Syntheses, Structures and Magnetic Properties of Two Novel Cu(II) Diphosphonate Coordination Polymers with N-Heterocyclic Auxiliary Ligand

By introducing the second organic N-heterocyclic ligand 2,2′-bipyridine (2,2′-bipy), two binuclear examples of Cu(II)-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H₅L=CH₃C(OH)(PO₃H₂)₂), [Cu₂(H₄L)₂(H₃L)(2,2′-bipy)₂] 1 and [Cu(H₃L)(2,2′-bipy)] 2, have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that both the two compounds possess zero-dimensional binuclear structures built through a single O–P–O bridge for 1 and a double O–P–O bridge for 2 in syn–anti fashion. Then H-bond and π–π interactions further expand the two zero-dimensional binuclear structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks of 1–2 centered at 423.5 nm for 1 and 423 nm for 2, respectively, are mainly caused by intraligand π*–π emission state of N-heterocyclic ligand 2,2′-bipy (λ _ex = 233 nm). The further magnetic study shows the two coordination polymers exhibit ferromagnetic behaviors derived from O–P–O bridges in syn–anti mode between the metal centers.     

Two d10 Coordination Polymers Based on the Substitutional Aromatic Multicarboxylate and N-donor Co-ligands: Syntheses, Structures and Luminescent Properties

Two new coordination polymers, formulated as Zn(3-NPA)(1,4-bimb) (1) and Cd(3-NPA)(1,2-bimb)(H₂O) (2) (3-NPAH₂?=?3-nitrophthalic acid, 1,4-bimb?=?1,4-bis(imidazol-1 -ylmethyl)benzene, 1,2-bimb?=?1,2-bis(imidazol-1-ylmethyl)-benzene) have been synthesized by hydrothermal reactions of the semirigid neutral ligand 1,4-bimb or 1,2-bimb with metal ions in the presence of 3-nitro phthalic acid. The two compounds were characterized by infrared spectroscopy, elemental analysis, thermo gravimetric analysis and single-crystal X-ray diffraction analysis. Polymer 1 possesses a new two-dimensional puckered rectangular grid architecture, with the 1,4-bimb ligands displaying a cis-conformation. In polymer 2, the 3-NPA^2? anions coordinate the Cd(II) ions in a tetra dentate mode to form a dimer unit, which is connected by the 1,2-bimb ligands resulting in a single layer. Intra layer hydrogen bond interactions are found between the water molecule and carboxylate oxygen atoms. Weak π···π interactions are observed between the layers through the benzene rings from the adjacent 3-NPA^2? and 1,2-bimb ligands. In addition, the luminescent properties of the two compounds were also investigated in this paper.     

Controllable Assembly of Two Zn(II) Polymers via Varying Auxiliary Ligand: From 4-Connected cds Net to 4-Connected sql Tetragonal Plane Net

Two new Zn(II) coordination polymers, namely [Zn(H₂ODPT)(bpe)(H₂O)] _n (1) and [Zn(H₂ODPT)(bpp)] _n (2) (H₄ODPT = 4,4′-oxydiphthalic acid, bpe = 1,2-bis(4-pyridyl)-ethane, bpp = 1,3-bis(4-pyridyl)-propane) were successfully synthesized via varying auxiliary ligands. Single crystal X-ray analysis reveals that 1 features a three-dimensional extended framework, which can be simplified into a 4-connected cds topological network; and, 2 features a two-dimensional layered framework, which can be simplified into a 4-connected sql tetragonal plane net. In addition, the luminescent and thermal stabilities properties were also investigated.     

Hydrothermal Synthesis, Crystal Structures and Photoluminescent Properties of Two New Co(II) Coordination Polymers Derived from Dicarboxylate and N-Donor Ligands

Two new Co(II) coordination polymers with 5-position substituted 1,3-benzenedicarboxylate and N-donor auxiliary ligands, [Co(5-OH-ip)(L₁)_1.5(H₂O)]_n (1) and [Co(5-NO₂-ip)(L₂)_1.5]_n (2) (5-OH-ip = 5-hydroxyisophthalic acid, 5-NO₂-ip = nitroisophthalic acid, L₁ = 1,4-bis(imidazol-1-yl) benzene and L₂ = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene), were synthesized by hydrothermal reactions. Complex 1 shows a 3-fold interpenetrating 3D framework with the topological symbol of (4⁴·6⁶). Complex 2 exhibits a 3D framework with the vertex symbol of (4²·6⁸). Furthermore the luminescent properties of 1 and 2 were investigated.     

Syntheses,Structures and Fluorescent Properties of Lead(II) Complexes Based on 5,6-Substituted 1,10-Phenanthroline Derivatives and Benzene Dicarboxylic Acids

Three new coordination polymers, [Pb(1,3-bdc)(MOPIP)₂]_n·nH₂O (1), [Pb(1,4-bdc)(MOPIP)]_n (2) and [Pb₂(1,4-bdc)₂(MEDPQ)₂]_n·nH₂O (3) (MOPIP = 2-(4-methoxyphenyl)-1H-imidazo[4,5-f] [1, 10] phenanthroline, MEDPQ = 2-methyldipyrido [3,2-f:2′,3′-h]quinoxaline, 1,3-H₂bdc = benzene-1,3-dicarboxylic acid, 1,4-H₂bdc = benzene-1,4-dicarboxylic acid), have been prepared through hydrothermal reactions. The transformation of coordination modes of organic carboxylate ligands and 5,6-substituted 1,10-phen derivatives has a crucial influence on the structures of these series. In compound 1, 1,3-bdc anion adopts a chelating bidentate and bridging monodentate coordination mode, which results in a hepta-coordinated environment of Pb(II) center. However, in complex 2, 1,4-bdc anion acts in the chelating bidentate mode, which results in a hexa-coordinated environment of Pb(II) center. Complex 3 shows face-to-face π···π interactions between MEDPQ and benzene rings, which are different to that of the complexes 1 and 2. The fluorescence property and thermal stability were also investigated.     

Construction of Two New Metal–Organic Entangled Frameworks Via Varying Flexible Bis(Imidazole)-based Auxiliary Ligands

Two new metal–organic entangled frameworks, namely [Cd(FA)_0.5(bix)_1.5(H₂O)] _n ·nNO₃ (1) and [Cd(FA)(bib)(H₂O)₂] _n (2) (FA = fumaric acid, bix = 4,4′-bis(imidazol-1-ylmethyl)benzene, bib = 1,4-bis(imidazolyl)butane), have been successfully hydrothermally synthesized through mixed ligands strategy. Single crystal X-ray diffraction analysis reveal that 1 is a 2D → 3D polycatenated framework, while 2 is a triply interpenetrated 4-connected dia topological net. Moreover, both compounds exhibit intense luminescence emission at room temperature.     

Hydrothermal Syntheses and Crystal Structures of Three Complexes Constructed with Dipyrido[3,2-a:2′,3′-c]phenazine and 2,4′-Biphenyldicarboxylic Acid

Three new metal complexes, [Pb(dppz)(2,4′-bpdc)] _n ·n(H₂O) (1), [Fe(dppz)(2,4′-bpdc)(H₂O)] _n (2) and [Cu(dppz)(2,4′-bpdc)(H₂O)] _n (3) (2,4′-H₂bpdc = 2,4′-biphenyldicarboxylic acid and dppz = dipyrido[3,2-a:2′,3′-c]phenazine), have been synthesized and characterized by elemental analysis, IR, X-ray single-crystal diffraction and powder X-ray diffraction. The complexes 1, 2 and 3 have 1D chains formed via coordination bonds, and unique three-dimensional or two-dimensional supramolecular structures are further formed due to π–π stacking interactions. The results reveal that the coordination preferences of metal ions play a critical role in the framework construction of these complexes. Meanwhile, the thermogravimetric analysis and photoluminescent property of compounds 1–3 have also been investigated.     

Synthesis, Crystal Structures and Luminescent Properties of pH-Dependent Zn (II) Coordination Polymers

Two new coordination polymers [Zn(L)(bib)] _n (1) and [Zn(L)(bib)_0.5] _n (2) [L = 5-hydroxyisophthalic acid and bib = 1,4-bis(2-methyl-imidazol-1-yl)butane] have been synthesized and characterized. X-ray single crystal diffractions show that complex 1 is a 2D layered structure and complex 2 is a 3D 6-connected topological net. Complex 1 are further assembled into a 3D supramolecular structure by intermolecular hydrogen bonding. Complex 2 features a two-fold interpenetrated pcu topology. Moreover, the fluorescent properties of complexes 1 and 2 were studied in the solid state at room temperature.     

A Series of Luminescent Lanthanide–Organic Complexes Constructed from In Situ Generated Dithiobenzoic Acid

Two types of lanthanide thiolato-carboxylate complexes, [Type I: [Yb(dtba) (Hdtba)] _n (1), Type II: [Ln(dtba)_1.5(biim)] _n (Ln = Pr (2a), Nd (2b), Sm (2c), Eu (2d), Gd (2e), Tb (2f), Dy (2g), H₂dtba = 2,2′-dithiodibenzoic acid, bimm = diimidazole)] have been obtained by hydrothermal method and characterized by the single-crystal X-ray diffraction, IR, 2D-COS IR, TG and the luminescence analysis. The H₂dtba ligand came from the in situ S–S function reaction of 2-mercaptobenzoic acid (H₂mba) under the hydrothermal condition. Complex 1 is a 2D bamboo-like sqr-topology layered structure, and the 3D (4, 4, 6)-connected supramolecular frameworks is produced by the hydrogen bonds of O–H···O. Complexes of type II (from 2a to 2g) are isostructural and they are assigned to 1D rope-like chains by introducing the chelating ligand of diimidazole. These 1D rope-like chains are further linked by N–H···O hydrogen bonds into a 3D supramolecular framework with CdSO₄-type topology. Photoluminescence studies reveal that complexes 2b, 2c, 2d, 2f, 2g exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.     

Tris-Alkoxylphenylterpyridine Cobalt(II) Complexes: Synthesis, Structure, and Magnetic and Mesomorphic Behaviors

Two novel cobalt(II) complexes [Co(L1)₂](BF₄)₂·CH₃CN·0.5H₂O (1) and [Co(L2)₂](BF₄)₂ (2) (L1 = 4′-(3,4,5-trimethoxy-phenyl)-[2,2′:6′,2″]terpyridine, L2 = 4′-(3,4,5-tris-hexadecyloxy-phenyl)-[2,2′:6′,2″]terpyridine) have been synthesized, and their structural, magnetic and mesomorphic properties were characterized by single crystal X-ray diffraction (XRD) analysis, temperature-dependent magnetic susceptibility, POM, DSC, and powder XRD analysis. The molecular structure of the complex 1 with short alkyl substituents exhibited that the metal ion has an N₆ coordination sphere of distorted octahedral geometry and various intermolecular π–π interactions are important factors influencing the crystalline array. The magnetic behaviour of 1 displayed a typical of gradual spin transition for cobalt(II) terpyridine complexes. On the other hand, the complex 2 possessing linear long alkyl chains showed a gradual spin transition between low-spin and high-spin with a thermal hysteresis loop (T _1/2↑ = 338 and T _1/2↓ = 327 K) triggered by the crystal-to-mesophase transition. The powder XRD and POM analyses were indicative of the liquid crystalline lamellar phase of 2.     

Synthesis,Crystal Structures,Luminescence, Biological and Catalytic Properties of Two d10 Metal-Organic Coordination Polymers Constructed from Mixed Ligands

Two d¹⁰ metal-organic coordination polymers, [Cd₂(4-cpa)₄(bmip)₂]_n (1) and [Zn(4-cpa)₂(4,4′-bpy)]_n (2), [4-cpa = 4-chlorophenylacetate, bmip = 1,3-bis(2-methylimidazoly)propane, 4,4′-bpy = 4,4′-bipyridine], were hydrothermally synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies indicated that both 1 and 2 display analogous wave-like infinite chain structures. The two coordination polymers are further extended into 3D supramolecular structures through π···π stacking interactions and C–H···O hydrogen bonds for 1 and π···π stacking interactions, C–H···π stacking interactions and C–H···O hydrogen bonds for 2. Both 1 and 2 emit the intense blue luminescence at room temperature. The 4-Hcpa ligand and complexes 1 and 2 have been screened for their herbicidal activities against Brassica napus L. and Echinochloa crusgalli L. The results are compared with the activity of quizalofop-P-ethyl. Both compounds exhibit high catalytic properties on degradation of methyl orange in Fenton-like process.     

Three New Coordination Polymers Constructed from Mixed Ligands: Syntheses,Luminescence and Magnetism

Three new coordination polymers, namely, {[Cd(H₂bptc)(IP)(H₂O)]·2H₂O} _n (1), {[Mn₂(IP)₂(dstc)]·6H₂O} _n (2) and {[Zn₂(IP)₂(dstc)]·3H₂O} _n (3) (IP = 1H-imidazo[4,5-f][1,10]-phenanthroline, H₄bptc = 3,3′,4,4′-benzophenonetetracarboxylic acid, and H₄dstc = 3,3′,4,4′-diphenylsulfonetetracarboxylic acid) have rationally designed and characterized by single crystal X-ray diffraction. Polymer 1 shows a 1D ribbon-like structure. Although compounds 2 and 3 feature 2D grid networks, the coordinative modes of dstc ligand and the arrangements of IP ligand are very different. Furthermore, the luminescence properties for 1 and 3, as well as the magnetism of 2 are explored in detail.     

Two New Luminescent Cadmium Thiolato-carboxylates with 2,2′-Bipyridine

Two new cadmium thiolato-carboxylate complexes, [Cd₂(mba)₂(2,2′-bpy)₂] (1), [Cd₂(dtba)₂(2,2′-bpy)₄]·4H₂O (2) (H₂mba = 2-mercaptobenzoic acid, H₂dtba = 2,2′-dithiodibenzoic acid, 2,2′-bpy = 2,2′-bipyridine) were obtained by reacting Cd(II) salts and the ligands of H₂mba and 2,2′-bpy, and were characterized by the single-crystal X-ray diffraction, IR, 2D-COS IR, solid UV, TG and XRD. In complex 2, the H₂dtba ligand came from the in situ S–S function reaction of H₂mba under the hydrothermal conditions. Complexes 1 and 2 are both 1D chains, but the difference lies in the linkage of the ligands. The 3D super-molecular frameworks of 1 and 2 are produced by π–π stacking interaction between the 2,2′-bpy ligands and the hydrogen bonds of O–H…O with ths-type and dia-type topology, respectively. The fluorescent emissions are observed in 1 and 2 with λ _em = 533 nm and λ _em = 436 nm, due to the ligand-to-metal charge transfer (LMCT) and π* → π transitions, respectively.     

Synthesis, Crystal Structures and Properties of Two Metal–Organic Frameworks Constructed from Pyridine Dicarboxylate and Flexible Bis(imidazole) Ligand

Two novel interesting metal–organic frameworks, [Zn(PDA)(bbi)] _n (1) and [Cd₂(PDA)₂(bbi)₂(H₂O)₂·10H₂O] _n (2) [H₂PDA = pyridine-2,6-dicarboxylic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)] have been isolated under hydrothermal conditions and structurally characterized. X-ray single crystal structure analysis reveals that complex 1 crystallize in monoclinic P2₁/c space group, while complex 2 crystallize in triclinic P-1 space group. The PDA^2? anions act in two different coordination modes: terminal chelating for 1 and chelating and bis-monoatomic bridging for 2. Polymeric chains of 1 and 2 are composed of Zn(II) and Cd(II) ions bridged by bbi ligands. The fluorescent properties of 1 and 2 were also investigated.     

Ancillary Ligand-Mediated Syntheses,Structures and Fluorescence of Three Zn/Cd(II) Coordination Polymers Based on Nitrobenzene Dicarboxylate

The Zn/Cd(II)-nbdc carboxylate motifs mediated by various dipyridyl-typed ligands afforded three new coordination compounds, namely, [Zn(nbdc)(bpa)_0.5(H₂O)]·H₂O (1), [Zn₂(nbdc)₂(bpp)₂]·H₂O (2), and [Cd(nbdc)(bpe)_0.5(H₂O)₂] (3) (H₂nbdc = 4-nitrobenzene-1,2-dicarboxylic acid, bpa = 1,2-bi(4-pyridyl)ethane, bpe = 1,2-di(4-pyridyl)ethylene, and bpp = 1,3-bis(4-pyridyl)propane), which were synthesized by hydrothermal reaction and characterized by elemental analysis, IR, thermal analysis (TGA), and fluorescent analysis. The single-crystal X-ray diffractions reveal that three complexes display a diverse range of connectivity topology from 1D to 3D, which is dependent on the type of dipyridyl-typed ligands and metal centers. Complex 1 is the 1D chain featuring Zn-carboxylate binuclears extended further by bpa coligands. Complex 2 is the 2D thick-layer containing double-stranded chains cross-linked further by bpp coligands. Complex 3 is the 3D framework with (6³)(6⁵.8) ins topology featuring Cd-carboxylate chiral layers pillared by bpe coligands. The thermal stabilities and fluorescence properties for complexes 1–3 are investigated.     

Preparation, Crystal Structures and Photoluminescence of Two New Zinc Complexes Based on 1H-Imidazo[4,5-f][1,10]-phenanthroline and Auxiliary Ligands

Two new coordination polymers [Zn(ip)(2,5-tda)(H₂O)₂] _n (1) and [Zn₂(ip)₂(5-npa)₂] _n (2) (2,5-tda = thiophene-2,5-dicarboxylic acid, ip = 1H-imidazo[4,5-f][1,10]-phenanthroline and 5-npa = 5-Nitroisophthalic acid) were synthesized and characterized by IR, elemental analysis, PXRD and X-ray diffraction. Single-crystal X-ray analyses revealed that 1 and 2 demonstrate a 1D chain structure. Complex 1 was bridged by 2,5-tda ligands in a μ₁ ? η¹:η⁰/μ₁ ? η¹:η⁰ coordination mode, and further extended into a 2D supramolecular structure by hydrogen bonding and π···π interactions. In 2, the 5-npa ligand acts as a bridging moeity, exhibiting μ₁ ? η¹:η¹/μ₁ ? η¹:η⁰ and μ₁ ? η¹:η⁰/μ₁ ? η¹:η⁰ coordination modes to link metal ions to form a 1D chain. The chains are further connected via hydrogen bonding interactions into a 2D supramolecular structure. The luminescent properties for 1 and 2 were investigated in the solid state at room temperature.     

Mixed Solvothermal Synthesis of a New Heterometallic Coordination Polymer Containing Two Distinct Inorganic Cd–O–Ca Chains

A new heterometallic coordination polymer, namely [Cd₂Ca₂(PBDC)(H₂O)₂(e-urea)(DMF)]_n·2n(DMF) (1 H₂PBDC = terephthalic acid, DMF = N,N-dimethylformamide, e-urea = ethyleneurea) has been synthesized by combining the PBDC ligand with Cd(II) and Ca(II) salts under mixed solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 is an extended three-dimensional framework containing two distinct inorganic Cd–O–Ca chains, and can be simplified into a 4-connected topological network based on three unequivalent nodes. Luminescent study reveals that 1 exhibits strong, ligand-centred luminescence in the solid-state at room temperature.     

Construction of Two New Metal–Organic Frameworks from Pamoic Acid and N-Containing Auxiliary Ligands

Two new metal–organic frameworks; namely, [Cd₂(pam)₂(bpe)_1.5(DMF)₂(H₂O)] _n ·2n(DMF) (1) and [Cd(pam)(bix)] _n (2) (H₂pam = pamoic acid, bpe = 1,2-di(4-pyridyl)ethylene, bix = 4,4′-bis(imidazol-1-ylmethyl)benzene, DMF = N,N′-dimethylformamide), were solvothermally synthesized via varying the auxiliary ligand. Single crystal X-ray diffraction analysis reveals that compound 1 shows a 2D→3D polythreaded motif based on (3,4)-connected 2D sheets, while compound 2 features a 4-connected sql tetragonal plane net, which further extended into a 3D supramolecular framework through intermolecular CH···π interactions. In addition, the luminescent and thermal stabilities properties of these two compounds were investigated.     

Synthesis,Crystal Structure and Luminescent Property of a New Zn(II) Coordination Polymer with Twofold Interpenetrated pcu Topology

A new Zn(II) coordination polymer; namely, [Zn(FA)(bmix)_0.5] _n ·nH₂O (1, H₂FA = fumaric acid, bmix = 1,4-bis(2-methyl-1H-imidazol-1-ylmethyl)benzene) was synthesized with fumaric acid and flexible 2-methylimidazole-based ligands with Zn(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction reveals that 1 features a twofold interpenetrating three-dimensional pillar-layered framework based on paddle-wheel shaped [Zn₂(COO)₄] subunits. The structure may be simplified to a 6-connected pcu topological network. Luminescent investigation reveals that 1 exhibits intense ligand-centered fluorescence at room temperature.     

Synthesis, Crystal Structures and Fluorescence Properties of Two One-Dimensional Cadmium(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two one-dimensional Cd(II) coordination polymers constructed by ribbon-like molecules, {[Cd(L₁)₂(NO₃)]·NO₃} _n (1) (L₁ = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)benzene) and [Cd(L₂)₂(NO₃)₂] _n (2) (L₂ = 1,3-bis(benzimidazol-1-yl)benzene) have been obtained through assembly of the two structurally similar flexible bis(benzimidazole)-based ligands and cadmium nitrate tetrahydrate. The cadmium(II) centers display different coordination environments with trigonal-bipyramidal geometry in 1, and a octahedral geometry in 2. Weak C–H···O interactions in 1 result in a two-dimensional supramolecular layer; two π–π interactions are present in 2 forming a three-dimensional supramolecular network structure. The solid state fluorescence properties of 1 and 2 were investigated.