Catching S2− and Cu2+ by a highly sensitive and efficient salamo-like fluorescence-ultraviolet dual channel chemosensor

Abstract

A highly sensitive and efficient fluorescence-ultraviolet dual channel chemical sensor H₂L based on the salamo-like bisoxime (6,6′-dimethoxy-2, 2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol) was synthesized, Cu²⁺ and S^2? ions can be detected respectively. For the identification of metal cations, the Cu²⁺ can quench the fluorescence intensity of probe H₂L at the excitation wavelength of 311?nm, and when the same equivalent of EDTA was added, the fluorescence intensity of L-Cu complex returned to its original intensity practically, completing the fluorescence “OFF-ON-OFF” cycle after adding the same amount of Cu²⁺ again. The mechanism was confirmed by high resolution mass spectrometry, and it was concluded that the probe H₂L and Cu²⁺ formed a complex. For the identification of anions, UV–Vis spectral identification and naked-eye recognition for S^2? were performed. The binding mode of the probe to the sulfur anion and the recognition mechanism were confirmed by ¹H NMR titration. In addition, the probe H₂L showed high selectivity and sensitivity to Cu²⁺ and S^2?, the detection limits of L-Cu and L-S systems toward Cu²⁺ and S^2? are 46 and 25?nM respectively. In terms of application, the content of Cu²⁺and S^2? in different water samples (distilled water, Yellow River water and tap water) with probe H₂L was successfully tested. These results indicated that the probe H₂L can be used as a highly selective and sensitive dual channel sensor to detect both Cu²⁺ and S^2? ions in the environment and biological systems.     

Synthetic and spectroscopic characterization of Rh(I)-( S )-amino acid complexes with diphosphine and triphosphine ligands

Reaction of [Rh(η⁴-cod)(S)-amino-acidato] ((S)-amino acidate?=?(S)-O₂C-CHR-NH₂; cod?=?cycloocta-1,5-diene) with 1,2-bis(diphenylphosphino)ethane (dppe) affords the ionic [Rh(dppe)₂]{(S)-O₂C-CHR-NH₂} (R?=?Me, I; Ph, II) complexes. Reactions with 1,3-bis(diphenylphosphino)propane (dppp) or 2,2,2-tris(diphenylphosphinomethyl)ethane (triphos) give the neutral [Rh(dppp){(S)-O₂C-CHR-NH₂}] (R?=?Me, III; Ph, IV) or [Rh(η²-triphos){(S)-O₂C-CHR-NH₂}] (R?=?Me, V; Ph, VI) complexes. The complexes are characterized by elemental analysis, UV–Vis-, IR-, ¹H/³¹P{¹H} NMR- and mass-spectroscopy. Two molecules of dppe coordinate to the Rh(I) symmetrically by replacing both cod and (S)-amino acidate to give I–II. Only one molecule of dppp (or triphos) coordinate to the Rh(I) asymmetrically by replacing only cod to give III–VI. Two diastereomeric Rh(I)-complexes are present in V and VI. The results further suggest that the ligands are arranged in a distorted square planar geometry around the Rh(I) centre. The use of triphos instead of dppe or dppp yields the same coordination sphere.     

A simple colorimetric chemosensor for relay detection of Cu2+ and S2− in aqueous solution

A simple colorimetric chemosensor 1 was developed for the sequential detection of Cu²⁺ and S^2?. Sensor 1 could rapidly detect Cu²⁺ by an obvious color change from colorless to yellow. The binding mode of 1 to Cu²⁺ was determined to be a 1:1 complexation stoichiometry through Job plot and ESI-mass spectrometry analyses. The sensing mechanism of Cu²⁺ by 1 was proposed by theoretical calculations. Importantly, the detection limit for Cu²⁺ was found to be 0.12 μM, which was much lower than the recommended value (31.5 μM) of the World Health Organization (WHO). Additionally, 1 could detect and quantify Cu²⁺ in real water samples. Moreover, the resulting 1-Cu²⁺ complex could be used as a highly selective colorimetric sensor for S^2? in the presence of various anions without any interference. The detection limit for S^2? was determined to be 1.66 μM, which was much lower than the guideline (14.8 μM) recommended by WHO in fresh water.     

Complexation Thermodynamics of p-tert-Butylcalix[4]arene Derivatives with Light Lanthanoid Nitrates in Acetonitrile

Abstract

Calorimetric titrations have been performed for the first time in anhydrous acetonitrile at 25°C to give the complex stability constant (K _S) and thermodynamic quantities for the complexation of light lanthanoid(III) nitrates (La-Gd) with 5,11,17,23-tetra-tert-butyl-26,28-bis(cyanomethoxy)-25,27-dihydroxy-calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-26, 28-bis(2-aminoethoxy)-25,27-dihydroxycalix[4]arene (2). X-ray crystallographic structures of 1 and 2 were also determined and compared. Possessing the cyanomethoxy and aminoethyl substituents, 1 and 2 displayed strikingly different cation binding abilities and selectivity profiles with much higher K _S values for La³⁺ and Ce³⁺, which may be related to the original structures in the solid state. Thus, the binding profile for 2 showed a rapid decrease in K _S with decreasing ionic diameter from La³⁺ to Pr³⁺ and then became flat up to Gd³⁺, while 1 gave a very flat profile which is superimposable with that for 2 between Pr³⁺-Gd³⁺. Thermodynamically, the complexation is driven absolutely by enthalpy which compensates the entropic loss arising from the structural freezing of the calix[4]arene derivatives upon simultaneous binding of lanthanoid ion by the phenolic oxygen and acetonitrile molecule in the cavity. The general validity and the meaning of the compensative enthalpy-entropy relationship observed are discussed.     

Synthesis and metal-ion binding properties of new N2S4- and N2S5-donor macrocycles

Synthetic procedures for new N₂S₄- and N₂S₅-donor macrocycles (2 and 4) were given. The ligands were prepared by the reaction of NaBH₄ with the appropriate macrocyclic diamide in the presence of boron trifluoride ethyl etherate in dry tetrahydrofuran (THF). Solvent extraction method was used to evaluate metal-ion binding properties of the new ligands. The solvent extraction experiments suggested that the reduced macrocycles have Ag⁺ and Hg²⁺ selectivities compared to Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺, Cu²⁺, Mn²⁺ and Cd²⁺ ions. The extraction constants (log K _ex) and complex compositions were determined for Ag⁺ and Hg²⁺ complex of compound (4).     

Reaction of Zn(II) with a BINOL-amino-acid Schiff base: An unusual off-on-off fluorescence response

An amino-acid based Schiff base (S)-2 is prepared from the condensation of (S)-3,3′-diformyl BINOL (BINOL?=?1,1′-bi-2-naphthol) with l-valine in the presence of tetrabutylammonium hydroxide in methanol. This compound is found to exhibit off-on-off fluorescence response toward Zn²⁺. The spectroscopic studies reveal that (S)-2 reacts with 1 equiv Zn²⁺ to form a dimeric [2+2] complex with greatly enhanced fluorescence. Excess amount of Zn²⁺ might cause dissociation of this dimeric complex to give significantly reduced fluorescence.     

Syntheses,spectroscopy, optical properties,and diastereoselectivity of copper(II)-complexes with chiral aminoalcohol based Schiff bases

Chiral aminoalcohol based Schiff bases (R or S)-2-{(E)-(2-hydroxy-1-phenylethylimino)methyl}phenol and (R/S)-2-{(E)-(2-hydroxy-2-phenylethylimino)methyl}phenol coordinate to copper(II)acetate to give enantiopure Λ/Δ- or Δ/Λ-bis[(R or S)-2-{(E)-(2-hydroxy-1-phenylethylimino)methyl}phenoxide-κ²N,O]copper(II), {Λ/Δ-Cu(R-L1)₂ (1) or Δ/Λ-Cu(S-L1)₂ (2)}, and racemic Δ/Λ- and Λ/Δ-bis[(R/S)-2-{(E)-(2-hydroxy-2-phenylethylimino)methyl}phenoxide-κ²N,O]copper(II), {Δ/Λ- and Λ/Δ-Cu(R/S-L2)₂ (3)}, respectively. The complexes are characterized by elemental analyzes, IR, UV–Vis, polarimetry, circular dichroism (CD), differential scanning calorimeter (DSC), and mass spectroscopy. Polarimetry shows the rotation to the left at ?113.6° (1) and to the right at +106.4^o (2). CD spectra show the expected mirror-image relationship with opposite sign of ellipticity maxima (Δε_max = +0.43 for 1 and ?0.42 M^?1 dm³ cm^?1 for 2 at 638 nm) due to the d-d transitions of the metal ion. CD spectral analyzes further reveal a diastereoselectivity or diastereomeric excess towards Λ-Cu(R-L1)₂ or Δ-Cu(S-L1)₂ configuration for 1 or 2 in solution. Similarly, the enantiomeric pair of Δ-Cu(R-L2)₂ and Λ-Cu(S-L2)₂ configurations (CD inactive) for 3 will be preferred in solution. Electronic spectra in different solvents reveal a negative solvatochromism by shifting absorption maxima of the MLCT band to higher energies in solvents of increasing polarity as well as acceptor number. DSC analyzes show an endothermic peak at 525.5 (1) or 528.7 K (2), corresponding to a thermally induced structural phase transformation from distorted square-planar to regular tetrahedral.     

乳酸类合成子构建的四连接螺旋手性配位聚合物的合成、结构和光催化性质

通过乳酸衍生物和3-溴-4-羟基苯甲酸的组合得到对映体3-溴-4-(((1R)-1-羧基乙基)氧基)苯甲酸(R-H₂bba)和3-溴-4-(((1S)-1-羧基乙基)氧基)苯甲酸(S-H₂bba)。以其为手性合成子在水热条件下分别与1,3-二(吡啶-4-基)丙烷(1,3-dpp)和Ni²⁺反应,构建了对映手性配位聚合物{[Ni(R-bba)(1,3-dpp)(H₂O)_0.5]·1.5H₂O}_n (HU12-R)和{[Ni(S-bba)(1,3-dpp)(H₂O)_0.5]·1.5H₂O}_n (HU12-S)。结构分析揭示HU12-R和HU12-S是具有dia网络特征的三维螺旋骨架。在骨架中,阴离子配体R-bba^2-和S-bba^2-分别与Ni²⁺中心连接在一起围绕2₁螺旋轴得到一对小的对映螺旋链,而1,3-dpp与Ni²⁺中心则围绕4₁螺旋轴构建出另外一对大的对映螺旋链。电化学测试显示HU12-R属n型半导体,具有低阻抗性质,对紫外可见光有很强的吸收能力。进一步光催化实验证实在紫外光照射下所得配合物对染料降解有明显催化效果。     

The Decomposition of Aqueous Dithionite and its reactions with polythionates SnO2−6 (n = 3–5) studied by ion-pair chromatography

Aqueous dithionite decomposes at 20°C and pH values not far from 7.0 to give thiosulfate and sulfite from which trithionate may form. Addition of thiosulfate accelerates this reaction only at pH < 6. The pH dependence is explained by formation of HS₂O₃^? ions which are reduced by dithionite to HS^? and SO^2?₃. Sulfide destroys dithionite by nucleophilic cleavage, probably with formation of sulfoxylate and thiosulfite ions. The polythionates S_nO^2?₆ (n = 3–5) are reduced by dithionite at pH = 7.0 and 20°C according to S_nO^2?₆ + S₂O^2?₄ + 2 H₂O→S₂O₃^2? + S_n–3SO₃^2? + 4H¹ + 2SO₃^2? The reaction rate rapidly increases with the number n of sulfur atoms. In secondary reactions sulfite attacks S_nO₆^2? ions with thiosulfate formation.     

Synthetic Ionophores. Part 20: Synthesis and Ionophore Character of 2-Aminothiophenol and 1,3-/1,4-Phenylene Based Silver Selective Receptors

Nucleophilic displacements of 1,3- and 1,4-bis(bromomethyl)benzenes with 2-aminothiophenol provide 1,3- and 1,4- bis(2-aminophenylthiomethyl)benzenes 3 and 11 which undergo intermolecular cyclodehydrochlorination with thiodiglycolyl dichloride and isophthaloyl dichloride to give respectively 6, 8 and 12,13. The diamine 3 and its N,N'-dibenzyl derivative 4 with pyridine-2,6-dicarbonyl dichloride give 7 and 5, respectively. The extraction and transport behaviour of these receptors have been determined towards alkali (Li⁺, Na⁺, K⁺),alkaline earth (Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺), Tl⁺, Ag⁺ and Pb²⁺ picrates.The participation of various ligating sites in binding have been evaluated through ¹³ NMR studies. The acyclic receptors 3, 4 and 11 show higher Ag⁺ selectivity than the cyclic analogs 6 and 12. In the case of acyclic receptor 3 the organisation induced by the 1,3-phenylene spacer and 2-aminophenylthio units and its flexibility generates optimal binding and selectivity towards Ag⁺. However, in cyclicreceptors 3 and 12 though the three thioether unitsare better organised, the inward placement of the NH_amide units restricts the entry of Ag⁺ into the cavity and lowers both the order of binding and selectivity. The lack of binding ability in 7due to an intramolecular NH_amide–-N_py H-bond isrestored in the N-benzyl derivative 5.     

贫电子环丙烷衍生物与2-巯基苯骈噻唑的反应研究

贫电子环丙烷衍生物1以精制四氢呋喃为溶剂, 与2-巯基苯骈噻唑(2)封管加热反应, 得到产物3和4. 产物3经IR, MS, ¹H NMR, ¹³C NMR和元素分析等数据确定其结构为: (R)-β-取代-(R)-γ-(2-巯基)苯骈噻唑基-γ-对位取代苯基丁酸或(S)-β-取代-(S)-γ-(2-巯基)苯骈噻唑基-γ-对位取代苯基丁酸(3); 产物4通过IR, MS, ¹H NMR, ¹³C NMR, 2D-NOESY谱和元素分析等数据确定其结构为: 反式-β-取代-γ-对位取代苯基-3-丁烯酸(4). 对生成产物的机理也进行了推测.     

N/S- und As/S-verbrückte [3]- und [5]-Ferrocenophane

Zusammenfassung Es wurden neue heterocyclische Ferrocenophane isoliert. 1,1-Dilithioferrocen reagiert mit den elektronenreichen Heterocyclen S₄N₄ und As₄S₄ zu 1,3-Dithia-2-aza[3]ferrocenophan (1) bzw. 1,5-Diarsa-2,3,4-trithia[5]ferrocenophan (2). Beide Verbindungen wurden mittels¹H- und¹³C-NMR-Spektroskopie, EI-Massenspektroskopie und CV-Messungen charakterisiert. Die Hauptprodukte aller Reaktionen sind Oligomere und Polymere.

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N/S- and As/S-bridged [3]- and [5]-ferrocenophanes

Summary New heterocyclic ferrocenophanes have been isolated. 1,1-Dilithioferrocene reacts with the electron rich heterocycles S₄N₄ and As₄S₄ to give 1, 3-dithia-2-aza[3]ferrocenophane (1) and 1,5-diarsa-2,3,4-trithia[5]ferrocenophane (2), respectively. Both compounds were characterized by¹H and¹³C NMR spectroscopy as well as by EI mass spectrometry and CV measurements. The main products of all reactions were oligomers and polymers.

     

Determination of Inorganic and Organic Thiophosphates with Ion-Selective Membrane Electrodes

Abstract

The conditions for the determination of sodium thiophosphate and sodium S-(2-amino-ethyl)-thiophos-phate in the presence of phosphate ion using ion-selective membrane electrodes are described. Both thiophosphates (inorganic and organic) are hydrolyzed in acidic medium. The phosphate ion is determined with Pb(II) using a Pb²⁺ – selective membrane electrode.

Cysteamine is determined by potentiometric titration with Hg(I1) using a Ag⁺/S^2? – crystal membrane electrode or by direct potentiometry with a Cu²⁺ selective membrane electrode. The results were verified by the iodination method.     

Synthesis of a chiral rod-like metal–organic framework from a preformed amino acid-based hexanuclear wheel

Abstract

We report the two-step synthesis of a chiral rod-like metal-organic framework (MOF). The chemical approach consists on the use of a previously prepared oxamato-based homochiral hexanuclear wheel, the ligand being a derivative of the natural amino acid l-alanine, with formula (Me₄N)₆{Cu^II₆[(S)-alama])₆}·10H₂O (1) [where (S)-alama=(S)-N-(ethyl oxoacetate)alanine]. The anionic hexacopper(II) wheels, stabilized by the presence of templating tetramethylammonium counter-cations, disassemble in the presence of cationic square-planar [Ni(cyclam)]²⁺ complexes to yield, after a supramolecular reorganization process that involves axial coordination of the [Ni(cyclam)]²⁺ cations through the free carbonyl groups of the copper(II) moieties, a neutral chiral rod-like, three-dimensional (3D) MOF with formula [Ni(cyclam)][Cu(S)-alama]₂·16H₂O (2). The resulting MOF constitutes one of the few examples where such a high-nuclearity metal complex is used as precursor for the construction of rod-like MOFs.     

Concave Reagents 25: Transition Metal Complexes of Concave 1,10-Phenanthrolines as Catalysts for [4 + 2]-Cycloadditions. Ligand Effects on the Exo/Endo-Selectivity

Abstract

Acryloyl pyrazoles 5 undergo cycloaddition with cyclopentadienes 6 to give new norbornenes 7 if the reaction is catalyzed by transition metal ions like Co²⁺ or Ni²⁺. The exo/endo-selectivity can be shifted towards exo by supramolecular control of the transition state using (concave) 1,10-phenanthrolines 1 or 2 as ligands. The products have been fully characterized.     

The Reactions of Sulfur,Selenium and Tellurium with Fluorosulfuric Acid

Abstract

In fluorosulfuric acid, four different sulfur species: S₂ ⁺., S⁺., S(II+), S(IV+), 3 different selenium species: Se₂ ⁺., Se(II+), Se(IV+), and 3 different Tellurium species: Te₂ ²⁺, Te(II+) and Te(IV+) have been observed spectrophotometrically and electrochemically by varying the composition of the solvent from basic (non-oxidizing) medium (0.1M solution of NaSO₃F) to oxidizing media (0.5M solution of SO₃).     

Determination of Chain Transfer Constant for Solvent When the Viscosity of the Polymerizing System Is Considered Important

Abstract

The chain transfer constant of the polymethyl methacrylate radical for N,N-dimethylaniline was determined in two solvents, benzene and dimethyl phthalate. Plots were made using1/P_n=k_t°R_p/k_p ²[M]²η + C_S1 [S₁]/[M] + C_S2 [S₂]/[M] +C_M where η=viscosity of monomer-solvents mixture, k_t°=rate coefficient of termination when η=1 cP, S₁=benzene or dimethyl phthalate, S₂=N,N-dimethylaniline, and other symbols have their usual meanings. The plots agreed well for the two solvents. If the plots were made without considering the viscosity term, two separate lines resulted for the two solvents. Thus it is essential to consider the viscosity of the polymerizing system in the analysis of chain transfer reactions when the termination reaction is diffusion-controlled and the viscosities of the monomer and solvent differ markedly.     

Three new homoleptic nickel(II) 1,1-dithiocarbamate complexes: synthesis,structure, electrical conductivity and DFT study

Abstract

Three new homoleptic complexes of nickel having the formula [Ni(L1)₂] [L1?=?C₁₄H₁₄N₁O₂S₂^-, N-(4-methoxybenzyl)(furfuryl)methane dithiocarbamate] (1), [Ni(L2)₂] [L2?=?C₁₇H₁₈N₁O₂S₂^–, N-bis(4-methoxybenzyl)methane dithiocarbamate] (2) and [Ni(L3)₂] [L3?=?C₁₉H₂₁N₁O₁S₂^-, N-(4-isopropylbenzyl)(4-methoxybenzyl)methane dithiocarbamate] (3), have been designed, synthesized, and characterized by elemental analysis, IR, ¹H and ¹³C NMR and UV-visible absorption spectra showing that all complexes having analogous geometry and coordination number. The molecular structure of 2 is confirmed by single-crystal X-ray crystallography, which indicates that +2 charges on the metal ion (Ni²⁺) are balanced by dithiocarbamate anion. The X-ray analysis for 2 reveals a distorted square planar geometry around Ni²⁺ ion. Both C?–?H···S and intermolecular C–H···Ni interactions are the only artifact for the resulting Ni-dithiocarbamate architecture in 2. The electrical conductivity measurement between temperatures range of 303–393 K reflects that all complexes exhibit weak semiconducting behavior. Powder XRD, EDAX, and SEM spectra confirm the formation of NiS as thermal decomposition product in 1–3. The crystalline size of samples 1–3 was found to be 20.31?nm, 20.97?nm, and 20.39?nm, respectively.     

First heteroleptic Mo<Subscript>3</Subscript>S<Subscript>7</Subscript> clusters containing non-innocent phenanthroline ligands

Reaction of the thiobromide [Mo₃S₇Br₆]²⁻ cluster anion with 5,6-dimethyl-1,10-phenanthroline (Me₂Phen) in solution leads to the substitution of two bromide ligands and the subsequent formation of a new mixed-ligand neutral complex [Mo₃S₇Br₄(Me₂Phen)] (I). Reaction of [Mo₃S₇Br₆]²⁻ with 5,6-dimethyl-1,10-phenanthroline in CH₂Cl₂ followed by treatment of I with Na(Dtc) · 3H₂O (Dtc = diethyldithiocarbamate) results in the new mixed-ligand cluster complex [Mo₃S₇(Dtc)₂(Me₂Phen)]²⁺ (IIa). Slow evaporation of the CHCl₃ solution of the complex in the presence of PF₆⁻ gives crystals of {[Mo₃S₇(Dtc)₂(Me₂Phen)]Br}PF₆ · 3CHCl₃ (II) characterized by X-ray structural analysis. Close contacts S...S result in the formation of cationic dimers {[Mo₃S₇(Dtc)₂(Me₂Phen)]₂}⁴⁺ which form infinite chains through additional S_ax...Br contacts. All compounds were characterized by IR, elemental analysis and ESI-MS. Synthesized complexes represent the first examples of heteroleptic Mo₃S₇ clusters containing phenanthroline ligands.     

[M(phen)3][Ni(mnt)2](M2+=Ni2+，Fe2+；phen=1，10-菲咯啉，mnt2-=马来二腈二硫烯)离子对配合物的合成、晶体结构、电子光谱和磁性质

本文制备了2种新的离子对配合物[M(phen)3][Ni(mnt)2](phen=1,10-菲咯啉,mnt2-=马来二腈二硫烯;M2+=Ni2+,1;Fe2+,2),并进行了结构表征。2种离子对配合物晶体的空间群都为P21/n,具有类似的晶胞参数和堆积结构。紫外可见-近红外光谱显示在近红外区域没有出现明显的吸收峰。在2到400 K的温度范围内,化合物1表现居里-外斯型的顺磁性行为,并在磁性[Ni(phen)3]2+离子之间存在弱的反铁磁作用,而且在八面体配位环境下Ni2+离子自旋基态S=1。化合物2在40 K向上显示抗磁性,意味[Fe(phen)3]2+离子处于低自旋态。低于40 K时,弱居里尾巴可能是由于小部分顺磁性[Ni(mnt)2]-杂质导致的。