Two cobalt(II) complexes based on a flexible bis(5,6-dimethylbenzimidazole) and rigid organic dicarboxylate ligands

Two new bis(5,6-dimethybenzimidazole)-based Co^II complexes, Co(pydca)(L)₂·2H₂O (1) and [Co(bdc)(L)] _n (2) (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)-2-propanol, H₂pydca = pyridine-2,6-dicarboxylic acid, H₂bdc = 1,4-benzenedicarboxylic acid) were synthesized and characterized by physicochemical, spectroscopic methods and single-crystal diffraction. The cobalt(II) centers display different environments with distorted square-pyramidal geometry in 1 and a perfect tetrahedral geometry in 2. Complex 1 is a mononuclear structure, which is further assembled into a 3D supramolecular network via strong hydrogen bonding as well as π–π interactions; while complex 2 possesses a 2D corrugated (4,4) network that is further formed into a (3,4,4)-connected network with (6².8⁴)(6³)₂(6⁴.8²)₂-3,4,4T25 topology due to classical hydrogen bonds. The fluorescence and catalytic performances of the two complexes for the degradation of methyl orange by sodium persulfate have been investigated.     

Diverse topologies of three cobalt(II) coordination polymers constructed from flexible bis(benzimidazole) and dicarboxylate ligands

Three cobalt(II) coordination polymers {[Co(L1)(nda)(H₂O)₂]·2H₂O} _n (1), [Co(L2)(tbi)(H₂O)] _n (2) and [Co(L2)(bpdc)(H₂O)] _n (3) (L1 = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)-2-propanol, L2 = 1,3-bis(benzimidazol-1-yl)-2-propanol, H₂nda = 2,6-naphthalenedicarboxylic acid, H₂tbi = 5-tert-butyl isophthalic acid and H₂bpdc = 4,4′-biphenyldicarboxylic acid) were synthesized and characterized by physicochemical and spectroscopic methods. Complex 1 exhibits a 1D loop-like structure, which is further extended into a 3D 3,3,4T31 network through two O–H···O hydrogen bonding interactions. Complex 2 displays a 1D ladder-like chain, arranged into a 2D supramolecular network with 3,3,4L34 topology via classical O–H···O hydrogen bonding interactions, whereas complex 3 features a 2D 3,4L13 layer structure and further assembles into a 3D framework with a twofold interpenetrating sqc65 topology through O–H···O hydrogen bonding interactions. The fluorescence and catalytic properties of these complexes for the degradation of Congo red in a Fenton-like process have been investigated.     

Two manganese(II) coordination polymers containing semirigid bis(benzimidazole) ligands: synthesis,crystal structures,and catalytic properties

Two ternary mixed Mn(II) coordination polymers (CPs), namely [Mn(L1)(Hnip)₂] _n (1) and [Mn(H_0.5L2)₂(H_1.5btc)₂] _n (2) (H₂nip = 5-nitroisophthalic acid, L1 = 1, 4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H₃btc = 1,3,5-benzenetricarboxylic acid, L2 = 4,4′-bis(benzimidazol-1-ylmethyl)biphenyl), have been synthesized under hydrothermal conditions and structurally characterized. CP 1 exhibits a non-interpenetrated six-connected pcu framework with the point symbol {4¹²·6³}, while CP 2 features a metal-carboxylate loop-like chain, which is further assembled into a 3D supramolecular network via hydrogen bonds and π–π interactions. The thermal stabilities, luminescence, and catalytic properties of both CPs for the degradation of methyl orange in a Fenton-like reaction have also been investigated.     

Synthesis,characterization, and crystal structures of 2D cobalt(II) and nickel(II) coordination polymers containing flexible bis(benzimidazole) ligands

Three coordination polymers, namely {[Ni(L1)(nip)(H₂O)]·2H₂O} _n (1), [Co(L2)(tbip)] _n (2), and {[Co₂(L3)₂(bptc)]·3H₂O} _n (3) (L1 = 1,4-bis(5,6-dimethylbenzimidazole)butane, L2 = 1,4-bis(5,6-dimethylbenzimidazole)-2-butylene, L3 = 1,3-bis(5,6-dimethylbenzimidazole)propane, H₂nip = 5-nitro-isophthalic acid, H₂tbip = 5-tert-butyl-isophthalic acid, H₄bptc = biphenyl-3,3′,4,4′-tetracarboxylic acid), have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single-crystal X-ray diffraction analysis. Complexes 1 and 2 both feature a two-dimensional (4,4) layer with (4⁴ × 6²) topology. Complex 3 possesses a uninodal 4-connected 2D htb network. The fluorescence spectra and catalytic properties of the complexes for the degradation of methyl orange by sodium persulfate in a Fenton-like process are reported.     

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.     

Synthesis,crystal structures,luminescence, and photocatalytic properties of two 1D Co(II) coordination polymers constructed with semirigid bis(benzimidazole) and dicarboxylate ligands

Two ternary cobalt(II) coordination polymers (CPs), namely [Co(L1)(npht)] _n (1) and {[Co₂(L2)₂(npht)₂(H₂O)]·H₂O} _n (2) (L1 = 4,4′-bis(benzimidazol-1-ylmethyl)biphenyl, L2 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, and H₂npht = 4-nitrophthalic acid) have been synthesized and structurally characterized by X-ray crystallography. Both CPs feature similar 1D infinite chains containing two distinct loops. CP 1 further forms a 3D supramolecular network via weak C–H···O hydrogen bond interactions. CP 2 shows a 1D two-layer chain structure, assembled through π–π stacking interactions. The electrochemical, luminescence, and photocatalytic activities of the two CPs for the removal of methylene blue under visible or UV light were investigated. Possible photocatalytic mechanisms are discussed.     

One- and two-dimensional cobalt(II) coordination polymers derived from flexible bis(benzimidazole) and aromatic carboxylate co-ligands

Two new coordination polymers, formulated as [Co(L1)(btec)_0.5] _n (1) and {[Co(L2)(bdc)]·H₂O} _n (2) (L1 = 1,3-bis(2-methylbenzimidazol-1-ylmethyl)benzene, H₂bdc = 1,3-benzenedicarboxylic acid, H₄btec = 1,2,4,5-benzenetetracarboxylic acid, L2 = 1,3-bis(benzimidazol-1-ylmethyl)benzene), have been hydrothermally synthesized and characterized by physicochemical and spectroscopic methods as well as single-crystal X-ray diffraction. The cobalt atoms present different environments, with a trigonal pyramidal geometry in 1 and a distorted octahedral configuration in 2. Complex 1 shows a 2D (4,4) network linked by L1 and btec^4? anions, giving an uninodal 4-connected sql topology with a point symbol of {4²·6²}, while complex 2 displays a 1D ladder-like chain structure, which is further assembled into a 3D supramolecular architecture via C–H···π hydrogen bonding interactions. The fluorescence properties of both complexes have been investigated in the solid state.     

Assembly of 1D and 3D cobalt(II) coordination polymers based on isophthalic acid and flexible benzimidazolyl-based ligands

Two new metal–organic coordination polymers {[Co(L1)(nip)]·H₂O} _n (1) and [Co(L2)(ip)] _n (2) (H₂ip = isophthalic acid, L1 = 1,3-bis(benzimidazol-1-ylmethyl)benzene, L2 = 1,4-bis(5-methylbenzimidazol-1-ylmethyl)benzene, H₂nip = 5-nitroisophthalic acid) have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as single-crystal X-ray diffraction analysis. The analysis reveals that complex 1 has a 1D double chain structure connected by L1 and nip^2? ligands, which is further assembled into a 3D bbf (moganite network) supermolecular framework via two types of C–H···O hydrogen bond interactions. Complex 2 possesses a 3D MOF with a four-connected cds (CdSO₄ network) topology. The fluorescence and catalytic properties of the complexes for the degradation of Congo red have been investigated.     

Effect of carboxylate coligands on the crystal structures of two nickel(II) coordination polymers constructed from a flexible bis(5,6-dimethylbenzimidazole) ligand

Two Ni(II) coordination polymers, [Ni(dmbbbi)(pic)₂·3H₂O] _n (1) and [Ni(dmbbbi)_1.5(pdc)·2H₂O] _n (2) (dmbbbi = 1,1′-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), Hpic = 2-picolinic acid, H₂pdc = pyridine-2,6-dicarboxylic acid), have been hydrothermally synthesized by self-assembly of nickel chloride with a flexible bis(5,6-dimethylbenzimidazole) ligand and two different pyridine carboxylic acids. The compounds were characterized by physico-chemical and spectroscopic methods and by single-crystal diffraction. Compound 1 possesses 1D ribbon-like chains connected by dmbbbi ligands in bis-bridging mode, which are further extended into a 2D supramolecular network through O–H···O hydrogen bonding interactions between pic anions and lattice water molecules, giving a novel trinodal (3,3,4)-connected topology with the point symbol of (4.6.8)₂(6.8⁴.10). Compound 2 shows a 2D undulant {6³} hexagonal (hcb) network. The structures of the two complexes are further stabilized by intramolecular π···π stacking interactions between the imidazole and N-containing nickel chelate rings. In addition, the fluorescence properties of 1 and 2 have been investigated in the solid state.     

Two cobalt(II) metal–organic frameworks based on mixed 1,2,4,5-benzenetetracarboxylic acid and bis(benzimidazole) ligands

Two cobalt(II) metal–organic frameworks constructed from 1,2,4,5-benzenetetracarboxylic acid and flexible bis(5,6-dimethylbenzimidazole) ligands, namely {[Co_1.5(Hbtec)(L1)_1.5(H₂O)₂]·(H₂O)} _n and {[Co(H₂btec)(L2)]·(L2)_0.5(H₂O)₂} _n [L1 = 1,4-bis(5,6-dimethylbenzimidazole-1-ylmethyl)benzene, H₄btec = 1,2,4,5-benzenetetracarboxylic acid, L2 = 1,4-bis(5,6-dimethylbenzimidazole)butane], have been hydrothermally synthesized and characterized by physicochemical and spectroscopic methods and by single-crystal X-ray diffraction. The cobalt atoms present different coordination environments, with trigonal-bipyramidal and octahedral geometries in 1, and a tetrahedral geometry in 2. Complex 1 has a 2D (6,3) wave like layer structure, which is further linked by hydrogen bonding to generate a 3D supramolecular architecture. It is a trinodal (4,4,4)-connected topology with a point symbol of {4²·6·8³}₂{4²·6²·8²}{4³·6³}₂. Complex 2 is a 2D (6,3) honeycomb net, further linked into a 3D supramolecular network via two modes of π–π stacking interactions. The degradation of methyl orange in a Fenton-like process using complexes 1 and 2 as catalysts has been investigated.     

Three 2D mixed-ligand Co(II) coordination polymers containing flexible bis(benzimidazole) ligands with different spacers

Three new Co(II) coordination polymers, [Co(L1)(bpdc)] _n (1), [Co(L2)(ndc)(H₂O)·2H₂O] _n (2) and [Co(L3)(ndc)(H₂O)·H₂O] _n (3) (L1 = 1,2-bis(5,6-dimethylbenzimidazole)ethane, L2 = 1,3-bis(5,6-dimethylbenzimidazole)propane, L3 = 1,4-bis(5,6-dimethylbenzimidazole)butane, H₂bpdc = 4,4′-biphenyldicarboxylic acid, H₂ndc = 2,6-naphthalenedicarboxylic acid) have been synthesized under hydrothermal conditions and structurally characterized by X-ray crystallography. All three complexes feature (4,4) networks that extend into 3D supramolecular frameworks via hydrogen bonding interactions. The luminescence properties and catalytic activities of these complexes with respect to the degradation of methyl orange in a Fenton-like process have been investigated.     

Synthesis,crystal structures,luminescence and catalytic properties of three silver(I) coordination polymers with bis(imidazole) and benzenedicarboxylic acid ligands

Three new silver coordination compounds with empirical formula [Ag₂(L1)₂·(ntp)·(H₂O)_3.25]_n (1), [Ag_1.5(L1)_1.5·(H_0.5bdc)·(H₂O)₄]_n (2) and [Ag(L2)(Hmip)]_n (3) (L1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L2 = 1,1′-(1,4-butanediyl)bis-1H-benzimidazole, H₂ntp = 2-nitroterephthalic acid, H₂bdc = 1,3-benzenedicarboxylic acid, H₂mip = 5-methylisophthalic acid) were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction and physico-chemical spectroscopic methods. The silver centers display different environments with a linear geometry in 1 and 2 and distorted T-shaped geometry in 3. In 1–3, the bidentate N-donor ligands (L1 and L2) bridge neighboring silver centers to form 1D infinite chain structures. Complexes 2 and 3 are extended into 2D layers, and 1 is packed into a 3D 3,4,4,6-connected supermolecular network via classical O–H···O hydrogen bonds, while 3 is further extended into 3D framework through π–π interactions. The luminescence properties of complexes 1, 2 and 3 were investigated in the solid state. These coordination polymers possess a remarkable activity for degradation of methyl orange by persulfate in a Fenton-like process.     

Two dinuclear copper(II) complexes based on 5,6-dimethylbenzimidazole ligands: synthesis, crystal structures, and catalytic properties

Two new dinuclear copper(II) complexes, Cu₂(L1)₄(mal)₂(H₂O)₂ (1) (L1 = 5,6-dimethylbenzimidazole, mal = malonate), Cu₂(L2)₂(pydca)₂·4H₂O (2) (L2 = 1,5-bis(5,6-dimethylbenzimidazole)pentane, pydca = pyridine-2,6-dicarboxylate) have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The Cu(II) atoms in 1 and 2 both have square pyramidal coordination geometry. In 1, the two similar mononuclear structures are linked by π–π stacking as well as multiple hydrogen bonding interactions to generate a 2D supramolecular layer, while complex 2 is connected with two different patterns of π–π stacking and hydrogen bonding interactions into a 3D supramolecular network. The catalytic activities of 1 and 2 for the degradation of Congo red have been investigated.     

Synthesis,structures and characterization of two cobalt(II) coordination polymers with 2,5-dichloroterephthalic acid and flexible bis(benzimidazole) ligands

Two Co(II) coordination polymers (CPs), namely [Co(L1)(DCTP)]_n (1) and [Co(L2)(DCTP)]_n (2) [L1?=?1,4-bis(5,6-dimethylbenzimidazol-1-yl)butane, L2?=?1,5-bis(5,6-dimethylbenzimidazol-1-yl)pentane, H₂DCTP?=?2,5-dichloroterephthalic acid] were synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, powder X-ray diffraction (PXRD) and infrared spectroscopy. CP 1 has a 2D (4,4) corrugated sheet structure, which is further extended into a 2D double layer by C–H···O weak hydrogen bonding interactions, while CP 2 displays a 2D layer with hcb network, which is assembled into a 3D supramolecular framework through C–H···O hydrogen bonding. Both CPs exhibited promising photocatalytic activities for the degradation of methylene blue under UV irradiation. In addition, the thermal stabilities and the luminescence properties of both CPs have been investigated.     

Synthesis,crystal structures and photocatalytic properties of four silver(I) coordination polymers based on semirigid bis(pyrazole) and carboxylic acid co-ligands

Four Ag(I) coordination polymers, formulated as [Ag(L1)(tpa)_0.5] _n (1), {[Ag(L2)(ndc)_0.5]·0.5H₂ndc} _n (2), [Ag(L3)_0.5(ndc)_0.5] _n (3) and {[Ag(L3)]·H₃bptc} _n (4) (L1 = 4,4′-bis(pyrazole-1-ylmethyl)-biphenyl, L2 = 4,4′-bis(3,5-dimethylpyrazol-1-ylmethyl)-biphenyl, L3 = 1,4-bis(3,5-dimethylpyrazol-1-ylmethyl)benzene, H₂tpa = terephthalic acid, H₂ndc = 2,6-naphthalenedicarboxylic acid, H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid), have been hydrothermally synthesized and structurally characterized. Complex 1 features the rare binodal (4,4)-connected 2D 4,4L10 topological network with a point symbol of {3²·4.6²·7}₂{3²·6²·7²}. Complex 2 has a folded ladder-like chain structure, which is further extended into a 3D supramolecular network via O–H···O hydrogen bonding and π···π stacking interactions. Complexes 3 and 4 both possess 1D zigzag chain structures. Complex 3 is further extended into a binodal (3,4)-connected network with the point symbol of {4.8⁴·10}{6²·8²}₂ by Ag···O weak interactions, while complex 4 is further connected through O–H···O hydrogen bonding and π···π interactions to afford a 2D supramolecular structure. The photoluminescence spectra and photocatalytic properties of these complexes for degradation of methylene blue and methyl orange are reported.     

Two new cadmium(II) coordination polymers with bis(benzimidazole) ligands

Two new cadmium(II) coordination polymers, {[Cd(L1)(tbta)]·H₂O} _n (1) and [Cd(L2)(tbta)] _n (2) (L1 = 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H₂tbta = tetrabromoterephthalic acid and L2 = 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene) are obtained under hydrothermal conditions and structurally characterized by single crystal X-ray diffraction methods, IR spectroscopy, TGA and elemental analysis. The L1 and L2 ligands differ by subtle variation of substituents at semi-rigid bis(benzimidazole) bakcbones. Complex 1 features a 3D threefold interpenetrating dia array with a 4-connected 6⁶ topology. Complex 2 displays a 2D {4⁴.6²} sql/Shubnikov tetragonal plane network. Complexes 1 and 2 possess high thermal stabilities and promising fluorescence behavior in the solid state.     

Synthesis, crystal structures and catalytic properties of Ag(I) and Co(II) 1D coordination polymers constructed from bis(benzimidazolyl)butane

Two metal–organic coordination polymers, {Co(bbbi)_0.5(bm)(Hbtc)} _n (1) and {Ag₂(bbbi)₂(ntp)(H₂O)·4H₂O} _n (2), [bbbi = 1,1-(1,4-butanediyl)bis-1H-benzimidazole, bm = benzimidazole, H₃btc = 1,2,4-trimellitic acid, and H₂ntp = 2-nitroterephthalic acid], have been hydrothermally synthesized and characterized by physico-chemical and spectroscopic methods and single-crystal diffraction. 1 Features a 1D ladder-like chain and is further connected by O–H···O hydrogen bonding interactions to yield a 3D supramolecular architecture. 2 Possesses a 1D infinite zigzag chain connected by bbbi ligands in bis-monodentate mode, which is further extended into a 3D complicated supramolecular network by face-to-face π–π stacking interactions and O–H···O hydrogen bonds. Moreover, both compounds exhibit catalytic properties on degradation of methyl orange in Fenton-like process.     

Synthesis, crystal structures and electrochemical properties of CoIII complexes with hexadentate ligand containing thioether-amidopyridyl donor set

Two new cobalt(III) complexes of the hexadentate ligand [1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane] (H₂bpctb) with N₄S₂ donor set atoms have been synthesized. A reaction of Co(CH₃COO)₂·4H₂O with (H₂bpctb) leads to the formation of [Co^III(bpctb)]PF₆ (1) having a CoN₂(pyridine)N′₂(amide)S₂(thioether) coordination by symmetric bpctb^2? ligand. A similar reaction under slightly different conditions, however, gives [Co^III(L ^a )(L ^b )] (2), resulting from a C–S bond cleavage reaction triggered by an acetate ion as a base, having CoN₂(pyridine)N′₂(amide)S(thioether)S′(thiolate) coordination. These two Co(III) complexes have been characterized by elemental analyses and spectroscopic methods, and the crystal and molecular structures of [Co^III(bpctb)]PF₆ (1) in the form of the solvate (1·MeOH·H₂O) and of [Co^III(L ^a )(L ^b )] (2) have been determined by X-ray crystallography. The Co atoms of both complexes exhibit distorted octahedral geometry. The electrochemical investigation of [Co(bpctb)]PF₆·MeOH·H₂O (1·MeOH·H₂O) and [Co^III(L ^a )(L ^b )] (2) by cyclic voltammetry reveals a reversible Co^III–Co^II redox process at E _1/2 = ?0.32 V (ΔE _p = 80 mV); for 1, and E _1/2 = ?0. 87 V (ΔE _p = 70 mV) for 2.     

Self-assembly of two 2D cobalt(II) coordination polymers constructed from 5-tert-butyl isophthalic acid and flexible bis(benzimidazole)-based ligands

Two cobalt(II) coordination polymers, [Co(L1)(tbi)(H₂O)] _n (1) and [Co(L2)(tbi)] _n (2) (L1 = 1,4-bis(benzimidazole)butane, L2 = 1,4-bis(2-methylbenzimidazole)butane, H₂tbi = 5-tert-butyl isophthalic acid) have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single-crystal X-ray diffraction analysis. Both complexes exhibit similar 2D (4,4) layer structures, constructed from tbi^2? and bis(benzimidazole)-based bridging ligands. The cobalt centers display different coordination environments, with an octahedral geometry in 1 and a distorted square-pyramidal configuration in 2. The thermal stabilities, fluorescence and catalytic properties of both complexes have been investigated.     

Zero-, one- and two-dimensional bis-triazole-bis-amide-based copper(II) complexes tuned by polycarboxylates with different protonation degrees: assembly, structures and properties

Three bis-triazole-bis-amide-based copper(II) complexes with different dimensionality, [Cu(dtcd)₂ (1,3-HBDC)₂]·2H₂O (1), [Cu(dtcd) (1,3,5-H₂BTC)₂]·2H₂O (2) and [Cu₄(μ ₃-OH)₂(dtcd)₂(SIP)₂]·4H₂O (3) (dtcd = N,N′-di(4H-1,2,4-triazole) cyclohexane-1,4-dicarboxamide, 1,3-H₂BDC = 1,3-benzenedicarboxylic acid, 1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid, NaH₂SIP = sodium 5-sulfoisophthalate), have been synthesized under different pH values and structurally characterized. Complex 1 exhibits a zero-dimensional mononuclear structure with one carboxyl group of 1,3-HBDC coordinating to copper(II), while the other carboxyl group is protonated. In complex 2, the Cu^II ions are bridged by the dtcd ligands forming a one-dimensional chain, in which only one carboxyl group of 1,3,5-H₂BTC coordinates with the metal, while the others are protonated. Complex 3 possesses a two-dimensional network based on tetranuclear Cu₄ clusters supported by the dtcd and nonprotonated SIP ligands. The various structures clearly indicate that the pH and polycarboxylates have a great influence on the dimensionality and structures of 1–3. The luminescence properties of 1–3 and magnetic properties of 3 were investigated.