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1.
Solvothermal reactions of aromatic 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylic acid (H4EBTC) and Mg2+ salts in the presence of different supporting ligands afforded the coordination polymers [Mg(H2EBTC)(DMF)2(H2O)2] (1), [Mg3(HEBTC)2(H2O)4]·solvent (2) and [Mg2(EBTC)(H2O)5]·solvent (3). The crystal structures of 1–3 were determined by the single crystal X-ray diffraction technique, where CP 1 showed a one-dimensional zigzag MgO6 coordination octahedral chain structure; 2 exhibited a two-dimensional MgO6 coordination octahedral framework with trinuclear [Mg3(COO)6] SBUs, and 3 featured a three-dimensional MgO6 coordination octahedral framework with binuclear [Mg2O(COO)2] SBUs. The various structures in CPs 1–3 of Mg2+ ions with the H4EBTC ligand were ascribed to the conformational flexibility and the coordination mode diversity of the H4EBTC ligand. Interestingly, the zwitterionic supporting ligand 2-aminoterephthalic acid or 4-aminobenzenesulphonic acid played a vital role in the initial formation process of nuclear crystals but only as a structural induction agent, which modulated the dimensionality of these Mg2+-based CPs. Additionally, the three CPs emitted bright blue luminescence at ambient conditions, and the emission lifetimes and absolute quantum yields were also investigated.Crystal structure diversity and dimensionality of three Mg2+-based CPs, which emit bright ligand-based luminescence at ambient conditions, are modulated by reaction temperature and structural induction agents. 相似文献
2.
High temperature oxide melt solution calorimetry studies on (M′ = Nb5+, M′′ = Mn3+ and Fe3+ and x = 0.20, 0.30 and 0.40) oxides and a new family of Ta containing Li excess disordered cathode materials, (M′ = Ta5+, M′′ = Fe3+ and x = 0.20, 0.30 and 0.40), synthesized by a rapid quenching method, are reported in this study. The enthalpies of formation determined from high temperature calorimetry studies reveal that the stability of compounds increases with the increasing Li content per formula unit. The reaction between more basic Li2O and acidic transition metal oxides results in the more negative enthalpies of formation for these compounds. The work reveals that the formation enthalpy term plays a more important role in the stabilization of such disordered Li ion materials at room temperature whereas configurational entropy along with lattice entropy (vibrational and magnetic) contributes to the stabilization at high temperature from which the samples are quenched.Enthalpies of formation from oxides (ΔHf,ox) of novel disordered Li1+xTaxFe1−2xO2 and reported (M′′ = Mn3+ and Fe3+). 相似文献
3.
2,2′,2′′,4,4′,4′′,6,6′,6′′-Nonanitro-1,1′:3′,1′′-terphenyl (NONA) is currently recognized as an excellent heat-resistant explosive. To improve the atomistic understanding of the thermal decomposition paths of NONA, we performed a series of reactive force field (ReaxFF) molecular dynamics simulations under extreme conditions of temperature and pressure. The results show that two distinct initial decomposition mechanisms are the homolytic cleavage of the C–NO2 bond and nitro–nitrite (NO2 → ONO) isomerization followed by NO fission. Bimolecular and fused ring compounds are found in the subsequent decomposition of NONA. The product identification analysis under finite time steps showed that the gaseous products are CO2, N2, and H2O. The amount of CO2 is energetically more favorable for the system at high temperature or low density. The carbon-containing clusters are a favorable growth pathway at low temperatures, and this process was further demonstrated by the analysis of diffusion coefficients. The increase of the crystal density accelerates the decomposition of NONA judged by the analysis of reaction kinetic parameters and activation barriers. In the endothermic and exothermic stages, a 20% increase in NONA density increases the activation energies by 3.24 and 0.48 kcal mol−1, respectively. The values of activation energies (49.34–49.82 kcal mol−1) agree with the experimental data in the initial decomposition stage.The bimolecular and fused ring compounds are found in the high-temperature pyrolysis of NONA using ReaxFF molecular dynamics simulations. 相似文献
4.
Grzegorz Lisak Klaudia Wagner Jonathan E. Barnsley Andrei Veksha Gregory Huff Anastasia B. S. Elliott Pawe Wagner Keith C. Gordon Johan Bobacka Gordon G. Wallace Ari Ivaska David L. Officer 《RSC advances》2018,8(52):29505
We present a simple and effective way of using metal and metal–ligand modifications to tune the electrochemical and optical properties of conducting polymers. To that end, a polyterthiophene functionalized with terpyridine moieties was synthesized and then the resulting film''s surface or bulk was modified with different metal ions, namely Fe2+, Zn2+ and Cu2+ and terpyridine. The modification of the terpyridine functionalized polyterthiophene film by Fe2+ increased the absorptivity and electrochemical capacitance of the conducting polymer, and improved its conjugation. Further modification by Zn2+ and Cu2+ resulted in dramatically different spectroelectrochemical properties of the film. Moreover, the influence of the solvents (ACN and 1 : 1 ACN : H2O) in conjunction with the metal ion applied for the modification was found crucial for the electrochemical and optical properties of the films.We present a simple and effective way of using metal and metal–ligand modifications to tune the electrochemical and optical properties of conducting polymers. 相似文献
5.
Fabien Silly 《RSC advances》2020,10(10):5742
Star-shaped 2,4,6-tris(4′,4′′,4′′′-trimethylphenyl)-1,3,5-triazine molecules self-assemble at the solid–liquid interface into a compact hexagonal nanoarchitecture on graphite. High resolution scanning tunneling microscopy (STM) images of the molecules reveal intramolecular features. Comparison of the experimental data with calculated molecular charge density contours shows that the molecular features in the STM images correspond to molecular LUMO+2.Intramolecular contrast in the STM images of 2,4,6-tris(4′,4′′,4′′′-trimethylphenyl)-1,3,5-triazine molecules recorded at room-temperature and at the liquid–solid interface. 相似文献
6.
Nusaybah Alotaibi Hassan H. Hammud Ranjith Kumar Karnati Syed Ghazanfar Hussain Javed Mazher Thirumurugan Prakasam 《RSC advances》2020,10(30):17660
Recently, carbon nanostructures have attracted interest because of their unique properties and interesting applications. Here, CoC@SiO2-850 (3) and CoC@SiO2-600 (4) cobalt–carbon/silica nanocomposites were prepared by solid-state pyrolysis of anthracene with Co(tph)(2,2′-bipy)·4H2O (1) complex in the presence of silica at 850 and 600 °C, respectively, where 2,2′-bipy is 2,2′-bipyridine and tph is the terephthalate dianion. Moreover, Co(μ-tph)(2,2′-bipy) (2) was isolated and its X-ray structure indicated that cobalt(ii) has a distorted trigonal prismatic coordination geometry. 2 is a metal–organic framework consisting of one-dimensional zigzag chains within a porous grid network. 3 and 4 consist of cobalt(0)/cobalt oxide nanoparticles with a graphitic shell and carbon nanotubes embedded in the silica matrix. They were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS revealed that the nanocomposites are functionalized with oxygen-containing groups, such as carboxylic acid groups. In addition, the presence of metallic cobalt nanoparticles embedded in graphitized carbon was verified by XRD and TEM. The efficiency of 3 for adsorption of crystal violet (CV) dye was investigated by batch and column experiments. At 25 °C, the Langmuir adsorption capacity of 3 for CV was 214.2 mg g−1 and the fixed-bed column capacity was 36.3 mg g−1. The adsorption data were well fitted by the Freundlich isotherm and pseudo-second-order kinetic model. The adsorption process was spontaneous and endothermic.A cobalt–carbon@silica nanocomposite was synthesized from a cobalt 2,2′-bipyridine terephthalate complex and its adsorption behavior towards crystal violet dye was tested using batch and column techniques. 相似文献
7.
Mengting Liu Qun Zhou Jianping Wang Junjun Liu Changxing Qi Yongji Lai Hucheng Zhu Yongbo Xue Zhengxi Hu Yonghui Zhang 《RSC advances》2018,8(23):13040
Chemical investigation of the coral-derived fungus Aspergillus terreus led to the discovery of ten butenolide derivatives (1–10), including four new ones (1–4). The new structures were characterized on the basis of comprehensive spectroscopic analysis, including 1D and 2D NMR and HRESIMS data. Compounds 1 and 2 were a pair of rare C-8′′ epimers with vicinal diol motifs. The absolute configurations of 1–4 were determined via [Mo2(AcO)4] induced circular dichroism (ICD) spectra and comparison of their experimental ECD spectra. Importantly, the structures of reported aspernolides D and G, butyrolactone VI and 4′,8′′-diacetoxy butyrolactone VI have been correspondingly revised via a combined strategy of experimental validations, 13C NMR predictions by ACD/Labs software, and 13C NMR calculations. Herein we provide valuable referenced 13C NMR data (C-7′′, C-8′′, and C-9′′) for the structure elucidations of butenolide derivatives with 1-(2-hydroxyphenyl)-3-methylbutane-2,3-diol, 2-(2,3-dihydrobenzofuran-2-yl)propan-2-ol, or 2,2-dimethylchroman-3-ol motifs. Additionally, all the isolates (1–10) were assessed for anti-inflammatory activity by measuring the amount of NO production in lipopolysaccharide (LPS)-induced RAW 264.7 mouse macrophages, and compound 10 showed an even stronger inhibitory effect than the postive control indomethacin, presenting it as a promising lead compound for the development of new anti-inflammatory agents.Chemical investigation of the coral-derived fungus Aspergillus terreus led to the discovery of ten butenolide derivatives (1–10), including four new ones (1–4). 相似文献
8.
M. Adel Youssef Siva S. Panda Riham A. El-Shiekh ElSayed M. Shalaby Dalia R. Aboshouk Walid Fayad Nehmedo G. Fawzy Adel S. Girgis 《RSC advances》2020,10(37):21830
A set of dispiro[indoline-3,2′-pyrrolidine-3′,3′′-pyrrolidines] 8a–l was regioselectively synthesized utilizing multi-component azomethine cycloaddition reaction of 3-(arylmethylidene)pyrrolidine-2,5-diones 5a–e, isatins 6a–c and sarcosine 7. Single crystal X-ray studies of 8c add conclusive support for the structure. Compounds 8e and 8g reveal cholinesterase inhibitory properties with promising efficacy against both AChE and BChE and were found to be more selective towards AChE than BChE as indicted by the selectivity index like Donepezil (a clinically used cholinesterase inhibitory drug). Molecular modeling studies assist in understanding the bio-observations and identifying the responsible parameters behind biological properties.Dispiro[indoline-3,2′-pyrrolidine-3′,3′′-pyrrolidines] were regioselectively synthesized revealing cholinesterase (AChE, BChE) inhibitory properties. 相似文献
9.
Core–shell magnetic Fe3O4@PVBC–TMT (Fe3O4@polyvinylbenzyl chloride–trithiocyanuric acid) nanoparticles containing trithiocyanuric acid groups were fabricated and employed for the fast removal of heavy metals from an aquatic environment. The morphology, structure and properties of Fe3O4@PVBC–TMT nanoparticles were characterized by a series of modern analytical tools. The adsorption behavior of the Fe3O4@PVBC–TMT nanoparticles for heavy metals ions in aqueous solutions was investigated by batch experiments. The maximum removal capacities of the Fe3O4@PVBC–TMT nanoparticles toward Mn2+, Ni2+, Cu2+, Cd2+ and Pb2+ ions were 127.4, 146.6, 180.5, 311.5, and 528.8 mg g−1, respectively. Importantly, it is found that Pb2+ ions can be completely and quickly removed by the Fe3O4@PVBC–TMT nanoparticles. The equilibrium was established within 6 min, and the removal efficiencies were found to be 99.9%, 99.8% and 99.5% for Pb2+ ions at the initial concentrations of 100 mg L−1, 200 mg L−1 and 300 mg L−1, respectively. It is hoped that the core–shell magnetic Fe3O4@PVBC–TMT nanoparticles may find application in wastewater treatment.Core–shell Fe3O4@PVBC–TMT nanoparticles were fabricated and served as a valid magnetic adsorbent for the removal of heavy metals ions. 相似文献
10.
Yelei Gong Hao Li Wenle Pei Jincheng Fan Ahmad Umar M. S. Al-Assiri Yao Wang Nicolaas Frans de Rooij Guofu Zhou 《RSC advances》2019,9(52):30432
In this study, a graphene-based composite 4HQ-rGO/Cu2+ was prepared via the supramolecular assembly of graphene nanosheets with 4-hydroxyquinoline (4HQ) and copper(ii) ions. The as-prepared supramolecular assembly exhibited an excellent and enhanced sensing performance towards acetic acid at room-temperature, which was due to the fact that the D–π–A molecules, i.e. 4HQ, were able to accelerate the charge transfer between the graphene nanosheets and 4HQ molecules when acetic acid was attached. In addition, at room temperature, the copper(ii) ions also played a critical role as the main active site for gas adsorption, and thus the as-fabricated sensor exhibited a high response, outstanding selectivity, and ultra-fast response/recovery time. To examine the selectivity of the Cu2+ ions for the supramolecular assembly, various other transition metal ions such as Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Cd2+ were attached to the 4HQ-rGO assembly, and their acetic sensing performance was determined. Interestingly, the supramolecular assembly with the Cu2+ ions (4HQ-rGO/Cu2+) exhibited the best sensing performance compared to other metal ion-based 4HQ-rGO materials. Compared with the typical acetic acid gas sensors reported in the literature, it is noteworthy to mention that the as-prepared 4HQ-rGO/Cu2+ supramolecular assembly exhibited the shortest gas response time (within 5 s) at room temperature. The presented study demonstrates that the as-prepared supramolecular assembly is a promising material as a room temperature acetic acid gas sensor in practical applications.The as-prepared 4HQ-rGO/Cu2+ sensor possessed a high response, outstanding selectivity and fast response-recovery characteristic, which was mainly attributed to the supramolecularly assemble of 4-hydroxyquinoline, and Cu2+ with graphene nanosheets. 相似文献
11.
R. H. Kadam R. B. Borade M. L. Mane D. R. Mane K. M. Batoo Sagar E. Shirsath 《RSC advances》2020,10(47):27911
Sol–gel-synthesized Co–Cu–Zn ferrite nanoparticles diluted with Dy3+ ions were investigated in terms of their structural, morphological, elastic, magnetic and dielectric properties. X-ray diffraction patterns showed the formation of a single-phase cubic spinel structure. As the concentration of Dy3+ ions was increased, the lattice length gradually increased from 8.340 to 8.545 Å, obeying Vegard''s law. The Williamson–Hall (W–H) method was employed to observe the change in the lattice strain. Crystallite size obtained from W–H plots followed a pattern similar to that observed using the Scherrer equation. The cation distribution suggested a strong preference of Dy3+ ions for the octahedral B site while Cu2+ and Fe3+ ions were distributed over both A and B sites. The microstructures of the samples were visualized using transmission electron microscopy. Mechanical properties such as stiffness constant, longitudinal and transverse wave velocities, Young''s modulus, bulk modulus, rigidity modulus, Poisson''s ratio and Debye temperature were investigated by acquiring infrared spectra recorded in the range of 300 to 800 cm−1. Replacement of Fe3+ ions with the strongly magnetic Dy3+ ions increased the saturation magnetization and coercivity. Dielectric constant increased with Dy3+ substitution but decreased with applied frequency.Improvement in various properties of Co–Cu–Zn ferrite upon Dy substitution. 相似文献
12.
High-performance energetic materials are mainly used in the military, aerospace industry and chemical fields. The ordinary technology of producing energetic materials cannot avoid the domination of its unique needs. At present, revealing the underlying mechanism of the formation of high-energy materials is of great significance for improving their quality characteristics. We pay special attention to the decomposition and reactive molecular dynamics (RMD) simulation of 5,5′-dinitro-2H,2H′-3,3′-bi-1,2,4-triazole (DNBT). Various forms were captured in the simulation, and the form is determined by the temperature of the initial reactant. By observing the heating pattern and morphological changes under the initial thermal equilibrium, interesting temperature jumps were found in 325 K and 350 K. Observation of continuous heating (simulated temperatures are 2600 K, 2900 K, 3200 K and 3500 K) shows that DNBT has the maximum heating rate at 3500 K. In addition, N2 occupies this dominant position in the product, moreover, N2 and NO2 respectively dominate the gas phase products during the initial heating process. According to the transition state analysis results of the intermediates, we found 4 interesting intermediate products, which were determined by high frequency reaction under the 4 simulated temperatures and performed with transition state calculations. It shows that the selection of reactant temperature and its activity is the key to orderly decomposition of DNBT. It is expected that these findings will be widely used in comprehensive decomposition devices and to improve the concept of learning military and industrial technology.The performance and behavior of DNBT under RMD simulation at high temperature (2600 K, 2900 K, 3200 K and 3500 K).Energetic materials (EMs), such as TNT, RDX, TATB, nitroguanidine and nitro imidazoles, have risen in the scientific community because of their unique properties.1–4 Findings and discoveries of nitro metal salts and high energy density materials (HEDMs) in the early stage has obviously indicated the beginning of the epoch of EMs. The detonation velocity and pressure depend on the material density, with a high energy density trending to increase the explosive capability. Notably, this dinitrotriazoles are the only ones among these energetic materials whose large-scale industrial production has been an accustomed pursuit.5 Research on triazoles with high thermo stabilities reported by Seth and Matzger in 2016 further highlights the high expectations and applications for triazole materials.6 Dinitrotriazoles have been observed and researched as coordination polymerization, water–salts degradation,7 lighting sensor for fluorescent materials8 and energetic nano microcapsules9 successfully, in contrast with the traditional mechanical,10 electronic11 and optical properties,12 moreover, dinitrotriazoles are applied in various fields of material science and technology such as fuel cells13 and catalysts,14etc.5,5′-Dinitro-2H,2H′-3,3′-bi-1,2,4-triazole (DNBT) is a potential explosive that can be synthesized in two steps starting from aminoguanidinium carbonate and oxalic acid. The synthesis strategies of DNBT include conventional ways are evaluable, related report mentioned by the crystallization screening experiment that the water solubility is relatively stable for DNBT under the environment of methyl cyanide (MeCN) with a proportion 1 : 2 and 1 : 1.515.15 DNBT prepared via these techniques is always have a diversity sample such as form of crystal, water activity slurry, crystallization of the initial solvates, non-solvates titration (crystal powder used for catalyst), whatsmore, removing these diversity sample is improved to be a changeable task which can turn on the limitation and potential application of DNBT. Despite that, the investigation of thermal decomposition phenomenon16 is still one of the urgent problems to be solved in the current research for EMs, meanwhile, could be a good solution and approaches for DNBT to reveal the insight of the structure from crystal between the inner-molecule and inter-molecules. Nevertheless, the molecule structure analysis and the response character during the decomposition for reaction of DNBT get fail to obtain more effective results from the reactants and products, more than this, existing experimental methods cannot meet the current needs as dealing with these micro-mechanism issues. Unfortunately, these similar issues begin to need a sufficient discussion and the tow mechanism of hot smoking vapored formation which dominated by the polyyne model17 and energetic ion salt research,18–20 are still debating. To learn and comprehensive mechanisms of rules for decomposition reaction under the consideration of choosing starting temperature and setting reactive condition, shall be helpful and advantageous to produce of DNBT controllably and efficiently.In recent years, many kinetic models and dynamic simulations have been developed to describe the chemical process of thermal degradation for nitro-compound and nitro ion salts, though there will be temperature and pressure enhancement in these simulations, it has been proven extensively that the enhancement will not give rise to any artificial feature.21–25 It''s a common approach of various molecular dynamics (MD) simulation to increase temperature significantly to overcome the limit for time scale. However, these processes are adopted to both comparing and fitting the elementary reactions with experimental observations to determine dominant reaction in the total conversions, and also cannot provide dynamic details of chemical conversion. Reactive force field with lg potential terms (ReaxFF-lg) become one of the opportunities to solve these problems by simulating chemical reactions via reactive molecular dynamics simulation (RMD), which can parsing more details of complicated chemical procedure under a given specific condition as time and space scale, the energy terms component described as eqn (1)–(3), where Ereax is the energy evaluated from the previous ReaxFF,26Elg is the long-range correction using the low-gradients method.27EReax-lg = EReax + Elg1EReax = Ebond + Elp + Eover + Eunder + Eval + Epen + Ecoa + Etors + Econj + EH-bond + EvdW + ECoulomb23The unknown decomposition and degradation mechanism of different nitro-compound push us to extend the previous studies to more intentional reactive behavior for DNBT during analyses performed by combine the results in the micro scale28–31 that gave us a remarkable understanding of the thermal decomposition behavior of DNBT. Moreover, as a classic secondary explosive32–35 and from the perspective of safety, this makes us need to pay more attention to the performance of heating trend. More interesting information has been found. The initial degradation and decomposition accompany with temperature for DNBT undergoes the following stage, (i) selection of the initial thermal equilibrium temperature, (ii) dynamic changes for the potential and temperature of the system during heating process in the high temperature range, (iii) evaluating the generation of product and statistic the high frequency reaction during the decomposition process. Besides that, the transition state calculation and analysis of the electronic structure for the intermediate product in high-frequency decomposition reactions are also been investigated and discussed. 相似文献
13.
ngel L. García Adrin Ochoa-Tern Antonio Tirado-Guízar Jesús Jara-Corts Georgina Pina-Luis Hisila Santacruz Ortega Victoria Labastida-Galvn Mario Ordoez Jorge Pen 《RSC advances》2022,12(10):6192
In this work, both experimental and theoretical methods were used to study the photophysical and metal ion binding properties of a series of new aminobenzamide–aminonaphthalimide (2ABZ–ANAPIM) fluorescent dyads. The 2-aminobenzamide (2ABZ) and 6-aminonaphthalimide (ANAPIM) fluorophores were linked through alkyl chains (C2 to C6) to obtain four fluorescent dyads. These dyads present a highly efficient (0.61 to 0.98) Förster Resonant Energy Transfer (FRET) from the 2ABZ to the ANAPIM due to the 2ABZ emission and ANAPIM excitation band overlap and the configurational stacking of both aromatic systems which allows the energy transfer. These dyads interact with Cu2+ and Hg2+ metal ions in solution inhibiting the FRET mechanism by the cooperative coordination of both 2ABZ and ANAPIM moieties. Both experimental and theoretical results are consistent and describe clearly the photophysical and coordination properties of these new dyads.The aminobenzamide–aminonaphthalimide fluorescent dyads allow the determination of Cu2+ and Hg2+ metal ion concentration from Förster Resonant Energy Transfer measurements. 相似文献
14.
Nopawit Khamto Lada Chaichuang Puracheth Rithchumpon Worrapong Phupong Phuangthip Bhoopong Suriya Tateing Wilart Pompimon Natthawat Semakul Ni-orn Chomsri Puttinan Meepowpan 《RSC advances》2021,11(50):31433
2′,4′-Dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (DMC, 1) was isolated from seeds of Syzygium nervosum A.Cunn. ex DC. exhibiting intriguing biological activities. Herein, thirty three DMC derivatives including 4′-O-monosubstituted-DMC (2), 7-O-acylated-4-hydroxycoumarin derivatives (3), stilbene–coumarin derivatives (4), 2′,4′-disubstituted-DMC (5), and flavanone derivatives (6), were synthesised through acylation, alkylations, and sulfonylation. These semi-synthetic DMC derivatives were evaluated for in vitro cytotoxicity against six carcinoma cell lines. It was found that most derivatives exhibited higher cytotoxicity than DMC. In particular, 4′-O-caproylated-DMC (2b) and 4′-O-methylated-DMC (2g) displayed the strongest cytotoxicity against SH-SY5Y with IC50 values of 5.20 and 7.52 μM, respectively. Additionally, 4′-O-benzylated-DMC (2h) demonstrated the strongest cytotoxicity against A-549 and FaDu with IC50 values of 9.99 and 13.98 μM, respectively. Our structure–activity relationship (SAR) highlights the importance of 2′-OH and the derivatisation pattern of 4′-OH. Furthermore, molecular docking simulation studies shed further light on how these bioactive compounds interact with cyclin-dependent kinase 2 (CDK2).Semi-synthetic DMC derivatives were synthesised and displayed biological potency against various cancer cell lines. 相似文献
15.
Green-emitting carbon quantum dots (G-CQDs) were prepared using tartaric acid and bran by one-pot solvothermal treatment and had photoluminescence quantum yields (PL QY) as high as 46%. The morphology of the G-CQDs is characterized by TEM, which shows the average diameter of G-CQDs is approximately ∼4.85 nm. The FT-IR spectra display the presence of –OH, C–N, N–H and –COOH on the surface of the G-CQDs. The emission wavelength of the G-CQDs was ∼539 nm in the case of ∼450 nm excitation wavelength, which corresponds to the green fluorescence. Furthermore, the G-CQDs were used as a fluorescent probe for detection Cu2+ ions, and demonstrated a linear distribution between ln(F/F0) and the Cu2+ ions concentration. Specifically, the Cu2+ ion concentration should fall in the G-CQD concentration range of 0–0.5 mM and the detection limit is 0.0507 μM. Thus, due to the excellent chemical stability and good luminescence performance, these G-CQDs could be excellent probes widely used in detection fields.Green-emitting carbon quantum dots (G-CQDs) were prepared using tartaric acid and bran by one-pot solvothermal treatment and had photoluminescence quantum yields (PL QY) as high as 46%. 相似文献
16.
Alexander V. Finko Anatolii I. Sokolov Dmitry A. Guk Victor A. Tafeenko Anna A. Moiseeva Dmitry A. Skvortsov Andrei A. Stomakhin Andrei A. Beloglazkin Roman S. Borisov Vladimir I. Pergushov Mikhail Ya. Melnikov Nikolay V. Zyk Alexander G. Majouga Elena K. Beloglazkina 《RSC advances》2022,12(12):7133
A series of new organic ligands (5Z,5Z′)-2,2′-(alkane-α,ω-diyldiselenyl)-bis-5-(2-pyridylmethylene)-3,5-dihydro-4H-imidazol-4-ones (L) consisting of two 5-(2-pyridylmethylene)-3,5-dihydro-4H-imidazol-4-one units linked with polymethylene chains of various lengths (n = 2–10, where n is the number of CH2 units) have been synthesized. The reactions of these ligands with CuCl2·2H2O and CuClO4·6H2O gave Cu2+ or Cu1+ containing mono- and binuclear complexes with Cu2LClx (x = 2–4) or CuL(ClO4)y (y = 1, 2) composition. It was shown that the agents reducing Cu2+ to Cu1+ in the course of complex formation can be both a ligand and an organic solvent in which the reaction is carried out. This fundamentally distinguishes the selenium-containing ligands L from their previously described sulfur analogs, which by themselves are not capable of reducing Cu2+ during complexation under the same conditions. A higher cytotoxicity and reasonable selectivity to cancer cell lines for synthesized complexes of selenium-containing ligands was shown; unlike sulfur analogs, ligands L themselves demonstrate a high cytotoxicity, comparable in some cases to the toxicity of copper-containing complexes.Mono- and binuclear Cu(+1/+2) complexes of bis-5-(2-pyridyimethylene)-2-selenohydantoins were obtained by the reactions of corresponding ligands with copper(+2) chloride or perchlorate in BuOH/DCM mixtures. 相似文献
17.
Ewa Radzikowska Renata Kaczmarek Dariusz Korczyski Agnieszka Krakowiak Barbara Mikoajczyk Janina Baraniak Piotr Guga Kraig A. Wheeler Tomasz Pawlak Barbara Nawrot 《RSC advances》2020,10(58):35185
3′-N-(2-Thio-1,3,2-oxathiaphospholane) derivatives of 5′-O-DMT-3′-amino-2′,3′-dideoxy-ribonucleosides (NOTP-N), that bear a 4,4-unsubstituted, 4,4-dimethyl, or 4,4-pentamethylene substituted oxathiaphospholane ring, were synthesized. Within these three series, NOTP-N differed by canonical nucleobases (i.e., AdeBz, CytBz, GuaiBu, or Thy). The monomers were chromatographically separated into P-diastereomers, which were further used to prepare NNPSN′ dinucleotides (3), as well as short P-stereodefined oligo(deoxyribonucleoside N3′→O5′ phosphoramidothioate)s (NPS-) and chimeric NPS/PO- and NPS/PS-oligomers. The condensation reaction for NOTP-N monomers was found to be 5–6 times slower than the analogous OTP derivatives. When the 5′-end nucleoside of a growing oligomer adopts a C3′-endo conformation, a conformational ‘clash’ with the incoming NOTP-N monomer takes place, which is a main factor decreasing the repetitive yield of chain elongation. Although both isomers of NNPSN′ were digested by the HINT1 phosphoramidase enzyme, the isomers hydrolyzed at a faster rate were tentatively assigned the RP absolute configuration. This assignment is supported by X-ray analysis of the protected dinucleotide DMTdGiBuNPSMeTOAc, which is P-stereoequivalent to the hydrolyzed faster P-diastereomer of dGNPST.Separated P-diastereomers of 3′-N-(2-thio-1,3,2-oxathiaphospholane) derivatives of 5′-O-DMT-3′-amino-2′,3′-dideoxy-ribonucleosides were used to prepare P-stereodefined NNPSN′ dinucleotides and short NPS-, NPS/PO- and NPS/PS-oligomers. 相似文献
18.
Sanil Rajak Olivier Schott Prabhjyot Kaur Thierry Maris Garry S. Hanan Adam Duong 《RSC advances》2019,9(48):28153
The synthetic difficulties associated with quaterpyridine (qtpy) complexes have limited their use in the formation of various metallosupramolecular architectures in spite of their diverse structural and physicochemical properties. Providing a new facile synthetic route to the synthesis of functionalised qtpy mimics, we herein report the synthesis of three novel –NH2 functionalized qtpy-like complexes 12–14 with the general formula M(C16H14N12)(NO3)2 (M = Co(ii), Ni(ii) and Cu(ii)) in high yield and purity. Characterization of these complexes has been done by single crystal X-ray diffraction (SCXRD), thermogravimetric analysis, UV-Vis, infrared, mass spectrometry and cyclic voltammetry. As indicated by SCXRD, in all the synthesized complexes, the metal ions show a strongly distorted octahedral coordination geometry and typical hydrogen bonding networks involving DAT groups. In addition, complexes 12–14 have been analyzed as potential photocatalysts for hydrogen evolution reaction (HER) displaying good turnover numbers (TONs). Hydrogen produced from these photocatalysts can serve as the possible alternative for fossil fuels. To the best of our knowledge, this is the only study showcasing –NH2 functionalized qtpy-like complexes of Co(ii), Ni(ii) and Cu(ii) and employing them as photocatalysts for HER. Thus, a single proposed strategy solves two purposes-one related to synthesis while second is related to our environment.Facile synthesis of three novel –NH2 functionalized qtpy-like complexes, their characterizations and study of their photocatalytic properties for hydrogen evolution reaction. 相似文献
19.
Electrochemical reactions in electrospray may affect the electrospray ionization mass spectrometry (ESI-MS) detection of the analytes. During ESI-MS analysis of 2,3′-bisindolylmethanes in the positive-ion mode, when methanol or acetonitrile was used as the solvent, electrochemical oxidation products as the dehydro and radical cations were observed. Lower sample introduction rates tended to result in a higher oxidation ratio of 2,3′-bisindolylmethanes. The ESI-MS experiments of 2,3′-bisindolylmethanes in different acetonitrile/methanol solvent mixtures indicated that abundant H+, Na+ or K+ would facilitate the adduct formation process, and otherwise electrochemical oxidation dominated the ionization process. Additionally, when dichloromethane was used as the solvent, [M − 3H]+, [M − 2H]+˙ and [M − 3H + O]+ ions are the predominant ions, and the experimental results revealed that the dehydrogenation and oxidative dehydrogenation reactions of 2,3′-bisindolylmethanes in dichloromethane are electrochemical reactions.The electrochemical oxidation reactions of 2,3′-bisindolylmethanes were affected by the solvent in the positive-ion electrospray ionization mass spectrometry (ESI-MS). 相似文献
20.
Xue Han Zhixin Qin Mengyao Zhao Jiajia Song Fei Qu Fengli Qu Rong-Mei Kong 《RSC advances》2018,8(61):34877
The illegal adulteration of melamine in dairy products for false protein content increase is a strong hazard to human health. Herein, a simple and sensitive colorimetric method was developed for the quantification of melamine in dairy products based on a Cu2+-hydrogen peroxide (H2O2)-3,3′,5,5′-tetramethylbenzidine (TMB) system. In this strategy, Cu2+ exhibits peroxidase-like activity and can catalyze the oxidation of TMB to oxidized TMB (oxTMB) in the presence of H2O2 with a blue colour change of the solution. However, the presence of melamine quickly interacts with H2O2 leading to the consumption of H2O2 and thus strongly hinders the oxidation of TMB. Under the optimal conditions, the absorbance change of oxTMB has a linear response to the concentration of melamine from 1 to 100 μM with a detection limit of 0.5 μM for melamine. The proposed method has many merits including more simplicity, good selectivity, and more cost-effectiveness without using any nanomaterials. The method was further successfully applied to detect melamine in dairy products including milk and infant formula powder.Convenient and sensitive colorimetric detection of melamine in dairy products based on a Cu(ii)-H2O2-3,3′,5,5′-tetramethylbenzidine system was reported. 相似文献