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Wang Z, Ju S, Wang Y, Zhang R, Ma L, Song J, Lin K. The isosbestic point in the Raman spectra of the hydration shell. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 317:124413. [PMID: 38728849 DOI: 10.1016/j.saa.2024.124413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/16/2024] [Accepted: 05/05/2024] [Indexed: 05/12/2024]
Abstract
Isosbestic point is often observed in a series of spectra, but their interpretation is still controversial, such as whether the continuum model can produce an isosbestic point. In order to answer this question, the Raman spectra of hydration shell with continuous distribution structure in different ionic aqueous solutions were separated by Raman ratio spectra, and an isosbestic point was successfully observed. Our experimental results show that the continuum model can indeed produce the isosbestic point. In order to deepen the understanding of the isosbestic point, we calculate the first moment of the Raman spectra and conduct molecular dynamics (MD) simulations. Both experimental and theoretical findings indicate that elevated temperatures lead to increased disorder among water molecules within the hydration shell.
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Affiliation(s)
- Zhiqiang Wang
- School of Physics, Xidian University, Xi'an, 710071, P. R. China
| | - Siwen Ju
- School of Physics, Xidian University, Xi'an, 710071, P. R. China
| | - Yuxi Wang
- School of Flexible Electronics (SOFE) & State Key Laboratory of Optoelectronic Materials and Technologies (OEMT), Sun Yat-sen University, Shenzhen, 5181071, P. R. China
| | - Ruiting Zhang
- School of Physics, Xidian University, Xi'an, 710071, P. R. China.
| | - Lin Ma
- School of Physics, Xidian University, Xi'an, 710071, P. R. China
| | - Jiangluqi Song
- School of Physics, Xidian University, Xi'an, 710071, P. R. China
| | - Ke Lin
- School of Physics, Xidian University, Xi'an, 710071, P. R. China; Interdisciplinary Research Center of Smart Sensor, Xidian University, Xi'an, 710071, P. R. China.
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2
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Ditter AS, Smiles DE, Lussier D, Altman AB, Bachhav M, He L, Mara MW, Degueldre C, Minasian SG, Shuh DK. Chemical and elemental mapping of spent nuclear fuel sections by soft X-ray spectromicroscopy. JOURNAL OF SYNCHROTRON RADIATION 2022; 29:67-79. [PMID: 34985424 PMCID: PMC8733983 DOI: 10.1107/s1600577521012315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/20/2021] [Indexed: 05/03/2023]
Abstract
Soft X-ray spectromicroscopy at the O K-edge, U N4,5-edges and Ce M4,5-edges has been performed on focused ion beam sections of spent nuclear fuel for the first time, yielding chemical information on the sub-micrometer scale. To analyze these data, a modification to non-negative matrix factorization (NMF) was developed, in which the data are no longer required to be non-negative, but the non-negativity of the spectral components and fit coefficients is largely preserved. The modified NMF method was utilized at the O K-edge to distinguish between two components, one present in the bulk of the sample similar to UO2 and one present at the interface of the sample which is a hyperstoichiometric UO2+x species. The species maps are consistent with a model of a thin layer of UO2+x over the entire sample, which is likely explained by oxidation after focused ion beam (FIB) sectioning. In addition to the uranium oxide bulk of the sample, Ce measurements were also performed to investigate the oxidation state of that fission product, which is the subject of considerable interest. Analysis of the Ce spectra shows that Ce is in a predominantly trivalent state, with a possible contribution from tetravalent Ce. Atom probe analysis was performed to provide confirmation of the presence and localization of Ce in the spent fuel.
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Affiliation(s)
- Alexander Scott Ditter
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
| | - Danil E. Smiles
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
| | - Daniel Lussier
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
- Department of Chemistry, University of California Berkeley, 420 Lattimer Hall, Berkeley, CA 94720, USA
| | - Alison B. Altman
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
- Department of Chemistry, University of California Berkeley, 420 Lattimer Hall, Berkeley, CA 94720, USA
| | - Mukesh Bachhav
- Idaho National Laboratory, 1955 N. Freemont Avenue, Idaho Falls, ID 83415, USA
| | - Lingfeng He
- Idaho National Laboratory, 1955 N. Freemont Avenue, Idaho Falls, ID 83415, USA
| | - Michael W. Mara
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
- Department of Chemistry, University of California Berkeley, 420 Lattimer Hall, Berkeley, CA 94720, USA
| | - Claude Degueldre
- Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW, United Kingdom
| | - Stefan G. Minasian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
| | - David K. Shuh
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
- Correspondence e-mail:
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Sahu G, Banerjee A, Samanta R, Mohanty M, Lima S, Tiekink ERT, Dinda R. Water-Soluble Dioxidovanadium(V) Complexes of Aroylhydrazones: DNA/BSA Interactions, Hydrophobicity, and Cell-Selective Anticancer Potential. Inorg Chem 2021; 60:15291-15309. [PMID: 34597028 DOI: 10.1021/acs.inorgchem.1c01899] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Five new anionic aqueous dioxidovanadium(V) complexes, [{VO2L1,2}A(H2O)n]α (1-5), with the aroylhydrazone ligands pyridine-4-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)hydrazide (H2L1) and furan-2-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)hydrazide (H2L2) incorporating different alkali metals (A = Na+, K+, Cs+) as countercation were synthesized and characterized by various physicochemical techniques. The solution-phase stabilities of 1-5 were determined by time-dependent NMR and UV-vis, and also the octanol/water partition coefficients were obtained by spectroscopic techniques. X-ray crystallography of 2-4 confirmed the presence of vanadium(V) centers coordinated by two cis-oxido-O atoms and the O, N, and O atoms of a dianionic tridentate ligand. To evaluate the biological behavior, all complexes were screened for their DNA/protein binding propensity through spectroscopic experiments. Finally, a cytotoxicity study of 1-5 was performed against colon (HT-29), breast (MCF-7), and cervical (HeLa) cancer cell lines and a noncancerous NIH-3T3 cell line. The cytotoxicity was cell-selective, being more active against HT-29 than against other cells. In addition, the role of hydrophobicity in the cytotoxicity was explained in that an optimal hydrophobicity is essential for high cytotoxicity. Moreover, the results of wound-healing assays indicated antimigration in case of HT-29 cells. Remarkably, 1 with an IC50 value of 5.42 ± 0.15 μM showed greater activity in comparison to cisplatin against the HT-29 cell line.
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Affiliation(s)
- Gurunath Sahu
- Department of Chemistry, National Institute of Technology, Rourkela, 769008 Odisha, India
| | - Atanu Banerjee
- Department of Chemistry, National Institute of Technology, Rourkela, 769008 Odisha, India
| | - Rajib Samanta
- Department of Chemistry, National Institute of Technology, Rourkela, 769008 Odisha, India
| | - Monalisa Mohanty
- Department of Chemistry, National Institute of Technology, Rourkela, 769008 Odisha, India
| | - Sudhir Lima
- Department of Chemistry, National Institute of Technology, Rourkela, 769008 Odisha, India
| | - Edward R T Tiekink
- Research Centre for Crystalline Materials, School of Medical and Life Sciences, 5 Jalan Universiti, Sunway University, Bandar Sunway 47500, Selangor Darul Ehsan, Malaysia
| | - Rupam Dinda
- Department of Chemistry, National Institute of Technology, Rourkela, 769008 Odisha, India
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Zhang N, Tang J, Ma Y, Liang M, Zeng D, Hefter G. A spectroscopic study of solvent effects on the formation of Cu(ii)-chloride complexes in aqueous solution. Phys Chem Chem Phys 2021; 23:6807-6814. [PMID: 33724283 DOI: 10.1039/d0cp05243d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A combination of electronic (UV-vis) and X-ray absorption (EXAFS, XANES) spectroscopies has been used to investigate the formation of copper(ii)/chloride complexes in concentrated aqueous solutions. It is established that lowering the water activity by the addition of Mg(ClO4)2 at a constant Cl-/Cu(ii) ratio results in the replacement of water molecules by Cl- ions in the primary coordination shell of Cu(ii). This behavior closely parallels the effect of increasing the Cl-/Cu(ii) ratio and demonstrates that full understanding of the stoichiometry and structures of the complexes formed in concentrated metal-ion chloride solutions requires explicit consideration of the role of the solvent.
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Affiliation(s)
- Ning Zhang
- College of Science, Central South University of Forestry and Technology, Changsha 410004, Hunan, P. R. China.
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5
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Abstract
Based on Beer's law, it is assumed that the absorbance of a mixture is that of the neat materials weighted by their relative amounts (linear mixing rule). In this contribution, we show that this is an assumption that holds only under various approximations for which no change of the chemical interactions is just one among several. To understand these approximations, which lead incrementally to different well known mixing rules, we finally derive the linear mixing rule from the Lorentz-Lorenz relation, with the first approximation that the local electric field is correctly described in this relation. Further levels of approximation are that the local field equals the applied field (Newton-Laplace mixing rule) and that the change of the index of refraction and, equivalently, absorption is weak (Gladstone-Dale/Arago-Biot mixing rule). Even then the linear mixing rule is only strictly valid if the indices of refraction in the transparency region at higher frequency than the absorption have the same value and the mixing is homogeneous relative to the resolving power of the light ("micro-homogeneous"). Under these preconditions, linear mixing of the individual absorbances is established. We illustrate the spectral differences between the different mixing rules, all of which are based on volume and not on mass fractions, with examples. For micro-heterogeneous samples, a different linear mixing rule governs the optical properties, which refers to the experimental quantities, reflectance, and transmittance. As a result, for such samples, mixtures of already comparably high content give only weak signals due to band flattening, which are hard to distinguish from baseline effects.
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Affiliation(s)
- Thomas G Mayerhöfer
- Leibniz Institute of Photonic Technology (IPHT), Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology (IPHT), Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
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6
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Mayerhöfer TG, Pahlow S, Popp J. The Bouguer-Beer-Lambert Law: Shining Light on the Obscure. Chemphyschem 2020; 21:2029-2046. [PMID: 32662939 PMCID: PMC7540309 DOI: 10.1002/cphc.202000464] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/10/2020] [Indexed: 01/21/2023]
Abstract
The Beer-Lambert law is unquestionably the most important law in optical spectroscopy and indispensable for the qualitative and quantitative interpretation of spectroscopic data. As such, every spectroscopist should know its limits and potential pitfalls, arising from its application, by heart. It is the goal of this work to review these limits and pitfalls, as well as to provide solutions and explanations to guide the reader. This guidance will allow a deeper understanding of spectral features, which cannot be explained by the Beer-Lambert law, because they arise from electromagnetic effects/the wave nature of light. Those features include band shifts and intensity changes based exclusively upon optical conditions, i. e. the method chosen to record the spectra, the substrate and the form of the sample. As such, the review will be an essential tool towards a full understanding of optical spectra and their quantitative interpretation based not only on oscillator positions, but also on their strengths and damping constants.
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Affiliation(s)
- Thomas G. Mayerhöfer
- Spectroscopy/ImagingLeibniz Institute of Photonic TechnologyAlbert-Einstein-Str. 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich Schiller University, JenaHelmholtzweg 407743JenaGermany
| | - Susanne Pahlow
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich Schiller University, JenaHelmholtzweg 407743JenaGermany
| | - Jürgen Popp
- Spectroscopy/ImagingLeibniz Institute of Photonic TechnologyAlbert-Einstein-Str. 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich Schiller University, JenaHelmholtzweg 407743JenaGermany
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7
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Krishnamoorthy K, Kewalramani S, Ehlen A, Moreau LM, Mirkin CA, Olvera de la Cruz M, Bedzyk MJ. Enzymatic Degradation of DNA Probed by In Situ X-ray Scattering. ACS NANO 2019; 13:11382-11391. [PMID: 31513370 DOI: 10.1021/acsnano.9b04752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Label-free in situ X-ray scattering from protein spherical nucleic acids (Pro-SNAs, consisting of protein cores densely functionalized with covalently bound DNA) was used to elucidate the enzymatic reaction pathway for the DNase I-induced degradation of DNA. Time-course small-angle X-ray scattering (SAXS) and gel electrophoresis reveal a two-state system with time-dependent populations of intact and fully degraded DNA in the Pro-SNAs. SAXS shows that in the fully degraded state, the DNA strands forming the outer shell of the Pro-SNA were completely digested. SAXS analysis of reactions with different Pro-SNA concentrations reveals a reaction pathway characterized by a slow, rate determining DNase I-Pro-SNA association, followed by rapid DNA hydrolysis. Molecular dynamics (MD) simulations provide the distributions of monovalent and divalent ions around the Pro-SNA, relevant to the activity of DNase I. Taken together, in situ SAXS in conjunction with MD simulations yield key mechanistic and structural insights into the interaction of DNA with DNase I. The approach presented here should prove invaluable in probing other enzyme-catalyzed reactions on the nanoscale.
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8
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Ganguly A, Das S. Compaction-induced strengthening of intercalation within RNA double helices at high ionic strength of the medium: Spectral elucidation and anomalous thermodynamics. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Tikhomirova AA, Tcyrulnikov NA, Wilson RM. Synthesis, characterization, DNA binding and cleaving properties of photochemically activated phenanthrene dihydrodioxin. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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10
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Modulation of probe-genomic DNA interaction within the confined interior of a reverse micelle: Is the bulk-like properties of water truly achieved in large reverse micelles? Int J Biol Macromol 2018; 118:1203-1210. [PMID: 29969635 DOI: 10.1016/j.ijbiomac.2018.06.180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/29/2018] [Accepted: 06/28/2018] [Indexed: 11/20/2022]
Abstract
The prime motivation of the present study is to explore the effect of reverse micellar confinement on the binding interaction of an anthracene-based probe 9-methyl anthroate with herring-sperm DNA. The structural modification of the genomic DNA from its native B-form to the non-native C-form and subsequently to the condensed Ψ-form as a function of the level of hydration (W0, defined as [water] / [surfactant]) of the reverse micellar core is found to reveal a remarkable regulatory role on the stability of the stacking interaction (intercalation) of the probe within the DNA helix; the interaction being progressively stabilized at higher W0. Particularly, a close perusal of the dynamical aspects of the interaction is found to be counter-intuitive to the popular notion of the properties of the confined water within the reverse micelles typically approaching bulk-like properties at sufficiently high hydration levels (W0 > 10).
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11
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Ichimura K. Isosbestic Points Do Not Always Work as the Measure to Determine the Oneness of a Reaction as Exemplified by the Photoisomerization of Azobenzene Tethered to Polymer Chains. CHEM LETT 2018. [DOI: 10.1246/cl.180120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kunihiro Ichimura
- R & D Center, Murakami Co. Ltd, 1-6-12 Ohnodai, Midori-ku, Chiba 267-0056, Japan
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12
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Bilger D, Figueroa JA, Redeker ND, Sarkar A, Stefik M, Zhang S. Hydrogen-Bonding-Directed Ordered Assembly of Carboxylated Poly(3-Alkylthiophene)s. ACS OMEGA 2017; 2:8526-8535. [PMID: 31457389 PMCID: PMC6645037 DOI: 10.1021/acsomega.7b01361] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/20/2017] [Indexed: 06/10/2023]
Abstract
Hydrogen-bonding-induced ordered assembly of poly(3-alkylthiophene)s derivatives bearing carboxylic acid groups has been investigated from diluted and concentrated solutions to solid films using ultraviolet-visible absorption spectroscopy, polarized optical microscopy, and four-point probe conductivity measurements. In dilute solutions, the polymer undergoes a spontaneous structural transition from disordered coil-like to ordered rodlike conformations, which is evidenced by time-dependent chromism. Many factors such as alkyl-chain length, types of solvents, and temperature are studied to understand the assembly behavior. Transition kinetics of the assembly process reveals a universal second-order rate law, indicating an intermolecular origin due to hydrogen bonding. When more concentrated, hydrogen bonding drives nematic liquid-crystalline gelation above a critical concentration and the gels are thermally reversible. Under an appropriate balance of mechanical and thermal stresses, uniform liquid-crystalline monodomains are obtained through the application of a mechanical shear force. The dried films made from the sheared solutions display both optical and electrical anisotropies, with a more than 200% increase in charge transport parallel to the direction of shear as opposed to that in the perpendicular one.
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Affiliation(s)
- David
W. Bilger
- Department
of Chemistry and Biochemistry, California
Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Jose A. Figueroa
- Department
of Chemistry and Biochemistry, California
Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Neil D. Redeker
- Department
of Chemistry and Biochemistry, California
Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Amrita Sarkar
- Department
of Chemistry and Biochemistry, University
of South Carolina, Columbia, South Carolina 29208, United States
| | - Morgan Stefik
- Department
of Chemistry and Biochemistry, University
of South Carolina, Columbia, South Carolina 29208, United States
| | - Shanju Zhang
- Department
of Chemistry and Biochemistry, California
Polytechnic State University, San Luis Obispo, California 93407, United States
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Chung HJ, Ko DY, Moon HJ, Jeong B. EF-Hand Mimicking Calcium Binding Polymer. Biomacromolecules 2016; 17:1075-82. [DOI: 10.1021/acs.biomac.5b01694] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Hee Jung Chung
- Department of Chemistry and
Nanoscience, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea
| | - Du Young Ko
- Department of Chemistry and
Nanoscience, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea
| | - Hyo Jung Moon
- Department of Chemistry and
Nanoscience, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea
| | - Byeongmoon Jeong
- Department of Chemistry and
Nanoscience, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea
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14
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Parker VD, Li Z, Hao W. Is the Single-Transition-State Model Appropriate for the Fundamental Reactions of Organic Chemistry? Experimental Methods and Data Treatment, Pertinent Reactions, and Complementary Computational Studies. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2014. [DOI: 10.1016/b978-0-12-800256-8.00001-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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GUCHHAIT BISWAJIT, PRADHAN TUHIN, BISWAS RANJIT. Effects of acid concentration on intramolecular charge transfer reaction of 4-(azetidinyl) benzonitrile in solution. J CHEM SCI 2014. [DOI: 10.1007/s12039-013-0558-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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17
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Gana FZ, Rashid I, Badwan A, Alkhamis KA. Determination of solid-state acidity of chitin-metal silicates and their effect on the degradation of cephalosporin antibiotics. J Pharm Sci 2012; 101:2398-407. [PMID: 22499263 DOI: 10.1002/jps.23142] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/06/2012] [Accepted: 03/16/2012] [Indexed: 11/11/2022]
Abstract
It was of interest to determine the solid-state acidity of chitin-metal silicate coprocessed excipients and to correlate this acidity to the chemical stability of cefotaxime sodium in the presence of the aforementioned excipients. The solid-state acidities of chitin aluminum silicate, chitin magnesium silicate, and chitin calcium silicate were determined by reflectance spectroscopy using structurally different dye molecules. The chemical stability of cefotaxime sodium was assessed at 50 °C in a 4% (w/v) slurry system in the pH range 6.6-10.5 and in the solid-state in the Hammett acidity range 6.1-7.8. The solid-state acidity was found to be reproducible because one or more structurally different dye molecules gave reliable solid-state acidity values. A significant discrepancy in pH stability profile of cefotaxime sodium between the solid-state and the slurry system was observed. Furthermore, chitin aluminum silicate showed minimum drug stability in the solid-state, close to where the maximum drug stability in the slurry was observed. This unexpected effect might be ascribed to the catalytic properties of chitin aluminum silicate. The slurry method was not able to predict efficiently the solid-state surface acidity and stability of cefotaxime sodium. Moreover, the solid-state chemical stability might be influenced by factors other than the solid-state acidity.
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Affiliation(s)
- Fatima Zohra Gana
- Faculty of Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
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18
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Novel ferrocene derivatized poly(2,5-dithienylpyrrole)s: Optoelectronic properties, electrochemical copolymerization. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2011.12.097] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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19
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Boudouris BW, Ho V, Jimison LH, Toney MF, Salleo A, Segalman RA. Real-Time Observation of Poly(3-alkylthiophene) Crystallization and Correlation with Transient Optoelectronic Properties. Macromolecules 2011. [DOI: 10.1021/ma201316a] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bryan W. Boudouris
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Victor Ho
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Leslie H. Jimison
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Michael F. Toney
- Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States
| | - Alberto Salleo
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Rachel A. Segalman
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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20
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Panda D, Datta A. Implications of area normalization of multi-component spectra. APPLIED SPECTROSCOPY 2008; 62:341-344. [PMID: 18339246 DOI: 10.1366/000370208783759740] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Debashis Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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21
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Gao Y, Wang CC, Wang L, Wang HL. Conjugated polyelectrolytes with pH-dependent conformations and optical properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:7760-7. [PMID: 17559239 DOI: 10.1021/la063536s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We report here the synthesis and characterization of two new conjugated polymers: poly{2,5-bis[3-(N,N-diethylammonium acetate)-1-oxapropyl]-1,4-phenylenevinylene} (P1') and poly{2,5-bis[3-(N,N,N-triethylammonium bromide)-1-oxapropyl]-1,4-phenylenevinylene} (P2). Both polymers exhibit unique pH-dependent optical properties in aqueous solution. These pH-dependent optical properties are attributed to the mutual electrostatic repulsions of positive charges pendent on the benzene rings. This electrostatic repulsion leads to an increased or decreased torsional angle in the conjugated backbone, thus affecting the effective conjugation length of these polymers. The UV-vis spectra of P1 in various pH solutions exhibit a near-isosbestic point, which indicates changes in the composition of the two distinct conformations (the charged and the neutral forms). The transition between the highly charged state and the neutral state was clearly observed in the UV-vis and photoluminescence studies on both P1 and P2. This transition is particularly sensitive in the pH range from 6.2 to 7.0, a range that would allow the detection of minor environmental changes. P2 has a quantum efficiency of 14% in water, which is considered to be relatively high among water-soluble PPVs.
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Affiliation(s)
- Yuan Gao
- Physical Chemistry and Spectroscopy, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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