1D Ladder Research Articles

Comparison of Electrical Conductivity and Schottky Behavior of 4‐[2‐(9‐anthryl)vinyl]pyridine Based Two 1D Coordination Polymers of Zn(II) and Cd(II)

AbstractWith the increase in demand of electronic devices in the modern civilization, research in material science is being projected to grow in faster rate. In this facet, coordination polymer (CP) based electronic device is one of the promising candidates to the material researchers. Herein, two new Zn(II) and Cd(II) based one‐dimensional (1D) CPs, denoted as [Zn(4‐avp)2(5‐nip)] ⋅ (solvent)x (1) and [Cd(4‐avp)(5‐nip)(CH3OH)] (2) have been synthesized using relatively less explored highly conjugated polycyclic aromatic hydrocarbon (PAH) based monodentate ligand, 4‐[2‐(9‐anthryl)vinyl]pyridine (4‐avp) and bidentate linker 5‐nitroisophthalic acid (H25‐nip). In this instance, the CP 1 creates 1D chain polymer, while CP 2 is made up with 1D ladder polymer. It is interesting to note that both the CPs exhibit semiconducting nature and generate metal‐semiconductor (MS) junction Schottky barrier diodes (SBDs). However, Cd‐based CP 2 shows higher charge transport as compared to Zn‐CP 1, which could be due to stronger π⋅⋅⋅π contacts as well as larger size of Cd metal in CP 2. The experimental results are well corroborated with theoretical density of states (DOS) calculations.

Syntheses and photochemically antibiotic degradation of two Co(II)-based coordination polymers

Two new Co(II)-based coordination polymers (CPs), designated as [Co2(bbp)4(1,3-bdc)4]n(1) and [Co(bbp)3(NO3)2(H2O)]n(2) (bbp = 3,5-bis(benzoimidazo-1-ly) pyridine; 1,3-H2bdc = 1,3-benzenedicarboxy acid), were synthesized using a dual ligand approach. The characterization of these CPs involved single- crystal -XRD, UV–visible, FT-IR, and TGA analysis. Both CPs 1 and 2 exhibit a distorted octahedral geometry. Both 1 and 2 show a 1D ladder chain, and this chain-like structure undergoes further development into a more intricate two-dimensional (2D) supramolecular network. The thermal stability analysis revealed that 1 and 2 are stable at temperatures of 119 °C and 286 °C, respectively, with no significant mass loss. Notably, both CPs displayed semiconducting properties. The photocatalytic degradation capabilities of CPs 1 and 2 were investigated against antibiotics such as metronidazole (MDZ), Tinidazole (TDZ), ornidazole (ODZ), and furazolidone (FZD). CP 1 exhibits exceptional photocatalytic activity against FZD. A dosage of 5 mg/L of CP 1 resulted in a remarkable degradation efficiency of 92.2 % for 40 ppm FZD. Additionally, a proposed photodegradation mechanism was investigated through radical trapping experiments.

Single-Crystal One-Dimensional Porous Ladder Covalent Polymers.

The synthesis of single-crystal, one-dimensional (1D) polymers is of great importance but a formidable challenge. Herein, we report the synthesis of single-crystal 1D ladder polymers in solution by dynamic covalent chemistry. The three-dimensional electron diffraction technique was used to rigorously solve the structure of the crystalline polymers, unveiling that each polymer chain is connected by double covalent bridges and all polymer chains are packed in a staggered and interlaced manner by π-π stacking and hydrogen bonding interactions, making the crystalline polymers highly robust in both thermal and chemical stability. The synthesized single-crystal polymers possess permanent micropores and can efficiently remove CO2 from the C2H2/CO2 mixture to obtain high-purity C2H2, validated by dynamic breakthrough experiments. This work demonstrates the first example of constructing single-crystal 1D porous ladder polymers with double covalent bridges in solution for efficient C2H2/CO2 separation.

Water Content-Controlled Formation and Transformation of Concomitant Pseudopolymorph Coordination Polymers.

Two concomitant pseudopolymorph coordination polymers {[Cd2L2(OAc)4]·2DMSO} n (1) and {[CdL(OAc)2]·2.75H2O} n (2) were synthesized by self-assembly of 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (L) and cadmium acetate in DMSO. Single-crystal X-ray diffraction confirmed that 1D ladder structural motifs exist for pseudopolymorphs 1 and 2 which contain DMSO and water guest molecules, respectively. Our study illustrated the active role of solvent water content in obtaining compound 2. We find that the presence of water as an impurity in the DMSO solvent creates the possibility of formation of concomitant pseudopolymorph coordination polymers which is a unique event. Furthermore, our analyses showed the effect of environmental humidity on the transformation of unstable compound 1. 1D ladder pseudopolymorphic compound 1 could be transformed to guest-free 1D linear compound [CdL(OAc)2(H2O)] n (3') (the powder form of single crystals of 3) through a scarce case of water absorption from air. Also, the crystalline material of coordination polymer 3 was transformed to coordination polymer 2 through the dissolution-recrystallization structural transformation process in DMF or DMSO. Our study clarified that the amount of water in the reaction container can control the formation of one of the compounds 2 or 3. In the presence of a significant amount of water, compound 3 (coordinated water) will be produced, whereas if a small amount of water is present, compound 2 (uncoordinated water) is prepared as an exclusive product.

Photocatalytic properties of two Co(II) coordination polymers with tri(2-methylimidazole) and multicarboxylate

Two new coordination polymers with the formula {[Co2(tmpa)2(tdc)2(H2O)4]·H2O}n (1) and {[Co2(tmpa)2(btec)]·DMF·H2O}n (2) (tmpa = tris(4-(2-methyl-1H-imidazol-1-yl)phenyl)amine, tdc2− = 2,5-thiophenedicarboxylicate, btec4− = 1,2,4,5-benzenetetracarboxylicate) were obtained under hydrothermal conditions and characterized by PXRD, UV–vis DRS and SEM. 1 has (3,3)-connected 1D ladder chains, which further extend into a (3,5)-connected 2D supramolecular framework built byOH···O hydrogen-bonding interactions. 2 exhibits (4,4)-connected 2D networks showing point symbol (42·64)(4·64·8). 1 and 2 both displayed high photocatalytic activities for the decomposition of methylene blue (MB) and methyl violet (MV). 1 and 2 can degrade 87.2% and 91.7% MB, respectively, in 75 min under visible light irradiation. 1 and 2 could degrade 82.2% and 91.8% MV, respectively, in 105 min under visible light irradiation. Therefore, 2 possessed better photocatalytic performance. The trapping experiments and ESR test indicated that O2– was the primary species in the process of MB degradation of 1 and 2. In addition, Hirshfeld surface analysis was also adopted to further address the probable mechanistic pathway.

Explosive and pollutant nitroaromatic sensing through a Cd(II) based ladder shaped 1D coordination polymer

In the existing leanings of environmental and national security issues, establishment of appropriate sensors for explosive as well as pollutant nitroaromatic compounds may be considered as one of the most prodigious job for material researchers. In the current study a new Cd(II) based 1D ladder coordination polymer (CP), [Cd(4-bpd)(3-cbn)2]n, has been synthesized and well characterized through single crystal X-ray diffraction analysis. Interestingly, the supramolecular assembly of this compound has efficiently identified 2,4,6-trinitrophenol through fluorescence quenching method. The Stern–Volmer coefficient (Ksv) has been calculated as 6.047 × 103 M−1, which can be attributed to the quenching of the emission intensity. The limit of detection (LOD) has been determined as 0.260 μM following the 3σ method along with almost 95% fluorescence intensity reduction. FESEM study revealed that the crystalline nature of the compound has been altered upon interaction with the above mentioned nitroaromatic analyte. Theoretical studies were performed to get the insight idea of fluorescence quenching mechanism which also substantiated the experimental observation. The present study can pave the way for the fabrication of future generation technology in sensor field.

Localization and Criticality in Antiblockaded Two-Dimensional Rydberg Atom Arrays.

Controllable Rydberg atom arrays have provided new insights into fundamental properties of quantum matter both in and out of equilibrium. In this work, we study the effect of experimentally relevant positional disorder on Rydberg atoms trapped in a 2D square lattice under antiblockade (facilitation) conditions. We show that the facilitation conditions lead the connectivity graph of a particular subspace of the full Hilbert space to form a 2D Lieb lattice, which features a singular flat band. Remarkably, we find three distinct regimes as the disorder strength is varied: a critical regime, a delocalized but nonergodic regime, and a regime with a disorder-induced flat band. The critical regime's existence depends crucially upon the singular flat band in our model, and is absent in any 1D array or ladder system. We propose to use quench dynamics to probe the three different regimes experimentally.

Syntheses of cobalt and nickel coordination polymers composed of 1,3-adamantanedicarboxylate and bis(4-(1H-imidazol-1-yl)phenyl)methanone ligands

Two coordination polymers, {[Co2(L1)2(adc)2]·5H2O}n (1) and {[Ni(L1)2(Hadc)2]}n (2) (L1 = bis(4-(1H-imidazol-1-yl)phenyl)methanone, H2adc = adamantane-1,3-dicarboxylic acid), have been synthesized and structurally characterized. In 1, Co1 is five-coordinated by three oxygen atoms of two adc2- and two nitrogen atoms from two L1 ligands. The neighboring [Co(adc)]2 dimers are linked through four L1 ligands to form a 1D ladder structure. In 2, Ni1 is six-coordinated by two oxygen atoms from two Hadc- ligands, four nitrogen atoms from four distinct L1 ligands to give a slight distorted octahedral geometry. The [Ni(Hadc)2] units are bridged by L1 ligands to form 1D looped chains.

EPR, Magnetic, and Computational Characterization of Linear and Zigzag Ladder‐type Chains of Exchange Coupled Cu(II) Complexes with Picolinic and Dipicolinic Acid Ligands

AbstractWe report magnetic, EPR, and computational studies on two representative examples of structurally well‐characterized one dimension (1D) molecular systems: the copper complexes catena‐[bis(μ‐pyridine‐2‐carboxylato)‐copper dihydrate] and catena‐[(μ2‐pyridine‐2,6‐dicarboxylato)‐diaqua‐copper(II)], hereafter 1 and 2, respectively. Experimental and theoretical results confirmed that the structural chains in both compounds behave as magnetic chains in which the copper ions are weakly coupled by isotropic exchange. Magnetic susceptibility measurements of 1 suggested that the copper ions are antiferromagnetically coupled whereas EPR measurements suggested ferromagnetic coupling at temperature above 100 K which becomes antiferromagnetic at low temperatures. Computational calculations would indicate that the ferromagnetic‐antiferromagnetic change may be due to dCu−Oap shortening on lowering temperature temperature (a fact that was observed experimentally by XRD at low temperatures), which redistributes the small Cu(II) unpaired spin density delocalized on the apical ligand to copper. The 1D magnetic behavior of the zigzag ladder chain of 2 is less detectable than that of the single chain of 1. Magnetic susceptibility measurements in conjunction with computational calculations showed that the pathways that give rise to the 1D ladder transmit ferromagnetic exchange interactions with different strengths, with the stronger interaction being transmitted along the rungs. The role of the weaker exchange interactions transmitted along the rails on the magnetic dimensionality of 2 is analyzed.

Humidity-Induced Structural Transformation in Pseudopolymorph Coordination Polymers.

Three cadmium coordination polymers, namely, {[CdL(OAc)2](C2H5OH)}n (1), {[CdL(OAc)2](CH3CN)}n (2), and [CdL(OAc)2(H2O)]n (3), were synthesized by an exoditopic 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene Schiff base ligand (L) and cadmium acetate in the presence of different solvent systems. Single-crystal X-ray diffraction, powder X-ray diffraction, and thermogravimetric analysis showed that 1D ladder pseudopolymorphic compounds (1 and 2) transformed to the solvent-free 1D linear compound 3 through a rare case of water absorption from air at room temperature. Interestingly, compound 3 was transformed to compound 1 through a dissolution-recrystallization structural transformation process. The results illustrated that solvents and humidity have an important role in the formation of pseudopolymorphs with the same or different structural motifs.

From zero-dimensional complexes to one-dimensional coordination polymers adjusted by the solvents or ligand substituent groups

A new ligand, 6-(4-carboxyphenyl)-3-(2-chloroimidazo[1,2-a]pyridin-3-yl)picolinic acid (H2L1), was used to construct two zero-dimensional (0D) complexes ([Zn(HL1)2] (1) and ([Ni(HL1)2(H2O)2] (3)), and one one-dimensional (1D) zig-zag chain coordination polymer ([Zn(L1)(H2O)2]n (2)) which was further assembled into porous three-dimensional (3D) supramolecular framework. The various dimensionality of 1–3 essentially originates from the types of organic solvents, because protic EtOH solvent resulted in completely deprotonated 2-connected L12− in 2, conversely, polar MeCN only caused partial deprotonation to give 1-connected HL1− in 1 and 3. Moreover, through changing 2-chloroimidazo[1,2-a]pyridine ring to pyridine ring, 0D Ni(II) complex (3) was adjusted to 1D ladder chain Ni(II) coordination polymer ([Ni(L2)(H2O)2]n•2H2O (4)) which should be ascribed to ligand substituent group effects. The photoluminescent or magnetic properties of 1–4 were also researched.

Anions effect construction of 1D naphthalene diimide supramolecular chains by π interactions and fluorescence detect iodide anion

Five diverse 1D supramolecular chains, {[4-pmntd]}n(1), {H2[4-pmntd]•2Br−}n(2), {H2[4-pmntd]•2NO3−}n(3), {H2[4-pmntd]•2ClO4−}n(4), {H2[4-pmntd]•2BF4−}n(5), (where 4-pmntd was N,N′-bis (4-pyridylmethyl)naphthalene diimide) were synthesized and characterized by X-ray single-crystal structure analysis, IR spectroscopy, elemental analyses, thermogravimetric analyses, fluorescence detection. The anions effect construction of their 1D chain structural diversity through different π interactions. Compound 1 through the adjacent pyridine rings parallel π∙∙∙π interactions formed 1D linear chain structure. Compound 2 through Br− anion∙∙∙π interactions and halogenbond interactions formed 1D zigzag chain structure. Compound 3 through lone pair∙∙∙π interactions of naphthalene diimide and the adjacent carboxyl group formed 1D stairway chain structure. Compound 4 through ClO4− anion∙∙∙π interactions formed 1D ribbon chain structure. Compound 5 through parallel π∙∙∙π interactions of the adjacent naphthalene diimide planes and pyridine rings formed 1D ladder chain structure. The five compounds’ fluorescence properties and thermal stabilities were investigated. The compound 2 solution could fluorescence detection for iodide anion via fluorescence quenching.

1D ladder and 2D bilayer coordination polymers constructed from a new T-shaped ligand: luminescence, magnetic and CO2 gas adsorption properties

1D ladder and 2D bilayer coordination polymers are constructed by using a new T-shaped ligand, in which the 2D bilayer exhibits CO2 gas adsorption features.

Unusual porous crystals via catenation of 1D ladders: unprecedented mixture effects on the adsorption of xylene isomers in a SCSC mode

The pseudo 2D open-channel crystals formed via catenation of 1D ladders show unusual mixture effects on the adsorption of o-, m-, and p-xylene isomers in a SCSC mode, and are a practical template for structural determination of small hydrocarbons.

Coordination Polymers Constructed from Semi-Rigid N,N′-Bis(3-pyridyl)terephthalamide and Dicarboxylic Acids: Effect of Ligand Isomerism, Flexibility, and Identity

Reactions of the semi-rigid N,N′-bis(3-pyridyl)terephthalamide (L) with divalent metal salts in the presence of dicarboxylic acids afforded [Cd(L)0.5(1,2-BDC)(H2O)]n (1,2-H2BDC = benzene-1,2-dicarboxylic acid), 1, {[Cd(L)1.5(1,3-BDC)(H2O)]·5H2O}n (1,3-H2BDC = benzene-1,3-dicarboxylic acid), 2a, {[Cd(1,3-BDC)(H2O)3]·2H2O}n, 2b, {[Cd(L)0.5(1,4-BDC)(H2O)2]·H2O}n (1,4-H2BDC = benzene-1,4-dicarboxylic acid), 3, and [Cu(L)0.5(5-tert-IPA)]n (5-tert-IPA = 5-tert-butylbenzene-1,3-dicarboxylic acid), 4, which have been structurally characterized by single crystal X-ray diffraction. Complexes 1 and 3 are two-dimensional (2D) layers with the bey and the hcb topologies, and 2a and 2b are one-dimensional (1D) ladder and zigzag chain, respectively, while 4 shows a 3-fold interpenetrated three-dimensional (3D) net with the cds topology. The structures of these coordination polymers containing the semi-rigid L ligands are subject to the donor atom positions and the identity of the dicarboxylate ligands, which are in marked contrast to those obtained from the flexible bis-pyridyl-bis-amide ligands that form self-catenated nets. The luminescence of 1 and 3 and thermal properties of complexes 1, 3, and 4 are also discussed.

Template-directed hierarchical copper(II)-organophosphonate compounds: Syntheses, crystal structures, magnetic and luminescence properties

Three new copper organodiphosphonate compounds, [C4N2H14][Cu(hedph2)2], I, [C4N2H12][Cu3(hedp)2(H2O)4], II and [C6N2H18][Cu3(hedp)2].4H2O, III have been synthesized hydrothermally in the presence of copper nitrate, 1-hydroxyethane-1,1-diphosphonic acid (hedpH4) and various organic aliphatic amines. Molecular structure of compound I is formed in presence of templated 1,4-diaminobutane (DAB). One-dimensional ladder structure of compound II and two-dimensional layer structure of III are observed in the presence of templated piperazine (PIP) and 1,6-diaminohexane (DAH), respectively. The coordination behaviour of the diphosphonate ligand and the organic amines play the crucial role for isolating the different dimensionality amongst the hybrid structures. Although, the compounds II and III display eight-membered rings assembled through vertex-sharing Cu-polyhedra and CPO3 tetrahedra, but the higher coordination mode of diphosphonate ligand can make the 2D layer structure of II instead of 1D ladder of I. The dc-magnetic measurements and theoretical fitting of interacting Cu•••Cu exchange interactions exhibit the antiferromagnetic ordering with weak ferromagnetic coupling in higher-dimensional structures. All the compounds are well characterized by powder XRD, IR, elemental and thermal analysis. The magnetic and luminescence properties of compounds I‒III have also been studied.

Transition Metal Ions Regulated Structural and Catalytic Behaviors of Coordination Polymers

Three new coordination polymers (CPs), I [Cu­(L)­(H2O)]·2H2O, II [Zn­(L)], and III [Ag­(HL)­(CH3CN)], were synthesized by employing a novel pyrazole-based dicarboxylate ligand (H2L) through a solvothermal strategy. Single-crystal structural analysis established that compounds I and II exhibit two-dimensional (2D) sheet structures, while compound III possesses a one-dimensional (1D) ladder structure due to the connectivity of terminal solvent moiety. The geometries of metal ions vary from square planar (Cu2+ ion) to distorted tetrahedral (Zn2+ and Ag+ ion). Topological study showed that compound I has made a (4·62)2(42·62·82) net, while compounds II and III have exposed common (44·62) sql net and (42·6) net, respectively. The Lewis acidic nature of compounds I, II, and III has been confirmed with various heterogeneous catalytic reactions. For the first time, one-pot multicomponent synthesis of α-amino amidine has been performed by the three CPs and the reaction kinetics has been altered by the variation of Lewis acidic metal centers. The roles of metal ions for structural variations and the catalytic performances are investigated in a series of CPs.

Two Zn(II) coordination polymers for highly selective detection of phenol based nitroaromatics and removal of water soluble organic dyes

Two new coordination polymers, namely, [Zn2(ctpy)2(bdc)]n (1) and [Zn(ctpy)(suc)0.5]n (2) (Hctpy ​= ​2,2’:6’2’’-terpyridine-4’-carboxylic acid, H2bdc ​= ​1,4-benzene dicarboxylic acid, H2suc ​= ​succinic acid) have been synthesized under solvothermal condition. Structural analysis reveals that complexes 1 and 2 exhibit 1D ladder chain structures formed with the coordinated Zn(II) and Hctpy as ladder chains and the coordinated H2bdc/H2suc as the bars. The neighbouring chains are further linked by π … π packing to form 2D layer structures. Both the two complexes show highly selective detection of 2,4,6-trinitrophenol, 2,4-dinitrophenol, 4-nitrophenol and 2-nitrophenol from benzene based nitroaromatics (NACs), and efficient removal of Congo Red (CR) from aqueous solution.

Syntheses, structures, and properties of four coordination polymers based on 2,7‐di(pyridin‐4‐yl)‐9H‐fluoren‐9‐one

Four coordination polymers (CPs), [Cd(2,7‐dpfo)2(NO3)2(CH3OH)]n (1), [Zn(2,7‐dpfo)(NO3)(CH3COO)]n (2), [Co(2,7‐dpfo)2(H2L)]n (3), and [Ni(2,7‐dpfo)2(H2L)]n (4) (where 2,7‐dpfo is 2,7‐di(pyridin‐4‐yl)‐9H‐fluoren‐9‐one and H4L is 1,1′:4′,1′′‐terphenyl‐4,2′,5′,4′′‐tetracarboxylic acid), were synthesized and structurally characterized. Compounds 1–4 were determined by elemental analyses, single crystal X‐ray diffraction analyses, powder X‐ray diffraction, infrared spectroscopy, and thermogravimetric analyses. Compound 1 displays a one‐dimensional (1D) zigzag chain structure, while compound 2 possesses a 1D ladder chain structure. Compounds 3 and 4 are isostructural and consist of 1D chains. The solid‐state luminescent properties of 1 and 2 and the magnetic properties of 3 and 4 were also investigated.

Syntheses, Structures and Properties of Three Coordination Polymers with 3D Network, 2D Lattice, 1D Ladder Structures

AbstractThree coordination polymers (CPs), [Ni1.5(L)(bipy)2(H2O)3]n(1), [Zn(L)(Hbipy) (H2O)]n⋅2n(H2O) (2) and [Cu(bipy)2(H2O)2]n⋅2n(H2L)⋅ 3nH2O (3) (NaH2L=5‐sulfoisophthalic monosodium salt, bipy=4,4′‐bipyridine) have been synthesized by solvothermal methods. They were characterized by X‐ray single crystal diffraction, elemental and thermogravimetric analyses. Introduction of the auxiliary N‐donor ligand (bipy) can lead to three Ni(II), Zn(II) and Cu(II) CPs with three‐dimensional (3D) 4‐connected network of the point symbol of (75⋅9), one‐dimensional (1D) ladder and two‐dimensional (2D) lattice frameworks, respectively. Compound 1 is racemic, whose topological structure can be divided into left‐handed and right‐handed helices. The fluorescence emission peaks of compounds 1–3 are located at 416 nm, 412 nm and 455 nm, respectively, which may be attributed to the ligand to metal charge transfers. Variable‐temperature magnetic susceptibility measurements can reveal that there are ferromagnetic and antiferromagnetic exchange interactions between the neighboring spins in compounds 1 and 3, respectively, and compound 2 is a diamagnetism system. Compound 1 shows the second‐harmonic generation (SHG) response that is 4 times those of potassium dihydrogen phosphate (KDP).