phen)₄]²⁺.     

Crystal structure and characterization of two cadmium(II) coordination polymers with a multidentate N-donor tecton 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole

Two new cadmium(II) complexes [Cd_1.5(L)Cl₂(H₂O)]_{2 n} (1) and [CdL₂] _n (2) with a multidentate N-donor building block 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (HL) have been prepared and characterized by elemental analysis, infra-red spectra, powder X-ray diffraction (XRD), and single-crystal XRD. 1 is a 2-D layered coordination polymer constructed from linkage of [Cd₃(μ-Cl)₄] trinuclear units with HL spacers, while 2 shows a 2-D layer structure. 3-D supramolecular architectures are further assembled in 1 and 2 via hydrogen-bonding contacts. Both 1 and 2 are thermally stable to 450?°C, and 2 showed strong fluorescent emission bands.     

Synthesis,structures, sorption and magnetic properties of coordination polymers based on 3d metal pivalates and polydentate pyridine-type ligands

The reactions of 3d metal pivalates with pyridine-containing ligands of different structures afforded the 1D coordination polymers [Co₂(Piv)₄(dpe)₂] _n , [Ni(Piv)₂(dpe)(EtOH)₂] _n , [Cu₂(Piv)₄(dpe)] _n , [Cu(Piv)₂(dpe)] _n , [Ni(Piv)₂(4-ptz)(EtOH)₂] _n , and [Cu₂(Piv)₄(4-ptz)· ·mSolv] _n (Solv is EtOH, m = 2; Solv is C₆H₆, m = 1; Piv^? is pivalate, dpe is trans-1,2-bis(4-pyridyl)ethylene, 4-ptz is 2,4,6-tris(4-pyridyl)-1,3,5-triazine), as well as the 3D coordination polymer [{Cu₂(Piv)₄}₃(3-ptz)₂] _n (3-ptz is 2,4,6-tris(3-pyridyl)-1,3,5-triazine). The sorption and magnetic properties of a series of the synthesized compounds and magnetic properties of the earlier characterized coordination polymer [Mn₂(O₂CC₆H₅)₄(dpe)₂·dpe] _n were studied. It was shown that the desolvation of the complexes [Ni(Piv)₂(4-ptz)(EtOH)₂] _n and [Cu₂(Piv)₄-(4-ptz)·2EtOH] _n resulted in the formation of the crystal structures, in which the pores are accessible to nitrogen and hydrogen at 78 K (S _BET are up to 92 m² g^?1). The temperature dependences of the molar magnetic susceptibility for [Co₂(Piv)₄(dpe)₂] _n , [Mn₂(O₂CC₆H₅)₄-(dpe)₂·dpe] _n , [Ni(Piv)₂(dpe)(EtOH)₂] _n , [Ni(Piv)₂(4-ptz)(EtOH)₂] _n , and [Cu₂(Piv)₄-(4-ptz)·2EtOH] _n are described in terms of models taking into account the zero-field splitting and exchange interactions or isotropic exchange Hamiltonians.     

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

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 Cu^II-bbtz lines are connected by SiMo₁₂ anions and bbtz to generate a ladder-like chain. Adjacent chains share the same Cu^II 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 Cu^II 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.     

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

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 cadmium compounds with adenine and carboxylate ligands: syntheses,structures and photoluminescence

Two cadmium(II) coordination compounds, [Cd₃(CH₃CO₂)₄(ad)₂(CH₃CN)₂]_n (1) and [Cd₃(5-SIP)₂(H-ad)₂(H₂O)₆]_n (2) (H-ad = adenine and 5-SIP = 5-sulfoisophthalate), were synthesized and characterized. Compound 1 features a two-dimensional (2-D) layered structure based on linear trinuclear [Cd₃(CH₃CO₂)₄] units bridged by monoanionic adenine ligands. In 2, the 5-SIP^3? ligands link Cd(II) ions to form a one-dimensional (1-D) ladder, which is further linked by neutral adenine ligands to give a 2-D layered structure. In both structures, the carboxylate ligands link Cd(II) ions to form low-dimensional structures, which are further connected by adenine ligands to give high-dimensional structures. Compounds 1 and 2 exhibit emissions centered at 382 and 416 nm, respectively, which can be attributed to the ligand centered π–π* transition.     

A new hybrid material constructed from octamolybdate anion and neutral dinuclear copper units

A new organic–inorganic hybrid material constructed from octamolybdate anion and neutral dinuclear copper(I) units, H₄{[Cu₂(ophen)₂]₂[Mo₈O₂₆]}[Cu₂(ophen)₂] · H₂O (1) (Hophen =2-hydroxy-1,10-phenanthroline), has been prepared under hydrothermal condition and characterized by elemental analysis, IR, XPS, TGA and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P 1, with a = 9.9091(8), b = 13.3981(8), c = 14.8266(10) Å, α = 84.6310(10), β = 83.0620(10)°, γ = 77.7800(10), V = 1905.0(2) ų, Z = 1. Compound 1 contains a centrosymmetric polyoxoanion {[Cu₂(ophen)₂]₂[Mo₈O₂₆]}^4?, in which the β-[Mo₈O₂₆]^4? is bisupported by two copper(I) coordination groups through the terminal oxygen atoms. The discrete molecules of 1 are extended into a 3-D supramolecular array through C–H ··· O hydrogen bonds and strong aromatic π–π stacking contacts.     

Effect of the central metal on coordination of 1,10-phenanthroline-5,6-dione in Keggin-based hybrid compounds

Two new Keggin-based hybrid compounds, [Cu₂(pdon)₃][PMo^VI ₁₁Mo^VO₄₀]·3H₂O (1) and [Mn₂Cl(H₂O)₂(pdon)₄][PMo₁₂O₄₀]·2H₂O (2) (pdon = l, l0-phenanthroline-5,6-dione) (pdon), were synthesized under hydrothermal conditions. By using different metal ions and tuning the ratio of metal to ligand, pdon shows different coordination modes. In compound 1, pdon with three kinds of coordination modes link Cu^II ions to form a 1D wave chain and Keggin-type polyanions [PMo^VI ₁₁Mo^VO₄₀]^4? fringe this 1D chain; hydrogen bonding interactions extend these 1D chains into a 2D supramolecular network. Compound 2 exhibits a discrete structure, in which pdon shows a single chelating coordination. Electrochemical properties of the title compounds have been investigated.