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Bhakta V, Guchhait N. Switching of photoinduced proton transfer from one six-membered hydrogen-bonded ring to other: a molecule of hydrazine and pH sensor. Phys Chem Chem Phys 2024; 26:19290-19301. [PMID: 38963224 DOI: 10.1039/d4cp01998a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The present study describes photophysical properties of 3-(benzo[d]oxazol-2-yl)-5-bromo-2-hydroxybenzaldehyde (HBOB) and (E)-2-(benzo[d]oxazol-2-yl)-4-bromo-6-(hydrazonomethyl)phenol (HBON) molecules with asymmetric two-way proton transfer sites. The purpose of this study is to know the direction of ESIPT out of the two-way proton transfer pathways in these molecules in both the solid and solution state. The steady state and time-resolved spectral behaviour of HBOB and HBON and a comparison of the spectral features with the two distinct control compounds 2-(benzo[d]oxazol-2-yl)-4-bromophenol (HBO) and (E)-4-bromo-2-(hydrazonomethyl)phenol (HBN) having single 6-membered hydrogen bonded network reveal that HBOB undergoes imine-amine photoisomerisation by proton transfer towards the oxazole side and HBON undergoes towards the hydrazone side with characteristic Stokes' shifted emission. Proton transfer forms with the red shifted emission of these molecules shows fast decay than the locally excited state. In the solid state, extremely high fluorescence intensity was observed, following a similar type of ESIPT pattern. Calculated ground (S0) and excited state (S1) energy barriers for the PT process obtained using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) corroborate the unidirectional excited state intramolecular proton transfer (ESIPT) process for HBOB and HBON, and the theoretical spectral features validate our experimental absorption and emission spectra well. Interestingly, the unique unidirectional ESIPT behaviour of HBOB was utilised to detect hydrazine both in solution and solid phases. On the other hand, HBON was found to be a good fluorescence pH sensor with a ratiometric color change from yellow to green in acidic and basic media.
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Affiliation(s)
- Viki Bhakta
- Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata, 700009, India.
| | - Nikhil Guchhait
- Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata, 700009, India.
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Tang L, Hao Y, Peng L, Liu R, Zhou Y, Li J. Ion current rectification properties of non-Newtonian fluids in conical nanochannels. Phys Chem Chem Phys 2024; 26:2895-2906. [PMID: 38170851 DOI: 10.1039/d3cp05184f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Ionic current rectification generated by the geometric asymmetry of conical nanochannels has gradually attracted attention, but most studies have been limited to Newtonian fluids. In this study, the ionic current rectification characteristics in conical nanochannels filled with non-Newtonian fluids are investigated by numerical simulations. Electroosmotic flow and ion transport in Sisko fluids are solved using the Poisson-Nernst-Planck equations and the Navier-Stokes equations. The effects of the Debye parameter, power-law indexes and applied voltage on the ionic current, axial potential, ion concentration, radial velocity and rectification ratio in the nanopores are investigated. When κRt = 1, the current rectification ratio increases with the increase of the power-law index. However, when κRt = 6, the current rectification ratio first increases and then decreases with the increase of the power law index, reaching the maximum value at n = 1.0. These findings have positive implications for the construction of some nanodevices such as nanofluidic diodes.
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Affiliation(s)
- Lei Tang
- School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan, 430063, China.
| | - Yu Hao
- School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan, 430063, China.
| | - Li Peng
- School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan, 430063, China.
| | - Runxin Liu
- School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan, 430063, China.
| | - Yi Zhou
- College of General Aviation and Flight, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Jie Li
- School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan, 430063, China.
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Numerical Investigation of Diffusioosmotic Flow in a Tapered Nanochannel. MEMBRANES 2022; 12:membranes12050481. [PMID: 35629807 PMCID: PMC9143036 DOI: 10.3390/membranes12050481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/27/2022] [Accepted: 04/27/2022] [Indexed: 11/21/2022]
Abstract
Diffusioosmosis concerns ionic flow driven by a concentration difference in a charged nano-confinement and has significant applications in micro/nano-fluidics because of its nonlinear current-voltage response, thereby acting as an active electric gating. We carry out a comprehensive computation fluid dynamics simulation to investigate diffusioosmotic flow in a charged nanochannel of linearly varying height under an electrolyte concentration gradient. We analyze the effects of cone angle (α), nanochannel length (l) and tip diameter (dt), concentration difference (Δc = 0–1 mM), and external flow on the diffusioosmotic velocity in a tapered nanochannel with a constant surface charge density (σ). External flow velocity (varied over five orders of magnitude) shows a negligible influence on the diffusioosmotic flow inside the tapered nanochannel. We observed that a cone angle causes diffusioosmotic flow to move towards the direction of increasing gap thickness because of stronger local electric field caused by the overlapping of electric double layers near the smaller orifice. Moreover, the magnitude of average nanoflow velocity increases with increasing |α|. Flow velocity at the nanochannel tip increases when dt is smaller or when l is greater. In addition, the magnitude of diffusioosmotic velocity increases with increasing Δc. Our numerical results demonstrate the nonlinear dependence of tapered, diffusioosmotic flow on various crucial control parameters, e.g., concentration difference, cone angle, tip diameter, and nanochannel length, whereas an insignificant relationship on flow rate in the low Peclet number regime is observed.
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Zhang X, Xu M, Yang J, Hu N. Ion Transport in pH-Regulated Double-Barreled Nanopores. Anal Chem 2022; 94:5642-5650. [PMID: 35352923 DOI: 10.1021/acs.analchem.1c05654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single-molecule detection and characterization with nanopores is a powerful technique that does not require labeling. Multinanopore systems, especially double nanopores, have attracted wide attention and have been applied in many fields. However, theoretical studies of electrokinetic ion transport in nanopores mainly focus on single nanopores. In this paper, for the first time, a theoretical study of pH-regulated double-barreled nanopores is conducted using three-dimensional Poisson-Nernst-Planck equations and Navier-Stokes equations. Four ionic species and the surface chemistry on the walls of the nanopores are included. The results demonstrate that the properties of the bulk salt solution significantly affect nanopore conductivity and ion transport phenomena in nanopores. There are two ion-enriched zones and two ion-depleted zones in double-barreled nanopores. Due to the symmetry of the double-barreled nanopore structure and surface charge density, there is no ionic rectification effect in double-barreled nanopores. The ion selectivity is similar to that of conventional single pH-regulated nanopores.
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Affiliation(s)
- Xiaoling Zhang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University, Chongqing 400030, P. R. China.,Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, P. R. China.,Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, P. R. China
| | - Mengli Xu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University, Chongqing 400030, P. R. China
| | - Jun Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University, Chongqing 400030, P. R. China
| | - Ning Hu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing University, Chongqing 400030, P. R. China
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Wang K, Gao G, Wang X. Photooxidation of
IR
‐820 by
Calixpyridinium‐Induced
Assembled Material and Its
pH‐Controlled
Visual Multicolor Luminescence. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202100802] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kui Wang
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University Tianjin 300387 China
| | - Guo‐Jie Gao
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University Tianjin 300387 China
| | - Xiao‐Yan Wang
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University Tianjin 300387 China
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Liu TJ, Ma T, Lin CY, Balme S, Hsu JP. Origin of Ultrahigh Rectification in Polyelectrolyte Bilayers Modified Conical Nanopores. J Phys Chem Lett 2021; 12:11858-11864. [PMID: 34874161 DOI: 10.1021/acs.jpclett.1c03513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The switching of "ON" and "OFF" states of an ionic diode is investigated by considering a conical nanopore partially functionalized two polyelectrolyte (PE) layers via layer-by-layer deposition. Through observing the inversion of its rectification behavior, we demonstrate the function of the PE bilayers in ionic transport regulation. The ionic diode exhibits an ultrahigh ion rectification at a low level of pH. In an aqueous NaCl solution at pH 2, for example, the ratio of the current at "ON" state and that at "OFF" state can be about 800 and 200 for 1 and 100 mM, respectively. This remarkable gating behavior can be explained by the anion-pump-induced ion accumulation in the neutral region as well as the depletion zone at the interface. Our results further demonstrate the possibility of achieving an ultrahigh rectification in an ionic diode having a unipolar-like configuration.
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Affiliation(s)
- Tien-Juin Liu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Tianji Ma
- Institut Européen des Membranes, UMR5635 UM ENSM CNRS, Place Eugène Bataillon, 34095 CEDEX 5 Montpellier, France
| | - Chih-Yuan Lin
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Sébastien Balme
- Institut Européen des Membranes, UMR5635 UM ENSM CNRS, Place Eugène Bataillon, 34095 CEDEX 5 Montpellier, France
| | - Jyh-Ping Hsu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
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Peters WS, Jensen KH, Stone HA, Knoblauch M. Plasmodesmata and the problems with size: Interpreting the confusion. JOURNAL OF PLANT PHYSIOLOGY 2021; 257:153341. [PMID: 33388666 DOI: 10.1016/j.jplph.2020.153341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 05/14/2023]
Abstract
Plant tissues exhibit a symplasmic organization; the individual protoplasts are connected to their neighbors via cytoplasmic bridges that extend through pores in the cell walls. These bridges may have diameters of a micrometer or more, as in the sieve pores of the phloem, but in most cell types they are smaller. Historically, botanists referred to cytoplasmic bridges of all sizes as plasmodesmata. The meaning of the term began to shift when the transmission electron microscope (TEM) became the preferred tool for studying these structures. Today, a plasmodesma is widely understood to be a 'nano-scale' pore. Unfortunately, our understanding of these nanoscopic channels suffers from methodological limitations. This is exemplified by the fact that state-of-the-art EM techniques appear to reveal plasmodesmal pore structures that are much smaller than the tracer molecules known to diffuse through these pores. In general, transport processes in pores that have dimensions in the size range of the transported molecules are governed by different physical parameters than transport process in the macroscopic realm. This can lead to unexpected effects, as experience in nanofluidic technologies demonstrates. Our discussion of problems of size in plasmodesma research leads us to conclude that the field will benefit from technomimetic reasoning - the utilization of concepts developed in applied nanofluidics for the interpretation of biological systems.
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Affiliation(s)
- Winfried S Peters
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA; Department of Biology, Purdue University Fort Wayne, Fort Wayne, IN, 46805, USA.
| | - Kaare H Jensen
- Department of Physics, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 08544, USA.
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
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Barman B, Kumar D, Gopmandal PP, Ohshima H. Electrokinetic ion transport and fluid flow in a pH-regulated polymer-grafted nanochannel filled with power-law fluid. SOFT MATTER 2020; 16:6862-6874. [PMID: 32638819 DOI: 10.1039/d0sm00709a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this article, we have discussed extensively electrokinetic ion transport and fluid flow through a slit polymer-grafted nanochannel filled with power-law fluid. The rigid walls of the channel are coated with the ion and fluid penetrable polymer layer containing a pH-regulated zwitterionic functional group (e.g., succinoglycan). The mathematical model is based on the non-linear Poisson-Boltzmann equation for electric double layer potential and the flow field within the polymer layer is governed by a modified Darcy-Brinkman equation; the Cauchy momentum equation governs the fluid flow outside of the polymer layer along with the equation of continuity for incompressible fluid. In order to consider a wide range of pertinent parameters, we adopt a finite difference based numerical tool to solve the coupled set of governing equations. We have analyzed several interesting features of electrokinetic transport phenomena through such a polymer-grafted nanochannel for a wide range of electrostatic and hydrodynamic properties of the polymer layer, parameters describing the non-Newtonian rheology of the background fluid, and the pH and concentration of the bulk electrolyte. In addition, we have also illustrated the ionic current across the undertaken nanochannel and observed that it can be either cation selective, anion selective or non-selective, depending on the critical choice of the pertinent parameters.
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Affiliation(s)
- Bhanuman Barman
- Department of Mathematics, National Institute of Technology Patna, Patna 800005, India
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Wu F, Luo X, Yang J, Ren M, Wei X, Yan Z. A Dual‐Mode Colorimetric/Fluorescent Sensor Comprising Rhodamine B and Piperazine: Response to Acidic pH Values and Investigation of Recognition Mechanism. ChemistrySelect 2020. [DOI: 10.1002/slct.202000140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fang‐hui Wu
- School of Chemistry and Chemical EngineeringAnhui University of Technology Maanshan 243002 China
| | - Xiang‐rui Luo
- School of Chemistry and Chemical EngineeringAnhui University of Technology Maanshan 243002 China
| | - Jun‐qing Yang
- School of Chemistry and Chemical EngineeringAnhui University of Technology Maanshan 243002 China
| | - Mei‐juan Ren
- School of Chemistry and Chemical EngineeringAnhui University of Technology Maanshan 243002 China
| | - Xian‐wen Wei
- School of Chemistry and Chemical EngineeringAnhui University of Technology Maanshan 243002 China
| | - Zhengquan Yan
- School of Chemistry and Chemical EngineeringQufu Normal University Jining Shi, Qufu 273165 China
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