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A coumarin-based probe, FP2, was designed for the differential detection of fluoride anions and thiols, i.e., the corresponding nucleophilic substitution products from fluorine-containing G agents and sulfur-containing V agents, thus having the potential to discriminate between these two nerve agents. FP2 with two functional reaction groups, α, β-unsaturated ketone and silyl groups, can react selectively with fluoride anions and thiols at the μM level respectively. Intriguingly, in the THF solution, FP2 reacts with the fluoride anion but not with the thiol, whereas in the EtOH/HEPES solution, FP2 reacts with the thiol but not with the fluoride anion. As a result, FP2 can produce different fluorophores in the two detection solutions, thus displaying significant fluorescence changes. In addition, the FP2 detection system can show a significant color change from colorless to yellow within seconds when detecting fluoride anions in THF detection solutions, and from yellow to light blue when detecting thiols in EtOH/HEPES solutions, which will facilitate visual detection by emergency responders at the scene of an incident involving a nerve agent.

Recently, organic–inorganic hybrid lead halides have been explored as photoluminescent (PL) materials with flexible structural tunabilities and high photoluminescence quantum efficiencies, which can be modified by the structure regulating functions of organic cations. Here, by adopting different saturated organic cations as structure directing agents (SDAs), a series of organic–inorganic hybrid lead halides have been solvothermally synthesized and characterized with different structural types. Compound [(CH3)2NH2]2[H2DABCO]2Pb3I12 (1, DABCO = 1,4-diazabicyclo[2.2.2]-octane) features a linear zero-dimensional (0D) [Pb3I12]6− trimer, and [(Me)6-en]2Pb3I10 (2) and [H2N-Prpipz]2Pb3Br10 (3) contain two different types of one-dimensional (1D) [Pb3X10]4− chains based on the C3-symterric [Pb3X11] trimer and [PbX6] unit, respectively. In the structures of H[(Me)2-DABCO]Pb3I9 (4) and H[(Me)4-pipz]Pb3I9 (5, pipz = piperazine), the C3-symmetric [Pb3I11] trimers are interlinked to form the same two-dimensional (2D) corrugated [Pb3I9]3− layers. Under the excitation of UV irradiation, these hybrid lead halides exhibit tunable luminescence properties from yellow, orange to red emissions with the largest Stokes shift of 335 nm. The PL nature is also investigated based on temperature-dependent PL emission, time-resolved PL and theoretical calculations, etc. These hybrid lead halides provide new types of structural models to probe into the PL properties and understand the underlying structure–property relationship.

In falling film liquid desiccant systems, finding a suitable pair of liquid desiccant and contact surface is of primary engineering interest. This requires knowledge on the wetting characteristics of the liquid on the solid substrate, which consequently requires intensive experimental investigation. In this study, the wetting characteristics of a new ionic liquid aqueous solution in an aluminum fin-tube substrate were experimentally investigated. Then, a simple method for estimating the wetted area on the substrate through image processing was developed. Visual analysis of the surface wetting was also conducted, and three types of wetting patterns are discussed. Experimental results on the static contact angle and contact angle hysteresis suggest that the ionic liquid solution is mostly wetting, and the aluminum surface is slightly to moderately rough. It was found that the wettability of the ionic liquid solution increases as the ionic liquid mass fraction increases. The wetting hysteresis phenomenon and the factors contributing to its occurrence were also clarified. The results from this study would be useful for the development of a new model or improvement of existing wetting models, which can help improve the prediction and control of the heat and mass transfer performance in internally cooled/heated fin-tube contactors.

Four asymmetric complexes with different conjugate structures based on benzimidazole derivatives with formulas of [ZnL1Cl2] (1) (L1: 1-((quinoline-2-yl) methylene)-2-quinoline-2-yl benzimidazole), [CdL2Cl2]n (2) (L2: N1,N2-bis((quinoline-2-yl) methylene)o-phenylenediamine), [HgL3Cl2] (3) (L3: 2-(quinoline-2-yl)benzimidazole), and (HgCl4)(L4)2(C6H7)2 (4) (L4: 1,2,3-((quinoline-2-yl) methylene) benzimidazoleion) are obtained. Interestingly, L1–L4 are derived from the half-condensed asymmetrical Schiff base ligand [N1-((quinoline-2-yl) methylene) N2-(H-(quinoline-2-yl) methylene-hydroxy)o-phenylenediamine] (L) by means of a metal(II)-induced method. To the best of our knowledge, it is the first example of one Schiff base ligand transforming into three different benzimidazole derivatives from the single quinoline ring (L3), double quinoline rings (L1) to three quinoline rings (L4). Complexes 1, 3, and 4 are new mononuclear complexes, while complex 2 is a one-dimensional (1D) chlorine bridged Cd(II)-bis Schiff...

Using five Schiff base ligands (E)-N-(pyridine-2-yl) (CH═NPhR) (where R = 4–CH3, L1; 2,6-(CH3)2, L2; 2,4,6-(CH3)3, L3; 2,6-(C2H5)2, L4; 2,6-(i-C3H7)2, L5), nine Zn(II)/Cd(II) complexes, namely, Zn1–Zn3, Cd1, Cd2, Cd3a, Cd3b, Cd4, and Cd5, have been successfully synthesized. The structures of the Zn(II)/Cd(II) complexes have been established by single crystal X-ray diffraction and further physically characterized by 1H NMR, FT–IR, and elemental analysis. The crystal structures of these complexes indicate that the structures of ligand and anions can directly influence the formation of 1D → 3D supramolecular metal–organic frameworks (SMOFs) via C–H···O/C–H···Cl hydrogen bonds and π···π interactions. Upon irradiation with UV light, the nine Zn(II)/Cd(II) complexes display deep blue emissions of 401–436 nm in acetonitrile solution and light blue or bluish green emissions of 485–575 nm in the solid state, respectively. The photoluminescence properties of nine Zn(II)/Cd(II) complexes can be finely and predictabl...

Two novel transition metal complexes formulated as [Cu(4,5–Himdc)(phen)]n (1) and [Mn(5,6–Hbidc)(H2O)]n (2) (4,5–H3imdc = imidazole–4,5–dicarboxylic acid, 5,6–H3bidc = 1H–benzimidazole–5,6–dicarboxylic acid, phen = 1,10–phenanthroline,) have been synthesized under hydro(solvo)thermal method at a relatively low temperature and characterized by elemental analysis, IR spectroscopy, and X–ray single–crystal diffraction. 1 based on 4,5–H3imdc displays one–dimensional zigzag chain structure. 2 based on 5,6–H3bidc features a two–dimensional framework with 4–connected topology. Thermal stabilities and luminescence properties of the two complexes were investigated.

This study involves exploring a new design of an internally cooled/heated desiccant contactor by using a new ionic liquid (IL) solution as the sorptive solution. In order to optimize its operative performance, a semitheoretical model based on the principle of minimum energy is developed to predict the film rupture and wetting ability of the IL solution over a comprehensive range of IL mass fraction and flow rates. A first experimental validation of the fundamental equations of the theoretical model is presented and used as a reference to minimize deviations between predicted results and measured data by calibrating dedicated characteristic coefficients. The noteworthy quantitative and qualitative agreement in the whole range of IL mass fractions and flow rates is promising for contributing to the design of optimized system configurations and control strategies.

With the help of ascorbic acid as reductant, an exceedingly rare example of a visible single-crystal-to-single-crystal transformation from a CuII-framework to a CuI-chain under mild conditions has been observed, which involves the metal valence tautomerism and restructuring of bonds. The two compounds exhibit the properties of solvatochromism and luminescence aggregation-induced-emission towards CH3OH, respectively.

Five new compounds with mixed-ligand formulated as (H4bptc)(phen) (1), [In(phen)2Cl2](H4bptc)(NO3)(H2O) (2), [In(Hbptc)(phen)(H2O)]2 (3), In(2,6-pydc)(phen)(H2O)Cl (4), and {[In(2,6-pydc)(Ox)0.5(H2O)2](H2O)}2 (5) have been synthesized under hydrothermal conditions. Compounds 1–5 display white, green and blue fluorescence at 298 K in the solid state, respectively. It is shown that 1 assumes solvent-dependent photoluminescence. By contrast, the different polarities of solvents do not alter the luminescence position of 3 and 5. The thermogravimetric curves show that binuclear compounds 3 and 5 have excellent thermal stability, whose structures are stable up to 190 and 272 °C, respectively.

Six novel luminescent materials In(III)-2,3-H2qldc/phen metal–organic assemblies (MOAs), namely, [In2(phen)3Cl6]·CH3CN (In1), [In2(phen)3Cl6]·CH3CN·2H2O (In2), [In2(phen)2Cl6] (In3), [In(3-qlc)2(phen)Cl] (In4), [In(3-qlc)2(2,2′-bipy)Cl]·2H2O (In5) and [In(3-qlc)3(phen)]·H2O (In6) (2,3-H2qldc = quinoline-2,3-dicarboxylic acid; 3-Hqlc = quinoline-3-carboxylic acid, which is formed from the decarboxylation reaction of 2,3-H2qldc; phen = 1,10-phenanthrolin; 2,2′-bipy = 2,2′-bipyridine) have been hydro(solvo)thermally synthesized and characterized by single-crystal X-ray diffraction, infrared (IR), elemental analysis, 1H NMR spectra, and thermogravimetric analysis (TGA). The crystal structures of In1–In6 indicate that the hydrogen bonding and π···π stacking interactions play critical roles in the formation of the extended supramolecular array. In1 displays the rare hexatomic ring 3D (4,5)-connected supramolecular architecture through twofold interpenetrating of 2D cell membrane-like structures. In2 exhibits a ...

Two novel Ag(I) complexes zero-dimensional (0D) [Ag(ibz)(Hibz)]2 (Ag1) (Hibz = 4-(1H-imidazolyl)benzoic acid) and two-dimensional (2D) [Ag(imbz)(Himbz)]n (Ag2) (Himbz = 4-(1H-imidazolyl-1-methyl)benzoic acid) have been synthesized through the hydrothermal method. By changing the ligands from rigid Hibz to flexible Himbz, the distance between two aromatic rings in the ligand is controlled to get different dimensional complexes. Both complexes have been characterized by single-crystal X-ray diffraction, infrared (IR), elemental analysis and thermal gravimetric analyses (TGA). Ag1 is coordinated with two nitrogen atoms, forming a two-coordination linear configuration. While Ag2 possesses interesting 2D frameworks, exhibiting two-fold interpenetrating sql topology structure. The luminescent properties of Ag1 and Ag2 are investigated both in the solid state and in different solvents (DMSO, CH3CN and CH3OH) at 298 K and 77 K. Ag1 displays stable blue luminescent in the solid state and in solvents at 298 K and 77 K. Whereas, Ag2 shows tunable luminescence by changing the temperature from 298 K to 77 K, indicating thermochromic luminescence for Ag2. The emission efficiency of Ag1 and Ag2 is found with quantum yields ranging from 0.073 to 0.208, which is much higher than that of free ligand.

A series of lanthanide complexes with formulae {[KEu(Hqlc)(qlc)(H2O)6(OH)]2+·2Cl−}n (1·Eu), {[Eu(qlc)2(phen)(H2O)2]+·Cl−}·CH3CN (2·Eu), [Eu(qlc)2(phen)(NO3)]·H2O (3·Eu), [Ln(qlc)2(H2O)4]·(qlc)·(H2O) (Ln = Eu(4·Eu), Sm(5·Sm), Gd(6·Gd), Tb(7·Tb), Dy(8·Dy), Ho(9·Ho)) (Hqlc = quinoline-3-carboxylic acid, phen = 1,10-phenanthrolin) are synthesized under solvo(hydro)thermal conditions and characterized by single-crystal X-ray diffraction, infrared spectra, elemental analysis, and powder X-ray diffraction. Complex 1 exhibits two-dimensional (6,3)-connected hcb networks and possesses a stable structure through typical O/C–H⋯Cl intermolecular hydrogen bonds. Complexes 2–4 display three diverse dimer structures, due to the synergistic effect from coordination modes of Hqlc ligand and anion effect. Complexes 5–9 are isostructural with complex 4. Eu-complexes 1–4 could provide intense and bright characteristic 5D0 → 7FJ red luminescence under UV excitation in the solid state at 298 K and 77 K. In complexes 2 and 3, the coordinate phen ligand could play the antenna role in the energy transfer process. Therefore, the luminescence lifetimes of complexes 2 (779.62 and 792.65 μs) and 3 (947.21 and 1095.59 μs) are longer than those of complexes 1 (456.93 and 499.33 μs) and 4 (283.70 and 46 469 μs) in the solid state at 298 K and 77 K. Complexes 5, 7 and 8 exhibit characteristic Sm3+, Tb3+ and Dy3+ ion luminescence. Furthermore, through controlling the concentration of complexes 3 and 4 in poly(methyl methacrylate) (PMMA), a series of 3–PMMA and 4–PMMA hybrid materials are obtained, respectively. They all display strong and characteristic red luminescence emissions at a concentration of 8%. Compared with 3 and 4, the luminescence intensities and luminescence lifetimes of 3–PMMA and 4–PMMA are increased, due to the replacement of water molecules by PMMA.

Poly(methyl methacrylate) (PMMA) films doped with Cu(I)-based imidazole derivative coordination polymers [Cu3I3(bib)1.5]n (1) and [Cu4I4(bix)2]n (2) [bib = 1,4-bis(1-imidazolyl)benzene and bix = 1,4-bis(imidazol-1-ylmethyl)benzene] were synthesized and their photophysical properties were studied. 1 and 2 were prepared by a solvothermal method and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy, 1H NMR, PXRD and thermal gravimetric analyses. Molecular structural analysis reveals that 1 exhibits a unique one-dimensional (1D) infinite triplex chain and 2 is built from a [Cu4I4]n cluster which possesses an interesting two-dimensional (2D) (4,4)-connected sql (square lattice) network. Detailed structural characterization of the supramolecular organization of 1 and 2 revealed overall three-dimensional (3D) interlinked networks driven by extensive π⋯π stacking interactions. Both 1 and 2 display remarkable narrow band emission with a smaller full width at half-maximum (FWHM) (77 K, 34.63 and 60.07 nm; 298 K, 121.95 and 126.83 nm) in the solid state at 77 K, which leads to excellent monochromaticity. The combination of such a narrow FWHM and the large red-shift of 62 nm from 298 K to 77 K endows 2 with a more prominent thermochromism effect than 1, with emissions strongly depending on temperature and tunable from yellow to red by changing the temperature from 298 K to 77 K. Here, the role of the [Cu4I4]n cluster in controlling the performance of thermochromic luminescence is highlighted. Meanwhile, 1 and 2 demonstrate stronger and longer lifetime yellow luminescence emissions at concentrations of 0.8% (τ = 156.62 μs) and 1.0% (τ = 92.28 μs) in poly(methyl methacrylate) (PMMA). Furthermore, development of easy-to-prepare hybrid materials 1–PMMA and 2–PMMA leads to bright yellow luminescence polymer film materials with outstanding thermal stability in daily applications (321 °C and 500 °C).

Two new indium coordination polymers (CPs) with mixed-ligand formulated as {[In(1,4-bda) 1.5 (phen)]·2H 2 O} n ( In1 ) and {In(1,4-bda)(2,2′-bipy)Cl} n ( In2 ) (1,4-H 2 bda = 1,4-benzenedicarboxylic acid; phen = 1,10-phenanthrolin; 2,2′-bipy = 2,2′-bipyridine) have been synthesized and characterized by single-crystal X-ray diffraction, infrared (IR), elemental analysis and thermal gravimetric analyses (TGA). In1 exhibits one-dimensional (1D) ladder chain, which further forms three-dimensional (3D) structure with π⋯π stacking interaction. Formation of 3D compact supramolecular framework in In2 is generated through C–H…Cl hydrogen bonding contacts and π⋯π stacking interaction. The photoluminescence (PL) characterizations to In1 and In2 affected by solvent and temperature are studied in detail. Thermogravimetric curves showed that In1 and In2 start to undergo phase transition until ca. 450 °C and 495 °C, respectively.

Nine IIB group complexes, [ZnL1Cl2] (Zn1), [CdL1Cl2]2 (Cd1), [HgL1Cl2] (Hg1), [ZnL2Cl2] (Zn2), [CdL2Cl2] (Cd2), [HgL2Cl2] (Hg2), [ZnL3Cl2] (Zn3), [CdL3Cl2] (Cd3) and [HgL3Cl2] (Hg3), have been synthesized from the corresponding ortho-(6-methoxy-pyridyl)(CH[double bond, length as m-dash]NAr) (where Ar = 2,6-iPr2C6H3, L1; 4-MeC6H4, L2; 2-OMeC6H4, L3) Schiff base and structurally characterized by elemental analysis, FT-IR, (1)H NMR and X-ray single-crystal analysis. Crystallographic studies reveal that the center metal of the complexes adopts a distorted tetrahedron geometry (except for Cd1 and Cd3, which display square pyramidal geometry) and C-HCl hydrogen bonds and ππ stacking interactions contribute to three-dimensional supramolecular structures. The series of complexes exhibit tunable luminescence from blue, through green, to light yellow by varying the temperature (298 K and 77 K), both in solution and in the solid state. Moreover, the quantum yields range from 0.027 to 0.422, and decrease according to the order of the periodic table (ZnCdHg). These results indicate that the center atom of the complexes leads to the geometry differences and hence to the tunable luminescence properties. Because Zn1-Zn3 exhibited higher molar extinction coefficients and a distinct absorption region, they were employed as co-sensitizers in ruthenium dye N719-sensitized photoanodes to deliver light-electricity efficiency enhancement, being assembled with counter-electrodes and electrolyte to prepare ZnX/N719 (where ZnX = Zn1, Zn2, and Zn3) co-sensitized dye sensitized solar cell (DSSC) devices. The prepared co-absorbent could overcome the deficiency of N719 absorption in the low-wavelength region of the visible spectrum, and offset competitive visible-light absorption of I3(-). Application of these prepared complexes in N719-sensitized solar cells enhanced their performance by 10-36%, which indicated a potential application of these types of complexes in DSSCs.

This work reports on two new complexes with the general formula [Cd3(IBA)3(Cl)2(HCOO)(H2O)]n (1) and {[Cd1.5(IBA)3(H2O)6]·3.5H2O}n (2), which can be synthesized by the reaction of Cd(II) with rigid linear ligand 4-HIBA containing imidazolyl and carboxylate functional groups [4-HIBA = 4-(1H-imidazol-1-yl)benzoic acid]. Single-crystal X-ray diffraction analyses indicate that complex 1 is a 2D "wave-like" layer structure constructed from trinuclear units and complex 2 is just a mononuclear structure. Surprisingly, both complexes 1 and 2 appear as a 3D supramolecular network via intermolecular hydrogen bonding interactions. What's more, due to their strong UV-visible absorption, 1 and 2 can be employed as co-sensitizers in combination with N719 to enhance dye-sensitized solar cell (DSSC) performance. Both of them could overcome the deficiency of the ruthenium complex N719 absorption in the region of ultraviolet and blue-violet, and the charge collection efficiency is also improved when 1 and 2 are used as co-sensitizers, which are all in favor of enhancing the performance. The DSSC devices using co-sensitizers of 1/N719 and 2/N719 show an overall conversion efficiency of 8.27% and 7.73% with a short circuit current density of 17.48 mA cm(-2) and 17.39 mA cm(-2), and an open circuit voltage of 0.75 V and 0.74 V, respectively. The overall conversion efficiency is 27.23% and 18.92% higher than that of a device solely sensitized by N719 (6.50%). Consequently, the prepared complexes are high efficiency co-sensitizers for enhancing the performance of N719 sensitized solar cells.

We design two novel d10 metal complexes [Zn(3-qlc)2]n (Zn1), [Cd(3-qlc)2]n (Cd1) (3-Hqlc = quinoline-3-carboxylic acid), which display similar 2D layer structures, and further form 3D 6-connected primitive cubic (pcu) network topology via π⋯π stacking interactions with the point symbol {412·63}. Complexes Zn1 and Cd1 exhibit tunable luminescence and photovoltaic properties as a new type of multifunctional materials. Zn1 and Cd1 show tunable luminescence from blue to green by varying the temperature in the solid state. What's more, both of them exhibit excellent aggregation-induced emission (AIE) properties in DMSO/water mixtures. Encouraged by the UV-visible absorption in an ethanol solution result, Zn1 and Cd1 can be considered as co-sensitizers in combination with N719 to investigate their effect on enhancing the dye-sensitized solar cells (DSSCs) performance. Zn1 and Cd1 could overcome the deficiency in the ruthenium complex N719 absorption in the ultraviolet and blue-violet region, offsetting competitive visible light absorption of I3− and reducing the charge recombination of injected electrons. After being co-sensitized with Zn1 and Cd1, the devices co-sensitized by Zn1/N719 and Cd1/N719 yield an overall efficiency of 7.75% and 7.70%, which are 44.59% and 43.66% higher than that of the device sensitized only by N719 (5.36%).

Based on a new design of 4-cyanobenzyl-based 1,2,4-triazole ligand 4-(1,2,4-triazolylmethyl) cyanobenzene (TMCB), a series of cadmium complexes 1–5′ from a mononuclear to three-dimensional (3D) structure have been synthesized through hydro(solvo)thermal reactions; they were generally formulated as [Cd(TMCBA)2]n (1), [Cd(TMCB)(1,4-bda)(H2O)]n (2), {[Cd2(TMCB)4(1,4-bda)2(H2O)2]n·3H2O}n (3), {[Cd(TMCB)4(H2O)2]·(NO3)2·(H2O)2}n (4), [Cd1.5(1,4-bda)1.5(DMF)2]2n (5) and [Cd1.5(1,4-bda)1.5(DMF)2]2n (5′) (TMCBA = 4-(1,2,4-triazolylmethyl) benzoic acid, which is formed from the hydrolysis of TMCB; 1,4-H2bda = 1,4-benzenedicarboxylic acid; the difference between two genuine supramolecular isomers of 5 and 5′ is the use of TMCB as the additive agent for the reaction). Complexes 1–5′ exhibit tunable luminescence with emission maxima containing deep blue, blue, light blue, green and deep green region at 298 K or 77 K in both different solvents (polarity: DMSO > CH3OH > CHCl3) and solid state. Interestingly, the good thermal stability accompanied by their compensated adsorption to ruthenium complex N719 in the region of low wavelength, enabled 1 and 4 to serve as co-sensitizers in combination with N719 in dye sensitized solar cells (DSSCs). After co-sensitization with N719, the overall conversion efficiency of 1 and 4 were found to be 7.68% and 6.85%, which are 40.40% and 25.23% higher than that for DSSCs only sensitized by N719 (5.47%) under the same conditions, respectively. The improvement in efficiency is attributed to the fact that complexes 1 and 4 overcome the deficiency of N719 absorption in the low wavelength region of ultraviolet and blue-violet, offset competitive visible light absorption of I3− and reduce charge recombination due to the formation of an effective cover layer of the dye molecules on the TiO2 surface. As a result, the synthesized complexes are promising candidates as co-adsorbents and co-sensitizers for highly efficient DSSCs.

Organic light-emitting materials D1~D3 containing triphenylamine donors, bipyridine acceptors and olefinic linkers were synthesized and characterized. The optical, electrochemical properties of materials were studied by UV-Vis spectra, fluorescence emission spectra and cyclic voltammetry method. The results show that the maximal absorption peaks of three compounds are in the range of 404nm~408nm and fluorescence emission peaks at the region of 534nm~557nm in dichloromethane solutions, respectively. Cyclic voltammetry measurement showed that these compounds had HOMO energy level in the range of-5.02eV~-5.16eV, which is proper for hole injection. The properties indicate that these compounds have potential for the application as light-emitting materials or hole-transporting materials.

A rare 3D tetranuclear {In4(μ2-OH)3} building block based MOF {[In4/3(μ2-OH)(2,6-pydc)(1,4-bda)0.5(H2O)]·2H2O}n (2) was obtained through a crystal transformation from a dimeric complex In3(2,6-pydc)3(1,4-bda)1.5(H2O)6 (1). With a 2D + 3D → 3D compact structure, 2 retains crystallinity in boiling water and organic solvents, exhibiting exceptional fluorescence quenching behaviour for the DMSO molecule.

A novel indium complex {[InL(NO3)(OH)] · NO3 · CH3OH}2 (1) is isolated from the refluxing reaction of a tetradentate Schiff base ligand, N,N′-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine (L), and In(III) nitrate hydrate. The room temperature (298 K) and cryogenic temperature (77 K) emission spectra of 1 are recorded in solid state and different solvents (CH3OH, CHCl3, CH3CN and DMSO). Complex 1 exhibits a pronounced bathochromic shift in emission spectra as solvent polarity increases (polarity order: DMSO > CH3CN > CHCl3), indicating a change in dipole moment of 1 upon excitation. Further bathochromic shift exists in CH3OH (467 nm) solution. An extended work is developed to discuss on maximum emission and lunminescent lifetime of 1 dispersed in the deuterated reagents (CD3OD, CDCl3, CD3CN and DMSO-d6). The results exhibit that the similar emission also exists in deuterated reagents and the longer lifetime is observed due to the scarcity of O H, N H, and C H oscillators. The quantum yield of 1 decreases with increasing polarity of solvent within the region of 7.8–15.4%. Commission Internationale de L'Eclairage (CIE) 1931 demonstrates that the color gamut of 1 is blue.

In order to phytoremediation the soils contaminated by arsenical chemical weapons abandoned by Japan at some region of Jilin Province and ready for the estimate of the ecological safety, this paper analyzed organic species in soil with GC-MS, disscussed extraction and testing of inorganic arsenic in soil with hydrochloric acid, studied species of arsenic in soil such as available forms, valence state, and combined state, and inferred conversion process of arsenical chemical agent. The results indicate that after simple destroying and long time burial, almost all arsenical chemical agents in soil at this region are converted into inorganic arsenic due to explosion, burning, natural oxidation and microorganism, which primarily exists as As (V). Organic arsenic was only detected at where shells were buried (destroyed), in leaded shells and contaminated soil, with its content 3.65%~32.03%; Organic arsenic content of soil in other part is less than 10%. In contaminated soil of this region, water soluble arsenic and available arsenic extracted from disodium hydrogen phosphate take 0.81~2.58% and 7.49~15.96% of total arsenic respectively. Exchangeable As and binding As (Al-As, Fe-As, reducible As and Ca-As) take 40% of total arsenic, residual As takes 49.38~66.43%. The results may be used as basis for determining remedy methods and assessing ecological safety at this region.

A series of lanthanide complexes [LnL(NO3)3]·CH3CN [Ln=Ce, (1•Ce); Nd, (2•Nd); Tb, (3•Tb); Dy, (4•Dy); Ho, (5•Ho); Er, (6•Er); Tm, (7•Tm); Yb (8•Yb)] have been synthesized by the reaction of N4 chelate ligand N,N'-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine (L) with lanthanide salts. Photoluminescence spectra of complexes 2•Nd, 3•Tb, 4•Dy, and 8•Yb show the strong characteristic luminescence from visible to near infrared (NIR) region. Further, the singlet state (32,467 cm−1) and the lowest triplet (23,202 cm−1) energy level of L are calculated, indicating that the energy transfer from L to Tb3+ ion is more effective than that to Dy3+ ion. An extended work is developed to discuss on the effect of deuterated reagent and temperature on luminescent properties of 3•Tb and 8•Yb.

Two new lanthanide coordination polymers formulated as [Ln(BDC)1.5(DMF)(H2O)]n [Ln = Tb (1), Gd (2)] [H2BDC = 1,4-benzenedicarboxylic acid, DMF = N,N′-dimethylformamide] were synthesized under solvothermal conditions. The coordination polymers were characterized by IR spectroscopy, elemental analysis and X-ray single-crystal diffraction. The two coordination polymers are isostructural and exhibit twofold interpenetrating pcu three-dimensional open frameworks constructed by tetradentate ligand of H2BDC. The fluorescence properties of 1 and 2 were investigated at 298 or 77 K both in solid state and in CH2Cl2 solvent dispersed as suspensions. Coordination polymer 1 exhibits characteristic Tb3+ ions emission transitions of 5D4 → 7FJ (J = 6–2) at 77 or 298 K both in the solid-state and in CH2Cl2 solvent. Moreover, the vibrational structure of 1 is more defined at 77 K, which exhibits another two 5D4 → 7F1 and 5D4 → 7F2 transitions more than that at 298 K. The lifetimes of 1 are longer at 77 K (915.2 μs in the solid state and 874.11 μs in the CH2Cl2 solvent) than that at 298 K (866.31 μs in the solid state and 801.04 μs in the CH2Cl2 solvent), which may be caused by the increase of radiative rate and decrease of non-radiative rate at low temperature. The singlet excited state (28,653 cm−1) and the lowest triplet energy level (23,641 cm−1) of H2BDC ligand were calculated based on the UV–Vis absorbance edges of ligand and the phosphorescence spectrum of Gd3+ coordination polymer (2) at 77 K, showing that the effective extent of energy transfer from H2BDC ligand to Tb3+ ion. Finally, thermal behaviors of the two coordination polymers were studied by thermogravimetric analysis, which exhibit thermal stability to 250 °C.

BET (Brunauer Emmett and Teller) surface area and pores distribution for the samples DX 09 Carbon were measured for of DX 09 carbon by N2 adsorption (195 °C) with Autosorb-1C (American Quantachrome Company).The adsorption of benzene over DX 09 Carbon was measured in the static vacuum adsorption equipment, which was self-constructed in laboratory. It was experimentally found that the BET surface area is about 1008 m2/g, and the structure coefficients for DX-09 carbon were W=0.365 and B=1.32*10-6 measured by benzene adsorption and calculated by D-R equation.

In this work, we present the synthesis of three novel 3D Cd(II) coordination polymers, {[Cd(IN)2]·H2O}n (1), [Cd2(IN)2(SO4)(DMF)2]n (2) and {[Cd3(IN)5.5]·0.5OH−}n (3) (HIN = isonicotinic acid). Coordination polymers 1 and 2 were obtained via solvothermal reactions. The synthesis of coordination polymer 3 was realized by a simple temperature induced single crystal to single crystal transition from 1. Single-crystal X-ray diffraction analyses revealed that 1–3 exhibit three different structural types: 1 displays a (6,3)-connected rtl net with the Schlafli symbol (4·62)2 (42·610·83) constructed from mononuclear [CdO4N2] clusters with the help of HIN. 2 is defined as a 6-connected pcu net with the Schlafli symbol {412·63} which is built from binuclear [Cd2(SO2)2] clusters and HIN linkers. 3 can be regarded as a 9-connected ncd net with the Schlafli symbol {36·422·58}, which consists of paddlewheel trinuclear [Cd3(O2C)5] clusters and a bridging HIN. Coordination polymers 1–3 display luminescence with emission maxima containing deep blue, blue, light blue and green at 298 K or 77 K both in solvents (polarity: DMF > CH3OH > CH2Cl2) and in the solid state. The lifetime of all the molecules is in microsecond scale.

Hydrolysis of cellulose and hemicelluloses of lignocellulosic materials to obtain reducing sugar can be used to produce ethanol by microbial fermentation. Effective pretreatment is necessary for optimal hydrolysis. This study investigated the positive effect of freeze-thaw treatment on low temperature sulfuric acid pretreatment for convert wheat straw to reducing sugar. Freeze-thaw treatment conditions were optimized: at -20°C for 12h, and at room temperature (25°C) for 1h, followed. After twice repeating of freeze-thaw treatment and pretreatment with 2wt% sulfuric acid for 16h at 80°C and enzymatic digestibility with 20U/g of cellulase loading, 67% cellulose and hemicelluloses were converted to glucose and xylose. The yield of furfural was decreased by 65% during sulfuric acid pretreatment. The time of acid hydrolysis was shortened by 20%.

A blue-green-emitting three-dimensional supramolecular compound (C10O2N2H8)(C9O7H6) (1) was synthesised under hydrothermal conditions and structurally characterised by elemental analysis, IR spectrum, 1H NMR and single-crystal X-ray diffraction. The crystal belongs to triclinic system with P 1¯ space group. The crystal structure is stabilised by O–H…O, O–H…N hydrogen bonds and π–π interactions (π–π stacking distance is 3.282 A). Compound 1 exhibits intense green luminescence in solid state at 298 K (λem = 546 nm). In addition, absorption and fluorescence characteristics of compound 1 have been investigated in different solvents (DMSO, CH3CN and CH3OH). The results show that compound 1 exhibits a large red shift in both absorption and emission spectra as solvent polarity increases (polarity: DMSO>CH3CN>CH3OH), indicating a change in dipole moment of compound 1 upon excitation. Although the emission spectra of compound 1 in CH3OH are close to it in dimethyl sulfoxide (DMSO), it is revealed that the luminesc...

New N-dichloroacetyl-5-aryl-1,3-oxazolidines 4 were synthesized by cycloaddition reaction of an aryl substituted hydroxyalkylamine 1 with aldehyde or ketone 2, followed by acylation, without isolation of the intermediate product 3. The structures of compounds 4 were determined by spectral and elemental analyses. The structure of 4b was determined by an X-ray crystallographic analysis. The bioassay results demonstrate that these compounds could alleviate chlorsulfuron injury to maize.

The article used acid protease to remove the protein in wheat straw, and investigated the influence of wheat straw without the protein to enzymatic hydrolysis. By the single factor experiments, the cellulose degradation rate of wheat straw removed the protein was significantly higher than untreated, in the same conditions of enzymatic hydrolysis. It is shortening 24h of enzymatic hydrolysis time and reducing enzyme dosage 90mg/g. By the orthogonal experiments, the optimal reaction conditions for enzymatic hydrolysis of wheat straw with protein removed is the cellulase dosage 170mg, enzymatic time 56h, solid-liquid ratio 1:20, pH 4.8, the reaction temperature 50°C. Compared to the untreated, the cellulose degradation rate increased by 35.58%.

BET (Brunauer Emmett and Teller) surface area and pore volume were measured for the samples of HCP by N2 adsorption (–195 °C) with Autosorb-1C (American Quantachrome Company). Both physi-sorption and chemi-sorption of CO2 at a given temperature were also carried out with Autosorb-1C after the samples of HCP had been pretreated in vacuum or helium at a given temperature.

In this article, the fire risk of aluminium conductors which were in poor contact and short circuit of low-voltage were validated. Meanwhile, the temperature of aluminium droplets which were falling during experiments was measured. As a result, it showed that the common combustible, such as hay, cotton, paper and polyurethane foam can be ignited under bad contact and short conditions, which aimed to provide the important references for exploring the fire scene and investigating the reasons of electrical fires once the relevant evidences existed.

In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs.

The straw biomass pretreatment technology is the key to the study of fuel ethanol. Freeze-thaw pretreatment of wheat straw is in its infancy. In this paper, we investigated influencing factors including the ratio of solid to liquid, crushed particle size, the difference of the solid to liquid in the wet milling processing. When the solid-liquid ratio is 1:18, hydrolysis rate can be increased by 17.93% and when crushed particle size of 120 meshes, enzymatic hydrolysis rate of 39.55%. Due to the traditional freeze-thaw technology is simply freezing and thawing process, the enzymatic hydrolysis rate only can be increased by about 15%. Therefore, we improve traditional process by wet grinding and freeze-thaw combining at the same time to take advantage of the cold weather in winter for the purpose to improve treatment effectiveness and feasibility of freezing and thawing. After this treatment, enzymatic hydrolysis rate increased by 57.50%.

In order to obtain the high dielectric constant and low loss materials by using the two main methods for synergy, the 3-phases TiO2/(PVDF+Fe3O4) composites with the fixed Fe3O4 fraction have been prepared by using a simple blending and hot-molding technique. The dielectric measurement results show that no synergistic effect but a cancellation effect has been found here, corresponding to the decrease of dielectric constant and conductivity. The value of the relative dielectric constant dropped to the original level of polymer matrix. The reasons for the counter result are present here. It is helpful and reference for the proper choice for multiphase composite system.

A trivalent native outer membrane vesicle vaccine that has potential to provide broad based protection against Neisseria meningitidis serogroup B strains has been developed. Preliminary immunogenicity studies in mice showed that the vaccine was capable of inducing an effective broad based bactericidal antibody response against N. meningitidis serogroup B strains. These findings in mice have been repeated with a cGMP trivalent NOMV vaccine and extended to show that the bactericidal antibody response induced by the vaccine in mice is effective against strains belonging to serogroups C, Y, W135, X, and NadA-expressing serogroup A strains. Taken together these results suggest that this experimental vaccine may provide protection against both serogroup B and non-serogroup B N. meningitidis strains.

From 1-D to 3-D zinc coordination polymers based on multifunctional flexible 4-(1,2,4-triazole-methylene)-benzonitrile (tzbt), {[Zn(tzbt)2(bdc)]·2H2O}n (1), [Zn(tzbc)2]n (2), and [Zn(bpdc)(H2O)]n (3) (bdc = 1,4-benzenedicarboxylic acid, tzbc = 4-(1,2,4-triazole-methylene)-benzoic acid, bpdc = 4,4′-biphenyldicarboxylic acid), were synthesized under hydrothermal conditions. The tzbt was synthesized by N-alkylation and hydrolyzed in situ to produce tzbc (in 2). Single-crystal X-ray diffraction analysis reveals that 1 displays 1-D wave-like chains based on [Zn(bdc)]n. 2 is a chiral twofold interpenetrating 2-D architecture constructed with “V”-shaped tzbc. 3 is a 3-D chiral compound constructed from achiral H2bpdc with right-handed helical chains. 1–3 display stable blue-emitting luminescence with emission maxima ranging from 383 to 410 nm, depending on ligand-centered π*→π transitions. The effects of different polarity solvents and temperature on luminescence are discussed. TGA and VT-XPRD reveal that 2 has thermal stability to 360 °C.

Hybridizing collective spin excitations and a cavity with high cooperativity provides a new research subject in the field of cavity quantum electrodynamics and can also have potential applications to quantum information. Here we report an experimental study of cavity quantum electrodynamics with ferromagnetic magnons in a small yttrium-iron-garnet (YIG) sphere at both cryogenic and room temperatures. We observe for the first time a strong coupling of the same cavity mode to both a ferromagnetic-resonance (FMR) mode and a magnetostatic (MS) mode near FMR in the quantum limit. This is achieved at a temperature ~ 22 mK, where the average microwave photon number in the cavity is less than one. At room temperature, we also observe strong coupling of the cavity mode to the FMR mode in the same YIG sphere and find a slight increase of the damping rate of the FMR mode. These observations reveal the extraordinary robustness of the FMR mode against temperature. However, the MS mode becomes unobservable at room temperature in the measured transmission spectrum of the microwave cavity containing the YIG sphere. Our numerical simulations show that this is due to a drastic increase of the damping rate of the MS mode., Comment: 11 pages, 7 figures, 1 table

Using Schiff-base ligands (E)-N-(6-methoxypyridin-2-yl)(CH═NAr) (where Ar = C6H5, L1; 2-MeC6H4, L2; 2,4,6-Me3C6H2, L3), six Zn(II)/Hg(II) complexes, namely, [ZnL1Cl2] (Zn1), [HgL1Cl2] (Hg1), [ZnL2Cl2] (Zn2), [HgL2Cl2] (Hg2), [ZnL3Cl2] (Zn3), and [HgL3Cl2] (Hg3) have been synthesized under solvothermal conditions. The structures of six complexes have been established by X-ray single-crystal analysis and further physically characterized by EA, FT-IR, (1)H NMR, and ESI-MS. The crystal structures of these complexes indicate that noncovalent interactions, such as hydrogen bonds, C-H···Cl, and π···π stacking, play essential roles in constructing the resulting supramolecular structures (1D for Hg3; 2D for Zn2, Hg2; 3D for Zn1, Hg1, and Zn3). Upon irradiation with UV light, the emission of complexes Zn1-Zn3 and Hg1-Hg3 could be finely tuned from green (480-540 nm) in the solid state to blue (402-425 nm) in acetonitrile solution. It showed that the ligand and metal cation can influence the structures and luminescence properties of complexes such as emission intensities and maximum wavelengths. Since these ligands and complexes could compensate for the absorption of N719 in the low-wavelength region of the visible spectrum and reduce charge recombination of the injected electron, the ligands L1-L3 and complexes Zn3/Hg3 were employed to prepare cosensitized dye-sensitized solar cells devices for investigating the influences of the electron-donating group and coordination on the DSSCs performance. Compared to DSSCs only being sensitized by N719, these prepared ligands and complexes chosen to cosensitize N719 in solar cell do enhanced its performance by 11-41%. In particular, a DSSC using L3 as cosensitizer displays better photovoltaic performance with a short circuit current density of 18.18 mA cm(-2), corresponding to a conversion efficiency of 7.25%. It is much higher than that for DSSCs only sensitized by N719 (5.14%).

The photophysical properties of ZnII/HgII Schiff base complexes could be fine and predictably tuned over a wide range of wavelengths by changing the ligand structures. A new series of polydentate Schiff base-type ligands, N,N′-bis(2-pyridinylethylidene)R3-1,2-diamine (L1–L6), which contain a flexible, semi-rigid or rigid group (R3 = butyl, cyclohexane, tolyl and phenylene), has been designed and employed for synthetizing new mononuclear or binuclear trans ZnII/HgII complexes with a general formula of [M(L1)Cl2] (L1 = N,N′-bis(2-pyridinylethylidene)phenylene-1,2-diamine, M = Zn, 1a; M = Hg, 1b), [M(L2)Cl2] (L2 = N,N′-bis(2-pyridinylethylidene)toluene-3,4-diamine, M = Zn, 2a; M = Hg, 2b), [M2(L3)Cl4]·nCH2Cl2 (L3 = N,N′-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine, M = Zn, n = 0, 3a; M = Hg, n = 1, 3b), [M2(L4)Cl4]·nCH3OH (L4 = N,N′-bis(2-pyridinylethylidene)cyclohexane-1,2-diamine, M = Zn, n = 1, 4a; M = Hg, n = 0, 4b), [M2(L5)Cl4] (L5 = N,N′-bis(3-methoxy-2-pyridinylmethylene)-cyclohexane-1,2-diamine, M = Zn, 5a; M = Hg, 5b), [M2(L6)Cl4]·nCH3CN (L6 = N,N′-bis(3-methoxy-2-pyridinylmethylene)butane-1,4-diamine, M = Zn, n = 4, 6a; M = Hg, n = 0, 6b). All the ligands and complexes have been characterized by elemental analyses, IR spectra, and 1H NMR spectra. Twelve structures of L5, L6, 1a–6a, 1b, 3b, 5b and 6b crystallized in three different conditions are further determined by single-crystal X-ray diffraction analyses. Their properties are fully characterized by UV-vis and fluorescence spectra both in solution and the solid state at room temperature. The luminescence color of these ZnII/HgII Schiff base complexes could be tuned from blue to green to red (429–639 nm for 6a–1a, 434–627 nm for 6b–1b) in solution by changing the ligand conjugated systems from flexibile (L6) to semi-rigid (L3–L5) to rigid (L1–L2). The spectra of the free Schiff bases L6–L1 are centered around 402–571 nm, which are perturbed upon the coordination to the ZnII/HgII ion. Both the electrochemical data and TD-DFT calculations show that the HOMO–LUMO band gap from the ligand to the complex is reduced by complexation. Meanwhile, the emission efficiencies of ZnII-complexes are found to be strongly dependent on the Schiff-base ligands with quantum yields ranging from 14% to 25% for 1a–6a. However, the emission efficiencies dramatically decline in HgII-complexes with quantum yields ranging from 4% to 19%, due to the heavy atom effect.

A novel polydentate Schiff base ligand N(1),N(3)-bis[(6-methoxypyridin-2-yl)methylene]benzene-1,3-diamine (L) and its two dinuclear sandwich-like complexes {[CdL(NO3)(H2O)]·NO3}2 (1) and {[CdL(CH3CN)(H2O)]·(ClO4)2·(CH3CN)2}2 (2) were synthesized. Both C-H∙∙∙O, C-H∙∙∙N and π-π non-covalent interactions had essential roles in constructing the resulting three-dimensional supramolecular networks. L emits a more intense blue-green fluorescence emission around 493 nm than in dilute solution, exhibiting stacking-induced emission properties. Complexes 1 and 2 exhibited the dual properties of exceptional solvatochromism and fluorescence quenching towards CH3OH molecules. As these compounds could overcome the absent absorption of ruthenium complex N719 in the low wavelength region of the visible spectrum, offset the competitive visible light absorption of I3(-) and reduce the charge recombination of injected electrons, the Schiff base ligand l and complexes 1 and 2 were used as co-sensitizers in combination with N719 to investigate their effect on enhancing the performance of dye-sensitized solar cells. A short circuit current density of 14.37 mA cm(-2), an open-circuit voltage of 0.71 V and a fill factor of 0.61 corresponding to an overall conversion efficiency of 6.17% under AM 1.5 G solar irradiation were achieved when 1 was used as a co-sensitizer, which are much higher than the results obtained for dye-sensitized solar cells sensitized by N719 alone (5.06%).

Poly(methylmethacrylate) (PMMA) doped with Tb-based imidazole derivative coordination polymer {[Tb(3)(L)(μ(3)-OH)(7)]·H(2)O}(n) (1) (L = N,N'-bis(acetoxy)biimidazole) was synthesized and its photophysical properties were studied. The L'(L' = N,N'-bis(ethylacetate)biimidazole) ligand was synthesized by an N-alkylation reaction process followed by ester hydrolysis to produce ligand L. Polymer 1 and ligand L' have been characterized by (1)H NMR and IR spectroscopy, elemental analysis, PXRD and X-ray single-crystal diffraction. Coordination polymer 1 is the first observation of a CdCl(2) structure constructed with hydroxy groups and decorated by ligand L in lanthanide N-heterocyclic coordination polymers. In the 2D layered structure of 1, each Tb3 metal center is connected with three Tb1 and three Tb2 metal centers by seven hydroxyl groups in different directions, resulting in a six-membered ring. After doping, not only the luminescence intensity and lifetime enhanced, but also their thermal stability was increased in comparison with 1. When 1 was doped into poly(methylmethacrylate) (1@PMMA), polymer film materials were formed with the PMMA polymer matrix (w/w = 2.5%-12.5%) acting as a co-sensitizer for Tb(3+) ions. The luminescence intensity of the Tb(3+) emission at 544 nm increases when the content of Tb(3+) was 10%. The lifetime of 1@PMMA (914.88 μs) is more than four times longer than that of 1 (196.24 μs). All τ values for the doped polymer systems are higher than coordination polymer 1, indicating that radiative processes are operative in all the doped polymer films. This is because PMMA coupling with the O-H oscillators from {[Tb(3)(L)(μ(3)-OH)(7)]·H(2)O}(n) can suppress multiphonon relaxation. According to the variable-temperature luminescence (VT-luminescence) investigation, 1@PMMA was confirmed to be a stable green luminescent polymer film material.

The effects of captopril (Cap) and verapamil (Ver) alone and in combination on intracellular Na+ concentration ([Na+]i) in cultured aortic smooth muscle cells(ASMC) of rabbits was evaluated by a direct measurement of [Na+]i with fluorescent dye sodium-binding benzofuran isophthalate (SBFI) combined with digital image. [Na+]i in resting cells was found to be 11.9±0.7 mmol/L. Angiotensin II (Ang-II, 0.1-10 μmol/L) induced an increase of [Na+]i in concentration-dependent manner. Ver (0.1- 10 μmol/L) inhibited Ang-II (1 μmol/L)-induced increase in [Na+]i, while Cap enhanced Ang-II-induced increase in [Na+]i at 10 μmol/L but not at 0.1-1 μmol/L. Ver(0.1-1 μmol/L)abolished enhancement of Ang-II-induced increase in [Na+]i by Cap. Thus, the inhibition of Cap-enhanced [Na+]i by Ver may provide a new hypothesis for the underlying molecular mechanism of synergistic effect of the combination of Ca2+ antagonists and angiotensin-converting enzyme inhibitors in controlling blood pressure.

Two rare 2D Ga/In-based coordination polymers in which one metal center coexists with three distinct aromatic ligands were synthesized. Helical channels along the 21 screw axis are exhibited to form a hcb net. The compounds exhibit tunable fluorescence from blue, green, white to yellow light by varying the temperature and solvents.

Five IIB group complexes, [ZnL1Cl2] (1), {[CdL1Cl2]}2 (2), [Cd(L1)2(NO3)2]·H2O (3), [HgL1Cl2] (4), and [ZnL2Cl2] (5) [L1 = 1-[2-(6-methoxy-2-pyridylmethyl)]-2-[2-(6-methoxy-pyridyl)]benzimidazole; L2 = 2-[2-(6-methoxypyridyl)]benzimidazole] have been synthesized and structurally characterized by elemental analysis, IR spectroscopy, 1H NMR, 13C NMR and X-ray single-crystal analyses. The structural investigations testify that the ionic radius and counterions (Cl− and NO3−) cooperatively affect the coordination mode of central metal. As small and medium radii, four-coordinated Zn2+ (1 and 5) and five-coordinated Cd2+ (2) possess tetrahedron and trigonal bipyramid geometries, respectively. Though Hg2+ (4) has a larger radius, its three-coordinated geometry is trigonal planar in order to eliminate repulsive forces. Further observations illustrate that Cd2+ (3) is bound to two ligands L1 when NO3− is the counter anion, forming seven-coordinated monocapped trigonal prismatic geometry. Complexes 1–5 display bright blue luminescence with the emission maxima (λmax) ranging from 399 to 499 nm at 298 K, depending on the N,N′-chelating ligand-centered π* → π transition. Upon cooling to 77 K, the complexes show rich structured emission profiles compared to those at 298 K. The emission lifetimes of L and 1–5 are on the microsecond scale. The emission efficiency of 1–5 is shown by quantum yields ranging from 0.23 to 0.40. Complexes 1–5 offer a good insight into the opportunities in the utilization of blue materials for application and function.