New Cd(ii) coordination polymers bearing Y-shaped tricarboxylate ligands as photocatalysts for dye degradation

Two Cd(ii) coordination polymers derived from a Y-shaped tricarboxylate ligand were synthesized and their photocatalytic properties against decomposition of methylene blue were investigated experimentally and computationally.

Structures and photocatalytic properties of two new Zn(ii) coordination polymers based on semi-rigid V-shaped multicarboxylate ligands

Two new metal-organic coordination polymers (CPs), aqua-2,2'-bipyridine-5-(4'-carboxylphenoxy)isophthalatezinc(ii) polymer [Zn(HL)(2,2'-bipy)(H₂O)] _n (1) and tris-4,4'-bipyridine-bis-5-(4'-carboxylphenoxy)isophthalatetrizinc(ii) polymer [Zn₃(L)2(4,4'-bipy)₃] _n (2) (H₃L = 5-(4'-carboxylphenoxy)isophthalic acid, 4,4'-bipy = 4,4'-bipyridine and 2,2'-bipy = 2,2'-bipyridine), were obtained under hydrothermal conditions and characterized by microanalysis, FTIR spectroscopy and single crystal X-ray diffraction. The single crystal X-ray diffraction indicated that in both the CPs the coordination networks exhibited varied topologies and coordination modes around the Zn(ii) centers. CP 1 exhibits a one-dimensional (1D) chain structure, which further forms a 3D supramolecular architecture via intermolecular π⋯π and hydrogen bonding interactions, while 2 possesses a 3D framework generated from a 2D layered motif comprising zinc and tripodal carboxylate subunits pillared by 4,4'-bpy ligands. Apart from the structural investigation, the photocatalytic performances of both the coordination polymers to photodecompose an aqueous solution of methyl violet (MV) were examined. The results indicated that both the CPs displayed the potential to photodecompose aromatic dyes and in particular 2 showed good photocatalytic activity for dye degradation under light irradiation. The photocatalytic mechanism through which these CPs executed degradation of dyes has been explained with the assistance of band gap calculations using density of states (DOS) and its decomposed partial DOS calculations.

Enhanced Water Stability and Photoresponsivity in Metal-Organic Framework (MOF): A Potential Tool to Combat Drug-resistant Bacteria

In this work, we have successfully synthesized a bimetallic (Zinc and Cobalt) Zeolitic Imidazolate Framework (Zn50Co50-ZIF), a class in a wider microporous Metal-Organic Framework (MOF) family. The synthesized nanostructures maintain both water stability like ZIF-8 (solely Zn containing) and charge transfer electronic band in the visible optical spectrum as ZIF-67 (solely Co containing). Crystal structure from XRD, high resolution transmission electron microscopy (HRTEM) followed by elemental mapping (EDAX) confirm structural stability and omnipresence of the metal atoms (Zn and Co) across the nanomaterial with equal proportion. Existence of charge transfer state consistent with ZIF67 and intact ultrafast excited state dynamics of the imidazolate moiety in both ZIF-8 and ZIF-67, is evidenced from steady state and time resolved optical spectroscopy. The thermal and aqueous stabilities of Zn50Co50-ZIF are found to be better than ZIF-67 but comparable to ZIF-8 as evidenced by solubility, scanning electron microscopy (SEM) and XRD studies of the material in water. We have evaluated the photoinduced ROS generation by the mixed ZIF employing dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. We have also explored the potentiality of the synthesized material for the alternate remediation of methicillin resistant Staphylococcus aureus (MRSA) infection through the photoinduced reactive oxygen species (ROS) generation and methylene blue (MB) degradation kinetics.

Photocatalytic and Ferric Ion Sensing Properties of a New Three-Dimensional Metal-Organic Framework Based on Cuboctahedral Secondary Building Units

A new three-dimensional microporous metal-organic framework based on Zn(II) clusters with the formula {[Zn₇(NDC)_5.5(μ₄-OH)₃]·7DMF} _n (1) (H₂NDC = 1,4-naphthalenedicarboxylic acid) had been synthesized and characterized. The MOF 1 displays an uncommon bsn topology, which is based on a unique heptanuclear Zn₇(OH)₃(CO₂)₁₁ cluster as a secondary building unit. The MOF had been employed as a photocatalyst for the photodegradation of model organic dyes rhodamine B and methyl violet in light. The results of photocatalytic experiments showed that 1 can successfully be employed as the photocatalyst for the benign decomposition of these dyes. A mechanism for the photcatalysis exhibited by 1 had been proposed using the results of density of states (DOS) and partial DOS calculations. The fluorescence properties of the MOF have been investigated, which revealed that 1 could be exploited as the luminescent sensor to recognize Fe³⁺ ions with perceptible quenching (K _sv = 6.55 × 10⁴ M-¹) and a limit of detection of 1.16 ppm.

Crystal structure of catena-poly[diaqua-bis(μ2-4-((4-(pyridin-2-ylmethoxy)phenyl)diazenyl)benzoato-κ3 O,O′:N)cadmium(III)], Cd(C19H14O3N3)2(H2O)

C38H30N6O7Cd, monoclinic, C2/c (no. 15), a = 16.937(3) Å, b = 6.1323(12) Å, c = 33.322(7) Å, β = 99.31(3)°, V = 3415.4(12) Å3, Z = 4, R gt(F) = 0.0314, wR ref(F 2) = 0.0668, T = 296(2) K.

Syntheses and photocatalytic properties of three new d10-based coordination polymers: effects of metal centres and ancillary ligands

Three d¹⁰-based coordination polymers with three different nitrogen-based ancillary ligands have been synthesized and their photocatalytic properties were explored in the decomposition of methyl violet.

Ligand ratio/solvent-influenced syntheses, crystal structures, and magnetic properties of polydentate Schiff base ligand-Dy(iii) compounds with β-diketonate ligands as co-ligands

Tuning the synthesis conditions and further regulating the magnetic dynamics of single-molecule magnets (SMMs) are crucial challenges for chemists.

Structural Diversity of Six Coordination Polymers Based on the Designed X-Shaped Ligand 1,1,1,1-Tetrakis[(3-pyridiniourea)methyl]methane

In this study, six coordination polymers (CPs), {[Ag₂(L)(CF₃SO₃)]·CF₃SO₃·2H₂O·DMF}_n (1), {[Ag(L)]·SbF₆·4DMF·H₂O}_n (2), {[Zn(L)_0.5(I)₂]·3.75H₂O}_n (3), {[Cd₂(L)(I)₄(H₂O)(DMF)]·4H₂O·3DMF}_n (4), {[Hg₂(L)(I)₄]·H₂O·4DMF}_n (5) and {[Hg₂(L)(Cl)₄]·2H₂O·3DMF}_n (6), were obtained based on the designed X-shaped urea-based ligand. X-ray single crystal diffraction analysis revealed that complex 1 displayed a 3D (3,4)-connected {6·8²}{6⁴·8²}-tcj net. Complex 2 featured a 2D 4-connected {4³·6³} sheet. Complexes 3 and 5 exhibited a 1D polymeric loop chain. Complex 4 displayed a 1D polymeric fishbone chain. Complex 6 showed a 2D 4-connected {4⁴·6²}-sql sheet. Structural comparison revealed that not only the metal ions, but also the anions played crucial roles in the control of final structures.

Assembly of a series of coordination polymers built from rigid a tetracarboxylate ligand and flexible bis(imidazole) linker: syntheses, structural diversities, luminescence sensing, and photocatalytic properties

Hydrothermal reactions of aromatic terphenyl-4,2'',5'',4'-tetracarboxylic acid (H₄tta) and transitional metal cations in the presence of two flexible N-donor ancillary ligands afforded four novel coordination polymers, namely, {[Zn(tta)_0.5(m-bimb)]·H₂O}_n (1), [Ni₂(tta)(m-bimb)₂(H₂O)]_n (2), [Ni(H₂tta)(o-bimb)·H₂O]_n (3), and [Cd(tta)_0.5(o-bimb)]_n (4), from solvothermal reactions in the presence of bis(imidazole) bridging linkers (m-bimb = 1,3-bis(imidazol-1-ylmethyl)benzene, and o-bimb = 1,2-bis(imidazol-1-ylmethyl)benzene). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses (EA), powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Compound 1 displayed a 2-fold 3D → 3D parallel entangled (4,4)-connected bbf net with the point symbol of (6⁴·8²)(6⁶)₂. Compound 2 featured a predocumented 3D (4,8)-connected (3²·5³·6)(3⁴·4⁴·5⁹·6¹¹) net. Compound 3 exhibited a 2D 4-connected sql sheet with the point symbol of (4⁴·6²), and compound 4 showed a 2D 4-connected (3²·6²·7²) kgm sheet. To our delight, fluorescence measurements showed that compound 1 could selectively and sensitively detect Cr³⁺ cations and nitrobenzene derivatives (nitrobenzene (NB), p-nitrotoluene (PNT), and p-nitroaniline (PNA)), which suggested that CPs of 1 was a promising bifunctional luminescence sensor material that could sense metal ions and small organic molecules. Moreover, 1 showed excellent photocatalytic activity.

A novel Ag(i)-calix[4]arene coordination polymer for the sensitive detection and efficient photodegradation of nitrobenzene in aqueous solution

Nitrobenzene (NB) is a widespread and highly toxic organic pollutant in water, and consequently its detection and removal have attracted considerable attention. In the present study, we designed and synthesized a novel coordination polymer, [AgL_0.5(NO₃)]_n (1), {L = 25,26,27,28-tetra[(3-pyridylmethyl)oxy]calix[4]arene}, from AgNO₃ and a tetra-pyridyl-functionalized calix[4]arene ligand, which possessed a 2D network based on [Ag₄L(NO₃)₄] units. The 1-modified glassy carbon electrode (1/GCE) exhibited good electrocatalytic activity toward the reduction of NB, offering the selective detection of NB in a wide linear range (1-2450 μM) and a low detection limit (0.62 μM). Furthermore, it displayed excellent photocatalytic activity for the degradation of NB in aqueous solution under UV light. The kinetics of the catalytic degradation reaction and the stability of the catalyst were also studied. These results indicated that compound 1 is a favorable material for the effective determination and degradation of NB, which makes it a promising candidate in both monitoring water quality and treating wastewater.

A luminescent zinc(ii) coordination polymer with unusual (3,4,4)-coordinated self-catenated 3D network for selective detection of nitroaromatics and ferric and chromate ions: a versatile luminescent sensor

A zinc coordination polymer is a sensor for detection of TNP, Fe³⁺, Cr₂O₇²⁻ and CrO₄²⁻.

Selective fluorescent sensing and photocatalytic properties of three MOFs based on naphthalene-1,4-dicarboxylic acid and 2,4,5-tri(4-pyridyl)-imidazole

Three MOFs display high sensitivity in the detection of NB and Ca²⁺ or Co²⁺ ions as luminescent probes. Moreover, 3 exhibits a relatively good photocatalytic degradation activity of rhodamine B.

Structures, luminescence and photocatalytic properties of two nanostructured cadmium(II) coordination polymers synthesized by sonochemical process

By varying the dicarboxylate coligands, two nano-sized cadmium(II) coordination polymers (CPs), [Cd(bix)(DCTP)]_n (1) and [Cd(bix)₂(BPDC)]_n (2) (bix=1,4-bis(imidazol-1-ylmethyl)benzene, H₂DCTP=2,5-dichloroterephthalic acid, H₂BPDC=biphenyl-4,4'-dicarboxylic acid) were synthesized hydrothermally and sonochemical irradiation. CPs 1-2 and their nanostructures have been characterized by elemental analysis, single-crystal X-ray diffraction, and scanning electron microscopy (SEM). CP 1 features a uninodal 4-connected 2D sql network consisting of two different helical arrays. Whilst, CP 2 displays 2D layer which constructed by the linear chains and M2L2 type discrete loops. The effect of ultrasonic power and temperature on the morphology and size of CPs 1-2 are investigated in detail. Nano-sized 1-2 show the relatively high photocatalytic performance for degradation of Methylene Blue (MB) under UV irradiation.

Three new Zn-based metal–organic frameworks exhibiting selective fluorescence sensing and photocatalytic activity

Three MOFs with different 2D networks have been crystallised in a one-pot solvothermal reaction. They all display high sensitivity in the detection of ACE and relatively good photocatalytic activity in the degradation of RhB.

Structural assembly from 1D to 3D motivated by the linear co-ligands, and the magnetic and photocatalytic properties of five NiII coordination polymers with 5-(4′-carboxylphenyl)nicotinic acid

Five structural diversity nickel(ii) complexes based on 5-(4′-carboxylphenyl) nicotinic acid and linear co-ligands are described. The antiferromagnetic interactions exist in them expect for 2. All of them could accelerate the degradation rate of MO under visible light irradiation.

Sonochemical synthesis of two nanostructured silver(I) coordination polymers based on semi-rigid bis(benzimidazole) ligands

Nanoparticles of two silver(I) coordination polymers (CPs), [Ag₂(L1)₂(DCTP)]_n (1) and [Ag₂(L2)(DCTP)]_n (2) (L1=1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, L2=1,4-bis(benzimidazol-1-yl)-2-butene, H₂DCTP=2,5-dichloroterephthalic acid), were synthesized by the sonochemical approach and hydrothermal method. Both CPs were characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, scanning electron microscopy (SEM), and thermogravimetric analyses (TGA). CP 1 exhibits a 2D 4-connected sql net with the point symbol {4⁴.6²}. While CP 2 displays a 2D 3,4-connected 3,4L13 net with the point symbol {4.6²}₂{4².6².8²}. The structural diversity indicates that semi-rigid bis(benzimidazole) co-ligands play important roles in tuning the structures of the mixed Ag(I) CPs. The ultrasound irradiation time, temperature, and power showed significant effects on the morphology and growth process of the nanoparticles of two silver(I) CPs. The luminescence and photocatalytic properties of the nanoparticles of CPs 1-2 on the degradation of methyl blue (MB) were also investigated in detail.

Ultrasonic synthesis of two nanostructured cadmium(II) coordination supramolecular polymers: Solvent influence, luminescence and photocatalytic properties

Two nanoparticles of cadmium(II) coordination polymers (CPs) formulated as [Cd(L)(DCTP)]_n (1) and [Cd(L)₂(DCTP)·2H₂O]_n (2) (L=1,2-bis(2-methylbenzimidazol-1-ylmethyl)benzene, H₂DCTP=2,5-dichloroterephthalic acid) were prepared by the sonochemical approach in different solvents and characterized by elemental analysis, IR spectra, scanning electron microscopy (SEM), and powder X-ray diffraction. Structural determination reveals that CP 1 displays a 2D four-connected sql net layer, Whilst CP 2 exhibits a 1D "V"-like chain structure. Luminescence properties, thermal behavior, and photocatalytic activities of the nanoparticles of CPs 1 and 2 on the degradation of methylene blue were investigated. The photocatalytic mechanism is carried out by introducing t-butyl alcohol (TBA) as a widely used OH scavenger. Furthermore, the influence of solvents, reaction time, and ultrasound irradiation temperature on the morphology and size of the nanostructure CPs 1 and 2 were investigated. The results indicated that an increase of time and ultrasound irradiation temperature decreased the nanostructured size.

A series of five-coordinated copper coordination polymers for efficient degradation of organic dyes under visible light irradiation

Five-coordinated copper(ii) coordination polymers 1–5 are highly efficient and universal photocatalysts for the degradation of the organic dyes methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) under visible light irradiation.