场效应管电位滴定检测仪的研制

介绍了用场效应管研制的电位滴定终点检测仪的工作原理，性能及其应用。     

A Novel Donor-Acceptor Thiophene-Containing Oligomer Comprising Dibenzothiophene-S,S-dioxide Units for Solution-Processable Organic Field Effect Transistor

A π-conjugated thiophene-containing oligomer with a D-A-D-A-D (D: donor, A: acceptor) architecture, namely, 2,6-bis{[4-(7-n-hexylthiophen-2-yl)thiophen-2-yl]-(dibenzothiophene-5,5-dioxide-3,3΄-diyl)}-bis((2-ethyl-hexyl)oxy)benzo[1,2-b:4,5-b’]dithiophen (BDT(DBTOTTH)₂), was synthesized by Stille coupling reactions. There are obvious shifts in the Ultraviolet-visible (UV-vis) and photoluminescence (PL) spectra of the thin film relative to its solution, indicating the existence of the π-π stacking in the solid state of the oligomer BDT(DBTOTTH)₂. The optical band gap of the oligomer determined from its absorption onset in UV-Vis spectra is 2.25 eV. It agrees with the value of 2.29 eV determined from the cyclic voltammetry (CV) measurement. Its highest occupied and lowest unoccupied molecular orbital (HOMO/LUMO) energy levels, which were calculated from its onset of oxidation and reduction waves in CV curve, are −5.51 and −3.22 eV, respectively. The oligomer is a P-type semiconductor material with a good thermal stability and solubility, which can be used to fabricate organic field effect transistors (OFETs) by the spin coating technique. The OFET with n-octadecanylltrichlorosilane (OTS)-modified SiO₂ dielectric layer exhibited a mobility of 1.6 × 10⁻³ cm²/Vs.     

Supramolecular Sensor for Astringent Procyanidin C1: Fluorescent Artificial Tongue for Wine Components

An artificial tongue that detects astringent components for a comprehensive evaluation of taste has not been established to date. Herein, we first propose fluorescent polythiophene (PT) derivatives ( S1 – S3 ) modified with 3-pyridinium boronic acid as supramolecular chemosensors for wine components including astringent procyanidin C1. After numerous attempts for the synthetic conditions, more than 95 mol % of the PT unit was modified with the pyridinium boronic acid moiety. To evaluate the PT derivatives as chemosensors of the artificial tongue, qualitative and quantitative analyses were performed with four types of wine components (i.e., sweet, sour, bitter, and astringent tastes) in combination with pattern recognition models. Notably, procyanidin C1 in the actual wine sample was successfully detected in a quantitative manner. In other words, we have established an authentic artificial tongue using PT based supramolecular chemosensors.     

A Green and Wide-Scope Approach for Chiroptical Sensing of Organic Molecules through Biomimetic Recognition in Water

Optical chirality sensing has attracted a lot of interest due to its potential in high-throughput screening in chirality analysis. A molecular sensor is required to convert the chirality of analytes into optical signals. Although many molecular sensors have been reported, sensors with wide substrate scope remain to be developed. Herein, we report that the amide naphthotube-based chirality sensors have an unprecedented wide scope for chiroptical sensing of organic molecules. The substrates include, but are not limited to common organic products in asymmetric catalysis, chiral molecules with inert groups or remote functional groups from their chiral centers, natural products and their derivatives, and chiral drugs. The effective chirality sensing is based on biomimetic recognition in water and on effective chirality transfer through guest-induced formation of a chiral conformation of the sensors. Furthermore, the sensors can be used in real-time monitoring on reaction kinetics in water and in determining absolute configurations and ee values of the products in asymmetric catalysis.     

A High‐Performance Organic Field‐Effect Transistor Based on Platinum(II) Porphyrin: Peripheral Substituents on Porphyrin Ligand Significantly Affect Film Structure and Charge Mobility

Organic field‐effect transistors incorporating planar π‐conjugated metal‐free macrocycles and their metal derivatives are fabricated by vacuum deposition. The crystal structures of [H₂(OX)] (H₂OX=etioporphyrin‐I), [Cu(OX)], [Pt(OX)], and [Pt(TBP)] (H₂TBP=tetra‐(n‐butyl)porphyrin) as determined by single crystal X‐ray diffraction (XRD), reveal the absence of occluded solvent molecules. The field‐effect transistors (FETs) made from thin films of all these metal‐free macrocycles and their metal derivatives show a p‐type semiconductor behavior with a charge mobility (μ) ranging from 10^?6 to 10^?1 cm² V^?1 s^?1. Annealing the as‐deposited Pt(OX) film leads to the formation of a polycrystalline film that exhibits excellent overall charge transport properties with a charge mobility of up to 3.2×10^?1 cm² V^?1 s^?1, which is the best value reported for a metalloporphyrin. Compared with their metal derivatives, the field‐effect transistors made from thin films of metal‐free macrocycles (except tetra‐(n‐propyl)porphycene) have significantly lower μ values (3.0×10^?6–3.7×10^?5 cm² V^?1 s^?1).     

Technologies Employed in the Treatment of Water Contaminated with Glyphosate: A Review

Glyphosate [N-(phosphonomethyl)-glycine] is a herbicide with several commercial formulations that are used generally in agriculture for the control of various weeds. It is the most used pesticide in the world and comprises multiple constituents (coadjutants, salts, and others) that help to effectively reach the action’s mechanism in plants. Due to its extensive and inadequate use, this herbicide has been frequently detected in water, principally in surface and groundwater nearest to agricultural areas. Its presence in the aquatic environment poses chronic and remote hazards to human health and the environment. Therefore, it becomes necessary to develop treatment processes to remediate aquatic environments polluted with glyphosate, its metabolites, and/or coadjutants. This review is focused on conventional and non-conventional water treatment processes developed for water polluted with glyphosate herbicide; it describes the fundamental mechanism of water treatment processes and their applications are summarized. It addressed biological processes (bacterial and fungi degradation), physicochemical processes (adsorption, membrane filtration), advanced oxidation processes—AOPs (photocatalysis, electrochemical oxidation, photo-electrocatalysis, among others) and combined water treatment processes. Finally, the main operating parameters and the effectiveness of treatment processes are analyzed, ending with an analysis of the challenges in this field of research.     

A Nitro‐Functionalized Metal–Organic Framework as a Reaction‐Based Fluorescence Turn‐On Probe for Rapid and Selective H2S Detection

The toxic gas H₂S has recently emerged as one of the important signaling molecules in biological systems. Thus understanding the production, distribution, and mode of action of H₂S in biological system is important, but the fleeting and reactive nature of H₂S makes it a daunting task. Herein we report a biocompatible, nitro‐functionalized metal–organic framework as reaction‐based fluorescence turn‐on probe for fast and selective H₂S detection. The selective turn‐on performance of MOF remains unaffected even in presence of competing biomolecules.     

A Calixarene‐Based Metal–Organic Framework for Highly Selective NO2 Detection

A calixarene‐based metal–organic framework (Zr‐cal, [Zr₆O₄(OH)₄(FA)₆]₂(cal)₃], FA=formate, cal=1,3‐alt‐25,26,27,28‐tetrakis[(carboxy)methoxy]calixarene) was synthesized and characterized by single‐crystal X‐ray diffraction. The three‐dimensional framework is a 4,6‐connected network of gar topology and exhibits two equal but nonintersecting three‐dimensional pore systems. It has a specific BET surface area of 670 m² g^?1, and the calixarene cavities are accessible through the pore systems. The exposed calixarenes can be used for the visual detection and encapsulation of NO₂ through the formation of deeply colored charge–transfer complexes inside the MOF. The highly selective complexation was analyzed by UV/Vis and IR spectroscopy, and the stability of the material was confirmed by powder X‐ray diffraction and ¹H NMR spectroscopy. Finally, the MOF was used as a sensor material in a home‐made sensor cell and showed high sensitivity for NO₂.     

Molecular Imprinting of Small Molecules with Organic Silanes: Fluorescence Detection

Abstract

Small molecules, peptides, and proteins can be imprinted using mixtures of organic silanes. Molecular imprints may serve as artificial receptors, i.e., biosensor sensing elements for detection of chemical and biological toxins, drugs, and environmental hazards. One method for detection of imprint-bound molecules is fluorescence. Molecular imprints to N-acetyltryptophanamide (NATA) and fluorescein were prepared, and their respective binding constants determined using steady-state fluorescence spectroscopy. Stern-Volmer fluorescence quenching plots of imprint-bound molecules using potassium iodide (KI) and acrylamide indicate bound molecules are shielded from the solvent environment. Scatchard plot analysis revealed two binding affinities, i.e., aK_d = 0.13 and 2.5 μM for NATA binding to NATA imprints. Interestingly, NATA exhibited higher affinity, i.e., K_d = 1.3 and 35 nM, for the fluorescein imprint. These data support the usefulness of fluorescence techniques in molecular imprint-based detection technology.     

超分子在质量敏感压电化学传感器中的应用

以质量敏感为分析基础的压电化学传感器,其表面涂层往往决定其对分析物的选择性。超分子作为压电石英晶体涂层,应用主－客体分子识别的原理,显著提高压电化学传感器的选择性。该文详细论述了近十年有关超分子主体化合物在体波和表面波化学传感器的应用,并了涂膜技术及主－客体识别机理。     

Acyclic Cucurbit[n]uril-Type Receptors: Aromatic Wall Extension Enhances Binding Affinity,Delivers Helical Chirality,and Enables Fluorescence Sensing

We report the linear extension from M1 to M2 to anthracene walled M3 which adopts a helical conformation (X-ray) to avoid unfavorable interactions between sidewalls. M3 is water soluble (=30 mm ) and displays enhanced optical properties (ϵ=1.28×10⁵ m ⁻¹ cm⁻¹, λ_max=370 nm) relative to M2 . The binding properties of M3 toward guests 1 – 29 were examined by ¹H NMR and ITC. The M3 ⋅guest complexes are stronger than the analogous complexes of M2 and M1 . The enhanced binding of M3 toward neuromuscular blockers 25 , 27 – 29 suggests that M3 holds significant promise as an in vivo reversal agent. The changes in fluorescence observed for M3 ⋅guest complexes are a function of the relative orientation of the anthracene sidewalls, guest concentration, K_a, and guest electronics which rendered M3 a superb component of a fluorescence sensing array. The work establishes M3 as a next generation sequestering agent and a versatile component of fluorescence sensors.     

A Chiral Halogen‐Bonding [3]Rotaxane for the Recognition and Sensing of Biologically Relevant Dicarboxylate Anions

The unprecedented application of a chiral halogen‐bonding [3]rotaxane host system for the discrimination of stereo‐ and E/Z geometric isomers of a dicarboxylate anion guest is described. Synthesised by a chloride anion templation strategy, the [3]rotaxane host recognises dicarboxylates through the formation of 1:1 stoichiometric sandwich complexes. This process was analysed by molecular dynamics simulations, which revealed the critical synergy of halogen and hydrogen bonding interactions in anion discrimination. In addition, the centrally located chiral (S)‐BINOL motif of the [3]rotaxane axle component facilitates the complexed dicarboxylate species to be sensed via a fluorescence response.     

A New Chiral Binaphthalene‐Based Fluorescence Polymer Sensor for the Highly Enantioselective Recognition of Phenylalaninol

A new (S)‐binaphthalene‐based polymer ( P ‐ 1 ) was synthesized by the polymerization of 5,5′‐((2,5‐dibutoxy‐1,4‐phenylene)bis(ethyne‐2,1‐diyl))bis(2‐hydroxy‐3‐(piperidin‐1‐ylmethyl) benzaldehyde ( M ‐ 1 ) with (S)‐2,2′‐dimethoxy‐(1,1′‐binaphthalene)‐3,3′‐diamine ( M ‐ 2 ) through the formation of a Schiff base; the corresponding chiral polymer ( P ‐ 2 ) could be obtained by the reduction of polymer P ‐ 1 with NaBH₄. Chiral polymer P ‐ 1 exhibited a remarkable “turn‐on” fluorescence‐enhancement response towards (D )‐phenylalaninol and excellent enantioselective recognition behavior with enantiomeric fluorescence difference ratios (ef) as high as 8.99. More importantly, chiral polymer P ‐ 1 displays a bright blue fluorescence color change upon the addition of (D )‐phenylalaninol under a commercially available UV lamp, which can be clearly observed by the naked eye. On the contrary, chiral polymer P ‐ 2 showed weaker enantioselective fluorescence ability towards the enantiomers of phenylalaninol.     

Sensing A Paradigm Shift in the Field of Molecular Recognition: From Selective to Differential Receptors

Molecular recognition has evolved from a science designed to understand biological systems into a much more diverse area of research. While work continues to elucidate “nature's tricks” with respect to intermolecular interactions, much attention has turned to the perspective that molecular recognition, by design, can lead to new technologies. Applications ranging from molecular sensing to information storage and even working molecular machines have been envisioned. This review will highlight a few historical hallmarks of molecular recognition oriented at studying the basic science of intermolecular interactions, but then detail recent advances in molecular recognition aimed towards applications in the field of molecular sensing. Rational design can be used to create synthetic receptors with a good deal of predictability and selectivity, and many signal transduction mechanisms exist for converting these receptors into sensors. This is the first topic discussed. The concept of “differential” or “generalized” sensing is then presented, where one uses an array of sensors that do not necessarily conform to the “lock and key” principle. This approach to sensing is inspired by the mammalian senses of taste and smell, which we briefly describe. To mimic senses of taste and smell, one is naturally led to the use of combinatorial libraries, a direction of research that has seen continued growth over the past few years. We summarize the current state of the art in synthetic combinatorial receptors/sensors, and then predict a future direction that the field of molecular recognition will possibly take. The review is not meant for the specialist, but instead for a general audience. It does not present a highly detailed analysis of each individual topic: synthetic receptors, sensors, olfaction/gustation, and combinatorial receptors/sensors. Instead, this review shows how all these fields complement each other and fit together to create sensing devices. Our conclusion is that specific analyte sensing, differential sensing, and combinatorial chemistry can and will be combined to create sensor arrays, and give the subfield of molecular recognition that uses synthetic systems a bright future in this type of sensing scenario.     

Morphological similarity: A 3D molecular similarity method correlated with protein-ligand recognition

Recognition of small molecules by proteins depends on three-dimensional molecular surface complementarity. However, the dominant techniques for analyzing the similarity of small molecules are based on two-dimensional chemical structure, with such techniques often outperforming three-dimensional techniques in side-by-side comparisons of correlation to biological activity. This paper introduces a new molecular similarity method, termed morphological similarity (MS), that addresses the apparent paradox. Two sets of molecule pairs are identified from a set of ligands whose protein-bound states are known crystallographically. Pairs that bind the same protein sites form the first set, and pairs that bind different sites form the second. MS is shown to separate the two sets significantly better than a benchmark 2D similarity technique. Further, MS agrees with crystallographic observation of bound ligand states, independent of information about bound states. MS is efficient to compute and can be practically applied to large libraries of compounds.     

PLA Electrospun Fibers Reinforced with Organic and Inorganic Nanoparticles: A Comparative Study

In this work, different poly (lactic acid) (PLA)-based nanocomposite electrospun fibers, reinforced with both organic and inorganic nanoparticles, were obtained. As organic fibers, cellulose nanocrystals, CNC, both neat and functionalized by “grafting from” reaction, chitosan and graphene were used; meanwhile, hydroxyapatite and silver nanoparticles were used as inorganic fibers. All of the nanoparticles were added at 1 wt% with respect to the PLA matrix in order to be able to compare their effect. The main aim of this work was to study the morphological, thermal and mechanical properties of the different systems, looking for differences between the effects of the addition of organic or inorganic nanoparticles. No differences were found in either the glass transition temperature or the melting temperature between the different electrospun systems. However, systems reinforced with both neat and functionalized CNC exhibited an enhanced degree of crystallinity of the electrospun fibers, by up to 12.3%. From a mechanical point of view, both organic and inorganic nanoparticles exhibited a decreased elastic modulus and tensile strength in comparison to neat electrospun PLA fibers, improving their elongation at break. Furthermore, all of the organic and inorganic reinforced systems disintegrated under composting conditions after 35 days.     

Thiazolothiazole‐containing polythiophenes with low HOMO level and high hole mobility for polymer solar cells

Two regiochemically defined polythiophenes containing thiazolothiazole acceptor unit were synthesized by palladium(0)‐catalyzed Stille coupling reaction. The thermal, electrochemical, optical, charge transport, and photovoltaic properties of these copolymers were examined. Compared to P1 with head‐to‐head coupling of two middle thiophenes, P2 with head‐to‐tail coupling of two middle thiophenes exhibits 40 nm red shift of absorption spectrum in film and 0.3 eV higher HOMO level. Both polymers exhibit field‐effect hole mobility as high as 0.02 cm² V^?1 s^?1. Polymer solar cells (PSCs) were fabricated based on the blend of the polymers and methanofullerene[6,6]‐phenyl C71‐butyric acid methyl ester (PC₇₁BM). The PSC based on P1 :PC₇₁BM (1:2, w/w) exhibits a power conversion efficiency of 2.7% under AM 1.5, 100 mW cm^?2, two times of that based on P2 :PC₇₁BM. The higher efficiency is attributed to lower HOMO (?5.6 eV) and smaller phase separation scale in P1 :PC₇₁BM blend. Tiny change in thiophene connection of P1 and P2 lead to great difference in HOMO, phase separation scale, and efficiency of their photovoltaic devices. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A Luminescent Metal-Organic Framework with Boosted Picric Acid Fluorescence Detection Performance via a Complementary Capture-Quench Mechanism

The strong explosiveness, toxicity and environmental pollution of picric acid make its sensitive detection important. Recently, LMOF materials are showing great potential toward efficient detection of PA. However, hindered by the weak connections between LMOFs and analytes, a feasible fluorescence selectivity and sensitivity to desired compounds by constructed LMOFs remain challenging. Herein, we propose a new strategy by using the innate adsorption ability of MOFs. We choose NDC−Zn, a highly stable LMOF with unique pore structures. The topology of ligands can capture PAs specifically inside the pores and the selectivities are further elevated. PET effects are boosted due to longer and closer contact between ligands and trapped PAs, thus higher sensitivity is also achieved. Besides, a fluorescence enhancement at a visible wavelength was found as the concentration of PA increased, suggesting a potential application of naked-eye recognition for PA. NDC−Zn exhibited an outstanding detection sensitivity for PA with a quenching constant of 49657 M⁻¹, as well as distinctive fluorescence quenching among 9 nitro explosives. From DFT calculations, the fluorescence quenching mechanisms such as PET and the complexation between H₂NDC and PA were supported.