Two new 3-D coordination polymers with 5-tert-butyl isophthalic acid and flexible N-donor co-ligands bearing linear trinuclear secondary building blocks

Two new 3-D coordination polymers bearing linear trinuclear secondary building blocks with mixed bridging ligands, {[Ni₃(tbip)₂(Htbip)₂(bib)₂]·4H₂O}_n (1) and {[Co₃(tbip)₂(Htbip)₂(btb)₂]·4H₂O}_n (2) (H₂tbip = 5-tert-butyl isophthalic acid, bib = 1,4-bis(imidazol-1-yl)butane, btb = 1,4-bis(1,2,4-triazol-1-yl)butane), were obtained and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, single-crystal X-ray crystallography and powder X-ray diffraction. Both complexes 1 and 2 display similar 3D 6-connected pcu networks containing the linear trinuclear [M₃(COO)₆] (M = Ni and Co) clusters as nodes.     

Metal-controlled assembly of coordination polymers: Structural variation from 2D parallel interpenetration to 3D CsCl-type topology

Two novel metal-organic frameworks [Cd₂(hdb)₂(1,4-ndc)₂]_n (1) and [Ni₃(Hhdb)₂(1,4-ndc)₄(H₂O)₂]_n (2) have been synthesized under the similar hydrothermal conditions (hdb = 1,1′-(1,6-hexanediyl)bis(imidazole) and 1,4-ndc = 1,4-naphthalenedicarboxylate). The polymers (1) and (2) show 2D parallel interpenetration and 3D CsCl-type topology, respectively, which are mainly affected by the differences of the metal centers.     

Hydrothermal syntheses and characterization of a series of mixed-ligand luminescent CdII frameworks with novel 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate ligand and benzenedicarboxylate isomers

Under similar hydrothermal synthetic conditions using a novel flexible ligand 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetonitrile (PPAN), benzenedicarboxylate isomers (H₂pa = phthalate, H₂ip = isophthalate, and H₂tp = terephthalate) and Cadmium(II) acetate, three novel mixed-ligand Cd(II) coordination polymers {[Cd₂(PPAA)₂(μ-pa)(H₂O)]·2H₂O}_n (1), {[Cd₄(PPAA)₄ (μ₄-ip)₂]·2H₂O}_n (2) and {[Cd₂(PPAA)₂(μ-tp)]·2H₂O}_n (3) (PPAA⁻ = 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate) have been isolated, in 1–3 PPAN, and are also hydrolyzed into a novel PPAA⁻ ligand. Complex 1 is a 1D coordination polymer in which the tetra-nuclear [Cd₄(PPAA)₄]^4 + structural units are extended by tri-dentate μ-pa^2 − ligands. Complex 2 contains binuclear [Cd₂(PPAA)₂]^4 + structural units, which are extended by four tetra-dentate μ₄-ip^2 − ligands to link eight neighboring binuclear [Cd₂(PPAA)₂]^4 + units ultimately forming a 2D layered framework, while complex 3 contains 1D double chain containing [Cd(PPAA)]_n cation structural units, which are further extended by tetradentate μ-tp^2 − ligands to form a new 2D layered framework. All the complexes have been investigated by elemental analysis, FT-IR, thermal analysis and fluorescence characterization. The flexible coordination modes of PPAA⁻ are also briefly analyzed. The flexible coordination modes of PPAA⁻ and benzenedicarboxylate isomers also reveal great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.     

Two transition metal coordination polymers constructed from 1,4-naphthalenedicarboxylate and N/O-donor auxiliary ligands: Syntheses,structures and magnetic property

Two transition metal coordination polymers (CPs), namely, Cd(1,4-NDC)(py) (1), Co₂(1,4-NDC)₂(DMF)₂ (2) (1,4-NDCH₂ = 1,4-naphthalenedicarboxylic acid, py = pyridine, DMF = N,N-dimethylformamide) have been synthesized and characterized. Compound 1 contains one-dimensional chains, which are further linked by the NDC^2 − ligands to form a three-dimensional framework with a 5,5T2 topology network. There exist two types of left-hand helical chains interconnected to each other through the Cd(II) center in compound 1. Although compound 2 has been reported previously, in this work the synthetic method of 2 is modified to obtain high quality crystals. In addition, the magnetic property of compound 2 is investigated, which shows the metamagnetic behavior induced by the external field.     

Assembly of a pcu topological porous Cd-trimesate framework with free carboxylic acid group: Sorption and luminescent property

A six connected 3D porous coordination polymer {[Cd(HBTC)(BPz)]·3EtOH}_n (1) (H₃BTC = benzene-1,3,5-tricarboxylic acid, BPz = 3,3′,5,5′-tetramethyl-4,4′-bipyrazole) has been synthesized from mild solvothermal reaction of Cd(NO₃)₂·4H₂O with BPz and H₃BTC in ethanol. Complex 1 is a thermally stable microporous MOF having (Cd₂(COO)₂) as the secondary building unit (SBU) with a six connected pcu topology. The pores of the polymer are decorated with free COOH groups which show moderate N₂ sorption (38 cc g^− 1) at 77 K with a BET surface area of 129 m² g^− 1. Complex 1 also exhibited photoluminescent property in solid state with λ_max at 396 nm.     

Ionothermal syntheses of two coordination polymers constructed from 5-sulfoisophthalic acid ligands with 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid as solvent

Two coordination polymers, namely, [Co(IM)₆][Co₂(SIP)₃] (1) (IM = imidazole, H₃SIP = 5-sulfoisophthalic acid) and [BMIM]₂[Cd₂(SIP)₃] (2) (BMIM = 1-n-butyl-3-methylimidazolium) were synthesized in ionothermal reactions by using ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate as solvent. Single-crystal X-ray analyses revealed that 1 has an anionic 1D polymeric chain charge balanced by an uncommon [Co(IM)₆]²⁺ cation. Complex 2 features an anionic 2D layer containing unique tetranuclear [Cd₄(CO₂)₆(SO₃)₂] cluster wherein the four Cd atoms are co-planar. The imidazolium cation [BMIM]⁺ of the ionic liquid acting as charge compensating agent intercalated into the [Cd₂(SIP)₂]^2n? interlayers in structure 2. The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the anionic frameworks of 1 and 2.     

Structural characterization of ferromagnetic bridged-acetato and -dichlorido copper(II) complexes based on bicompartmental 4-t-butylphenol

The reaction of Cu(II) salts with 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-t-butylphenol (L^t-Bu-OH) afforded two bridged-phenoxido/hydroxido complexes. The dinuclear bridged acetate species [Cu₂(μ-L^t-Bu-O)(μ-CH₃COO)](PF₆)₂ (1) and the 1D polymeric doubly-bridged-chlorido {[Cu₂(μ-L^t-Bu-OH)(μ-Cl)₂](ClO₄)₂·4H₂O}_n (2). The two complexes were structurally characterized. Both complexes revealed ferromagnetic interactions; moderate in complex 1 (J = + 30.8 cm^− 1) and very weak (J = + 2.25 cm⁻¹) in 2.     

Syntheses,structures and photocatalytic properties of two coordination polymers based on bis(1,2,4-triazol-4-ylmethyl)benzene and multicarboxylates

Two coordination polymers {[Cu₄(OH)₂(btrb)₂(btc)₂]·4H₂O}_n (1) and {[Cd₂(btrb)(adc)₂(H₂O)]·H₂O}_n (2) were synthesized with hydrothermal method and characterized (btrb = 1,4-bis(1,2,4-triazol-4-ylmethyl)benzene, btc = 1,3,5-benzenetricarboxylate, adc = 1,3-adamantanedicarboxylate). 1 shows an unusual (3,10)-connected two-dimensional metal–organic framework based on the tetranuclear copper(II) cluster [Cu₄(μ₃-OH)₂]. 2 is an interesting three-dimensional network based on the one-dimensional metal–organic nanotube. 1 shows good photocatalytic activity for the degradation of methyl blue (MB). The luminescence of 2 was investigated.     

A unique 1D luminescent CdII coordination chain in situ resulted from C–S bond cleavage

Hydrothermal reaction of CdI₂ with BMSA (BMSA = (1H-Benzoimidazol-2-ylsulfanyl)acetic acid) resulted in a unique 1D Cd²⁺ coordination polymer (1) with BMT (BMT = benzoimidazole-2-thiol) as organic building blocks, which are generated from in situ C–S bond cleavage of BMSA. The polymer is composed of an inorganic skeleton chain [CdS₂]_n with BMT anchoring on both sides like wings. The free BMT ligand in (1) plays an important role in the construction of the 2D superamolecular structure via N–H?S hydrogen bonds. The luminescence emission spectrum of (1) features a broad luminescence with emission maxima at 390 nm when excited at 270 nm.     

Construction and photoluminescence properties of two novel zinc(II) and cadmium(II) benzyl-tetrazole coordination polymers

Two new d¹⁰ coordination polymers, Zn(Beta)₂ (1) and Cd₂(Beta)₃Cl(H₂O) (2) (Hbeta = 5-benzyl-tetrazole) have been synthesized by the in situ [3 + 2] cycloaddition reaction of 5-benzylacetonitrile, sodium azide and MCl₂ [M = Zn (1); M = Cd (2)] under hydrothermal condition. Complex 1 is a coordination polymer comprised of numerous mildly undulated two-dimensional (2D) layers with a (4, 4) topological network; while complex 2 is a 3D coordination framework constructed from the interconnection of various helical chains through cadmium–chlorine bridges. Furthermore, the luminescence properties of two complexes have been investigated.     

Porous Cd-carboxylate frameworks tuned by the bulk of linker: Interpenetrated nets,selective CO2 uptakes and high water vapor adsorption

Reported herein are two porous interpenetrated anionic Cd-carboxylate frameworks tuned by the length of organic linker. Shorter BDC linker and [Cd(COO)₄] building blocks in 1 generate a rare 4-connected 2-fold interpenetrating qtz network. But longer NDC linker in 2 produces a self-penetrated 8-connected bcu framework with [Cd₃(COO)₈] SBUs. 1 and 2 both show selective CO₂ adsorption and significantly, 2 exhibits the highest water vapor uptake performance (281 cm³·g^− 1 at 298 K and P/P₀ = 0.95) among all the interpenetrated MOFs.     

A new helical coordination polymer constructed on flexible dicarboxylate ligand and CdII center: Structure and luminescence

A novel cadmium coordination polymer [Cd₂L₂(bpp)₂]_n (1) (H₂L = 1,3-adamantanediacetic acid and bpp = 1,3-di-4-pyridylpropane) was prepared under hydrothermal condition. The three-dimensional (3D) structure is built from the interlinking lamellars. The Cd^II ions are six- and seven-coordinated and linked by L^2? ligands, which results in the right- and left-handed helical chains. The layers are stacked with each other via bpp to generate a 3D architecture. At room temperature, the complex 1 shows the strong fluorescent emission bands in the solid state.     

Pillar-layered Zn–triazolate–carboxylate frameworks tuned by the bend angles of ditopic ligands

In the utilization of three ditopic ligands with different bend angles as pillars, we reported herein three pillar-layered Zn–triazolate–carboxylate frameworks, namely, [Zn₂(ATRZ)₂(BDC)]_n (1), [Zn₂(ATRZ)₂(TPDC)]_n·2nDMF (2) and [Zn₂(ATRZ)₂(ADDC)]_n (3) (ATRZ = 3-amino-1,2,4-triazole, H₂BDC = 1,4-benzenedicarboxylic acid, H₂TPDC = 2,5-thiophenedicarboxylic acid, and H₂ADDC = 1,3-adamantanedicarboxylic acid). Single crystal structural analyses demonstrate that different geometries of ditopic carboxylate pillars not only result in Zn–ATRZ layers adopting various corrugated configurations, but also give rise to 3,4-connected self-interpenetrated net of 1 and non-interpenetrated nets of 2 and 3. All these compounds exhibit high thermal stability and blue photoluminescence.     

The irreversible crystal transformation of a novel Cadmium(II) supramolecular complex containing planar tetrameric water cluster

A new cadmium complex [CdL₂(CH₃COO)₂] · 3H₂O (1) has been synthesized by the reaction of 2-aminobenzimidazole (L) with cadmium acetate in an aqueous solution, and structurally characterized by single crystal X-ray diffraction and FT-IR spectra. Cyclic planar tetrameric water clusters with C_2h symmetry are observed to be encapsulated in the 3D open supramolecular architecture of 1 by hydrogen bonds interactions. Interestingly, 1 can convert irreversibly into single crystal 1a formulated [CdL₂(CH₃COO)₂] by losing its lattice water molecules at room temperature. Strong intermolecular N–H ⋯ O hydrogen bonds and aromatic rings π–π stacking interactions assemble 1a into another 3D interdigitated supramolecular network.     

A metal–organic framework containing meso-helical chains: Synthesis,characterization and luminescent property

A new metal–organic frameworks (MOFs), [Cd₃(pmb)₂(bpdc)₂] 2H₂O (1) (pmb = 3,5-bis(4-pyridylmethylenoxyl)benzoate, bpdc = 2,2′-biphenyldicarboxylate), has been synthesized by hydrothermal method and structurally characterized through IR, TG and single-crystal X-ray analysis. The infinite wave-like 1D metal–oxygen chains made by Cd₃N₄O₁₂ clusters in 1 bridged by the carboxylate of bpdc ligand, construct a 2D framework in which interesting meso-helical chains are constructed by metal centers and pmb ligands. Solid state luminescent spectrum of 1 also has been investigated at room temperature.     

Solvothermal synthesis and structural characterization of a Cd-triazole-benzenedicarboxylate framework

By employing mixed-ligands of 1,4-H₂BDC and Htrz (1,4-H₂BDC = 1,4-dicarboxybenzene, Htrz = 1-H-1,2,4-triazole) under solvothermal condition, a metal-organic framework, [(CH₃)₂NH₂][Cd₂Cl(1,4-BDC)(Trz)₂] (1), has been synthesized and characterized by single crystal X-ray diffraction. Compound 1 exhibits a three-dimensional structure with two kinds of channels along the c axis. In addition, powder X-ray diffraction, thermogravimetric analysis and photoluminescent properties of 1 were investigated in detail.     

Syntheses and structures of cadmium(II) and cobalt(II) coordination polymers based on 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) and carboxylate ligands

Two novel coordination polymers containing Cd(II) and Co(II) metals, connected via 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) (L) ligand, have been synthesized. Compound [Cd(L)₂(p-BDC)] · 2H₂O (1) (p-BDC = 1,4-benzenedicarboxylate anion) is a three-dimensional interdigitated supramolecular architecture. Compound [Co(L)(BTCA)_0.5] (2) (BTCA = 1,2,3,4-butanetetracarboxylate anion) possesses a unique (3,4)-connected 3D framework with (8³)₂(8⁵ · 10) topology.     

Hetero-trinuclear near-infrared (NIR) luminescent ZnLn2 (Ln = Nd,Yb or Er) complexes based on monomer ZnL Schiff-base precursor and o-vanillin

With the monomer [Zn(L¹)(H₂O)] (1) complex in situ formed by the deprotonated hexadentate Salen-type Schiff-base ligand H₂L¹ (H₂L¹ = N,N′-bis(3-methoxy-salicylidene)cyclohexane-1,2-diamine) and Zn(NO₃)₂ as the precursor, series of the hetero-trinuclear ZnLn₂ complexes [ZnLn₂(L¹)₂(L²)(NO₃)₂Cl] (Ln = Nd, 2; Ln = Yb, 3; Ln = Er, 4 or Ln = Gd, 5) were obtained from the further reaction with LnCl₃ (Ln = Nd, Yb Er or Gd) and the second o-vanillin (HL²) ligand, respectively. The photophysical properties of complexes 2–4 showed that the characteristic near-infrared (NIR) luminescence of Ln^3 + ions with two emission centers and emissive lifetimes in microsecond ranges, was sensitized from the excited state (both ¹LC and ³LC) of mixed H₂L¹–HL² ligands.     

A new 3D helical silver(I) cluster metal–organic framework with microporous structure and luminescent property

A new 3D helical silver(I) metal–organic polymer of {[Ag₂(ADC)(bib)_0.5]·H₂O}_n (1) (H₂ADC = 1,3-adamantanedicarboxylic acid, bib = 1,4-bis(2-methyl-imidazol-1-yl)butane), has been synthesized and characterized. Compound 1 exhibits significant void space that may be filled with guest H₂O molecules in spite of the metal-cluster that occurs in the solid. Preliminary thermal and fluorescence experiments show that compound 1 possesses strong fluorescent property and thermal stability, respectively.     

A polythreaded three-dimensional architecture of undulated layers originated by the contribution of different supramolecular interactions

The structure of compound [Cd₂(NDC)₂(L)₂(H₂O)]·0.5DMF (1) (NDC = 1,4-naphthalenedicarboxylate, L = pyrazino[2,3-f][1,10]phenanthroline and DMF = N,N′-dimethylformamide) is reported. Two independent Cd(II) atoms in a distorted [CdO₄N₂] octahedral environment and three unique NDC ligands showing different coordination modes give strongly undulated two-dimensional grid motifs. Dangling L ligands are chelated to every Cd(II) atom decorating both sides of the layers. Due to the marked undulation of the layers, the large open windows are threaded by the dangling ligands of other layers producing a three-dimensional polythreaded supramolecular array that can be also described as a single three-dimensional framework if the extended columnar face-to-face π–π interactions are considered.