Bulk-modified Carbon Paste Electrode Research Articles

Reduction products-directed different electrochemical sensing performance of polymolybdate-based metal-organic complex

In this paper, a kind of electrochemical sensing material with tunable activity and high stability is fabricated from polymolybdate-based metal–organic complex. The polymolybdate-based metal–organic complex: H2Ni(nppa)2(H2O)2[γ-Mo8O26] (1) is synthesized by introducing a flexible pyrazine-pyridine ligand containing amine groups: N-(pyridin-3-yl)pyrazin-2-amine (nppa) under hydrothermal condition. Complex 1 exhibit 1D chain structure based on polyoxoanions and metal ions. The nppa ligands are decorated on the 1D chain in monodentate fashion. Bulk-modified carbon paste electrode (CPE) fabricated by the title complex is used as the working electrode for electrochemically sensing inorganic and organic molecules in aqueous systems. 1-CPE displays electrochemical sensing activity towards BrO3– and ascorbic acid (AA) with low detection limits of 1.22 and 0.76 μM, respectively. Meanwhile, 1-CPE can achieve tunable electrochemical sensing performance, relying on different catalytic activity of reduction products corresponding to multi-step redox reactions. Additionally, its electrochemical activity can be retained under different acid environment.

Polyoxometalate-based metal–organic complexes constructed from a new bis-pyrimidine-amide ligand with high capacitance performance and selectivity for the detection of Cr(VI)

In this paper, three new polyoxometalates (POM)-based metal–organic complexes constructed from a new semi-rigid organic ligand N,N'-bis(4-pyrimidinecarboxamido)-1,2-cyclohexane (4-bpmah) H2[Cu(4-bpmah)2(SiMo12O40)(H2O)2]·2H2O (1), H[Cu(4-bpmah)2(PMo12O40)(H2O)2]·2H2O (2) and [Cu(4-bpmah)(H2O)2]·[Cu2(TeMo6O24)(H2O)10]·4H2O (3) were synthesized by hydrothermal method. Single crystal X-ray analyses showed that complexes 1 and 2 were isostructural, in which the isolated Keggin-type [SiMo12O40]4–/[PMo12O40]3– anions and [Cu(4-bpmah)2(H2O)2]2n+ units were expanded into 3D supramolecular structures through hydrogen bond interactions. In complex 3, the 1D [Cu(4-bpmah)(H2O)2]2n+ metal–organic chains and isolated [Cu2(TeMo6O24)(H2O)10]2n– units were expanded into a 3D supramolecular framework by the hydrogen bond interactions. In this paper, carbon cloth working electrodes composited by the title complexes (1/CC, 2/CC and 3/CC) were prepared and used as electrodes for supercapacitors. The performance of supercapacitors as well as the influence of electrolyte solution and title complexes quality load on the performance of supercapacitors were studied. Furthermore, the electrochemistry and electrocatalytic behaviors of complexes 1–3 bulk-modified carbon paste electrodes (1-CPE, 2-CPE and 3-CPE) toward the reduction of KBrO3, KNO2, Cr(VI), as well as their sensing behaviors on Cr(VI) were investigated.

Three polyoxometalates-based organic-inorganic hybrids decorated with Cu-terpyridine complexes exhibiting dual functional electro-catalytic behaviors.

By adjusting polyoxometalates in the same POM/Cu/terpyridine reaction systems, three new organic-inorganic hybrid solid materials based on Cu-terpyridine complexes, [Cu3(tpy)3(H2O)2(HPMoVI8VIV4O40(VIVO)2)]·2H2O (1), Cu5(tpy)5(H2O)2(α-PW12O40)2 (2), and [Cu3(tpy)3(H2O)4(α-P2W18O62)]·4H2O (3) (tpy = 2,2':6',2''-terpyridine), were prepared by using one-pot methods. X-ray structural analyses show that compounds 1-3 with a 1D chain structure constructed from Cu/tpy complexes were modified using bi-capped Keggin, Keggin and Wells-Dawson POMs. Compounds 1-3 have been fabricated to a bulk-modified carbon paste electrode to explore the electrochemical properties. Cyclic voltammetry demonstrates discrepant dual functional electro-catalytic activities toward the reduction of nitrite and the oxidation of ascorbic acid because of variant POMs. The results show that the PW12-Keggin-type hybrid exhibits a better dual functional electro-catalytic performance than bi-capped Keggin and Wells-Dawson hybrids for the reduction of nitrite and the oxidation of ascorbic acid.

Ionic liquids of imidazolium salts comprising hexamolybdate cluster: Crystal structures and characterization

The present work reports on the synthesis, crystal structure, thermal stability, conductivity and electrochemical behaviors of three new metal-containing ionic liquids(MILs) [CnH2n+1-mim]2[Mo6O19] (n=14, 16, 18) (mim=methylimidazole). Their structures were characterized by X-ray crystallography, IR spectroscopy and elemental analysis. The crystal packing consists of alternating inorganic bilayers of hexamolybdate and organic bilayers of 1-alkyl-3-methylimidazolium. Each [Mo6O19]2− is sandwiched among the four imidazolium rings in one layer, and connected to the imidazolium heads in neighboring layer through hydrogen bonds. The thermal behaviors of them were studied by differential scanning calorimetry and thermogravimetry. The melting point of three MILs are below 100°C and all of them show good thermal stability. The electrochemical behavior and electrocatalysis of three MILs bulk-modified carbon paste electrodes have been studied by cyclic voltammetry. The modified electrode shows good electrocatalytic activity towards the reduction of bromopropionic acid.

Bifunctional electro-catalysts based on the Keggin/Dawson-type polyoxotungstates and Cu-tris(imidazolyl) complexes

Three new inorganic-organic hybrid compounds based on the Keggin/Dawson POMs, [Cu2(Htib)2 (α-SiW12O40)] (1), [Cu2(Htib)2(H2tib)2 (H2O)4(α-HBW12O40)2]·8H2O (2), and [Cu2(H2tib)4(H2O)2(α-HP2W18O62)2]·14H2O (3) (tib=1,3,5-tris(1-imidazoly) benzene), have been obtained through hydrothermal methods. X-ray structural analyses show that compounds 1–3 are constructed from Cu-tib modified Keggin/Dawson POMs. Compounds 1–3 have been employed to fabricate bulk-modified carbon paste electrode (CPE) (noted as n-CPEs, n=1–3) to study their electrochemical properties. Cyclic voltammetries of n-CPEs (n=1–3) display bifunctional electrocatalytic activities toward reduction of nitrite and oxidation of ascorbic acid.

Structural and catalytic performance of a polyoxometalate-based hybrid compound

By introducing long rigid ligands into polyoxometalate (POM) systems, a new POM-based hybrid compound with CDS topology, {[Cu(bpe)]2(H2SiMo12O40)}·(bpe)·2H2O (1) (bpe = bis(4-pyridyl)ethylene), has been hydrothermally synthesized and characterized by physical methods. Single-crystal X-ray diffraction analysis shows that the ladder-like 1-D structure of 1 is formed from Keggin clusters modified by the wavy ([Cu(bpe)]n) chains. Compound 1 contains two types of tunnels along the a axis and the [1–10] axis, which are occupied by isolated bpe molecules. Compound 1 bulk-modified carbon paste electrode (1-CPE) displays good electrocatalytic activity toward the reduction of nitrite and bromate, and photocatalytic activities indicate that 1 presents good degradation activity and may be a photocatalyst to decompose some organic dyes.

Structural and catalytic performance of a polyoxometalate-based hybrid compound

By introducing long rigid ligands into polyoxometalate (POM) systems, a new POM-based hybrid compound with CDS topology, {[Cu(bpe)]2(H2SiMo12O40)}·(bpe)·2H2O (1) (bpe = bis(4-pyridyl)ethylene), has been hydrothermally synthesized and characterized by physical methods. Single-crystal X-ray diffraction analysis shows that the ladder-like 1-D structure of 1 is formed from Keggin clusters modified by the wavy ([Cu(bpe)]n) chains. Compound 1 contains two types of tunnels along the a axis and the [1–10] axis, which are occupied by isolated bpe molecules. Compound 1 bulk-modified carbon paste electrode (1-CPE) displays good electrocatalytic activity toward the reduction of nitrite and bromate, and photocatalytic activities indicate that 1 presents good degradation activity and may be a photocatalyst to decompose some organic dyes.

Hydrothermal Synthesis, Characterization and Electrocatalytic/Photocatalytic Activities of New Polyoxometalate Based Hybrid Compound

In this paper, we report the hydrothermal synthesis and physicochemical characterization of a complicated high-dimensional and high-connected POM-based hybrid compound, namely, [Ag3(pytz)2(H2O)]2.[HAgGeMo12O40]·H2O, which has been synthesized by reactions of pyridyltetrazoles and Keggin POMs. X-ray diffraction and crystallographic analyses reveals that the new compound exhibits POMs chains pillaring transition-metal complexes, which represents the highest coordination number of Keggin POMs up to date. Moreover, the new compound bulk-modified carbon-paste electrode (1-CPE) displays good electrocatalytic activity toward the reduction of nitrite, and the result of the photocatalytic activities indicates that the new compound presents better degradation activity and may be a potential photocatalyst to oxidative decomposition of rhodamine B dye in the presence of crystals [Ag3(pytz)2(H2O)]2·[HAgGeMo12O40]·H2O catalyst under ultraviolet-light irradiation.

Polycarboxylate-assisted assembly of cobalt(II) metal–organic coordination polymers from a “V”-shaped tri-pyridyl-bis-amide ligand

The aim of this study was to explore the influence of the position and angles of carboxyl groups of polycarboxylates on constructing coordination polymers. Three Co(II) metal–organic coordination polymers based on a tri-pyridyl-bis-amide ligand, namely [Co(L)(1,2-BDC)(H2O)2]·2H2O (1), [Co(L)(1,4-BDC)(H2O)2]·2H2O (2) and [Co(L)2(BTEC)0.5]·H2O (3) (L = N,N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,4-H2BDC = 1,4-benzenedicarboxylic acid, H4BTEC = 1,2,4,5-benzenetetracarboxylic acid), have been obtained by tuning the auxiliary polycarboxylate ligands. Structural analyses reveal that complexes 1–3 display diverse structures. Complex 1 displays a meso-helical chain linked by L ligands, which is further extended into a three-dimensional supramolecular framework through hydrogen-bonding interactions. The 1,2-BDC with a chelating coordination mode only acts as the hydrogen bond acceptor. In complex 2, the 1,4-BDC anions connect adjacent Co(II) atoms to form a linear chain, which is connected by hydrogen-bonding interactions to construct a 3D supramolecular network. Complex 3 exhibits a chain, which is composed of left-/right-handed Co-L helical chains and Co-BTEC linear chain. The 1D chains are ultimately extended into a two-dimensional supramolecular network by hydrogen-bonding interactions. Moreover, the thermal stability and the fluorescent properties of the title complexes and the electrochemical behaviors of a bulk-modified carbon paste electrode with complex 2 have been investigated at room temperature.

Synthesis and structure of a new polyoxometalate-based inorganic–organic hybrid and application as a chemically bulk-modified electrode

A new Keggin-type polyoxometalate-based inorganic–organic hybrid, [Cu(H2O)2(daphen)]2[SiW12O40]·9H2O (1) (daphen = 5,6-diamino-1,10-phenanthroline), was hydrothermally synthesized, and characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, fluorescence spectra, and thermal analysis. Single-crystal X-ray diffraction analysis reveals that in 1, [SiW12O40]4− is a tetradentate ligand with its four terminal oxygens coordinating to four Cu(II)–daphen fragments to form a 2D sheet with (4,4) topology. On the basis of the insolubility of 1 in water and common organic solvent and its reversible multielectron redox processes, 1 was used to fabricate a bulk-modified carbon paste electrode (1-CPE) by direct mixing. Electrochemistry indicated that 1-CPE is stable over hundreds of cycles and possessed electrocatalytic activity toward the reduction reactions of nitrite.

Effect of organic bicarboxylates on the structures of cobalt(II) coordination polymers derived from a semi-rigid bis(benzimidazole) derivative

Two new Co(II) coordination polymers, [Co(L)(glu)] (1) and [Co(L)(npht)]·H2O (2) (H2glu = glutaric acid, H2npht = 3-nitrophthalic acid, L = 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene), have been hydrothermally synthesized by self-assembly of cobalt chloride with a semi-rigid bis(benzimidazole) derivative and different organic bicarboxylic acids. Single crystal X-ray diffraction analysis reveals that complex 1 is a one-dimensional tube-like coordination polymer containing one helical [Co-L] and two linear [Co-glu] chains. In complex 2, two npht ligands connect two Co(II) atoms to form a binuclear [Co(npht)]2 subunit, which is further linked by L ligands with two kinds of conformations to form a 3-D CdSO4-like framework. In addition, the electrochemical behaviors of the title complexes in bulk-modified carbon paste electrodes, and their thermal stabilities and fluorescent properties were investigated in this paper.

Two copper(II) metal–organic networks derived from bis-pyridyl-bis-amide ligands and aromatic polycarboxylates: a 2-D layered structure and a 4-connected trinodal 3-D topology

Two metal–organic coordination polymers, [Cu3(4-bpcb)2(1,2,4-btc)2(H2O)2] (1) and [Cu3(3-bpcb)3(btec)1.5] (2), have been synthesized from hydrothermal reaction of copper chloride with mixed ligands [4-bpcb = N,N′-bis(4-pyridinecarboxamide)-1,4-benzene, 3-bpcb = N,N′-bis(3-pyridinecarboxamide)-1,4-benzene, 1,2,4-H3btc = 1,2,4-benzenetricarboxylic acid, and H4btec = 1,2,4,5-benzenetetracarboxylic acid]. X-ray diffraction analysis reveals that 1 exhibits a 2-D layer structure and 2 possesses a three-dimensional (3-D) network. In 1 and 2, CuII ions are connected by bridging 1,2,4-btc or btec to form 2-D polymeric layers. Cu-1,2,4-btc layer does not propagate into a 3-D coordination framework in 1 due to 4-bpcb showing monodentate coordination (via ligation of only one pyridyl nitrogen). In 2, Cu-btec 2-D layers are further extended into a 3-D network with (64.82)3 topology by 3-bpcb ligand in μ 2-bridging coordination (via ligation of two pyridyl nitrogens). The different structures of the two complexes illustrate the influence of different polycarboxylates and N-donor positions of organic ligands on the formation of such coordination architectures. Moreover, the thermal properties and electrochemical properties of the copper complexes bulk-modified carbon paste electrodes have been studied.

A new POM-templated metal–organic complex based on the flexible bis-pyridyl-bis-amide ligand

A new POM-templated metal–organic complex [Cu4(L)7(H2O)12(SiMo12O40)2]·7H2O [L = N,N′-bis(3-pyridinecarboxamide)-1,6-hexane], has been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The results reveal that the complex is a 2D metal–organic coordination framework of [Cu4(L)7(H2O)12]n8n+ cations containing decanuclear cycles with dimensions of ca. 17.55 × 57.42 A, in which the SiMo12O404− anions act as non-coordinated anionic templates. The electrochemical properties of a bulk-modified carbon paste electrode of the complex have been investigated, and the results indicate that the complex-modified CPE has good electrocatalytic activity toward the reduction of nitrite in aqueous 1 M H2SO4 solution.

The Role of the Coordination Modes of a Flexible Bis(pyridylamide) Ligand in the Topology of 2D Copper(II) Complexes

Two new two-dimensional copper(II) coordination polymers, [Cu(L)(BDC)]_H2O (1) and [Cu2(L)0:5(SIP)(OH)(H2O)] 2H2O (2) [L=N;N0-bis(3-pyridylamide)-1,6-hexane, H2BDC=1,3- benzenedicarboxylic acid, H3SIP=5-sulfoisophthalic acid (3,5-dicarboxybenzenesulfonic acid)], have been synthesized hydrothermally by self-assembly of the flexible bis-pyridyl-bis-amide ligand L and the aromatic polycarboxylate ligands H2BDC or H3SIP. X-Ray diffraction analysis reveals that complex 1 displays a metal-organic coordination layer with a binodal (3,5)-connected {42.67.8}{42.6} topology, in which the L ligands adopt a m2-bridging mode (via ligation of the pyridyl nitrogen atoms). Complex 2 also exhibits a layered network based on tetranuclear copper clusters [Cu4(μ3-OH)2(H2O)2(O2C-)4], L ligands and SIP anions, showing a binodal (4,8)-connected network with {414.610.84}{44.62} topology, in which the L ligands adopt a μ6-bridging coordination mode (via ligation of the pyridyl nitrogen and carbonyl oxygen atoms). Adjacent layers in 1 and 2 are further linked by hydrogen bonding interactions to form three-dimensional supramolecular frameworks. The electrochemical behavior of the two complexes in bulk-modified carbon paste electrodes has been investigated

Two new 2D copper(II) complexes constructed from a flexible bis-pyridyl-bis-amide ligand and two aromatic tricarboxylates: syntheses, crystal structures, fluorescence, and electrochemical properties

Two new 2D metal-organic complexes, namely [Cu(3-dpyb)(1,2,4-HBTC)(H2O)]·H2O (1) and [Cu3(3-dpyb)3(SIP)2(H2O)8]·6H2O (2) [3-dpyb = N,N’-bis(3-pyridinecarboxamide)-1,4-butane, 1,2,4-H3BTC = 1,2,4-benzenetricarboxylic acid, H3SIP = 5-sulfoisophthalic acid], have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction analyses. Single crystal X-ray analyses reveal that the two Cu(II) complexes show different 2D coordination networks, the 4-connected (44·62) topology for complex 1 and the (4·62)2(42·62·82) topology for complex 2. In the 2D layers of complexes 1 and 2, the 3-dpyb ligands adopt a typical μ 2-bridging mode (via ligation of two pyridyl nitrogen atoms), while 1,2,4-HBTC and SIP serve as a linear spacer and a ‘V’-like linker, respectively, to connect the adjacent Cu(II) centers. The adjacent 2D layers are extended to 3D supramolecular networks via hydrogen-bonding interactions. The fluorescence properties of both complexes and electrochemical properties of complex 2 have also been investigated. The complex 2 bulk-modified carbon paste electrode (2-CPE) displayed a one-electron redox wave in potential range of 600–200 mV in 1 M H2SO4 aqueous solution, and 2-CPE showed good electrocatalytic activity toward the reduction of nitrite.

Tuning the oxidation states of copper ions (+I/+II) to construct different Keggin-based topology structures

Through tuning the oxidation states of CuI/II, two Keggin-based compounds with different topologies, [(btx)4(PO40)] (1) and [(btx)4(SiW12O40)] (2) (btx = 1,6-bis(1,2,4-triazol-1-y1)hexane), were synthesized and structurally characterized. In 1, there exist decanuclear CuI circuits, which are linked through N1-containing btx ligands to construct a grid-like 2-D layer. Three sets of these layers interpenetrate to build a three-fold interpenetrating framework. The Keggin polyanions connect the adjacent three-fold interpenetrating frameworks to construct a 3-D structure. In 2, the CuII-btx moiety shows a (66) 3-D hexagonal channel-style framework. The Keggin polyanion offering four terminal oxygen atoms incorporates with this metal–organic framework imbedding the channels. The different oxidation states of copper ions (+I/+II) induces distinct coordination modes of btx and Keggin polyanions and affects the whole structural topologies. Tuning the oxidation states of copper ions is an effective strategy for obtaining POM-based topologies. In addition, the electrochemical properties of 1 and 2 bulk-modified carbon-paste electrodes are reported.

Two Supramolecular Microporous Metal–Organic Frameworks Templated by Keggin Polyoxometalates

Two new Keggin polyoxometalates (POM)-templated supramolecular metal–organic frameworks (MOF) with micropores, Cu3(L)6[H3(PMo12O40)2]·6H2O (1) and Cu3(L)6[H5(SiW12O40)2]·6H2O (2) (L = 1,2-bis(imidazol-1-ylmethyl)ethane), have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and cyclic voltammetry. These two isostructural compounds are constructed by two distinct moieties, a Keggin polyanion and a linear [Cu(L)2]+ subunit. The [Cu(L)2]+ subunits further form a microporous MOF through supramolecular interactions. The Keggin polyanions act as templates inducing the micropores. The electrochemical and electrocatalytic behavior of compounds 1 and 2 bulk-modified carbon paste electrodes (1-, 2-CPE) was studied.

Two new inorganic–organic hybrids based on Keggin polyoxometalate and methylene blue and application in chemically bulk-modified electrode

Two new inorganic–organic hybrids based on Keggin polyoxometalate and methylene blue (MB), [C16H18N3S]4[PMo12O40]·2DMF·H2O (1) and [C16H18N3S]4[GeMo12O40]·2DMF·H2O (2), were synthesized and characterized. X-ray diffraction analysis shows that the organic layers composed of the parallel MB cations and the inorganic layers of discrete Keggin polyoxoanions are alternatively arranged, and UV–vis diffuse reflectance spectra in the solid state indicate the presence of new bands attributed to charge-transfer transitions between the organic dye donors and polyoxometalate acceptors. The two charge-transfer salts 1–2 were used as a solid bulk modifier to fabricate a three-dimensional bulk-modified carbon paste electrode (1-CPE and 2-CPE). The results show that both 1-CPE and 2-CPE present stability and have good electrocatalytic activities toward the reduction of chlorate, bromate and nitrite.

Three copper(II) complexes connected through tetradentate carboxylate linkers and bidentate N-heterocyclic ligands: From 3-D MOF to 1-D chain

Three copper coordination polymers [Cu2(bbtc)(bbi)2]·3H2O (1) [bbi = 1,1-(1,4-butanediyl)bis(imidazole), bbtc = 3,3′,4,4′-benzophenonetetracarboxylate], [Cu3(Hbbtc)2(3-bpfp)3(H2O)2]·10H2O (2) [3-bpfp = bis(3-pyridylformyl)piperazine], and [Cu(H2bbtc)(4-bpfp)(H2O)]·H2O (3) [4-bpfp = bis(4-pyridylformyl)piperazine] have been hydrothermally synthesized by self-assembly of aromatic tetracarboxylate ligand bbtcd [bbtcd = 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride], and bidentate N-heterocyclic ligands bbi, 3-bpfp or 4-bpfp. X-ray diffraction analysis reveals that compound 1 is a novel three-dimensional (3-D) metal-organic framework with a binodal (4,4)-connected {62.84}{64.82}2 topology. Compound 2 possesses a two-dimensional (2-D) layered structure, in which a trinodal (3,4,4)-connected network with novel {3.62}2{3.63.72}2{32.62.72} topology can be found. Compound 3 displays a one-dimensional (1-D) ribbon polymer chain based on 4-bpfp ligands and H2bbtc2- anions. The adjacent layers for 2 and the adjacent chains for 3 are further linked by hydrogen bonding and π–π stacking interactions to form 3-D supramolecular networks. Importantly, bbtcd with different protonation extent displays three different coordination modes in compounds 1–3: the four carboxyl groups of bbtc4- anions combine with CuII ions by tetra(monodentate) mode in 1, three carboxyl groups of Hbbtc3− anions show tri(monodentate) coordination mode and the fourth carboxyl group is protonated in 2, whereas for 3 only two carboxyl groups H2bbtc2− anions adopt bis(monodentate) coordination mode and the other two are protonated. N-heterocyclic ligands play important roles in the construction of title complexes with different dimensionality. In addition, the electrochemical properties of the three copper compounds bulk-modified carbon paste electrodes have been reported.

Syntheses, crystal structures, and electrochemical properties of two cobalt complexes constructed with benzene tricarboxylates and 2,5-bipyridyl-1,3,4-oxadiazole

Two new cobalt complexes based on benzene tricarboxylates 1,2,4-H3BTC (1,2,4-H3BTC = 1,2,4-benzenetricarboxylate) or 1,3,5-H3BTC (1,3,5-H3BTC = 1,3,5-benzenetricarboxylate), and the bent dipyridyl ligand 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) or its 4-pyridyl N-donor analog (4-bpo), formulated as [Co(1,3,5-BTC)(4-bpo)(H2O)3]2[Co(H2O)6] · 10H2O (1) and [Co3(1,2,4-BTC)2(3-bpo)2(H2O)12] (2), have been hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, TG analyses, and single-crystal X-ray diffraction. Structure analysis reveals that 1 is a 3-D porous supramolecular network based on the 1-D polymer chain , in which discrete [Co(H2O)6]2+ units and lattice water molecules are dispersed. In 2, bridging 3-bpo and 1,2,4-BTC connect cobaltions to form a trinuclear cobalt unit. Adjacent trinuclear cobalt units are further linked by π–π stacking interactions and hydrogen-bonding interactions to form a 3-D supramolecular framework. Electrochemical properties of cobalt(II) compounds bulk-modified carbon paste electrodes (1-CPE and 2-CPE) have been studied.