A highly selective chemosensor derived from benzamide hydrazones for the detection of cyanide ion in organic and organic-aqueous media: design,synthesis, sensing and computational studies

ABSTRACT

A new, highly sensitive and selective chemosensing method has been developed for the detection of cyanide ion using benzamide hydrazone receptors (R1-R4). The sensing ability of these compounds towards CN^? in the presence of Br ^?, HSO₄ ^?, Cl^?, OH^?, I^?, F^?, AcO^?, NO₂ ^? and NO₃ ^? in DMF and DMF-Aqueous mixture (DMF:H₂O, 9:1 v/v) was investigated. The binding characteristics of the probe with cyanide ions carried out by ¹ H NMR titrations indicated the deprotonation of N-H group through H-bond interactions between benzamide hydrazones and cyanide ions; it has been theoretically supported by DFT. The binding constant (Ka) and stoichiometry of the host–guest complex formed was calculated by the Benesi–Hildebrand (B–H) plot, and strong interaction of the probe with CN^- ions forming a 1:2 binding stoichiometry has been noted in this study. In a DMF and aqueous medium for CN^? ion, the lower limit of detection (LOD in ppm) is compared to the limit of quantification (LOQ in ppm), which is quite better in terms of sensitivity.     

基于分子内电荷转移的阴离子比率荧光分子探针

设计合成了一种基于4-甲基-1-羟基二苯甲酮对硝基苯腙的比色和比率荧光阴离子受体1。此类受体以羟基和腙单元为识别位点,以硝基苯基为信号报告基团。向受体1的DMSO溶液中加入AcO-、H2PO4-、F-后,溶液颜色由黄色变为紫红色,而加入所研究的其它阴离子则无变化,从而实现对AcO-、H2PO4-、F-这三种离子的裸眼识别。利用紫外-可见吸收光谱、荧光光谱考察了其与AcO-,H2PO4-,F-,Cl-,Br-,I-等阴离子的识别作用。1H NMR滴定为受体分子与阴离子之间氢键作用本质提供了有力证据。     

Synthesis of Schiff Base Bearing Phenolic Hydroxy Group and Its Anion Recognition

A new anion receptor bearing phenolic hydroxy group based on 3,5-ditertbutylsalicylaldehyde-p-nitrophenylhydrazone (1) was designed and synthesized. Upon addition of AcO^- and F^-, the receptor exhibited visible color changes from deep yellow to purple. However, no obvious color changes were observed on addition of the other anions tested (H₂PO₄^-, Cl^-, Br^-, I^-). The binding properties of the receptor with anions such as AcO^- and F^- were investigated by UV-Vis and fluorescent titrations. The result indicated that the receptor 1 had a higher affinity to AcO^- and F^- and a 1:1 host-guest complex was formed through H-bond interactions between 1 and anions.     

[Ru(phen)2(H2bbim)](PF6)2配合物的阴离子识别研究

利用紫外-可见吸收光谱和核磁研究了[Ru(phen)2(H2bbim)](PF6)2配合物与Cl-,Br-,I-,NO3-,HSO4-,H2PO4-,OAc-和F-离子之间的作用。结果表明OAc-和F-可以使该配合物苯并联咪唑上的质子逐步脱去,相应的溶液颜色由黄色变为橙棕色,最后变为紫色。因此该配合物可以对阴离子实现目视识别。     

Inorganic Anionic Oxygen-Containing α-Nucleophiles-Effective Acyl Group Acceptors: Hydroxylamine Ranks First among the α-Nucleophile Series

Comparative analysis of the nucleophilicity of inorganic oxygen-containing -nucleophiles (hydroxylamine and ClO^-, BrO^--, HOO^--, NH₂O^-, and F^- ions) covering the pK _a range from -2 to 13.81 toward 4-nitrophenyl esters (4-nitrophenyl acetate, 4-nitrophenyl p-toluenesulfonate, diethyl 4-nitrophenyl phosphate, ethyl 4-nitrophenyl ethylphosphonate, and 4-nitrophenyl dimethylcarbamate) in water at 25°C (ionic strength 1.0, KCl) was performed in terms of the extrathermodynamic Brönsted relation. It was found for the first time that hydroxylamine anion ranks first among the series of -nucleophiles. It is more reactive than HOO^- ion with respect to 4-nitrophenyl acetate (by a factor of 8), 4-nitrophenyl p-toluenesulfonate (by a factor of 4) and 4-nitrophenyl dimethylcarbamate (by a factor of 10). The nucleophilicities of HOO^- and NH₂O^- ions toward diethyl 4-nitrophenyl phosphate and ethyl 4-nitrophenyl ethylphosphonate are comparable. Taking into account that neutral hydroxylamine exhibits an anomalously high reactivity, as compared to not only common organic but also inorganic -nucleophiles, it may be regarded as a unique -nucleophile. Both neutral hydroxylamine and its anion as O-nucleophiles ensure high rates of acyl group transfer throughout a wide range of pH.     

Synthesis and characterization of a new soluble conducting polymer and its electrochromic device

A mixture of isomers 2,5-di(4-methyl-thiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole, 2-(4-methyl-thiophen-2-yl)-5-(3-methyl-thiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole and 2,5-di(3-methyl-thiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (Me-SNS(NO₂)) were synthesized. Resulting monomers were polymerized chemically, producing soluble polymers in common organic solvents. The average molecular weight has been determined by gel permeation chromatography (GPC) as Mn=5.6×10³ for the chemically synthesized polymer. The monomers were also electrochemically polymerized in the presence of LiClO₄, NaClO₄ (1:1) as the supporting electrolyte in acetonitrile solvent. Resulting polymers were characterized via CV, FTIR, NMR, SEM and UV–Vis spectroscopy. Spectroelectrochemistry analysis of polymer revealed Π–Π^* transition below 300 nm, with an electronic band gap of 2.18 ev. Switching ability of the polymer was evaluated by kinetic study measuring percent transmittance (%T) at the maximum contrast point, indicating that poly(Me-SNS(NO₂)) is a suitable material for electrochromic devices.     

基于含偶氮酚羟基席夫碱新型简单比色传感器

A novel N-(2-hydroxy-5-chlorodibenzophenone)-N0-[2-hydroxy-5-azophenyl-benzaldehyde]-1,2-diaminobenzene receptor has been synthesized by simple steps with good yields. The anion recognition properties were studied by ultraviolet-visible spectroscopy. The resultsshowed that the receptor had a higher affinity to F^-, AcO^-, and H₂PO₄^-, but no evident binding with Cl^-, Br^-, and I^-. Upon addition of the three former anions to the receptors in DMSO, the solution exhibited an obvious color change from colorless to yellow, which could be observed by the naked eye, thus the receptor could act as a fluoride ion sensor even in the presence of other halide ions. The UV-Vis data indicates that a 1:1 stoichiometric complex is formed through hydrogen bonding interactions between receptor and anions.     

Thiazole-based chemosensor II: synthesis and fluorescence sensing of fluoride ions based on inhibition of ESIPT

Novel chemosensors based on 2-(2′-hydroxyphenyl)-4-phenylthiazole were synthesized and their anion sensing behaviors were investigated. Sensors 1 and 2 show fluoride ion selective behaviors related to their absorption and emission spectra amongst F^?, CH₃CO₂ ^?, H₂PO₄ ^?, Cl^?, Br^?, I^?, ClO₄ ^?, NO₃ ^?, and HSO₄ ^? anions. Sensor 2 shows color change upon interaction with F^?. Interactions of 1, 2 and 3 with F^? cause a red-shift in UV–vis absorption and a large Stokes shift in fluorescence emission due to the inhibition of ESIPT induced by the deprotonation of phenolic proton by F^?.     

Synthesis and spectral characterization of a new symmetric bidentate Schiff-base and its zinc complexes

A new symmetric bidentate Schiff base N,N′-bis [(E)-3-(2-nitrophenyl)allylidene)]benzene-1,2-diamine (L) and its complexes with general formula ZnLX₂ (X = chloride, bromide, iodide, thiocyanate and azide) are described. The authenticity of the ligand and complexes have been established by microanalysis, electronic, MS, FT-IR, ¹H and ¹³C NMR spectra, and by molar conductivity measurements. All compounds are non-electrolytes in DMF. The analytical data confirmed that the metal to ligand ratio in the complexes is 1 : 1. The complexes have pseudotetrahedral geometry with C_2V point group.     

Fading of a novel colorimetric receptor after recognizing H2PO4−

A novel selective and sensitive colorimetric receptor 1 (1, 10-phenanthroline-2, 9-dialdehyde bis-(-p-nitrophenylureasemicarbo-hydrazone)) based on urea showing distinctive color fading phenomenon towards H₂PO₄^? ion was reported. Fancifully, the recognition process of receptor 1 to H₂PO₄^? was not interfered by the existence of others anions. We have probed the binding mechanism of 1-H₂PO₄^? that H₂PO₄^? ion induced competitive hydrogen binding process via intramolecular hydrogen-bond by UV–vis, fluorescence, ¹H NMR titrations and ESI-MS experiments.     

Polymer‐based fluoride‐selective chemosensor: Synthesis,sensing property,and its use for the design of molecular‐scale logic devices

A new styryl‐type monomer, 2‐(4‐vinylbenzyloxy)‐1 ‐naphthaldehyde thiosemicarbazone (VNT), was synthesized and then copolymerized with methyl methacrylate (MMA) by reversible addition fragmentation chain transfer polymerization affording a series of poly(MMA‐co‐VNT)s with different functional unit content, predetermined molecular weight, and narrow molecular‐weight distribution. The desired copolymers were structurally confirmed by various spectroscopic characterizations. Colorimetric and fluorescent titration spectra revealed that the copolymers are highly selective toward fluoride anions over other competitive species including Cl^?, Br^?, I^?, H₂PO₄^?, AcO^?, and HSO₄^?. On addition of F^?, a remarkable colorless‐to‐yellow color change is easily observed by naked eyes. The influence of the copolymer composition and molecular weight on its sensing capacity was then carefully investigated. The results showed that higher VNT‐incorporation amount within the copolymer chains leads to higher sensitivity toward F^? ions. Interestingly, the chromogenic process of the polymeric sensor can be switched back and forth by successively adding F^? and HSO₄^? anions into the dimethyl sulfoxide solution of the polymer, which may be represented by a complementary “IMPLICATION/INHIBIT” logic gate at molecular level using both the ions as the chemical inputs. Based on such a reversible and reproducible sensing system, we designed a molecular‐scale sequential information processing circuit displaying “writing–reading–erasing–reading” behavior and “multiwrite” function in the form of binary logic. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

SYNTHESIS AND CATIONIC RING-OPENING POLYMERIZATION OF 1, 4-ANHYDRO-2, 3-DI-O-(P-AZIDOBENZYL)-α-D-RIBOPYRANOSE

New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1, 4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and ~(13)C-NMR spectroscopy. Acid chloride-AgCl_4 complex catalyst such as CH_2=C(CH_3)C~+OClO_4~- used in thepolymerization resulted in polymers with mixed structures, i.e. (1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units. However, with C_6H_5C~+OClO_4~- as catalyst, pure (1→5)-α-D-ribofuranan was obtained.The effects of catalyst, polymerization temperature and time on polymer stereoregularity were examined, andthe mechanism of the ring-opening polymerization was discussed.     

Encapsulation of LnIII Ions/Dyes within a Microporous Anionic MOF by Post‐synthetic Ionic Exchange Serving as a LnIII Ion Probe and Two‐Color Luminescent Sensors

A new anionic framework {[Me₂NH₂]_0.125[In_0.125(H₂L)_0.25] ? xDMF}_n ( 1 ) with one‐dimensional (1D) channels along the c axis of about 13.06×13.06 Ų, was solvothermally synthesized and well characterized. Post‐synthetic cation exchange of 1 with Eu³⁺, Tb³⁺, Dy³⁺, Sm³⁺ afforded lanthanide(III)‐loaded materials, Ln³⁺@ 1 , with different luminescent behavior, indicating that compound 1 could be used as a potential luminescent probe toward different lanthanide(III) ions. Additionally, compound 1 exhibits selective adsorption ability toward cationic dyes. Moreover, the RhB@ 1 realized the probing of different organic solvent molecules by tuning the energy transfer efficiency between two different emissions, especially for sensing DMF. This work highlights the practical application of luminescent guest@MOFs as sensors, and it paves the way toward other one/multi‐color luminescent host–guest systems by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels.     

基于二苯基咪唑的氟离子荧光探针的合成及性能

本文设计制备了一种二苯基咪唑衍生化的荧光探针1,利用紫外-可见吸收光谱和荧光光谱研究探针对阴离子的选择性。在探针的乙腈溶液中引入F_^-后,606 nm处的荧光强度发生明显的猝灭,并且可通过裸眼识别F_^-。探针对F_^-的识别表现出高灵敏性以及较好的抗干扰能力,检测限可低至9.43×10_^-8 mol L_^-1。此外,制备的1+F_^-体系对湿度较敏感,在水分影响下该体系的颜色和荧光强度能够实现可逆恢复。     

Equilibrium constants of HF,F-, HF-2 and H2F2 species in formic acid.

Equilibrium constants for the fluorinated species HF, F^-, HF^-₂ and H₂F₂ in formic acid and in a 1M potassium formate solution in formic acid have been studied by ¹⁹F NMR. The chemical shifts of these species have been determined from measurements of the shifts for various initial mixtures of differing concentrations of dissolved HF, F^- and HF^-₂. From these values, relative concentrations of HF, F^-, and HF^-₂ and H₂F₂ in each solution have been calculated through a numerical method. The following constants were obtained: K₁ = [H⁺][F^-]/[HF] = 1.1 x 10^-5M; K_D = [HF][F^-]/[HF^-₂] = 0.5 M; K′₁ = [H⁺][HF^-₂]/[H₂F₂]= 1.1 x 10^-5 M; K′_D = [HF]²/[H₂F₂]=0.5 M.     

A novel neutral receptor for selective recognition of H2PO 4 −

A new urea-based receptor was designed to selectively recognize H₂PO₄⁻ among other anions (such as F^-, Cl^-, Br^-, I^-, OH^-, AcO^-) in organic solvent (DMSO) through intermolecular hydrogen bonding. Addition of anions to the receptor caused changes in UV–vis spectrum which provided the first indication of its anion binding ability. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

酰腙类化合物的合成和阴离子识别研究

本文设计合成了3种新型的酰腙类受体分子。利用紫外-可见吸收光谱及 ¹H NMR考察了其与F^-、Cl^-、Br^-、I^-、CH₃COO^-、HSO₄^-、NO₃^-等阴离子的作用。结果表明，该类受体分子能较好地识别阴离子F^-和CH₃COO^-，在DMSO溶液中主客体之间形成氢键加合物。尤其对于受体3(间苯双对硝基苯氧乙酰腙)，加入F^-和CH₃COO^-时，溶液颜色有明显变化，受体3对这两种阴离子可实现裸眼识别。     

Neutral Hexacoordinate Phosphorus(V) Compounds Containing Tridentate Dianionic Ligands Obtained from Salicylideneamines, 2,2′-Azodiphenol and a Thio(Diphenol)

Abstract

Neutral hexacoordinate phosphorus(V) compounds of a number of univalent bidentate ligands are known.^l,2 The silylated forms of tridentate, dianionic Schiff base ligands: N-(2-hydroxyphenyl)salicylideneamine H₂L^I, N-(4-tert-butyl-2-hydroxyphenyl)-salicylideneamine H₂L^II, N-(2-hydroxy-4-nitrophenyl)salicylidene-amine H₂L^III, and 2,2′-azodiphenol H₂L^IV gave, with halogeno- and (trifluoromethyl)halogenophosphoranes, neutral hexa-coordinate derivatives with bis-chelate structures. The ligands form bicyclic five- and six-membered chelate rings in a meridional conformation, with two P-O bonds and one N→P donor bond. Hexacoordinate structures were evidenced by high-field ³¹P NMR chemical shifts (-136 to -148 ppm), characteristic J _PF coupling patterns and was further substantiated by crystal structures of Cl₃L^II (A) and F₃PL^II (B).     

新型三脚架苯甲醛苯腙醋酸根选择性比色化学传感器

本文合成了一个新的基于三脚架苯甲醛苯腙的能够选择地检测醋酸根离子的比色化学传感器1。用紫外可见吸收光谱证实了受体1在二甲基亚砜溶液中对醋酸根离子高选择的键合能力超越了其它阴离子。和其他所研究的阴离子相比,其在二甲基亚砜中紫外可见吸收光谱对具有高选择性醋酸根离子的存在显示了应答,当存在（2´10^-5mol·dm^-3）醋酸根离子时其溶液的颜色也由黄色变化到蓝色。当用其他不同的客体阴离子（F^-, Cl^-, Br^-, I^-, H₂PO₄ ^–和 OH^-）处理受体1时,仅出现了很小的紫外可见吸收光谱变化。受体1对醋酸根的结合常数 K_ass为1.69´ 10⁴。     

Effects on Coordination of Thioether Sites. 4. Structural Analysis of η3-Tripodal Ligand Manganese(I) Complexes

Crystal structures of a series of manganese(I) complexes containing tripodal ligands were determined. For [η³-{CH₃C(CH₂PPh₂)₂(CH₂SPh)-P,P′,S}Mn(CO)₃]PF₆ ( 1 ): a = 10.856(3) Å, b = 19.698(3) Å, c = 17.596(5) Å, β = 96.17(2)°, monoclinic, Z = 4, P2₁/c, R(F_o) = 0.068, R_w(F_o) = 0.055 for 3617 reflections with I_o > 2σ(I_o). For [η³-{CH₃C(CH₂PPh₂)(CH₂SPh)₂-P,P′,S}Mn(CO)₃]PF₆ ( 2 ): a = 9.890(2) Å, b = 20.403(4) Å, c = 10.269(3) Å, β = 117.44(2)°, monoclinic, Z = 2, P2_l, R(F_o) = 0.050, R_w(F_o) = 0.037 for 1760 reflections with I_o > 2σ(I_o). For [η³-{CH₃C(CH₂PPh₂)₂(CH₂S)-P,P′,S}Mn(CO)₃] ( 4 ): a = 8.191(7) Å, b = 10.495(3) Å, c = 19.858(6) Å, α = 99.61(2)°, β = 96.17(2)°, γ = 92.70(4)°, triclinic, Z = 2, P-I, R(F_o) = 0.048, R_w(F_o) = 0.039 for 2973 reflections with I_o > 2σ(I_o). There is no significant difference in the bond lengths of Mn-S bonds among three species in their crystal structures [2.325(2) Å in 1; 2.358(4) in 2; 2.380(2) in 4], but the better donating ability of thiolate in complex 4 appears on the lower frequencies of its carbonyl stretching absorptions.