Syntheses,structures of N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes and their application as redox sensor for Cu2+ ion

Rigid N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes L1 and L2 were easily synthesized from 1,1 ‐dicarboxyaldehydeferrocene and the corresponding amines. Ligands L1 and L2 were characterized by ¹H NMR, ¹³C NMR and single‐crystal X‐ray crystallography. The coordination abilities of L1 and L2 with metal ions such as Cu²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ were evaluated by cyclic voltammetry. The electrochemical shift (ΔE_1/2) of 125 mV was observed in the presence of Cu²⁺ ion, while no significant shift of the Fc/Fc + couple was observed when Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺, Cd²⁺ metal ions were added to the solution of L1 in the mixture of MeOH and H₂O. Moreover, the extent of the anodic shift of redox potentials was approximately equal to that induced by Cu²⁺ alone when a mixture of Cu²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ was added to a solution of L1. Ligand L1 was proved to selectively sense Cu²⁺ in the presence of large, excessive first‐row transition and late‐transition metal cations. The coordination model was proposed from the results of controlled experiments and quantum calculations. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis,structural characterization,EPR spectroscopy and Hirshfeld surface analysis of a novel Cu2+‐doped 3,14‐diethyl‐2,13‐diaza‐6,17‐diazoniatricyclo[16.4.0.07,12]docosane bis(perchlorate)

Cyclam derivatives and their metal complexes have been found to exhibit an anti‐HIV effect and stimulate the activity of stem cells from bone marrow. The strength of their binding to the CXCR4 receptor correlates with anti‐HIV and stem‐cell activities. Knowledge of the conformation and crystal packing of various macrocyclic metal complexes has become important in developing new effective anti‐HIV drugs. The synthesis and preparation of single crystals of a new Cu²⁺‐doped macrocyclic compound, (3,14‐diethyl‐2,6,13,17‐tetraazatricyclo[16.4.0.0^7,12]docosane)copper(II) bis(perchlorate)–3,14‐diethyl‐2,13‐diaza‐6,17‐diazoniatricyclo[16.4.0.0^7,12]docosane bis(perchlorate) (0.69/0.31), {[Cu(C₂₂H₄₄N₄)](ClO₄)₂}_0.69·(C₂₂H₄₆N₄²⁺·2ClO₄^?)_0.31, is reported. Characterization by X‐ray diffraction analysis shows that the asymmetric unit contains half of a centrosymmetric molecule. The macrocyclic ligand in the compound adopts the most stable trans‐III conformation. The Cu—N distances of 2.015 (3) and 2.047 (3) Å are normal, but the long axial Cu—O bond of 2.795 (3) Å may be due to a combination of the Jahn–Teller effect and the strong in‐plane ligand field. The crystal structure is stabilized by hydrogen bonding between secondary N—H groups, the N atoms of the macrocycle and the O atoms of the perchlorate anions. Hirshfeld surface analysis with 2D (two‐dimensional) fingerprint plots indicates that the main contributions to the crystal packing are from H…H (58.0%) and H…O/O…H (41.9%) interactions. Electron paramagnetic resonance (EPR) properties are also described.     

SnFe2O4 Nanocrystals as Highly Efficient Catalysts for Hydrogen‐Peroxide Sensing

SnFe₂O₄ nanocrystals (NC), prepared with a simple one‐step carrier‐solvent‐assisted interfacial reaction process, were developed as highly efficient catalysts for hydrogen peroxide sensing. These NCs, with a size of around 7 nm, served as the sensing catalyst and were decorated onto the pore surfaces of a porous fluorine‐doped tin oxide (PFTO) host electrode, prepared from commercial FTO glass with a simple anodic treatment, to form the sensing electrode for hydrogen peroxide. The SnFe₂O₄ NCs‐loaded PFTO electrode exhibited an ultra‐high sensitivity of 1027 mA m ^?1 cm^?2 toward hydrogen peroxide, outperforming Pt NCs‐loaded PFTO electrodes. The SnFe₂O₄ NCs‐loaded PFTO electrode proved a promising relatively low cost, high performance sensing electrode for hydrogen peroxide.     

A Sensitive Biosensor for Determination of Cu2+ by One‐step Electrodeposition

A simple one‐step electrodeposition method is described to fabricate three dimensional ordered macroporous chitosan?prussian blue?single walled carbon nanotubes (3DOM CS?PB?SWCNTs) film onto the gold electrode surface to fabricate a copper ions (Cu²⁺)‐specific DNAzyme biosensor. The new sensing strategy for sensitive and selective detection of Cu²⁺ was based on Au nanorods (AuNRs) as signal amplification labels. The electrochemical signal of glucose increased with the concentration of Cu²⁺ increasing. The morphologies and electrochemistry of the composites were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical techniques including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and so on. Linear correlations of copper ion concentration were obtained in the range from 10^?18 M to 10^?5 M, achieving with a limit of detection of 10^?19 M (S/N=3). Parameters affecting the biosensor response such as temperature, the cleavage time and the time of hybridization were optimized. This biosensor showed a wide range, low detection limit, good reproducibility and high stability. Additionally, these striking properties endow the biosensor with a great promise for analytical applications.     

Application of Luminescent BSA‐Capped CdS Quantum Dots as a Fluorescence Probe for the Detection of Cu2+

CdS Quantum dots (QDs) are synthesized in aqueous solution with bovine serum albumin (BSA) as the stabilizing agents using a stepwise procedure at room temperature. They can be used as a new fluorescence probe in the determination of Cu²⁺, which is proved to be a simple, rapid and specific method. Approximate concentrations of other physiologically important cations, such as Zn²⁺, K⁺ etc, have no effect on the fluorescence. Under the optimum condition, the response is linear to the concentration of Cu²⁺ in the range of 0‐80.0 μol/L, and the detection limit is 50.0 nmol/L. This method is used to the determination of Cu²⁺ in human hair, the recovery is 98‐104%. And the possible detection mechanism is also discussed.     

Water‐Soluble Luminescent Hybrid Composites Consisting of Oligosilsesquioxanes and Lanthanide Complexes and their Sensing Ability for Cu2+

Water‐soluble hybrid composites with great potential for selective and sensitive sensing and that are obtained through simple, rapid, and environmentally friendly methods are highly desirable and remain a challenging task. Herein, we present luminescent hybrid composites that were realized by linking Na₃[Ln(dpa)₃] (dpa=2,6‐pyridinedicarboxylic acid) to octa‐amino functionalized polyhedral oligomeric silsesquioxane (POSS‐NH₂) through hydrogen‐bonding interactions between the oxygen atoms of the carboxylate groups of dpa and the hydrogen‐bond‐donor amino groups. The resulting hybrid composites Ln(dpa)₃@POSS‐NH₂ are highly soluble in aqueous solutions and the quantum yield of Eu(dpa)₃@POSS‐NH₂ is as high as 56.5 % or 46.3 % in the solid state and in aqueous solution, respectively, as determined by using the integrating sphere method. The novel water‐soluble luminescent hybrid composites exhibit high thermal and photostability, and the emitted colors of the resulting hybrid composite can be finely tuned by changing the Eu³⁺/Tb³⁺ ratio. Interestingly, Eu(dpa)₃@POSS‐NH₂ hybrid composites exhibited an effective switch‐off fluorescence response to Cu²⁺ over other common metal ions in aqueous media.     

新型水溶性中氮茚衍生物的合成及铜离子荧光探针行为

设计合成了2个新型水溶性中氮茚季铵盐化合物4a{氯化2-[N'-(3-氰基-中氮茚-1-甲酰基)肼基]酰乙基-1-吡啶鎓盐}和4b{氯化2-[N'-(3-氰基-中氮茚-1-甲酰基)肼基]酰乙基-1-(2-甲基吡啶)鎓盐},采用红外光谱、核磁共振、质谱和元素分析对其进行了结构表征,并研究了它们的光谱性质.选取Cu2+,Zn2+,Ca2+,Cr3+,Co2+,Al3+,Mn2+,Ni2+,Ba2+,Hg2+,Fe3+,Cd2+,Mg2+,Pb2+,Li+和Ag+等16种常见金属离子,对2个化合物进行了离子识别实验.结果表明,化合物4a和4b在一定浓度范围内对铜离子均具有良好的选择性识别能力,受常见离子干扰小.由于空间位阻的影响,化合物4a具有比4b更高的灵敏性.     

Electrochemical Behaviour Study and Determination of Guanine, 6‐Thioguanine,Acyclovir and Gancyclovir on Fluorine‐doped SnO2 Electrode. Application in Pharmaceutical Preparations

An electroanalytical method using square wave voltammetry (SWV) is proposed for the quantification of Guanine (G), 6‐Thioguanine (TG), Acyclovir (Acy) and Ganciclovir (Gan) in different types of pharmacological samples. In addition, for the first time, a study of the electrochemical behavior (using cyclic voltammetry, CV) of guanine and its pharmacological derivatives on fluoride doped oxide (FTO) electrodes was carried out. The study of CV potential scanning demonstrated the charge transfer process was diffusion controlled and the diffusion coefficient was determined for all the studied products. Besides, electrochemical parameters, such as transfer coefficient, heterogeneous charge transfer constant and the number of electrons transferred (e) were determined namely, 4e for TG and 2e for G, Acy and Gan. SWV studies at pH 4 for G and 2 for TG, Acy and Gan showed linear ranges between 4.0×10⁻⁶ and 40.0×10⁻⁶ mol L⁻¹, with detection limits of 0.91×10⁻⁶ for G, and 1.50×10⁻⁶ for TG, 1.25×10⁻⁶ for Acy and 0.45×10⁻⁶ mol L⁻¹ for Gan. The method presents sensitivity and stability appropriate to be employed in quality control and routine quantification of drugs in pharmaceutical formulations.     

A Highly Selective and Sensitive Fluorescent Probe Recognition for Co2+ in Aqueous Media Based on 8‐Hydroxyquinolin‐2‐carbaldehyde‐2‐pyridylformylhydrazone Derivative

A new (8‐hydroxyquinolin‐2‐yl)methylene picolinohydrazide derivative ( L ) has been successfully synthesized and characterized. The probe L displays high selectivity to Co²⁺ in CH₃CN/HEPES (1:1, Ｖ/Ｖ, 10 mmol·L^?1, pH=7.4) with a fluorescence "ON‐OFF" response. The Co²⁺ ion recognition event possesses some distinct features including rapid response, high selectivity and sensitivity, good anti‐interference ability and being applicable within a wide pH range. Based on job's plot and ESI‐MS studies, the 1:1 binding mode was proposed. The binding constant of L and Co²⁺ is 1.63×10⁸ L·mol^?1 and the detection limit is 1.15 µmol·L^?1. Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co²⁺ in real environment.     

A New Luminescent Ruthenium(II) Polypyridine‐derived Dipicolylamine Complex as a Sensor for Cu2+ Ions

A chemo‐sensor [Ru(bpy)₂(bpy‐DPF)](PF₆)₂ ( 1 ) (bpy=2,2′‐bipyridine, bpy‐DPF=2,2′‐bipyridyl‐4,4′‐bis(N,N‐di(2‐picolyl))formylamide) for Cu²⁺ using di(2‐picolyl)amine (DPA) as the recognition group and a ruthenium(II) complex as the reporting group was synthesized and characterized successfully. It demonstrates a high selectivity and efficient signaling behavior only for Cu²⁺ with obvious red‐shifted MLCT (metal‐to‐ligand charge transfer transitions) absorptions and dramatic fluorescence quenching compared with Zn²⁺ and other metal ions.     

An Electrochemical Sensor for the Detection of Cu2+ Based on Gold Nanoflowers‐modifed Electrode and DNAzyme Functionalized Au@MIL‐101 (Fe)

In this study, we developed an electrochemical sensor for sensitive detection of Cu²⁺ based on gold nanoflowers (AuNFs)‐modified electrode and DNAzyme functionalized Au@MIL‐101(Fe) (MIL: Materials of Institute Lavoisier). The AuNFs‐modified indium tin oxide modified conductive glass electrode(AuNFs/ITO) prepared via electrodeposition showed improved electronic transport properties and provided more active sites to adsorb large amounts of oligonucleotide substrate (DNA1) via thiol‐gold bonds. The stable Au@MIL‐101(Fe) could guarantee the sensitivity because of its intrinsic peroxidase mimic property, while the Cu²⁺‐dependent DNA‐cleaving DNAzyme linked to Au@MIL‐101(Fe) achieved the selectivity toward Cu²⁺. After the DNAzyme substrate strand (DNA2) was cleaved into two parts due to the presence of Cu²⁺, the oligonucleotide fragment linked to MIL‐101(Fe) was able to hybridize with DNA1 adsorbed onto the surface of AuNFs/ITO. Due to the peroxidase‐like catalytic activity of MIL‐101(Fe) and the affinity recognition property of DNAzyme toward Cu²⁺, the electrochemical biosensor showed a sensitive detection range from 0.001 to 100 μM, a detection limit of 0.457 nM and a high selectivity, demonstrating its potential for Cu²⁺ detection in real environmental samples.     

Triphenyltin hydroxide as a precursor for the synthesis of nanosized tin‐doped TiO2 photocatalysts

¹H and ¹¹⁹Sn NMR results indicate that, when Ph₃SnOH is dissolved in CD₂Cl₂, it dehydrates to (Ph₃Sn)₂O, only a small amount of Ph₃SnOH remaining in equilibrium at room temperature. As a result, the reaction of TiCl₄ with Ph₃SnOH in CH₂Cl₂ proceeds via hydrolysis of the halide to precipitate amorphous TiO₂ that contains adsorbed organotin species. Calcination of the amorphous precursor to 723 K yields nanoparticles of tin‐doped TiO₂ photocatalysts, that contain anatase and rutile phases, and may also contain a segregated SnO₂ phase. The reaction conditions that lead to the formation of a SnO₂ phase have been studied and we have found that it is formed when the amorphous precipitate is not thoroughly washed with CH₂Cl₂ or when non‐recrystallized commercial Ph₃SnOH is used as a starting material. The catalysts obtained have a high activity for the photooxidation of toluene in the gas phase. In particular, a material obtained from non‐recrystallized Ph₃SnOH is particularly promising because the toluene photooxidation rate is more than twice as high as when using Degussa P25. Copyright © 2005 John Wiley & Sons, Ltd.     

A Novel Electrochemical Sensor for β2‐Agonists with High Sensitivity and Selectivity Based on Surface Molecularly Imprinted Sol‐gel Doped with Antimony‐Doped Tin Oxide

A novel strategy to improve the sensitivity of molecularly imprinted polymer (MIP) sensors was proposed for the determination of β₂‐agonists. The imprinted sol‐gel film was prepared by mixing silica sol with a functional monomer of antimony‐doped tin oxide (ATO) and a template of β₂‐agonists. ATO, which was embedded in the surface of the molecularly imprinted sol‐gel film, not only provides the excellent conductivity for biosensor but also increases the stability and the surface area of the MIP film. The imprinted sensor was characterised by field emission scanning electron microscope, fourier transform infrared spectroscopy and electrochemical methods. Under the optimal experimental conditions, the peak current was linear with the logarithm of the concentration of clenbuterol (CLB) in the range of 5.5 nM–6.3 µM, and a detection limit of 1.7 nM was obtained. Meanwhile, the electrochemical sensor showed excellent specific recognition of the template molecule among structurally similar coexisting substances. Furthermore, the proposed sensor was satisfactorily applied to determine β₂‐agonists in human serum samples. The good results indicated that highly effective molecularly imprinted sol‐gel films doped with ATO can be employed for other analytes.     

Comparative Studies of Some Novel Cu2+ and Fe3+ Chelates Derived From Tricine (L1) by Single Crystal X‐ray,Spectroscopic and Biological Data: Applications to Investigate Antitumor Activity

Novel Cu ²⁺ and Fe ³⁺ chelates derived from L ¹ were synthesized and characterized by single crystal X‐ray diffraction. The results indicate that the Fe (III) crystal, [Fe(L¹‐H)Cl₂], has an orthorhombic structure of the type pc2b while the dimeric Cu (II) crystal, [Cu(L¹‐H)Cl … ClCu(L¹‐H)], has a monoclinic with space group Cc. X‐ray diffraction and spectroscopic studies revealed that L ¹ acts as monobasic tetradentate with octahedral geometry in Fe (III) crystal while it behaves as dibasic tetradentate with distorted‐octahedral in the Cu (II) crystal. Also, the two chelates were characterized by spectral, magnetic and thermal analyses. DFT parameters were used to prove the liberation of a proton from COOH rather than NH groups. The kinetic and thermodynamic parameters of Fe (III) chelate were determined by Coats‐Redfern and Horowitz‐Metzger methods. Cyclic voltammogram provides information about the oxidation states of Cu (II) and Fe (III) chelates. Antitumor activity against Epitheliod carcinoma (Hela), breast cancer (MCF‐7) and antibacterial activities of chelates were investigated.     

Synthesis of N,N,N-4,4＂-Di-（4-methylphenyl）-2,2＇：6＇,2＂- terpyridine-N,N,N-tris（isothiocyanato） Ruthenium（Ⅱ） and Application to Colorimetric Hg^2＋ Sensor

A terpyridine derivative DPTP [di-（4-methylphenyl）-2,2＇：6＇,2＂-terpyridine] was conveniently synthesized from 2-bromopyridine via halogen-dance reaction, Kharash coupling and Stille coupling reaction. Then its corresponding ruthenium complex Ru-DPTP [N,N,N-4,4＇＇-di-（4-methy,phenyl）-2,2＇：6＇,2＂-terpyridine-N,N,N-tris（is,-thi,cyanat,）- ruthenium（H） ammonium] was obtained and fully characterized by IR, UV-Vis, ESI MS and elemental analysis. The MLCT absorption band of Ru-DPTP was blue-shifted from 570 to 500 nm upon addition of Hg^2＋. Among a series of surveyed metal ions, the complex showed a unique recognition to Hg^2＋, indicating that it can be used as a selective colorimetric sensor for Hg^2＋.     

NaY Zeolite Functionalized by Sulfamic Acid/Cu(OAc)2 as a Novel and Reusable Heterogeneous Hybrid Catalyst in Efficient Synthesis of Bis,Tris, and Tetrakis(indolyl)methanes, 3,4‐Dihydropyrimidin‐2(1H)‐ones,and 2‐Aryl‐1H‐benzothiazoles

An efficient acid‐catalyzed synthesis of some bis, tris, and tetrakis(indolyl)methanes, 3,4‐dihydropyrimidin‐2(1H )‐ones, and 2‐aryl‐1H ‐benzothiazoles is reported using NaY zeolite functionalized by sulfamic acid/Cu(OAc )₂ (NaY zeolite‐NHSO₃H /Cu(OAc )₂) in excellent yield. The heterogeneous catalyst has a simple work‐up procedure and could be recycled and reused for six reaction cycles.     

Mesoporous Molecular Sieve MCM‐41 as a Novel and Efficient Catalyst to Synthesis of 2‐Substituted Benzimidazoles

o‐Phenylenediamine derivatives readily react with benzoyl chloride derivatives in the presence of MCM‐41 as catalyst to yield 2‐substituted benzimidazoles in very good yields.     

[3+2]‐Cycloaddition for Fully Decorated Vinyl‐1,2,3‐Triazoles: Design,Synthesis and Applications

The s mall heterocyclic ring of the 1,2,3‐triazole module is one of the most widely investigated compounds in numerous applications of biological, medicinal, pharmaceutical and materially important molecules. In this regard, a large number of synthetic methodologies and approaches have already been reported to construct such a heterocyclic core structure in a selective manner. However, the vinyl‐substituted 1,2,3‐triazole moiety is another privileged segment in heterocyclic chemistry. The selective introduction of simple vinyl and functionalized vinyl groups onto the three different positions of the 1,2,3‐triazole framework can significantly improve the properties of the molecule. Accordingly, high‐yielding efficient approaches for the selective construction of vinyl‐containing 1,2,3‐triazoles becomes a promising branch of chemistry among practitioners of industry and academia. In this minireview, we have discussed recent advances in the construction of highly selective three different vinyl‐containing 1,2,3‐triazoles. In addition, representative synthetic methodologies and approaches for the corresponding three different classes of vinyl‐1,2,3‐triazoles and their applications have been described as well in this review.     

Highly Selective and Sensitive Membrane Sensors for Copper(II) Ion Based on a New Benzo‐Substituted Macrocyclic Diamide 6,7,8,9,10‐Hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione

Novel PVC membrane (PME) and coated graphite (CGE) Cu²⁺‐selective electrodes based on 5,6,7,8,9,10‐hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione are prepared. The electrodes reveal a Nernstian behavior over wide Cu²⁺ ion concentration ranges (1.0×10^?7–1.0×10^?1 M for PME and 1.0×10^?8–1.0×10^?1 M for CGE) with very low limits of detection (7.8×10^?8 M for PME and 9.1×10^?9 M for CGE). The potentiometric responses are independent of the pH of the test solutions in the pH range 2.7–6.2. The proposed electrodes possess very good selectivities for Cu²⁺ over a wide variety of the cations including alkali, alkaline earth, transitions and heavy metal ions. The practical utility of the proposed electrodes have been demonstrated by their use in the study of interactions between copper ions and human growth hormone (hGH) in biological systems, potentiometric titration of copper with EDTA and determination of copper content of a sheep blood serum sample and some other real samples.