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

Response of a Zn(II)-based metal-organic coordination polymer towards trivalent metal ions (Al3+, Fe3+ and Cr3+) probed by spectroscopic methods

A new zinc-based two-dimensional coordination polymer, [Zn(5-AIP)(Ald-4)]·H2O (5-AIP = 5-amino isophthalate, Ald-4 = aldrithiol-4), 1, has been synthesized at room temperature by the layer diffusion technique. Single-crystal X-ray diffraction analysis of 1 showed a two-dimensional bilayer structure. An aqueous suspension of 1 upon excitation at 300 nm displayed an intense blue emission at 403 nm. The luminescence spectra were interestingly responsive and selective to Al3+, Cr3+ and Fe3+ ions even in the presence of other interfering ions. The calculated detection limits for Al3+, Cr3+ and Fe3+ were 0.35 μM ([triple bond, length as m-dash]8.43 ppb), 0.46 μM ([triple bond, length as m-dash]22.6 ppb) and 0.30 μM ([triple bond, length as m-dash]15.85 ppb), respectively. Notably, with the cumulative addition of Al3+ ions, the luminescence intensity at 403 nm decreased steadily with a gradual red shift up to 427 nm. Afterward, this red shifted peak showed a turn-on effect upon further addition of Al3+ ions. On the other hand, for Cr3+ and Fe3+ ions, there was only drastic luminescence quenching and a large red shift up to 434 nm. This indicated the formation of a complex between 1 and these metal ions, which was also supported by the UV-Visible absorption spectra of 1 that showed the appearance of a new band at 280 nm in the presence of these three metal ions. The FTIR spectra revealed that these ions interacted with the carboxylate oxygen atom of 5-AIP and the nitrogen atom of the Ald-4 ligand in the structure. The luminescence lifetime decay analysis manifested that a charge-transfer type complex was formed between 1 and Cr3+ and Fe3+ ions that resulted in huge luminescence quenching due to the efficient charge transfer involving the vacant d-orbitals, whereas for Al3+ ions having no vacant d-orbital, turn-on of luminescence occurred because of the increased rigidity of 1 upon complexation.

Syntheses and structures of three macrocyclic supramolecular complexes and one ZnII-containing coordination polymer generated from a semi-rigid multidentate N-containing ligand

Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine (L), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(μ-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn₂Cl₄(C₁₂H₁₀N₆)₂]·2CH₂Cl₂, (I), the analogous chloroform monosolvate, [Zn₂Cl₄(C₁₂H₁₀N₆)₂]·CHCl₃, (II), bis(μ-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn₂I₄(C₁₂H₁₀N₆)₂]·2CH₂Cl₂, (III), and catena-poly[[[diiodidozinc(II)]-μ-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine] chloroform monosolvate], {[ZnI₂(C₁₂H₁₀N₆)]·CHCl₃}_n, (IV), by solution reaction with ZnX₂ (X = Cl and I) in a CH₂Cl₂/CH₃OH or CHCl₃/CH₃OH mixed solvent system at room temperature. Complex (I) is isomorphic with complex (III) and has a bimetallic ring possessing similar coordination environments for both of the Zn^II cations. Although complex (II) also contains a bimetallic ring, the two Zn^II cations have different coordination environments. Under the influence of the I^- anion and guest CHCl₃ molecule, complex (IV) displays a significantly different structure with respect to complexes (I)-(III). C-H...Cl and C-H...N hydrogen bonds, and π-π stacking or C-Cl...π interactions exist in complexes (I)-(IV), and these weak interactions play an important role in the three-dimensional structures of (I)-(IV) in the solid state. In addition, the fluorescence properties of L and complexes (I)-(IV) were investigated.

Structural diversity and photocatalytic activity of six Co(ii)/Ni(ii) complexes with three flexible phenylenediacetate isomers

Six coordination polymers show structural diversity have been reported. Their photocatalytic for the degradation of dye have been well studied.

Three water-stable luminescent two-dimensional CdII-based coordination polymers as sensors for highly sensitive and selective detection of Cr2O72− and CrO42− anions

Three 2D Cd^II-CPs with different topologies were prepared, in which 1 and 3 are rare examples which display excellent sensitivity, selectivity, recyclability and structural stabilities for the detection of Cr₂O₇²⁻/CrO₄²⁻.

Two cadmium(ii) coordination polymers as luminescent sensors for the detection of nitrofuran/nitroimidazole antibiotics

p-Terphenyl-2,2′′,5′′,5′′-tetracarboxylate acid and bis(imidazol-1-ylmethyl)benzene-based two Cd(ii) coordination polymers act as the luminescent sensors for the detection of nitrofuran/nitroimidazole antibiotics.

Cu(ii)/Ni(ii)–organic frameworks constructed from the homometallic clusters by 5-(2-carboxyphenoxy)isophthalic acid and N-ligand: synthesis, structures and visible light-driven photocatalytic properties

Four new complexes, namely, Cu₂(O-cpia)(btb)_0.5·(OH) (1), Cu₃(O-cpia)₂(bpy)₂ (2), [Ni₂(O-cpia)(phen)·(OH)·H₂O]·2H₂O (3) and [Ni₃(O-cpia)₂(bpy)₃·2H₂O]·2H₂O (4) (O-cpia = 5-(2-carboxyphenoxy)isophthalic acid, btb = 1,4-bis(1,2,4-triazol-1-yl)butane, bpy = 4,4′-bipyridine) were successfully isolated under hydrothermal conditions. The four complexes exhibit different architectures constructed from different homometallic clusters varying from mononuclear, binuclear to tetranuclear metal(ii) polyhedra as Second Building Blocks (SBUs). 1 features a 3D framework constructed from the tetranuclear clusters [Cu₄(μ₃-OH)₂] as SBUs, linked with Cu(1)O₄N and Cu(2)O₅ polyhedra by O-cpia/btb mixed linkers. 2 also exhibits a 3D structure based on trinuclear clusters [Cu₃(COO)₄] SBUs, bridged with Cu(1)O₃N₂ and Cu(2)O₄ polyhedra via O-cpia/bpy mixed ligands. 3 shows a 2D network consisting of tetranuclear clusters [Ni₄(μ₃-OH)₂] SBUs, which are bridged with Ni(1)O₄N₂ and Ni(2)O₆ through O-cpia ligands. It is worth noting that 4, with a 3D structure, is generated from the binuclear clusters [Ni₂(COO)₄] (Ni(1)O₄N) and mononuclear metal Ni(2) cores (Ni(2)O₄N₂) as SBUs, and bridged by O-cpia/bpy mixed ligands. Meanwhile, the degradation of dyes (RhB) by the complexes under visible light irradiation was studied. 1–4 are semiconducting in nature, with E_g of 1.30 eV (1), 1.78 eV (2), 2.85 eV (3) and 2.14 eV (4). Cu(ii) complexes 1 and 2 are highly efficient photocatalysts for the degradation of RhB under visible light irradiation.

Four Cu(ii)/Ni(ii)-metal–organic frameworks were constructed from different homometallic clusters by O-cpia/N-ligands. Cu(ii)-complexes show highly efficient photocatalysts for the degradation of RhB under visible light irradiation.

Luminescence sensing, electrochemical, and magenetic properties of 2D coordination polymers based on the mixed ligands p-terphenyl-2,2′′,5′′,5′′′-tetracarboxylate acid and 1,10-phenanthroline

Four 2D CPs were constructed and provided platforms to investigate the electrochemical behavior, luminescence sensing of Cr(vi) and pesticides, and magnetic properties.

Dicarboxylate-induced structural diversity of luminescent ZnII/CdII coordination polymers derived from V-shaped bis-benzimidazole

Six Zn^II/Cd^II CPs (1–6), derived from V-shaped bbib and dicarboxylates, have been synthesized; complex 2 is a good bifunctional chemosensor for the detection of Fe³⁺ and MnO₄⁻.

Cd(ii) and Cu(ii) coordination polymers constructed from the expanded 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene ligand: conventional and ultrasound-assisted synthesis, crystal structure, luminescence and magnetic properties

Metal nodes in extend 1D and 3D structures with N,N′-donor linker: the co-ligands decides!

Coordination driven self-assembly of [2 + 2 + 2] molecular squares: synthesis, crystal structures, catalytic and luminescence properties

Ten molecular squares were prepared through coordination-driven self-assembly and their catalytic activity and luminescence properties are reported.

Four new MOFs based on an imidazole-containing ligand and multicarboxylates: syntheses, structures and sorption properties

Four new coordination complexes based on M(ii)-L layer structures with different 3D frameworks and topologies have been successfully tuned by auxiliary dicarboxylates.

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.

Highly selective and sensitive detection of Hg2+, Cr2O72−, and nitrobenzene/2,4-dinitrophenol in water via two fluorescent Cd-CPs

Taking advantage of fluorescent Cd-CPs with 3,3′-thiodipropionic acid and imidazole ligands, herein, we demonstrate the synthesis of functional CPs, and develop two Cd-CP fluorescence sensing materials with highly selective and sensitive detection of Hg²⁺, Cr₂O₇²⁻, NB,/2,4-DNP in water.