Synthesis, crystal structures and photoluminescence of Zn–Ln heterometallic polymers based on pyridine-2,3-dicarboxylic acid

Three new two-dimensional 3d–4f isostructural heterometallic coordination polymers, namely [Ln₂Zn(2,3-pydc)₄(H₂O)₄·4H₂O]_n (Ln = Sm (1), Eu (2), Gd (3), 2,3-pydcH₂ = pyridine-2,3-dicarboxylic acid) have been successfully synthesized by the hydrothermal reactions of Ln₂O₃, Zn(NO₃)₂·6H₂O, H₂pydc and H₂O. X-ray diffraction analyses reveal that they possess a 2D heterometallic framework containing 1D lanthanide chains based on dimeric [Ln(2,3-pydc)₂(H₂O)₂]₂ unit. The Zn(II) ion, which is six-coordinated by four oxygen and two nitrogen atoms from four 2,3-pydc²⁻ ligands, as a bridge, links the lanthanide chains to make the 1D chains further extend into 2D layer framework. Furthermore, the neighboring layers are assembled into three-dimensional supramolecular network through inter-layer O–HO and C–HO hydrogen-bond interactions. In addition, the solid-state luminescent property of complex 2 was investigated.     

Synthesis,structures, and luminescence of lanthanide coordination polymers constructed from benzimidazole-5,6-dicarboxylate and oxalate ligands

Three novel coordination polymers [(Eu₂(Hbidc)₂(ox)₂·(H₂O)₃] (1), [Tb₂(Hbidc)₂(ox)(H₂O)₂]·4H₂O (2), [Er₂(Hbidc)₂(ox)] (3) have been synthesized with hydrothermal reaction (H₃bidc = Benzimidazole-5,6-dicarboxylic acid, H₂ox = Oxalic acid) and characterized by elemental analysis, IR and X-ray single crystal diffraction. 1, 2 and 3 have the same crystal system of triclinic, but they exhibit different kinds of metal-organic framework structures. The luminescent properties of 1 and 2 were studied at room temperature.     

3D pillar-layered 4d–4f heterometallic coordination polymers based on pyridine-3,5-dicaboxylate and oxalate mixed ligands

Three 4d–4f heterometallic polymers, Ln₂Ag₂(Hpydc)₂(pydc)₂(ox) · 4H₂O (Ln = Nd (1), Eu (2) and Er (3); H₂Pydc = pyridine-3,5-dicarboxylic acid, H₂ox = oxalic acid), have been successfully synthesized under hydrothermal condition and structurally characterized. Single-crystal X-ray diffraction analyses reveal that three compounds are isomorphous and exhibit 3D pillar-layered coordination frameworks constructed from two-dimensional lanthanide-carboxylate layers and [Ag(pydc)]^? pillars. Furthermore, the luminescent property of compound 2 was studied.     

Hexanuclear 4d–4f complexes [Ln2Ag4(ina)8(H2O)10][NO3]2 · 4H2O (Ln = Sm, Eu, Dy): Syntheses, structures and photoluminescent properties

Hexanuclear 4d–4f heterometallic complexes, [Ln₂Ag₄(ina)₈(H₂O)₁₀][NO₃] ₂ · 4H₂O [Ln = Sm (1), Eu (2), Dy (3) and Hina = isonicotinic acid], have been synthesized by the hydrothermal reaction of lanthanide oxides, Ag^I, and isonicotinic acid at a suitable temperature. Single-crystal X-ray diffraction studies indicate that these 4d–4f complexes consist of extended 1D zigzag chains structure built upon [Sm₂Ag₄(ina)₈(H₂O)₁₀] subunits connected by Ag–Ag interactions. Furthermore, the photoluminescent properties of the complex 2 were studied.     

Zn-Er heterometallic carboxylate framework based on 3,5-pyrazoledicarboxylic acid with nested sandwich structure and its luminescent property

A three-dimensional 3d-4f heterometallic coordination polymer, {[Er₂Zn(Hpdc)₄(H₂O)₈]·2H₂O}_n (1)(H₃pdc = 3,5-pyrazoledicarboxylic acid), was hydrothermally synthesized and characterized by techniques of single crystal X-ray diffraction, infrared spectra (IR), thermogravimetric analysis(TGA), elemental analysis, powder X-ray diffraction(PXRD), and luminescent measurements. X-ray crystal structure analyses reveal that complex 1 shows a 3D heterometallic framework with nested sandwich-type structure, built by the 2D Er-Hpdc networks, [Zn(Hpdc)₂(H₂O)₂] units, and hydrogen bonds. In addition, the solid-state luminescent property investigation shows that emission lifetime span of the complex was at the microsecond level in the visible region, which is classified as a phosphorescent material. Moreover, when excited at 375 nm, the complex exhibits the characteristic emission ⁴I_13/2 → ⁴I_15/2 of Er(III) at 1514 nm.     

Synthesis, crystal structure and photoelectric property of two novel coordinated complexes constructed by 4,4′-bipyridine and sebacic acid

Two two-dimensional (2D) new complexes: [M(bpy)(C₁₀H₁₆O₄)H₂O] [M = Ni (1), Co (2); bpy = 4,4-bipyridine, C₁₀H₁₈O₄ = sebacic acid] were synthesized by the hydrothermal reaction at 180 °C and characterized by elemental analysis, infrared spectra, and thermogravimetric spectra, single-crystal X-ray diffraction and surface photovoltage spectrum (SPS). The single-crystal X-ray diffraction showed that both complexes are isomorphous, crystallized in monoclinic system, and space group P2₁/c. In addition, The results of SPS for complexes (1) and (2) indicate that these two complexes exhibit positive surface photovoltage response in the range of 300–800 nm, which can be assigned to LMCT and d → d^* electronic transition. The SPS spectra of the two complexes are consistent with their UV–Vis spectra.     

Photoinduced linkage isomerism of binuclear bis(pyrazole-3,5-dicarboxylato)-bridged {RuNO} centres

The two novel binuclear pyrazole-3,5-dicarboxylato-bridged {RuNO}⁶ complexes K₂[{Ru(NO)Cl}₂(μ-pzdc)₂] (1) and [{Ru(NO)(H₂O)}₂(μ-pzdc)₂]·4H₂O (2) (pzdc = pyrazole-3,5-dicarboxylate) were synthesized and characterized by elemental analysis, mass spectrometry and spectroscopic methods (NMR, UV–vis, IR). 2 was investigated by means of single-crystal X-ray diffraction analysis. On irradiation, in both 1 and 2 the existence of photoinduced long-lived metastable isonitrosyl states SI were detected by low-temperature infrared spectroscopy.     

Template-assisted self-assembly: Synthesis,structures, and magnetic properties of lanthanide(III)-cobalt(II) coordination complexes constructed with deprotonated 3,5-pyridinedicarboxylic acid ligand

Two new 3d-4f complexes, [LnCo(3,5-pdc)₂(3,5-Hpdc) (H₂O)₇]·H₂O (Ln = Gd 2, La 3; 3,5-pdcH₂ = pyridine-3,5-dicarboxylic acid), have been synthesized by the self-assembly of Ln(III) oxides, 3,5-pdcH₂ and the template molecule [Co(3,5-pdc)(H₂O)₅]·H₂O (1) under hydrothermal conditions. Heterometallic complexes 2 and 3 are isostructural with supracyclic units containing four Ln(III) ions and two Co(II) ions, in which Co(II) and Ln(III) are linked by the deprotonated 3,5-pdcH₂ ligands in three kinds of bridging modes. The weak antiferromagnetic coupling of complex 2 and 3 imply that the large 3,5-pdc bridges with the greater separation ( > 7 Å) cannot lead to long range magnetic ordering, the strength of d_n-f_n exchange coupling increasing with decreases the size of the lanthanide ion.     

A 3D Gd–Ag coordination polymer constructed from pyridine-3,5-dicarboxylic acid: Synthesis, crystal structure and magnetic properties

A novel heterometallic coordination polymer, [AgGd(PDC)₂]·2H₂O (1) (H₂PDC = pyridine-3,5-dicarboxylic acid), have been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, thermogravimetric analysis and single-crystal X-ray diffraction. Complex 1 features an unusual three-dimensional network structure in which infinite gadolinium-carboxylate chains are linked by [Ag(PDC)₂]³⁻ metalloligands to form a mixed-metal coordination network. Moreover, the luminescent properties and magnetic properties of 1 have also been investigated.     

Four novel lanthanide(III) coordination polymers with 3D network structures containing 2-fold interpenetration

Four novel lanthanide(III) coordination polymers [Ln(L)_1.5(H₂O)₂]·5H₂O [Ln = Sm (1), Eu (2), Tb (3), Dy (4)] have been hydrothermally synthesized by the reaction of 1,2-bis[4-amino-5-carboxylmethylthio-(1,2,4-triazol-3-yl)]ethane (H₂L) with lanthanide(III) salts, and structurally characterized by single crystal X-ray diffraction. Polymers 1–4 are isostructural, in which all the Ln^III atoms are nine-coordinated and the carboxylate groups adopt three different coordination modes (bidentate chelate, bidentate bridging, bidentate chelate bridging) to connect Ln^III atoms. These polymers exhibit 3D network structures with 2-fold interpenetration, in which intriguing 1D channels are observed. Besides, the spectra properties of the title polymers are investigated, the strong luminescence characteristics of 2–3 are found.     

Hydrothermal syntheses,crystal structures and photocatalytic properties of three POM-templated organic–inorganic hybrid compounds

Three new POM-templated organic–inorganic compounds, Cu₂(3,5-bptp)₂[H₂SiW₁₂O₄₀]·4H₂O (1), Ag₂(3,5-bptp)₂[HPW₁₂O₄₀]·4H₂O (2), [Cu₄(OH)₃Cl(H₂O)₃(4-bpo)₃](SiW₁₂O₄₀)·5H₂O (3) (3,5-bptp = 3,5-bis(3-(pyrid-4-yl)-1,2,4-triazolyl)-pyridine, 4-bpo = 2,5-bis(4-pyridyl)-1,3,4-oxadiazole) were hydrothermally synthesized and characterized by elemental analysis and single crystal X-ray diffraction. Crystal structural analysis indicates that compounds 1 and 2 are isostructural and show one dimensional zigzag chains with [H₂SiW₁₂O₄₀]^2 − as guest molecules. Compound 3 is two dimensional sheets constructed from [Cu₄(OH)₃Cl(H₂O)₃] clusters and 4-bpo ligands with [SiW₁₂O₄₀]^4 − as guest molecules. Furthermore, the photocatalytic degradation of methyl orange (MO) with 3 was studied under visible light irradiation, indicating excellent photocatalytic activity.     

A hemidirected 1-D coordination polymer [Pb2(H2O)2(HBTC)2] · 3H2O extended in holodirected 3-D by weak Pb–O interactions

A new complex, [Pb₂(H₂O)₂(HBTC)₂] · 3H₂O (H₃BTC = 1,3,5-Benzenetricarboxylic acid) (1), has been synthesized under hydrothermal condition. The single-crystal analysis shows that 1 consists of 1-D double-chains with Pb(II) six-coordinated by three H₃BTC and one H₂O molecule with the Pb–O bond distances in the range of 2.56–2.76 Å. When the Pb–O bonding limit extends from 2.76 to 2.90 Å, the potential weak bonds of Pb–O can be found and the coordination number of Pb will increase from six to nine. As a result, the coordination geometry of Pb(II) transforms from hemidirected to holodirected and an infinite 3-D framework is obtained by the connection of the double-chains. The IR spectrum and the TGA–DTA curve of 1 are also reported in this paper.     

Synthesis, characterization and luminescent property of a novel zinc(II) 1,2,3,4-tetra(4-pyridyl)thiophene metal–organic framework

A novel metal–organic framework (MOF) [Zn(TPT)(MPDCO)(H₂O)·H₂O]n (TPT = 1,2,3,4-tetra (4-pyridyl)thiophene, MPDCO = 6-methylpyridine-2,4-dicarboxylic acid N-oxide) (1) was obtained via hydrothermal synthesis and characterized by the elemental analysis, IR spectroscopy, TG analysis, luminescent spectroscopy and single-crystal X-ray diffraction analysis. Single-crystal structural analysis reveals that a one-dimensional (1-D) ladderlike MOF is constructed through the mixed ligands, and it is further connected by the intermolecular hydrogen bonds to form a 3-D supramolecular network. Complex 1 exhibits efficient blue luminescence at room temperature, and the framework is stable below 235 °C.     

Two novel 3D 3d–4f polymers with triethylenetetraaminehexaacetic acid: Syntheses,structures, and magnetic properties

Two novel 3d–4f polymers [La(H₂O)₄][M₂TTHA(SCN)₂] · H₃O⁺ (M = Ni(1), Cu(2), H₆ TTHA = triethylenetetraaminehexaacetic acid) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis, IR and magnetic properties. Two complexes show 3D framework, comprising an unusual infinite 1D chain based on heterometallic La₂M₂ rings (M = Ni(1), Cu(2)).     

1D chain lanthanide coordination polymers with 6-hydroxynicotinic acid: Crystal structures and luminescent properties

Four new lanthanide coordination polymers {[Ln(HL)₂(H₂O)₅] · HL ·  H₂O}_n (Ln = Sm for 1, Eu for 2, Tb for 3 and Dy for 4) (H₂L = 6-hydroxynicotinic acid) have been synthesized and characterized by elemental analysis, FT-IR spectra and X-ray single-crystal diffraction. They all exhibit 1D chain structure, which are further linked via hydrogen bonds to form 3D supramolecular architecture. Luminescent properties of these lanthanide coordination polymers are studied.     

Novel heterobimetallic Cu/Mn coordination polymers prepared by “direct permanganate” synthesis

Two heterometallic Cu/Mn complexes [Cu(Me₂en)₂][Mn₂(ox)₃] · 2H₂O (1) (Me₂en = N,N-dimethylethylenediamine, H₂ox – oxalic acid) and [Cu(1,3-pn)(ox)(H₂O)][Mn(ox)(H₂O)₂] · H₂O (2) (1,3-pn = 1,3-diaminopropane) are prepared by the one-pot reaction of copper powder, tetrabutylammonium permanganate, oxalic acid and N-chelating ligands. Their structures are investigated by single-crystal X-ray analysis that reveals interesting variation in bridging motives of the oxalate groups composing the Mn-polymeric fragments.     

Syntheses,structural characterization and luminescent properties of M2(ATPA)3(DMF)2(H2O)2 (M = Nd,Sm, Eu,Gd, Tb,Dy; ATPA = 2-aminoterephthalate,DMF = N,N-dimethylformamide)

Six isomorphous metal–organic frameworks: M₂(ATPA)₃(DMF)₂(H₂O)₂ (M = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6); ATPA = 2-aminoterephthalate, DMF = N,N-dimethylformamide), were synthesized by the self-assembly of lanthanide ions, 2-aminoterephthalate, DMF and H₂O. Their crystal structures determined by X-ray crystallography reveal interpenetrating frameworks. Compounds 2, 3, 5 and 6 exhibit mainly ligand luminescence at room temperature while 3 exhibits enhanced Eu³⁺ emissions at 77 K. Magnetic studies indicate 4 is paramagnetic with slight Gd³⁺–Gd³⁺ couplings.     

Solvent-free synthesis of new open-framework metal oxalates with different 4-connected topologies

Three open-framework metal oxalates, formulated as (Hdbu)[In₂(OH)(ox)₃] (1), (Hthfa)[Eu₂(Hthfa)(H₂O)(ox)₄]⋅ 3H₂O (2), and (Hepc)[Bi(ox)₂] (3), were prepared under solvent-free conditions, where dbu = 1,8-diazabicyclo[5.4.0]undec-7-ene, ox = oxalate, thfa = tetrahydrofurfurylamine, and epc = 4-ethylpiperazine-1-carbaldehyde. Topological analyses reveal that these compounds have different 4-connected networks with sra (for 1), lon (for 2), and dia (for 3) topologies. Compound 2 displays a bright red luminescence as a result of excitation at 397 nm.     

Novel lanthanide coordination polymers with Eu-compound exhibits warm white light emission: Synthesis,structure, and magnetic properties

Five two-dimensional lanthanide coordination polymers: [Ln₂(TDA)₃(bipy)₂(H₂O)₂]·bipy·2H₂O (Ln = Nd (1), Sm (2), Eu (3), Tb (4), Yb (5), TDA = thiophene-2,5-dicarboxylic acid anion, bipy = 2,2′-bipyridine) were fabricated and structurally characterized. Compounds 1–5 are isostructural belonging to the triclinic system with space group P-1. Luminescence analyses were performed on coordination polymers containing Eu^3 + and Tb^3 +, and compound 3 shows a warm white light emission upon excitation.     

Three novel bismuth-based coordination polymers: Synthesis,structure and luminescent properties

Three novel bismuth-based coordination polymers, [(CH₃)₂NH₂][Bi(pdc)(bdc)]·2DMF, [(CH₃)₂NH₂][Bi(tdc)₂]·1.5DMF and [Bi(bpdc)₂H₂O]·xGuest (compounds 1–3) (H₂pdc = 3,5-pyridinedicarboxylic acid, H₂bdc = 1,4-benzenedicarboxylic acid, H₂tdc = 2,5-thiophenedicarboxylic acid, H₂bpdc = 4,4′-biphenyldicarboxylic acid), have been successfully synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction. Compounds 1 and 2, which are constructed by 9-coordinated or 8-coordinated Bi^3 +, feature three-dimensional structures with hms and dia topology, respectively. However, 5-coordinated Bi^3 + based compound 3 is a two-dimensional layered structure. Compound 1 can tune emissive performance by doping different lanthanide ions Tb^3 +, Eu^3 + and Dy^3 +. Furthermore, detection of nitro explosives is investigated. All of the compounds are characterized by elemental analysis, IR spectrum and thermogravimetric analysis.