Aromatic Polycarboxylate Research Articles

Two new luminescent Zn(II) compounds constructed from guanazole and aromatic polycarboxylate ligands

Two new Zn(II) compounds, namely [(CH3)2NH2]2n[Zn3(bpt)2(datrz)2]n (1) and [(CH3)2NH2)]n[Zn2(bptc)(datrz)]n·n(H2O) (2) (H3bpt = biphenyl-3,4′,5-tricarboxylic acid, H4bptc = biphenyl-3,3′,5,5′-tetracarboxylic acid, Hdatrz = 3,5-diamino-1,2,4-triazole), have been obtained by the self-assemble reactions of Zn(NO3)2, 3,5-diamino-1,2,4-triazole, aromatic polycarboxylate ligands under solvothermal conditions. Single crystal X-ray structural analyses reveal that both compounds display three-dimensional (3D) frameworks. Compound 1 features a trinodal (3, 4, 6)-connected topological network with the point symbol of {4.62}2{4.64.8}{46.64.85}. Compound 2 displays a binodal (4, 6)-connected topological network with the point symbol of {32.62.72}{34.42.64.75}. In addition, the thermal stabilities and luminescent properties of compounds 1 and 2 were also investigated in the solid state at room temperature.

Thorium(IV) organic frameworks with aromatic polycarboxylate ligands

Contrary to the fairly well established structural chemistry of uranium(VI) with aromatic polycarboxylate ligands, the knowledge on thorium(Th) structural chemistry with this family of ligands is very limited. In this paper, we report the synthesis, spectroscopic and thermal studies, and crystal structures of three Th organic frameworks with 1,2,4,5-benzenetetracarboxylate (btca) or 1,4-benzenedicarboxylate (bdc). Both [Th(btca)(DMF)2(H2O)] (1) and [Th(bdc)2(DMF)2] (2) (DMF = dimethylformamide) have two dimensional (2D) layered structures constructed with 9- (1) or 10- (2) fold coordinated Th polyhedrons and µ 4-btca (1) or µ 2-bdc (2) ligands, respectively, with two coordinated DMF molecules in cis- (1) or trans- (2) positions on each Th atom. The third phase, [Th(bdc)2] (3), has a 3D pillared framework built with eightfold coordinated Th polyhedrons and µ 4-bdc ligands. Their vibrational modes have been investigated and correlated to the structures. VT-PXRD confirmed that 3 is thermally robust to 500 °C and the weight loss at ~300 °C is due to the loss of water molecules in the solvent accessible voids in the crystal lattice. Thorium(IV) organic frameworks (TOC): Three new thorium organic frameworks with aromatic polycarboxylate ligands have been synthesized and characterized. 2D layered structures are favored at room temperature and a thermal robust, 3D thorium organic framework has been made under hydrothermal conditions. Their vibrational modes and thermal stabilities have been further investigated.

A novel coordination polymer constructed from flexible bis-methylbenzimidazole ligand and aromatic polycarboxylate

A novel coordination polymer [Zn(Bmb)0.5(H2O)2(Tba)] n (I) (Bmb = (1,4-bis(2-methylbenzimidazol-1-yl)butane, H2Tba = 5-tert-butyl-1,3-benzene dicarboxylic acid) has been hydrothermally synthesized and fully characterized by IR, fluorescence spectrum, single crystal and powder X-ray diffraction techniques (CIF file CCDC no. 992083). Crystal structure revealed that the title polymer crystallized in monoclinic, space group C2/c, a = 22.824(5), b = 10.742(2), c = 19.156(4) A, β = 102.37(3)°, Z = 8. A ladder-like chain is found in polymer I, which is expended to a 3D supramolecular structure through hydrogen bonding and π⋯π interactions.

Two 3D photoluminescent Zn(ii) complexes constructed from 5-amino-1-H-tetrazole with aromatic polycarboxylate ligands

Two new Zn(II) complexes, namely, [Zn2(BTEC)0.5(ATZ)2(H2O)3]·H2O (1) and [Zn1.5(2,5-PYDC)(ATZ)(H2O)]2 (2) have been assembled from 5-amino-1-H-tetrazole (HATZ) with two aromatic polycarboxylate ligands under hydrothermal conditions (H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, 2,5-PYDC = 2,5-pyridinedicarboxylic acid). Single crystal X-ray analysis reveals that both complexes display three-dimensional (3D) structures. Complex 1 is a binodal (4,4)-connected bbf net with a (64·82)(66)2 topological symbol. Complex 2 displays a trinodal (3,3,4)-connected net with (4·102)2(102·12)2(42·102·122) topology. In the two structures, all the HATZ ligands are deprotonated and act as the anions, and the ATZ− anions all connected two Zn(II) centers with a μ2-mode. In addition, the two complexes display photoluminescence at 442 nm (λex = 342 nm) and 468 nm (λex = 374 nm), respectively. And their thermal stability has also been studied.

Structural variation in silver(I) complexes with pyridazine ligand and aromatic polycarboxylic acids: Structural analysis with silver chains

To systematically explore the influence of pyridazine ligands and aromatic polycarboxylate on the existence of argentophilicity, four inorganic–organic hybrid Ag(I) complexes were obtained by one-pot ultrasonic reaction. Four complexes were named [Ag6(pdz)2(btc)2]n (1), [Ag2(pdz)(npt)]n (2), [Ag2(pdz)(pma)1/2]n (3), and [Ag2(pdz)(npa)·H2O]n (4) (pdz=pyridazine, H3btc=1,3,5-benzene tricarboxylic, H2npt=3-nitrophthalic acid, H4pma=pyromellitic acid, H2npa=1,4-naphthalenedicarboxylic acid). Structural analyses reveal that complexes 1–4 display diverse 2D or 3D frameworks, which all of the N-donor pdz ligands exhibit the same coordination mode but the distances of the silver atoms which link to the pdz ligands are different to each other. Complex 1 shows Ag6 clusters and the cluster is comprised by two distorted tetrahedron silver units. And the clusters are shared by two silver ions to form 1D silver chains. Complex 2 features 1D silver chains which are formed by the Ag4 units and the four Ag(I) ions are in the vertices of parallelogram. Complex 3 is an interpenetrating architecture with the pdz ligands alternately repeating up and down in ac plane. The structure of complex 4 is a 2D layer structure which the pdz and npt ligands alternately repeat along a axis. Moreover, complexes 1–4 indicate different photoluminescence behaviors in the solid state.

Three Cd(II) coordination polymers based on rigid 2,6-bis(3-(pyrid-3-yl)-1,2,4-triazolyl)pyridine ligand: Syntheses, crystal structures, and photocatalytic properties

Three Cd(II) coordination polymers, namely, {[Cd2(bptp)2(H2O)4]·3H2O}n (1), {[Cd2(Hbptp)(BTC)(H2O)]·4H2O}n (2) and {[Cd2(H2bptp)(BTEC)]·H2O}n (3) (1,3,5-H3BTC=1,3,5-benzenetricarboxylic acid and H4BTEC=1,2,4,5-benzenetetracarboxylic acid), have been successfully isolated by employing the rigid N-heterocyclic ligand 2,6-bis(3-(pyrid-3-yl)-1,2,4-triazolyl)pyridine (H2bptp) and different aromatic polycarboxylates. Complex 1 performs a helical chain structure, which is extended into 3D supermolecular framework due to its strong hydrogen bonding interactions. 2 demonstrates a binodal 3,4-connected 2D grid with the point symbol of (42·62·8)(42·6), while complex 3 features an interesting 2D structure with its 1D double chain looking like a folded paper lantern. The optical band gaps were analyzed by diffuse-reflectance UV–Vis spectra. The photocatalytic experiments for these complexes reflect well on their activities for the decomposition of MB under the irradiation of high-pressure mercury lamp. Complexes 1 and 2 present extremely good photocatalytic properties with their photocatalytic activities increasing from 17% (without any catalyst) to 87% for 1 and 96% for 2 after 2h of irradiation. In addition, the luminescent properties of 1–3 have also been investigated.

Syntheses, characterizations, thermal stability and photoluminescence of four silver coordination polymers with mixed ligands

Four silver(I) coordination polymers (CPs), namely, [Ag2(mpyz)(ipa)]n (1) [Ag3(mpyz)(btc)]n (2) [Ag4(apyz)2(ipa)·0.5 DMF]n (3) [Ag3(apyz)2(btc)]n (4), have been purposefully synthesized under ultrasonic treatment of methylpyrazine (mpyz), aminopyrazine (apyz), isophthalic acid (H2ipa), 1,3,5-benzenetricarboxylic acid (H3btc) and AgNO3. And they were characterized by elemental analysis and X-ray single-crystal diffraction. Complexes 1 and 2 based on the same auxiliary ligand mpyz show various structures with silver chain. Complex 1 features a three-dimensional (3D) structure which consists of 1D helical silver chains. Complex 2 possesses an infinite silver chain with repeated Ag-triangle units. Complexes 3 and 4 with apyz as auxiliary ligand exhibit different structures. Complex 3 exhibits a 2D 44-sql network with the 1D double chains and complex 4 shows Ag6 units which are connected by Ag⋯Ag interaction in the 3D coordination network. Effects of the aromatic polycarboxylates on the structures and the intricacy of the self-assembly process were discussed. Additionally, results about infrared spectroscopy (IR), thermogravimetric analyses (TGA) and photoluminescence spectra behaviours of the compounds were also discussed.

Crystal Structures and Properties of Cd(II) Coordination Polymers Supported by a New Chiral Aromatic Polycarboxylate Ligand

A series of six coordination polymers, namely, [Cd1.5(L)]n (1), [Cd1.5(L)(bpp)]n (2), {[Cd1.5(L)(p-bix)]·H2O}n (3), [Cd1.5(L)(m-bix)]n (4), {[Cd1.5(L)(dpa)3(H2O)]·2H2O}n (5), and {[Cd1.5(L)(bpbd)2.5]·2H2O}n (6) (Na3L = (S)-(−)-5-(1-carboxy-ethoxymethyl)-isophthalic acid trisodium salt), have been hydrothermally synthesized through the reaction of Na3L with divalent cadmium salts with or without the presence of ancillary nitrogen ligands (bpp = 1,3-bi(4-pyridyl)propane, p-bix = 1,4-bis(imidazol-1-ylmethyl)benzene, m-bix = 1,3-bis(imidazol-1-ylmethyl)benzene, dpa = 4,4′-dipyridylamine, bpbd = 2,3-bis(4′-pyridyl)-2,3-butanediol)). Complex 1 is a three-dimensional (3D) framework and displays a (4,8)-connected framework with {412·612·84}{46}2 (flu) topology. 2 features a 3D architecture too, in which the one-dimensional (1D) (Cd-bpp)n helical chains are alternately arranged in a right- and left-handed sequence. Complex 3 exhibits a homochiral 3D framework and is a new (3,8)-connected net with a Schläfli symbol of {4·5·6}2{42·56·618·7·8} topology. Complex 4 bears a homochiral layered structure, which is united together to generate a 3D supramolecular structure through interlayer C–H···O and C–H···π interactions. Interlayer C–H···π and N–H···N interactions led layered complex 5 to a 3D supramolecular architecture. Complex 6 shows a new (3,5,6)-connected net with a Schläfli symbol of {4·62}2{42·610·82·10}{42·66·82}2 topology. Complexes 3 and 4 crystallize in the chiral C2 space group, and their circular dichroism spectra exhibit obvious positive or negative Cotton effects. Moreover, 3 and 4 are second-harmonic generation (SHG) active, and the SHG efficiency is 0.5 and 0.4 times as much as that of urea, respectively.

Dimensional modulation and magnetic properties of triazole- and bis(triazole)-based copper(II) coordination polymers tuned by aromatic polycarboxylates

Five new metal–organic coordination polymers {[Cu3(μ2-OH)2(atrz)2(nph)2(H2O)2]·2H2O}n (1), {[Cu2(μ3-OH)(atrz)(1,2,4-btc)]·2H2O}n (2), {[Cu2(μ3-OH)(atrz)(1,2,4-btc)(H2O)]·H2O}n (3), [Cu(dth)0.5(nph)(H2O)]n (4) and [Cu(dth)(Hnip)2]n (5) [atrz=4-amino-1,2,4-triazole, dth=N,N'-di(4H-1,2,4-triazole)hexanamide, H2nph=3-nitrophthalic acid, 1,2,4-H3btc=1,2,4-benzenetricarboxylic acid and H2nip=5-nitroisophthalic acid] were hydrothermally synthesized and structurally characterized. Polymer 1 shows a one-dimensional (1D) chain. Polymers 2 and 3 exhibit similar tetranuclear CuII4 cluster-based three-dimensional (3D) frameworks with the same components. Polymer 4 possesses a 3D framework with a 412·63-pcu topology. Polymer 5 displays a 3D framework with a 44·610·8-mab topology. The magnetic properties of 1–4 were investigated.

Synthesis, characterization and properties of four dimeric ZnII–BMP coordination polymers modulated by a series of aromatic polycarboxylate acid

To systematically explore the influence of aromatic polycarboxylate ligands on building ZnII–BMP (1,5-bis(2-methylbenzimidazol) pentane) coordination polymers, four coordination polymers, namely {[Zn2(BMP)(PHSA)2]·H2O}n (1), [Zn4(BMP)2(BTEC)2(H2O)]n (2), [Zn2(BMP)(BTRC)(OH)]n (3), {[Zn3(BMP)(TCI)2(H2O)]·H2O}n (4) (H2PHSA=2-phenylsuccinic acid, H4BTEC=benzene-1,2,4,5-tetracarboxylic acid, H3BTRC=benzene-1,3,5-tricarboxylic acid, H3TCI=Tris (2-carboxyethyl) isocyanurate) are synthesized by varying aromatic polycarboxylate ligands. Systematic structure analysis shows that 1–4 are comprised by one or more ZnII dimer in which carboxylate ligands bridge two metal ions forming dinuclear cores, and BMP links these cores. In 1, PHSA2− bridges ZnII ions to generate paddle-wheel dimer [Zn2(η1-COO)4] and these dimers are further linked by BMP to form 2D structure. 2 exhibits a layer with two different dimers: [Zn2(η1-BTEC4−)2] and [Zn2(η1-BTEC4−)(μ2-H2O)] indicating that bridge water have subtle influences on the coordination geometry. [Zn2(η1-BTRC3−)(μ2-OH)] dimers in 3 are further linked by two kind of wavelike layers constructing the 2-fold interpenetrated 3D architecture. 4 shows a 2-fold interpenetrated 3D architecture with dimeric centre. Notably, besides ZnII dimer [Zn2(η1-TCI3−)3], a monuclear ZnII ion exists as a terminal of ligand BMP enhancing photoluminescence intensity of 4 subtlely.

Novel coordination polymers of Zn(ii) and Cd(ii) tuned by different aromatic polycarboxylates: synthesis, structures and photocatalytic properties

Six fascinating coordination polymers (CPs) showed good photocatalytic activities for the degradation of methylene blue (MB).

Structures and magnetic properties of mixed triazolyl-aromatic polycarboxylate-based metal complexes

Metal-triazolate complexes have recently receiving intense interest due to their various structures and promising applications in adsorption and magnetism. From the viewpoints of the synthesis of the triazolyl-aromatic polycarboxylate-based metal complexes and the effect of aromatic polycarboxylate coligand on the metal-triazolate subunits, in the present paper, the structural diversities as well as the relevant magnetic properties of the reaction system were summarized based on the available crystal structures and magnetic data reported within recent years.

Three interdigitated metal–quinolone complexes from self-assembly of mixed ligands and cadmium salts

Three interdigitated metal–quinolone complexes, [Cd2(cfH)2(btec)(H2O)2]·6H2O (1), [Cd2(ppaH)2(1,3-bdc)2]·4.25H2O (2) and [Cd2(LevofH)(1,3-bdc)2(H2O)2] (3) (cfH=ciprofloxacin, ppaH=pipemidic acid, LevofH=levofloxacin, btec=1,2,4,5-benzenetetracarboxylate, 1,3-bdc=1,3-benzenedicarboxylate) have been synthesized and characterized by elemental analyses, IR spectra, X-ray powder diffractions, TG analyses and single crystal X-ray diffraction. Compound 1 exhibits a (2D→3D) interdigitated architecture that is first assembled from 2D wavelike (6,3) nets with side arms. Compound 2 is the first example of (2D→3D) interdigitated metal–ppaH complex, which is constructed from sidearm-containing 2D layers of (4,4) topology. Compound 3 is built from 1D double chains with dangling levofloxacin ligands protruding from one side of the chain, and each pair of these double chains are interdigitated with each other to generate a perfect molecular zipper. By inspection of the structures of 1–3, it is believed that the short aromatic polycarboxylate ligands are important for the construction of interdigitated metal–quinolone complexes. The photoluminescent properties of compounds 1–3 have also been investigated.

Structural Diversities and Fluorescent and Photocatalytic Properties of a Series of CuII Coordination Polymers Constructed from Flexible Bis-pyridyl-bis-amide Ligands with Different Spacer Lengths and Different Aromatic Carboxylates

Thirteen new CuII coordination polymers, namely, [Cu(3-dppa)(1,3,5-HBTC)] (1), [Cu(3-dpha)(1,3,5-HBTC)(H2O)]·H2O (2), [Cu3(3-dpsea)(1,3,5-BTC)2(H2O)5]·4H2O (3), [Cu(3-dpba)(1,2-BDC)]·H2O (4), [Cu(3-dpha)(1,2-BDC)] (5), [Cu(3-dpsea)(1,2-BDC)]·H2O (6), [Cu2(3-dpyp)(1,3-BDC)2(H2O)4]·3H2O (7), [Cu(3-dppa)(1,3-BDC)(H2O)]·2H2O (8), [Cu(3-dppia)(1,3-BDC)(H2O)2]·2H2O (9), [Cu2(3-dpsea)2(1,3-BDC)2(H2O)2]·7H2O (10), [Cu(3-dpba)(1,4-NDC)]·3H2O (11), [Cu(3-dpyh)(1,4-NDC)(H2O)]·3H2O (12), [Cu(3-dpyh)0.5(1,4-NDC)]·H2O (13), have been purposefully synthesized under hydrothermal conditions [3-dppa = N,N′-di(3-pyridyl)propanediamide, 3-dpba = N,N′-di(3-pyridyl)butanediamide, 3-dpha = N,N′-di(3-pyridyl)hexanedioicdiamide, 3-dppia = N,N′-di(3-pyridyl)pimelicdiamide, 3-dpsea = N,N′-di(3-pyridyl)sebacicdiamide, 3-dpyp = N,N′-di(3-pyridinecarboxamide)-1,3-propane, 3-dpyh = N,N′-di(3-pyridinecarboxamide)-1,6-hexane, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid and 1,4-H2NDC = 1,4-naphthalenedicarboxylic acid]. Complexes 1–3 based on the same auxiliary ligand show various structures. Complex 1 features a one-dimensional (1D) ∞-like double-chain structure, which consists of a [Cu-1,3,5-HBTC]n chain and [Cu-3-dppa]n meso-helical chain. Complex 2 possesses a (2,4) undulated honeycomb (hcb) net. Complex 3 is a 3-fold interpenetrating three-dimensional (3D) framework, which shows trinodal (2,3,3)-connected topology with the Schläfli symbol of (10·122)2(103)2(12). Complexes 4–6 with 1,2-BDC as secondary ligand exhibit different two-dimensional (2D) layer structures. Complex 4 exhibits a 2D (2,4)-connected (4·124·14)(4) net. Complexes 5 and 6 have similar structures and show 2D networks with undulated sql topology. For complexes 7–10 based on 1,3-BDC secondary ligand, complex 7 shows a 1D zigzag chain, while complexes 8–10 have similar wave-like 2D structures. When 1,4-NDC was used as the auxiliary ligand, complex 11 is a 2D puckered (4,4) network, complex 12 reveals a 4-connected topology with the point symbol of (44·62), while complex 13 exhibits a 3-fold interpenetrating 3D α-Po framework. The structural diversity indicates that the bis-pyridyl-bis-amide ligands with different spacers and the aromatic polycarboxylates play important roles in tuning the dimensionalities and structures of the title complexes. The fluorescent and photocatalytic properties for 1–13 have also been investigated in detail.

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.

The design and construction of a series of metal–organic coordination polymers based on two isomeric semi-rigid bis-pyridyl-bis-amide ligands and three aromatic polycarboxylates

A series of metal–organic coordination polymers, namely, {[Cu3(4-bpah)4(1,3,5-BTC)2]·8H2O}n (1), {[Cu3(4-bpah)3(1,2-BDC)3(H2O)2]·4H2O}n (2), {[Cu(4-bpah)(1,3-BDC)(H2O)]}n (3), {[Co(4-bpah)(1,3-BDC)(H2O)]}n (4), {[Ni(4-bpah)(1,3-BDC)(H2O)]}n (5), {[Zn(4-bpah)(1,3-BDC)(H2O)]}n (6), {[Cd(4-bpah)(1,3-BDC)]}n (7), {[Cd(3-bpah)(1,3-BDC)]·H2O}n (8), {[Cu2(3-bpah)(1,3-BDC)2]·H2O}n (9), where 4-bpah = N,N′-bis(4-pyridinecarboxamide)-1,2-cyclohexane, 3-bpah = N,N′-bis(3-pyridinecarboxamide)-1,2-cyclohexane, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, have been synthesized under hydrothermal conditions. The structures of 1–9 have been determined by single crystal X-ray diffraction analyses and further characterized by infrared spectroscopy (IR), elemental analyses, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Complex 1 displays a 2D (42·83·10)(43·62·8)4(4)2 topological network. Complex 2 shows a 2D (3·4·5·62·7)2(3·42·52·7) topological framework that contains tri-flexural and left-hand helix chains. Complexes 3–6 reveal a similar 2D sql network with (44·62) topology. Complexes 7 and 8 show two different 2D double-layer structures with (42·6)(43·6·84·102)(4) and (42·6·86·12)(42·6)(8) topology, respectively. Complex 9 exhibits a new 3D 3-nodal topology with the Schlafli symbol (4·62)2(42·64)2(42·68·82·103). The successful construction of complexes 1–9 implies that using semi-rigid bis-pyridyl-bis-amide ligands can obtain various architectures with small voids. The effect of the isomeric semi-rigid bis-pyridyl-bis-amide ligands and the three aromatic polycarboxylates, as well as the central metal ions on the formation and structures of the title coordination polymers have been discussed. The fluorescent and photocatalytic properties of complexes 1–9 have also been investigated.

Structural modulation and properties of four cadmium(ii) coordination architectures based on 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole and aromatic polycarboxylate ligands

By using a multidentate N-donor tecton 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (Hppt) and different aromatic polycarboxylates, including terephthalic acid (H2tp), isophthalic acid (H2ip), 1,3,5-benzenetricarboxylic acid (1,3,5-H3btc), and 1,2,4,5-benzenetetracarboxylic acid (1,2,4,5-H4btec), four cadmium(II) coordination polymers {[Cd(ppt)(tp)0.5(H2O)2]·H2O}n1; {[Cd3(ppt)2(ip)2(H2O)]·H2O}n2; [Cd2(ppt)(btc)(H2O)4]n3; {[Cd3(ppt)2(btec)(H2O)3]·(H2O)3}n4 have been synthesized under solvothermal conditions. Complex 1 shows a new 2D two-fold interpenetrating brick wall plane with 3-connected net. Complex 2 features a 3D net with a rare (3,4,5)-connected topology net. Complex 3 is an intriguing two-fold interpenetrating 3D framework, which shows four nodal 3-connected topology with the Schlafli symbol of (72·9)(82·8)(6·7·9)(52·7). Complex 4 exhibits a 3D (4,6)-connected (44·610·8)(44·62) net. In addition, the thermal stability and photoluminescence properties of 1–4 and the Hppt ligand in the solid state have also been studied in detail.

Copper(II) coordination polymers constructed from aromatic polycarboxylate and flexible triazole ligands with different spacer lengths: syntheses, structures, and properties

{[Cu2(btm)2(Hbtc)(H2btc)2(H2O)]·9.5H2O}n (1), [Cu(bte)(H2btc)2]n (2) {[Cu(btp)(H2btc)2]·0.25H2O}n (3) (btm = bis(1,2,4-triazol-1-yl)methane, bte = bis(1,2,4-triazol-1-yl)ethane, btp = bis(1,2,4-triazol-1-yl)propane, H3btc = benzene-1, 3, 5-tricarboxylic acid) have been synthesized and structurally characterized. 1 features a 1-D double chain, which is interconnected by classical hydrogen-bonding (O–H⋯O) and π–π interactions to lead to a 3-D supramolecular architecture. 2 and 3 are both 1-D single chains, which are interconnected by π–π interactions to 2-D layer architectures. Elemental analysis, XRD, IR, TG and EPR spectra have been carried out and discussed.

Two novel 3D copper(II) complexes based on a rigid bis-pyridyl-bis-amide and two polycarboxylates mixed ligands: Assembly, structures and properties

Two novel three-dimensional (3D) copper(II) complexes [Cu3(3-bpcb)(1,2-BDC)2(μ2-OH)2] (1) and [Cu2(3-bpcb)1.5(SIP)(μ3-OH)]·H2O (2), based on a rigid bis-pyridyl-bis-amide ligand [3-bpcb=N,N′-bis(3-pyridinecarboxamide)-1,4-benzene] and two different polycarboxylates [1,2-H2BDC=1,2-benzenedicarboxylic acid, NaH2SIP=sodium 5-sulfoisophthalic acid] have been prepared under hydrothermal conditions. Single crystal X-ray diffraction analysis shows that complex 1 exhibits a 4-nodal mixed (3,4,4,5)-connected 3D structure with the (3·4·5)2(3·42·5·86)2(32·8·92·10)(42·82·102) Schläfli symbol, which is constructed from two-dimensional (2D) Cu(II)-μ2-OH-3-bpcb layers (3-bpcb: μ4-bridging coordination mode via two pyridyl nitrogen and two carbonyl oxygen atoms) and the 1,2-BDC bridging ligands. Complex 2 is also a 3D coordination polymer constructed from the μ2-bridging 3-bpcb ligands (via two pyridyl nitrogen atoms) and the 2D Cu(II)-μ3-OH-SIP sheets containing tetranuclear copper clusters, showing a novel 3-nodal (5,6,6)-connected (33·43·53·63·72·8)(33·43·53·6)(33·46·54·62) topology. The differences between the final 3D structures for complexes 1 and 2 might be attributed to the different aromatic polycarboxylates and the bis-pyridyl-bis-amide ligand with different coordination modes. Moreover, the electrochemical behavior of complex 1 and the fluorescence properties of the complexes 1–2 have been investigated.

Three cobalt(ii) coordination polymers based on V-shaped aromatic polycarboxylates and rigid bis(imidazole) ligand: syntheses, crystal structures, physical properties and theoretical studies

To investigate the effect of organic anions on the coordination frameworks, we synthesized three new complexes, namely, Co(SDBA)(BIMB) (1), Co2(SA)(BIMB)1.5(H2O) (2) and Co(FBA)(BIMB)0.5·H2O (3) (H2SDBA = 4,4′-dicarboxybiphenylsulfone, H4SA = 3,3′,4,4′-diphenylsulfonetetracarboxylate acid and H2FBA = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)), which were obtained by the reactions of 4,4′-bis(1-imidazolyl)biphenyl (BIMB), and three V-shaped aromatic polycarboxylates as organic anions with Co(NO3)2·6H2O. Single crystal structure analysis shows that complex 1 features a 3-fold interpenetrating three-dimensional (3D) framework with CdSO4-type topology. Complex 2 has a previously unknown 3D trinodal (4,4,6)-connected framework with a Schläfli symbol of (4·64·8)2(43·63)2(44·610·8). Complex 3 exhibits a three-dimensional 2-fold interpenetrating pillared helical-layer open framework of α-Po topology based upon binuclear paddlewheel units. The results reveal that the carboxylic building blocks with different conformations play a significant role in promoting the diversity of the observed structural motifs. The magnetic properties of the three complexes as well as the SHG and ferroelectric properties for 1 have also been investigated. Finally, theoretical calculations were carried out on the conformation of the BIMB ligand in the three complexes.