CH3OH H2O Research Articles

Effect of Methyl Red on the surface properties of DTAB in CH3OH–H2O

The purpose of this study is to investigate the effect of Methyl Red (MR) on the micellization and surface properties of a cationic surfactant, dodecyl trimethylammonium bromide (DTAB), in CH3OH–H2O mixed solvent systems at varying CH3OH parts by volumes (0.1, 0.2, 0.3, and 0.4) and temperatures (298.15 K, 308.15 K and 318.15 K). Surface tension and conductivity measurements were conducted to obtain the critical micelle concentration (CMC) and various surface properties such as premicellar slope (dγdlogC), maximum surface concentration (Γmax), minimum surface area occupied (πCMC), free energy of adsorption (ΔGadso), adsorption efficiency (pC20), packing parameter (P), and aggregation number (Nagg). The results indicate that the presence of MR significantly influences the behavior of DTAB in the mixed solvent system. In the absence of MR, the CMC increased with higher CH3OH content, while MR reduced the CMC, promoting micelle formation through dye-surfactant-ion-pair (DSIP) formation. Surface properties were enhanced in the presence of MR leading to higher surface pressure. Additionally, the free energy of adsorption (ΔGadso) became more negative with MR, indicating a more favorable adsorption process. Correlations of (dγdlogC), Γmax,γ0/γcmc, pC20, Nagg, CMC/C20 with the parts by volume of CH3OH at 298.15 K, 308.15 K, and 318.15 K are discussed with and without MR. The obtained results were used to examine the effect of MR on the surface properties of DTAB in the CH3OH–H2O medium. The change in properties can be explained in terms of the change in polarity of the medium and dye-surfactant ion pair (DSIP) formation.

Study on the Phase Equilibria of the Ternary Mixed Solvent System NaCl–NaBr–CH3OH–H2O at 298 and 323 K

Aiming to improve the utilization of bromine resources in bittern, the solubilities of the ternary NaCl–NaBr–CH3OH–H2O mixed solvent system at 298 and 323 K were measured by the method of isothermal dissolution equilibrium, and the corresponding phase diagrams were constructed. The results show that the phase diagrams at the two temperatures are similar, and both have only one univariant curve and one crystallization region corresponding to a solid solution Na(Cl, Br) without invariant points. Based on the extended Pitzer model, Pitzer parameters were calculated, and the activity product of the solid solution was regressed into a polynomial of Br– mole fraction in the solid solution. The solubilities of the ternary NaCl–NaBr–CH3OH–H2O mixed solvent system at 298 K were calculated. The computed results are in accordance with the experimental values.

Benzoindoxazine derivatives containing carbazole for detection of CN− and its application in plant seed extracts and cell imaging

Cyanide (CN−) is a highly toxic compound that exists in many substances and is harmful to the environment and human health. Therefore, it is of great significance to develop excellent CN− ion probes, especially solvent-induced on–off fluorescent probes. Based on the condensation reaction of indolo[2,1-b][1,3]oxazine molecules with aldehydes, probes (E)-13a-(2-(9-ethyl-9H-carbazol-3-yl)vinyl)-14,14-dimethyl-10-nitro-13a,14-dihydro-8H-benzo[e]benzo[5,6][1,3]oxazino[3,2-a]indole (NCO) and (E)-13a-(2-(9-benzyl-9H-carbazol-3-yl)vinyl)-14,14-dimethyl-10-nitro-13a,14-dihydro-8H-benzo[e]benzo[5,6][1,3]oxazino[3,2-a]indole (NBO) were synthesized to detect CN−. Compared with other cyanogen ion probes, NCO and NBO have special carbazole ring structures and large conjugate systems. When CN− is added to the probe-detection solution, color changes that are visible to the naked eye can occur. The UV–vis spectrum test using differential spectroscopy shows that the probe (i) has excellent solvent-induced switching characteristics and stability (CH3OH–H2O) and (ii) high selectivity, anti-interference ability, and sensitivity for the detection of CN−. The fluorescence limit of detections (LODs) are 1.05 µM for NCO and 1.34 µM for NBO. The UV LODs are 0.83 µM for NCO and 0.87 µM for NBO. Fluorescence spectroscopy shows that the probe has remarkable fluorescence properties. Fluorescence titration experiments, liver cancer cell (Hep G2) imaging, and cytotoxicity experiments all show that the probes have high biocompatibility, low toxicity, high cell permeability, and high sensitivity for the detection of CN− in cells. In addition, NCO and NBO have been successfully used for the detection of cyanogenic glycosides in the seeds of ginkgo, crabapple, apple, and cherry. Test strips were fabricated to detect CN−. After adding CN−, the color of the test strip changed significantly—from brown to light yellow; thus, the test strips have a high application value in the fields of drug quality control, drug safety testing, and pharmacological research.

Synthesis, Crystal Structure and DNA-Binding Study of a New Zinc(II) Complex Based on 2,6-Bis(imino)pyridyl Ligand

A new zinc complex [Zn(L1)Cl2]2‧CH3OH‧2H2O (complex 1), where L1 stands for 2,6-Bis{[(4-ethylphenyl)imino]ethyl}pyridine (L1) has been synthesized and characterized. The crystal structure of L1 and complex 1 have been determined by single-crystal X-ray diffraction. Both compounds crystallize in the monoclinic P21/c space group. For the ligand L1, the crystal parameters are a = 16.7487(7) A, b = 5.8177(3) A, c = 21.8427(10) A, β = 104.1350(10)° and Z = 4. For complex 1, the crystal parameters are a = 8.0216(14) A, b = 13.433(2) A, c = 24.640(4) A, β = 90.223(3)° and Z = 2. In the crystal structure of complex 1, L1 acts as a tridentate ligand and coordinated with Zn1 with three nitrogen atoms. Together with two chlorine atoms, Zn1 atom is five-coordinated in a trigonal bipyramidal geometry. Hydrogen bonds play great role in the crystal structure of complex 1 and form a two-dimensional network. Furthermore, the DNA-binding property of complex 1 with fish sperm DNA (FS-DNA) has been investigated by electronic absorption titration. The result suggests that complex 1 might interact with FS-DNA via groove binding mode. The single crystals of 2,6-Bis{[(4-ethylphenyl)imino]ethyl}pyridine (L1) and it’s Zinc(II) complex [Zn(L1)Cl2]‧CH3OH‧H2O (1) were determined. In the crystal structure of complex 1, Zn1 atom is five-coordinated in a trigonal bipyramidal geometry. A two-dimensional network is formed by hydrogen bonds. DNA-binding study indicated that complex 1 interact with FS-DNA via groove binding mode.

Hydrogen Generation over RuO2 Nanoparticle-Decorated LaNaTaO3 Perovskite Photocatalysts under UV Exposure.

The efficacy of LaNaTaO3 perovskites decoration RuO2 at diverse contents for the photocatalytic H2 generation has been explored in this study. The photocatalytic performance of RuO2 co-catalyst onto mesoporous LaNaTaO3 was evaluated for H2 under UV illumination. 3%RuO2/LaNaTaO3 perovskite photocatalyst revealed the highest photocatalytic H2 generation performance, indicating that RuO2 nanoparticles could promote the photocatalytic efficiency of LaNaTaO3 perovskite significantly. The H2 evolution rate of 3%RuO2/LaNaTaO3 perovskite is 11.6 and 1.3 times greater than that of bare LaNaTaO3 perovskite employing either 10% CH3OH or pure H2O, respectively. Interestingly, the photonic efficiency of 3%RuO2/LaNaTaO3 perovskite was enhanced 10 times than LaNaTaO3 perovskite in the presence of aqueous CH3OH solutions as a hole sacrificial agent. The high separation of charge carriers is interpreted by the efficient hole capture using CH3OH, hence leading to greater H2 generation over RuO2/LaNaTaO3 perovskites. This is attributed to an adjustment position between recombination electron–hole pairs and also the reduction of potential conduction alignment as a result of RuO2 incorporation. The suggested mechanisms of RuO2/LaNaTaO3 perovskites for H2 generation employing either CH3OH or pure H2O were discussed. The photocatalytic performances of the perovskite photocatalyst were elucidated according to the PL intensity and the photocurrent response investigations.

Complex organic molecules in protoplanetary disks: X-ray photodesorption from methanol-containing ices

Context.Astrophysical observations show complex organic molecules (COMs) in the gas phase of protoplanetary disks. X-rays emitted from the central young stellar object (YSO) that irradiate interstellar ices in the disk, followed by the ejection of molecules in the gas phase, are a possible route to explain the abundances observed in the cold regions. This process, known as X-ray photodesorption, needs to be quantified for methanol-containing ices.Aims.We aim at experimentally measuring X-ray photodesorption yields (in molecule desorbed per incident photon, displayed as molecule/photon for more simplicity) of methanol and its photo-products from binary mixed ices:13CO:CH3OH ice and H2O:CH3OH ice.Methods.We irradiated these ices at 15 K with X-rays in the 525–570 eV range from the SEXTANTS beam line of the SOLEIL synchrotron facility. The release of species in the gas phase was monitored by quadrupole mass spectrometry, and photodesorption yields were derived.Results.For13CO:CH3OH ice, CH3OH X-ray photodesorption yield is estimated to be ∼10−2molecule/photon at 564 eV. X-ray photodesorption of larger COMs, which can be attributed to either ethanol, dimethyl ether, and/or formic acid, is detected with a yield of ∼10−3molecule/photon. When methanol is mixed with water, X-ray photodesorption of methanol and of the previous COMs is not detected. X-ray induced chemistry, dominated by low-energy secondary electrons, is found to be the main mechanism that explains these results. We also provide desorption yields that are applicable to protoplanetary disk environments for astrochemical models.Conclusions.The X-ray emission from YSOs should participate in the enrichment of the protoplanetary disk gas phase with COMs such as methanol in the cold and X-ray dominated regions because of X-ray photodesorption from methanol-containing ices.

Influence of water content on the [2σ+2σ+2π] cycloaddition of dimethyl azodicarboxylate with quadricyclane in mixed methanol-water solvents from QM/MM Monte Carlo simulations.

Mixed quantum mechanics/molecular mechanics Monte Carlo (QM/MM/MC) simulations combined with the free energy perturbation (FEP) theory have been performed to investigate the mechanism and solvent effect of the [2σ+2σ+2π] cycloaddition reaction between dimethyl azodicarboxylate and quadricyclanes in the binary mixture solvents of methanol and water by varying the water content from 0 to 100 vol%. The two-dimensional potentials of mean force (2D PMF) calculations demonstrated that the mechanism of the reaction is a collaborative asynchronous procedure. The transition structures do not show large variation among different solvents. The calculated free energies of activation indicated that the QM/MM/MC method reproduced well the tendency of rate enhancement from pure methanol to methanol-water mixtures to "on water" with the water content increasing obtained in the experimental observation. The analyses of the energy pair distribution and radial distribution functions illustrated that hydrogen bonding plays an indispensable role in the stabilization of the transition structures. According to the results in methanol-water mixtures at different volume ratios, it is clear that the site-specific hydrogen bond effects are the central reason which leads to fast rate increases in progressing from a methanol-water volume ratio of 3 : 1 to 1 : 1. This work provides a new insight into the solvent effect for the [2σ+2σ+2π] cycloaddition reaction.

COMPETITION BETWEEN METHANOL AND WATER MOLECULES UPON THE FORMATION AND SOLVATION OF IONS IN THE CH3OH–H2O–HCl SYSTEM

IR spectroscopy and density functional theory (B3LYP/6-31++G(d, p)) are used to study the competition between methanol and water molecules during the formation of (CH3(H)O∙∙∙H∙∙∙O(H)CH3)+, (CH3(H)O∙∙∙H∙∙∙OH2)+, and (H2O∙∙∙H∙∙∙OH2)+ ions with strong quasi-symmetrical H-bonds and their solvation in the CH3OH–H2O–HCl system. When water is added to a solution of HCl in methanol, H2O molecules substitute CH3OH molecules in (CH3(H)O∙∙∙H∙∙∙O(H)CH3)+ ions to form mixed disolvates. Conversely, when methanol is added to an aqueous solution of HCl, (H2O∙∙∙H∙∙∙OH2)+ ions are maintained and CH3OH molecules are involved in their solvation. Provided that the fractions of methanol and water are commensurate, the solutions contain simultaneously (CH3(H)O∙∙∙H∙∙∙OH2)+ and (H2O∙∙∙H∙∙∙OH2)+ ions. The ratio between their concentrations depends on the content of HCl in the system. It is shown that the energy of the hydrogen bond system per one dissociated HCl molecule is the main factor determining the structure of CH3OH–H2O–HCl solutions, in particular, the composition of proton disolvates.

Multiple strong hydrogen bonded supramolecular cocrystals of 18-crown-6 with 5-nitroisophthalic acid: Solvent effect and optical nonlinearities

Novel cocrystals of 18-crown-6 (18C6) with 5-nitroisophthalic acid (5NIPA) have been prepared by reaction in a solution of CH3OH–H2O (2:3, v/v) and C2H5OH–H2O (2:3, v/v) systems. The cocrystals 18-crown-6.5-nitroisophthalic acid. CH3OH.2(H2O) (I) and 18-crown-6.5-nitroisophthalic acid.3(H2O) (II) have been characterized by X-ray diffraction and constructed supramolecular assembly is thoroughly investigated. CH3OH incorporation inducing centrosymmetric crystallization and acentric crystal packed supramolecular construction in presence of ethanol are the highlights of the study. Intermolecular interactions are quantified by Hirshfeld surface analysis. First-order molecular hyperpolarizability estimated by theoretical calculations indicate a significant microlevel nonlinearity in both cases and Z-scan studies suggest a promising third-order nonlinear optical behaviour. Supramolecular assembly afford multiple strong O–H ….O hydrogen bonds creating a facile atmosphere for optical nonlinearity and mainly these O ….O hydrogen bonds stabilize the structure.

An amphiphilic metallaclip with enhanced fluorescence emission in water: synthesis and controllable self-assembly into multi-dimensional micro-structures

A new amphiphilic organoplatinum(ii) metallaclip was designed and fabricated successfully through coordination driven self-assembly. It can further self-assemble into multi-dimensional well-defined micro-structures with different CH3OH/H2O ratios, and show enhanced fluorescence emission in water.

Preparative Separation and Purification of Trichothecene Mycotoxins from the Marine Fungus Fusarium sp. LS68 by High-Speed Countercurrent Chromatography in Stepwise Elution Mode.

The contamination of foods and animal feeds with trichothecene mycotoxins is a growing concern for human and animal health. As such, large quantities of pure trichothecene mycotoxins are necessary for food safety monitoring and toxicological research. A new and effective method for the purification of trichothecene mycotoxins from a marine fungus, Fusarium sp. LS68, is described herein. Preparative high-speed countercurrent chromatography (HSCCC) was utilized for the scalable isolation and purification of four trichothecene mycotoxins for the first time in stepwise elution mode, with a biphasic solvent system composed of hexanes–EtOAc–CH3OH–H2O (6:4:5:5, v/v/v/v) and (8.5:1.5:5:5,v/v/v/v). This preparative HSCCC separation was performed on 200 mg of crude sample to yield four trichothecene mycotoxins, roridin E (1), roridin E acetate (2), verrucarin L acetate (3), and verrucarin J (4) in a single run, with each of >98% purity. These compounds were identified by MS, 1H NMR, 13C NMR, and polarimetry. The results demonstrate an efficient HSCCC method for the separation of trichothecene mycotoxins, which can be utilized to produce pure commercial and research standards.

Effective reduction of p-nitrophenol catalyzed by nickel(II) adamantane complexes

Two Ni(II) adamantane complexes, [Ni(bqad)Cl2] (1) and [Ni(bpad)(dmbp)(H2O)](ClO4)2·CH3OH H2O (2) (bqad = N,N′-bis(2-quinolinylmethyl) amantadine, bpad = N,N′-bis(2-pyridylmethyl)amantadine, dmbp = 5,5′-dimethyl-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, infrared spectroscopy and single crystal X-ray diffraction. The nickel centers in complex 1 have a distorted tetragonal pyramidal geometry, while the coordination polyhedron of 2 can be described as a distorted octahedron. The reaction kinetics for reduction of p-nitrophenol to p-aminophenol catalyzed by these complexes has been investigated by UV–visible spectrophotometry. Complex 1 exhibits a higher turnover frequency of 1.4 min−1 for the reduction of p-nitrophenol.

In situ growth MoO3 nanoflake on conjugated polymer: An advanced photocatalyst for hydrogen evolution from water solution under solar light

A series of MoO3/PI composite photocatalysts were prepared via a facile in situ solid-thermal approach. Characterization results revealed that the growth of MoO3 nanoflakes epitaxial (010) face on the surface of PI and introduction of Mo did not change the skeleton structure but enhance the crystallinity of polyimide. The stronger interaction between MoO3 and substrate PI leads to the formation of Mo–N band and Mo5+ species. The measurements for the optical and electronic properties of MoO3/PI composites confirmed that MoO3 nanoflakes on the surface PI not only induce the absorption of visible light but also suppressed the radiative recombination of charge carriers, which endows the excellent photocatalytic activity of MoO3/PI samples in hydrogen evolution from a CH3OH–H2O solution 9:1 by volume) under solar energy driven. The enhancement of MoO3 nanoflake for the photocatalytic performance of PI is even more effective than that of Pt at the same loading amount. This work provides a promising choice to substitute noble metal as the cocatalyst on polymer photocatalyst and take a step forward effective utilization of renewable energy.

Solubility of Sodium Chromate in the NaOH–CH3OH–H2O System from (278.15 to 343.15) K

The solubility of sodium chromate in the NaOH–CH3OH–H2O system have been measured using the static analytical method at temperatures of (303.15, 313.15, 323.15, and 333.15) K. The measured results were respectively correlated by the Apelblat equation, the empirical equation, and the λ–h equation. Meanwhile, it was found that the liquid–liquid phase separation, also termed as oiling out, will happen under certain conditions. The relationship between the steady-state critical temperature and solvent composition was studied systematically using FBRM. The results show that the solubility of sodium chromate increases with increasing temperature and decreases with increasing concentration of sodium hydroxide, respectively. Three models were employed to correlate the experimental data, which fit the data well. Moreover, the Apelblat equation for the system has less deviations than the λ–h equation and the empirical equation. The results also show that the steady state critical oiling-out temperature increases wi...

Chemical Components of the Tuber of Alocasia cucullata

Alocasia cucullata Schott is mainly distributed in Guangxi, Guangdong, Sichuan, Guizhou, and Fujian Provinces in China (Wu, 1990). Its tuber (Chinese name “jianweiyu”) is a well-known ethnic medicine of the Zhuang nationality in China and is used to treat cancer, reduce swelling, for detoxification, and to ease pain. The antitumor effects of this herb have been preliminarily confirmed because of its widespread clinical application in China for centuries. Nevertheless, up to now, no systematic study has been done on the antitumor constituents of A. cucullata, and the occurrence of an N-acetyl-D-lactosamine (LacNAc)-specific lectin has been reported in a previous investigation of A. cucullata [1]. Our previous pharmacological study further showed the presence of cytotoxic activity in a 50% ethanol extract [2]. In this article we report the isolation of a total of 12 substances: steroid (1), alkaloids (2–4), and phenolic substances (5–12) for the first time from the genus Alocasia. Plant Material. The tubers of A. cucullata were collected in Sichuang Province, China, in May 2011 and identified by Prof. Bao-Kang Huang (Second Military Medical University, Shanghai, China). A voucher specimen (Zheng 5580) has been deposited in the Herbarium of the Shanghai University of Traditional Chinese Medicine. Processing of Plant Material. The tubers of A. cucullata (5 kg) were powdered and extracted three times with 50% EtOH. The extract was concentrated under reduced pressure to give a crude residue (200 g), which was extracted successively with petroleum ether, ethyl acetate, n-butanol. The n-butanol fraction, concentrated to dryness (30 g), was further fractionated on a silica gel chromatography column (600 g of silica gel 60, 70–230 mesh; CHCl3–MeOH–H2O [(15:0.4:1,10:0.4:1, and 5:0.4:1) gradient)] to give four fractions, Frs. A, B, C, and D which were further fractionated on a silica gel chromatographic column (RP-18): CC of Fr. A (2.2 g) (RP-18, 200 g; CH3OH–H2O 4:1) gave 1 (30 mg), 2 (36 mg), 3 (30 mg), and 4 (28 mg); CC of Fr. B (6.2 g) (RP-18, 400 g; CH3OH–H2O 1:1) gave 3 (20 mg), 4 (100 mg), 5 (46 mg), 6 (30 mg), 7 (58 mg), and Fr. B (0.9 g), which were pooled. Fraction B was chromatographed on Sephadex LH-20 (CH3OH–H2O 1:1) yielding 8 (32 mg). CC of Fr. C (5.2 g) (RP-18, 400 g; CH3OH–H2O 2:1) gave 9 (30 mg) and 10 (34 mg). CC of Fr. D (2.1 g) (RP-18, 400 g; CH3OH–H2O 4:1) gave 11 (21 mg) and 12 (25 mg). Compound 1, C35H60O6, white amorphous powder (MeOH), mp 134–135 C. ESI-MS m/z 577 [M + H]+. Its physical constants and spectral data were in agreement with those of -daucosterol [3]. Compound 2, C10H13N5O4, white amorphous powder (MeOH), mp 234.4–235.4 C. ESI-MS m/z 268 [M + H] +. Its physical constants and spectral data were in agreement with those of -adenosine [4]. Compound 3, C6H6N2O, white amorphous powder (MeOH), mp 129–130 C. ESI-MS m/z 121 [M – H]–. Its physical constants and spectral data were in agreement with those of niacinamide [5]. Compound 4, C9H7NO, white gum (MeOH). ESI-MS m/z 146 [M + H] +. Its physical constants and spectral data were in agreement with those of 1H-indole-3-carboxaldehyde [5]. Compound 5, C9H10O3, yellow oil, mp 49–50 C. ESI-MS m/z 167 [M + H]+. Its physical constants and spectral data were in agreement with those of paeonol [6]. Compound 6, C7H6O5, yellow powder. ESI-MS m/z 171 [M + H] +. Its physical constants and spectral data were in agreement with those of gallic acid [6].

Indole Alkaloids from the Roots of Catharanthus roseus

Catharanthus roseus (L.) G. Don is a well-known traditional herbal medicine, which is rich in indole alkaloids [1]. The chemical constituents of C. roseus have been investigated in our group [2, 3], and our further research has led to nine indole alkaloids (1–9) from the roots of C. roseus. Among them, compounds 1 and 2 were first isolated from the natural source, and their NMR data are reported for the first time. The roots of C. roseus were collected in March 2010 in Haikou City, Hainan Province, P. R. China. The plant was authenticated by Prof. Guang-Xiong Zhou of Jinan University. A voucher specimen (No. W1003021) has been deposited in the Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, P. R. China. Air-dried and powdered roots (5 kg) of C. roseus were extracted with 95% EtOH, and the residue was dissolved in H2O to form a suspension and extracted with CHCl3 to obtain an extract (62 g). The CHCl3 extract was subjected to silica gel column chromatography (CHCl3–CH3OH, 100:0 0:100) to give 9 fractions (Fr. 1–Fr. 9). Fractions 5–7 were subjected to ODS column chromatography in CH3OH–H2O separately, followed by preparative-HPLC in MeOH–H2O, leading to nine indole alkaloids. Compounds 1 and 2 were identified using MS, IR, UV, and 1D and 2D NMR analysis, and compounds 3–9 were identified by comparing their spectral data with those in the literature as 3-epi-yohimbine (3) [4], lochnerine (4) [5], antirhine (5) [6], 18-hydroxystrictamine (6) [7], (–)-dihydrocorynantheol (7) [8], corynanthine (8) [9], and 21-hydroxycyclolochnerine (9) [10].

Porosity and thermal collapse measurements of H2O, CH3OH, CO2, and H2O:CO2 ices

The majority of astronomical and laboratory based studies of interstellar ices have been focusing on ice constituents. Ice structure is a much less studied topic. Particularly the amount of porosity is an ongoing point of discussion. A porous ice offers more surface area than a compact ice, for reactions that are fully surface driven. In this paper we discuss the amount of compaction for four different ices--H2O, CH3OH, CO2 and mixed H2O : CO2 = 2 : 1--upon heating over an astronomically relevant temperature regime. Laser interference and Fourier transform infrared spectroscopy are used to confirm that for amorphous solid water the full signal loss of dangling OH bonds is not a proof for full compaction. These data are compared with the first compaction results for pure CH3OH, pure CO2 and mixed H2O : CO2 = 2 : 1 ice. Here we find that thermal segregation benefits from a higher degree of porosity.

Synthesis, crystal structure, and electrochemical properties of the complex of Cu(II) with 3-ethoxysalicylaldehyde-N,N-bis(3-aminopropyl)methylamine

Colorless crystals of CuL, where L = 3-ethoxysalicylaldehyde-N,N-bis(3-aminopropyl)methylamine, were obtained by self-assembly of 3-ethoxysalicylaldehyde-N,N-bis(3-aminopropyl)methylamine and Cu(NO3)2·4H2O in 2:1 (v/v) CH3OH–H2O. The Cu(II) complex was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction analysis. The monoclinic crystal belongs to space group P21/c with a = 10.3028(14) A, b = 14.0255(12) A, c = 17.355(14) A, β = 97.474(3)°, V = 2,487(2) A3, Z = 4, Dc = 1.344 g cm−3, μ = 0.913 mm−1, F(000) = 1,060, and final R = 0.0563, ωR = 0.0995. In the crystal structure, each Cu(II) atom is five-coordinated in a distorted square pyramid environment by two phenolic O atoms and three N atoms from the ligand. The molecules form a one-dimensional chain structure by intermolecular hydrogen bond interaction. The electrochemical properties of the Cu(II) complex were investigated.

Anion-directed assembly of cadmium(II)–dicyanamide coordination polymers based on a tripyridyltriazole ligand

Assemblies of a tripyridyltriazole ligand, 3,4-bis(2-pyridyl)-5-(3-pyridyl)-1,2,4-triazole (L223) with dicyanamide (dca) anion and different Cd(II) salts in CH3OH–H2O media afford four coordination polymers, namely {[Cd2(L223)2(dca)4(H2O)](H2O)4}n (1), {[Cd(L223)(dca)(ClO4)](H2O)0.25}n (2), and [Cd(L223)(dca)X]n (X−=Cl− for 3 and Br− for 4). All complexes were structurally determined by single-crystal X-ray diffraction. In 1 and 2, the Cd(II) centers are combined by L223 spacers to form [Cd2(L223)2] bimetallic subunits, which are bridged by dca anions to result in the 1D motif and 2D layer, respectively. Complexes 3 and 4 display isostructural 3D homochiral coordination networks that are constructed by 1D [Cd(L223)]n helical subunits and dca bridges. These results indicate that the counter anions of Cd(II) salts will be responsible for the diverse structures of coordination polymers 1–4. Their solid state properties such as thermal stability and fluorescence will also be presented.

Structural diversity and fluorescent properties of CdII coordination polymers with 5-halonicotinates regulated by solvent and ligand halogen-substituting effect

Seven CdII coordination polymers have been prepared from CdCl2 and 5-halonicotinic acids (HL–X, X = F or Cl) in different solvent media using a similar layered diffusion method. A pair of polymorphic isomers [Cd(L–F)2]n (1 and 2) can be assembled from CH3CN–H2O and CH3OH–H2O systems, respectively, featuring the 3-D (3,5)-connected (4·62)(4·67·82) network (5-connected node for each CdII ion and 2- or 3-connected linker for the two different types of L–F− ligand) and the 3-D (3,6)-connected ant framework with the point symbol of (4·62)2(44·62·88·10). While in DMF–H2O solvent, a 2-D layered complex [Cd(L–F)Cl(DMF)]n (3) is obtained with the (3,5)-connected net of (3·4·5)(32·4·5·62·74) topology, where the chloride anion is involved in coordination. When the HL–Cl ligand is utilized instead of HL–F, the assembling reactions in CH3CN–H2O and DMF–H2O media lead to the 3-D (3,5)-connected network of [Cd(L–Cl)2]n (4) and the 2-D (3,5)-connected net of [Cd(L–Cl)Cl(DMF)]n (6), which are isostructural to complexes 1 and 3, respectively. [Cd(L–Cl)2(H2O)2]n (5) can be generated from the CH3OH–H2O medium, showing a 2-D (4,4) layered structure, and the similar reaction in the C2H5OH–H2O solvent will produce a 3-D coordination framework {[Cd(L–Cl)2(H2O)0.5](C2H5OH)0.75(H2O)0.25}n (7) with the (3,6)-connected (3·4·5)(32·44·55·62·72) net. These structural divergences can be ascribed to the significant solvent modulation and halogen-substituting effect of 5-halonicotinates. Furthermore, their solid-state properties such as thermal stability and fluorescence have also been investigated.