Syntheses, structures and fluorescent properties of two novel coordination polymers in the U-Cu-H3pdc system

Two novel coordination polymers, UO2(C5H2N2O4)(H2O) (1) and (UO2)Cu(C5H2N2O4)2(H2O)2 (2), have been prepared by the hydrothermal reaction of uranyl nitrate hexahydrate [(UO2(NO3)2.6H2O], 3,5-pyrazoledicarboxylic acid (H3pdc) and copper(II) nitrate hemipentahydrate (Cu(NO3)2.2.5H2O) and characterized by single-crystal X-ray diffraction, thermogravimetric analyses (TGA) and fluorescence spectroscopy. Compound 1 (monoclinic, P2(1)/c, a=6.9556(6)A, b=11.302(1)A, c= 10.5288(9)A, beta=90.057(2) degrees and Z=4) consists of a two-dimensional sheet containing uranyl hexagonal bipyramids. Compound 2 (triclinic, P-1, a=5.1014(7)A, b=7.6067(11)A, c=10.2910(15)A, alpha=72.380(3) degrees, beta=86.796(3) degrees, gamma=84.447(3) degrees and Z=1) consists of two-dimensional sheets. Both structures contain the linear UO2(2+) moiety and have extended networks built up from the H3pdc ligand. Compound 1 exhibits the characteristic UO(2)2+ emission spectra when it is excited at the ligand or uranium excitation wavelength. With the addition of the copper metal center in compound 2, the uranium emission is absent regardless of the excitation wavelength.     

Syntheses,structures, and fluorescent properties of two uranium coordination polymers with carboxylic acids

Two U(VI)-containing coordination polymers, (UO₂)₂O₂(Suc)(2,2′-bipy)₂ (1) and UO₂(BC)₂(DMF) (2) (2,2′-bipy?=?2,2′-bipyridine, H₂Suc?=?succinic acid, HBC?=?benzoic acid, DMF?=?N,N-dimethylformamide), have been synthesized and characterized via elemental analysis, infrared spectroscopy, UV-Vis spectroscopy, and single-crystal X-ray diffraction. Structural analyses show that 1 is a 1-D chain coordination polymer in which U(VI) ions are connected by succinic acid ligand and the 1-D chain is connected into a 3-D supramolecular network by C?H···O hydrogen bonds between carbon of 2,2′-bipyridine and uranyl oxygen. For 2, monomeric entities are further assembled into a 1-D supramolecular network by C–H···O hydrogen bonds between carbon of DMF molecule and coordinated carboxylate oxygen. Thermogravimetric analyses and photoluminescent properties of 1 and 2 are discussed.     

Syntheses,characterization, and magnetic properties of two 3D frl topological frameworks constructed from nickel diphosphonates

Two 3D open-framework nickel diphosphonates, [Ni₃(H₂zdn)₂(bpe)₂]·4H₂O (1) and [Ni₃(H₂zdn)₂(bpy)₂]·bpy·4H₂O (2) (H₅zdn = zoledronic acid, bpe = trans-4,4-vinylenedipyridine, bpy = 4,4′-dipyridyl), have been prepared and structurally characterized. In complex 1, the metal centers are linked by zoledronate ligands to generate a 2D layer, containing 14- and 24-membered rings. These 2D layers are further pillared by the bpe ligands into a 3D network structure with cylindrical channels. Magnetic susceptibility measurements reveal ferrimagnetism at T _c = 3.8 and 4.4 K for complexes 1 and 2, respectively.     

System-pH-dependent supramolecular isomers of puckered three-dimensional layered hydrogen-bonded networks: Syntheses, characterization and fluorescent properties

Two true supramolecular isomers (1 and 2) formulated as [Zn(bipy)(H₂btc)₂]_n (bipy=2,2′-bipyridine, H₃btc=benzene-1,3,5-tricarboxylic acid) have been hydrothermally prepared through systematically changing the pH value of reaction mixture, and characterized by single-crystal X-ray diffraction, element analysis, infrared spectra (IR), and differential scanning calorimetry (DSC). Isomer 1 crystallizes in triclinic space group P-1, tetrahedral Zn(ΙΙ) ions possess four-coordinated environment, while isomer 2 crystallizes in monoclinic space group C2/c and the distorted octahedral Zn(II) ions adopt six-coordinated fashion. 1 and 2 can be regarded as supramolecular structural isomers, the formation of which should be undoubtedly attributed to the preference for pH-dependent crystallization leading to multiple connectivity (monodentate and chelating bidentate) of organic ligand despite the same stoichiometry employed. The supramolecular chemistry, which organizes the coordination complexes into three-dimensional (3D) layered open structure, is driven by a combination of hydrogen-bond and π-π interactions. Moreover, 1 emits fluorescence at 350.1 nm () and 2 exhibits fluorescent property at about 351.4 nm ().     

Syntheses,structures, and fluorescent properties of two helical complexes based on a long rigid N-heterocyclic ligand

A long N-heterocyclic ligand, 2,6-bis(3-(pyrid-3-yl)-1,2,4-triazolyl)pyridine (H₂bptp), and Zn(II)/Pb(II) yield {[Zn(bptp)(H₂O)]?·?2H₂O·CH₃CN} _n (1) and {[Pb(bptp)]?·?H₂O} _n (2). Single-crystal X-ray diffraction analysis reveals that 1 and 2 possess 2-D networks containing alternating left- and right-handed helical motifs. Topologically, 1 features a (4,4) topology, while 2 exhibits a (6,3) topology. The bptp^2? in 1 and 2 adopts syn-anti and syn-syn conformations, respectively. The results indicate that the long rigid N-heterocyclic ligand can adopt different conformations to coordinate with metals, beneficial to construction of helical structures with diverse topologies. The difference between the photoluminescence properties of the two complexes reveals that metal ions and coordination environment have significant influences on photoluminescence behavior.     

Syntheses and photophysical properties of fluorescent 2-aryl-3-hydroxy-4-chromenones

The particle detectors proposed for the Super-conducting Super Collider contain polystyrene scintillation fibers as a component. Scintillation fluors soluble in styrene are required which have improved light output and response time. New 2-aryl-3-hydroxy-4-chromenones related to 3-hydroxyflavone were prepared which displayed these improved properties. Improved solvent systems for chromenone formation were essential in the synthesis of two of the chromenones. One chromenone produced fluorescence emission at 560 nm with a quantum yield of 0.53 and a scintillation decay time of 5 nsec.     

Syntheses, crystal structure, and fluorescent properties of a lanthanide complex

A new complex [Dy₂(Pht)₂(HPht)₂(Phen)₂(H₂O)₄] (I), where Pht^2? = dianion of o-phthalic acid; HPht^? = mono-anion of o-phthalic acid; Phen = 1,10-phenanthroline, has been synthesized and the crystal structure was determined by X-ray crystallography. The I crystallizes in the triclinic system, space group $P\bar 1$ with lattice parameters a =10.1126(3) Å, b =10.7029(3) Å, c = 11.9360(3) Å, α = 90.2260(10)°, β = 99.5340(10)°, γ = 100.9810(10)°, V = 1249.87(6) ų, Z = 2, ρ_calcd = 1.881 mg m^?3. The photophysical property of I has been studied with excitation and emission spectra.     

Synthesis,characterization and fluorescent properties of lanthanide complexes with two aryl amide ligands

Two aryl amide ligands, N-(p-tolyl)-2-(quinolin-8-yloxy)acetamide (L¹ ) and N-(4-chlorophenyl)-2-(quinolin-8-yloxy)acetamide (L² ), were synthesized. With these ligands, two series of lanthanide(III) complexes were prepared, Ln(L ⁿ )₂(NO₃)₃ (n = 1, 2; Ln = La, Sm, Eu, Gd, Dy), and characterized by the elemental analyses, molar conductivity, ¹H NMR spectra, IR spectra and TG-DTA. The fluorescence properties of the complexes and the triplet state energies of the ligands were studied in detail. In addition, the quantum yields of both Eu(III) complexes and Eu(L⁰)₂(NO₃)₃ [where L⁰ is N-(phenyl)-2-(quinolin-8-yloxy)acetamide] 1 Wu, WN, Yuan, WB, Tang, N, Yang, RD, Yan, L and Xu, ZH. 2006. Spectrochim. Acta A, 65: 912[Crossref], [Web of Science ®] , [Google Scholar] were calculated. The results indicate that among the lowest triplet energies (T) of the three ligands, that of L² is most suitable to the resonance level (⁵D₁) of Eu(III) ion. Furthermore, Eu(L²)₂(NO₃)₃ has the highest fluorescence intensity and quantum yield of the three Eu(III) complexes.     

Syntheses,characterization and luminescent properties of two lead(II) fumarate metal-organic frameworks

It is of interest that the hydrous 3D metal-organic framework (MOF) {[Pb₂(fum)₂(H₂O)₄] · 2H₂O}_n (1) has been synthesized by the reaction of the fum dianion with the lead(II) ion (fum = fumarate) in the presence of pyrazole, while the anhydrous 3D MOF [Pb(fum)]_n (2) is obtained by the reaction of the fum dianion with the lead(II) ion in the presence of pyrazine. These complexes were further characterized by FT-IR spectroscopy, thermogravimetric analysis (TG), X-ray analysis and solid state photoluminescence spectra. The arrangement of the ligands displays a coordination gap around the Pb atom, occupied possibly by a stereoactive lone pair of electrons on lead(II), with the coordination around both the eight-coordinated lead atom in 1 and six-coordinated lead atom in 2 exhibiting a hemidirected geometry. The fum ligand shows different ligation behavior toward the lead(II) ions in these complexes. These compounds exhibit photoluminescence with the maximum emission located in the UV region.     

Syntheses,crystal structures and fluorescent properties of four one-dimensional lanthanide coordination polymers with 3-cyanobenzoato

The hydrothermal reactions of Nd(ClO₄)₃·6H₂O, Gd(ClO₄)₃·6H₂O, Dy(ClO₄)₃·6H₂O, Er(ClO₄)₃·6H₂O with 1,3-dicyanobenzene, give rise to four one-dimensional rare earth-based coordination polymers: [M(3-CNC₆H₄COO)₃(H₂O)₂] _n (where M?=?Nd (1), Gd (2), Dy (3), Er (4), 3-CNC₆H₄COO?=?3-cyanobenzoato), respectively. Their solid-state structures have been characterized by X-ray single-crystal diffraction studies. The results show that 1,3-dicyanobenzene hydrolyzed to give 3-cyanobenzoato under hydrothermal condition, and the four complexes are isomorphous. Crystal data for 1: triclinic, space group P-1, a?=?9.4063(19), b?=?11.485(2), c?=?12.616(3)?Å, α?=?66.38(3), β?=?74.01(3), γ?=?86.96(3)°, V?=?1197.9(4)?ų, Z?=?1, D _c?=?1.704?Mg?m^?3; for 2: triclinic, space group P-1, a?=?9.3712(19), b?=?11.446(2), c?=?12.627(3)?Å, α?=?65.86(3), β?=?73.89(3), γ?=?86.84(3)°, V?=?1184.8(4)?ų, Z?=?1, D _c?=?1.759?Mg?m^?3; for 3: triclinic, space group P-1, a?=?9.3425(19), b?=?11.432(2), c?=?12.703(3)?Å, α?=?65.28(3), β?=?73.80(3), γ?=?86.86(3)°, V?=?1180.6(4)?ų, Z?=?1, D _c?=?1.780?Mg?m^?3; for 4: triclinic, space group P-1, a?=?9.3425(19), b?=?11.432(2), c?=?12.703(3)?Å, α?=?65.28(3), β?=?73.80(3), γ?=?86.86(3)°, V?=?1180.6(4)?ų, Z?=?1, D _c?=?1.7794?Mg?m^?3. The fluorescence emission spectra of compounds 1 to 4 are also reported.     

Syntheses, structures, and properties of five coordination polymers containing fluorescent whitener

Fluorescent whitener (4,4'-bis(2-sulfonatostiryl)biphenyl) was incorporated with M/4,4'-bipy (M=Cd, Co; 4,4'-bipy=4,4'-bipyridine) 2D frameworks, Mn/4,4'-bipyH fragment, and the [Zn2(Im)2(ImH)4]2+ (ImH=imidazole) chain under hydrothermal conditions to obtain seven new coordination polymers: [Cd(4,4'-bipy)(L)(H2O)2] (1), [Co(4,4'-bipy)2(L)].2H2O (2), [Co(4,4'-bipy)2(H2O)2](4,4'-bipy)(L).2H2O (3), [Mn(4,4'-bipyH)2(L)2(H2O)2].4H2O (4), and [Zn2(Im)2(ImH)4](L) (5). Their structures were determined by single-crystal X-ray diffraction. In 1, binuclear [Cd2] units are bridged by 4,4'-bipys into a 2D cationic framework, which is further penetrated by L anions. 2 has an organic-inorganic hybrid layer consisting of [Co(4,4'-bipy)2] squarelike motifs and L anions. 3 features a pcu-like 3D cationic framework with the inclusion of L anions. In 4, the [Mn(4,4'-bipyH)2(H2O)2]4+ cationic fragment is sandwiched by L anions into a sandwichlike hybrid layer. 5 exhibits a 3D honeycomb-like structure with each nanotube encapsulating two parallel L anionic chains. TGA and PXRD indicate solids 1, 4, and 5 are thermally stable up to 280, 200, and 250 degrees C under an air atmosphere, respectively. 1 has bright blue-green luminescence with a peak maximum band at about 470 nm. 4 exhibits tunable emission between dark-red and weak-green under the excitation of 500 and 280 nm, respectively. 5 displays a bright blue-green emission with a peak band at 454 nm and a shoulder peak at 473 nm. It is attractive that the luminescent properties of solids 1, 4, and 5 are almost retained after heat treatment at 200, 200, and 250 degrees C for 2 h under an air atmosphere, respectively.     

Syntheses,urease inhibition activities,and fluorescent properties of transition metal complexes

Four transition metal complexes with Schiff base and 1,10-phenanthroline, [Cu(L)(phen)]₂·C₂H₅OH (1), [Zn(L)(phen)]₂·C₂H₅OH (2), [Ni(L)(phen)]₂·C₂H₅OH (3), and [Co(L)(phen)]₂·C₂H₅OH (4) (H₂L?=?1-((2-hydroxynaphthalen-1-yl)methylene)thiosemicarbazide; phen?=?1,10-phenanthroline) were synthesized and characterized by physico-chemical methods. The crystal structure of 1 was determined by X-ray single-crystal diffraction analysis. 1 crystallizes in the orthorhombic space group Pbca with a?=?15.008(9), b?=?16.100(10), c?=?37.54(2)?Å, V?=?9070(10)?ų, Z?=?8, GOOF?=?1.002, R ₁?=?0.0626, and wR ₂?=?0.0912. The fluorescence and urease inhibitory activities of the compounds were tested. The enzymatic activity study indicated that 3 possessed potent inhibition against jack bean urease, with IC₅₀?=?1.2?±?0.1?μM, and about 35 times more than 42.1?±?0.4 acetohydroxamic acid as positive reference. This suggests that inhibitory efficiency of these complexes can be strongly influenced by different transition metal ions.     

Syntheses, crystal structures and fluorescent properties of two d 10-metal coordination polymers based on 1,5-naphthalenedisulfonic acid

The first examples of two d ¹⁰ metal coordination polymers based on 1,5-naphthalenedisulfonic acid and benzimidazole, namely, [Cd(bim)₄(1,5-nds)] 1 and [Ag(bim)₂]·½1,5-nds 2 (bim = benzimidazole, 1,5-nds = 1,5-naphthalenedisulfonic acid) were synthesized successfully under solvothermal conditions. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, TG-DSC, PXRD, UV–Vis, and DFT. 1 exhibits a 3D supramolecular structure which started from 1D helical chain. 2 also shows a 3D architecture which was assembled via π–π interactions and hydrogen bonds. The hydrogen bonds formed by 1,5-nds play an important role in increasing the dimensionality of architectures of 1 (from 1D to 3D) and 2 (from 0D to 1D). Moreover, both 1 and 2 show excellent luminescent properties, 335 nm for 1 (λ _ex = 286 nm) and 341 nm and 389 nm for 2 (λ _ex = 234 nm), and may be the suitable candidates of fluorescent materials. From UV–Vis spectra, the remarkable absorption peaks can be found at 276 nm for 1 and 271 nm for 2. The simulated UV–Vis spectra (290.30 nm for 1 and 271.64 nm for 2) by Gaussian 09 DFT correspond well with the experimental results. From the electron density distribution of frontier molecular orbitals, it is known that the two absorption bands are attributed to the intra-ligand electron transition from HOMO?26 to LUMO and from HOMO?3 to LUMO+1 for 1, from HOMO?1 to LUMO+18 and LUMO+19 for 2.     

Syntheses and characterization of poly(iminophenol)s derived from 4-bromobenzaldehyde: Thermal, optical, electrochemical and fluorescent properties

Schiff base monomers[2-（4-bromobenzylideneamino）phenol and 2-（4-bromobenzylideneamino）-5-methylphenol] were synthesized by the condensation reaction of 4-bromobenzaldehyde with aromatic aminophenols.Then,the monomers were converted to their polyphenol derivatives by oxidative polycondensation reactions（OP） in an aqueous alkaline medium. The structures of the synthesized compounds were characterized by solubility tests,FT-IR,NMR,TG-DTA,DSC and SEC techniques.The HOMO-LUMO energy levels and electrochemical（E_g ） and optical（E_g） band gaps were calculated from cyclic voltammetry（CV） and UV-Vis measurements,respectively.Cyclic voltammetry（CV） was used to determine the electrochemical oxidation-reduction characteristics.Optical properties were investigated by UV-Vis and fluorescence analyses.Solid state electrical conductivities were measured on polymer films by four point probe technique using a Keifhley 2400 electrometer.The effects of electron-donating（-CH₃） group at p-position of -NH₂ group in aminophenol on electrochemical and thermal properties were also discussed.Photoluminescence（PL） properties of the synthesized materials were determined in solution forms using different solvents.Fluorescence measurements were carried out in various concentrated solutions to determine the optimum concentrations to obtain the maximal PL intensities.     

Syntheses,crystal structures,and properties of two molecular double-supporting polyoxotungstates

Two molecular double-supporting polyoxotungstates [SiW₁₂O₄₀{M(phen)₂H₂O}₂] · nH₂O (phen = 1,10′-phenanthroline, M = Mn 1, n = 2; M = Co 2, n = 3) were synthesized hydrothermally and characterized by elemental analyses, IR, TG, and X-ray single-crystal diffraction. The variable-temperature magnetic susceptibilities were measured at 2–300 K. The double-supporting polyoxotungstate molecule consists of a Keggin-type dodecatungstosilicate anion and a pair of transition metal complex fragments which are covalently linked to opposite sides of the Keggin anion. The transition metal ion locates in the center of a distorted octahedron. Multiple H-bonding interactions are observed between the coordinated waters of the transition metal complex fragments and terminal oxygen atoms of Keggin units and also between the bridging oxygen atoms of Keggin units and the lattice waters, which creates one-dimensional chains or two-dimensional layers. Between the layers or chains there are weak CH···O hydrogen bonding interactions and van der Waals forces. The molecular double-supporting polyoxotungstosilicate begins to decompose at ca. 500 °C. The variable-temperature magnetic behavior of 1 shows weak antiferromagnetic characteristics with a small value of θ = −0.289 K.     

Syntheses,crystal structures and fluorescent properties of imidazole based mixed-ligand nickle and cadmium complexes

Four novel mixed-ligand nickle and cadmium complexes [Cd(tolu)₂(imi)₃] (1) [CdCl₂(imi)₂]_n (2), [Ni(imi)₆](tolu)₂ (3) and [Ni(mand)₂(imi)₂]·H₂O (4) (imi = imidazole, Htolu = o-toluic acid, Hmand = mandelic acid) were synthesized and isolated in solid state based on nickle and cadmium salts, imidazole and different carboxylic acids. These complexes were characterized by FT-IR, elemental analyses, thermogravimetric (TG) analyses, UV–vis, X-ray structural analyses and fluorescence spectra. Complexes 1 and 4 are neutral mixed-ligand molecules. Complex 2 exhibits a 2D chain constructed by [CdCl₂(imi)₂] units. Complex 3 possesses [Ni(imi)₆]^2- anions with uncoordinated tolulate anions. In complexes 1–4, each imidazole ligand provides one nitrogen atom for coordination. Tolulate and mandelate ligands coordinate to the metal through carboxyl oxygen or hydroxyl oxygen atoms. Plenty of intramolecular hydrogen bonds as N–H?O and O–H?O interactions are observed in these complexes. Fluorescence properties of the complexes have been deeply investigated and the result reveals that Fe³⁺ ion has the greatest effect on fluorescence intensity of complex 3. The fluorescence intensity decreases with the increase of iron concentration.     

两个紫精-多酸杂化材料的合成、结构及其光致变色和光催化性质

分别利用1,1''-二甲基-4,4''-联吡啶(甲基紫精,MV)二氯化物和1,1''-二乙基-4,4''-联吡啶(乙基紫精,EV)二溴化物的阳离子作为电子受体,富电子的杂多酸阴离子作为电子给体,合成了 2 个新的紫精-多酸杂化晶态材料：(MV)₂[HPW^Ⅴ₂W^Ⅵ₁₀O₄₀]·2H₂O (1)和(EV)₂[Mo₈O₂₆] (2),并解析了其单晶结构,在化合物 1和 2中,阴、阳离子间均存在氢键相互作用。2具有光致变色性能,光响应时间为1 min以内。通过固体漫反射、电子顺磁共振和理论计算等手段,探究了2的光致变色机理。1和2对光降解有机染料(亚甲蓝、盐酸副玫瑰苯胺和罗丹明6G)均具有一定的催化性能。     

两个紫精-多酸杂化材料的合成、结构及其光致变色和光催化性质

分别利用1,1''-二甲基-4,4''-联吡啶(甲基紫精,MV)二氯化物和1,1''-二乙基-4,4''-联吡啶(乙基紫精,EV)二溴化物的阳离子作为电子受体,富电子的杂多酸阴离子作为电子给体,合成了 2 个新的紫精-多酸杂化晶态材料：(MV)₂[HPW^Ⅴ₂W^Ⅵ₁₀O₄₀]₂·2H₂O (1)和(EV)₂[Mo₈O₂₆] (2),并解析了其单晶结构,在化合物 1和 2中,阴、阳离子间均存在氢键相互作用。2具有光致变色性能,光响应时间为1 min以内。通过固体漫反射、电子顺磁共振和理论计算等手段,探究了2的光致变色机理。1和2对光降解有机染料(亚甲蓝、盐酸对甲苯胺和罗丹明6G)均具有一定的催化性能。     

Novel fluorescent quater‐ and quinquifurans: Syntheses and photophysical properties

In the quest for fast fluors for use in waveshifting polystyrene fibers, symmetrical oligofurans were investigated. Furan moieties were coupled by means of the Ullmann Reaction or by palladium‐catalyzed unsym‐metrical coupling; the latter gave higher yields. While the benzoxazole‐terminated quater‐ and quinquifurans we prepared were both stable and fast, exhibiting a green fluorescence and decay times of about 2.4 nsec, they were inferior to other types of fluors in solubility and emission intensity when incorporated into polystyrene.