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Open AccessEditorial

Special Feature Organo-Fluorine Chemical Science

by Helmut Martin Hügel and Neale Jackson

Appl. Sci. 2012, 2(2), 558-565; https://doi.org/10.3390/app2020558 - 4 Jun 2012

Cited by 20 | Viewed by 8868

Abstract

Fluorine is the 13th most abundant element and, with other fluorine containing functional groups, is a most effective element in biological substances, pharmaceuticals, agrochemicals, liquid crystals, dyes, polymers and a wide range of consumer products. This reflects its resistance to metabolic change due [...] Read more.

Fluorine is the 13th most abundant element and, with other fluorine containing functional groups, is a most effective element in biological substances, pharmaceuticals, agrochemicals, liquid crystals, dyes, polymers and a wide range of consumer products. This reflects its resistance to metabolic change due to the strength of the C-F bond providing biological stability and the application of its nonstick-interfacial physical characteristics. Its introduction often remains a synthetic challenge. The widespread use of organofluorines has increased the demand for the development of practical and simple reagents and experimental strategies for the incorporation of fluorine into all types of molecular structures and this was the reasoning behind this special feature on Organo-Fluorine Chemical Science.The contributed articles belong to two broad groups: (i) preparation of fluorine materials, polymers; (ii) the synthesis/applications of organo-fluorine molecules. [...] Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

Research

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2487 KiB

Open AccessArticle

Improved Permeate Flux of PVDF Ultrafiltration Membrane Containing PVDF-g-PHEA Synthesized via ATRP

by Kwang-Mo Kim, Sahng Hyuck Woo, Ju Sung Lee, Hyun Sic Park, Jinwon Park and Byoung Ryul Min

Appl. Sci. 2015, 5(4), 1992-2008; https://doi.org/10.3390/app5041992 - 21 Dec 2015

Cited by 17 | Viewed by 7949

Abstract

Polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane combined with polyvinylidene fluoride-graft-2-hydroxyethyl acrylate (PVDF-g-PHEA) was fabricated via non-solvent induced phase separation (NIPS). In this study, PVDF-g-PHEA was synthesized via atom transfer radical polymerization (ATRP) method, and then synthesized graft copolymer was characterized using Fourier transform [...] Read more.

Polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane combined with polyvinylidene fluoride-graft-2-hydroxyethyl acrylate (PVDF-g-PHEA) was fabricated via non-solvent induced phase separation (NIPS). In this study, PVDF-g-PHEA was synthesized via atom transfer radical polymerization (ATRP) method, and then synthesized graft copolymer was characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and thermogravimetry analysis (TGA). Moreover, PVDF membranes containing graft copolymer (PVDF-g-PHEA) showed lower water contact angle value than pristine PVDF membranes. Macrovoid holes were also observed in cross sectional scanning electron microscope (SEM) image of PVDF membrane containing PVDF-g-PHEA. Accordingly, it was confirmed that these characteristics led PVDF membrane blended with graft copolymer has high final permeate flux and normalized flux compared to pristine PVDF membrane. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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725 KiB

Open AccessArticle

Fluorine Based Superhydrophobic Coatings

by Jean-Denis Brassard, D.K. Sarkar and Jean Perron

Appl. Sci. 2012, 2(2), 453-464; https://doi.org/10.3390/app2020453 - 8 May 2012

Cited by 212 | Viewed by 19620

Abstract

Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been [...] Read more.

Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been realized via Stöber process and further functionalized using fluoroalkylsilane (FAS-17) molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles have been spin coated on flat aluminum alloy, silicon and glass substrates. Functionalization of silica nanoparticles with fluorinated groups has been confirmed by Fourier Transform Infrared spectroscopy (FTIR) by showing the presence of C-F and Si-O-Si bonds. The water contact angles and surface roughness increase with the number of spin-coated thin films layers. The critical size of ~119 nm renders aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticle suspended solution. On the other hand, seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150°, contact angle hysteresis was less than 2° having a critical roughness value of ~0.700 µm. The fluorinated silica nanoparticle coated surfaces are also transparent and can be used as paint additives to obtain transparent coatings. Full article

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300 KiB

Open AccessArticle

Further Successes of the Meisenheimer Model

by Jon Baker Baker and Max Muir

Appl. Sci. 2012, 2(2), 443-452; https://doi.org/10.3390/app2020443 - 4 May 2012

Cited by 3 | Viewed by 6300

Abstract

Our simple Meisenheimer model for predicting the principal site for nucleophilic substitution in aromatic perfluorocarbons is further tested on a series of recently published reactions in liquid ammonia primarily from Malykhin and coworkers. The model accurately predicts the experimental results for all of [...] Read more.

Our simple Meisenheimer model for predicting the principal site for nucleophilic substitution in aromatic perfluorocarbons is further tested on a series of recently published reactions in liquid ammonia primarily from Malykhin and coworkers. The model accurately predicts the experimental results for all of the reactions reported further confirming its general applicability. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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248 KiB

Open AccessArticle

Synthesis of Some New Fluorinated Hexahydroquinoline and Acridinedione Derivatives in Trifluoroethanol

by Cosmas O. Okoro, Mumiye A. Ogunwale and Tasneem Siddiquee

Appl. Sci. 2012, 2(2), 368-374; https://doi.org/10.3390/app2020368 - 18 Apr 2012

Cited by 11 | Viewed by 6962

Abstract

This article describes one-pot synthesis of new fluorinated hexahydroquinoline derivatives via unsymmetric Hantzsch reaction involving 5-trifluoromethyl-1,3-cyclohexanedione, aldehydes, acetoacetate ester, and ammonium acetate in trifluoroethanol (TFE). The reaction is simple and rapid with high yield. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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294 KiB

Open AccessArticle

Application of Liquid-Phase Direct Fluorination: Novel Synthetic Methods for a Polyfluorinated Coating Material and a Monomer of a Perfluorinated Polymer Electrolyte Membrane

by Takashi Okazoe, Daisuke Shirakawa and Koichi Murata

Appl. Sci. 2012, 2(2), 327-341; https://doi.org/10.3390/app2020327 - 10 Apr 2012

Cited by 15 | Viewed by 8744

Abstract

A new polyfluorinated anti-staining coating material CF₃O(CF₂CF₂O)_xCF₂-CONHCH₂CH₂CH₂Si(OCH₃)₃ has been developed by utilizing the PERFECT method, which employs a liquid-phase direct fluorination reaction with elemental [...] Read more.

A new polyfluorinated anti-staining coating material CF₃O(CF₂CF₂O)_xCF₂-CONHCH₂CH₂CH₂Si(OCH₃)₃ has been developed by utilizing the PERFECT method, which employs a liquid-phase direct fluorination reaction with elemental fluorine as a key step. Direct fluorination of a partially-fluorinated ester, which was prepared from a non-fluorinated poly(ethylene glycol) and a perfluorinated acyl fluoride, followed by methanolysis, gave the perfluorinated corresponding compound, which was led to the coating material for surface treating agents, and the methyl ester of the starting perfluorinated acyl fluoride. Application to the synthesis of a new perfluorinated bifunctional sulfonate monomer CF₂=CFOCF₂CF₂CF₂OCF(CF₂SO₂F)₂ for polymer electrolyte membranes (PEMs) of fuel cells was also developed. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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599 KiB

Open AccessArticle

Optimization of Fluorine Plasma Treatment for Interface Improvement on HfO₂/In_0.53Ga_0.47As MOSFETs

by Yen-Ting Chen, Yanzhen Wang, Fei Xue, Fei Zhou and Jack C. Lee

Appl. Sci. 2012, 2(1), 233-244; https://doi.org/10.3390/app2010233 - 19 Mar 2012

Cited by 7 | Viewed by 7567

Abstract

This paper reports significant improvements in the electrical performance of In_0.53Ga_0.47As metal-oxide-semiconductor field-effect transistors (MOSFET) by a post-gate CF₄/O₂ plasma treatment. The optimum condition of CF₄/O₂ plasma treatment has been systematically studied and [...] Read more.

This paper reports significant improvements in the electrical performance of In_0.53Ga_0.47As metal-oxide-semiconductor field-effect transistors (MOSFET) by a post-gate CF₄/O₂ plasma treatment. The optimum condition of CF₄/O₂ plasma treatment has been systematically studied and found to be 30 W for 3–5 min. Approximately 5× reduction in interface trap density from 2.8 × 10¹² to 4.9 × 10¹¹ cm⁻²eV⁻¹ has been demonstrated with fluorine (F) incorporation. Subthreshold swing has been improved from 127 to 109 mV/dec. Effective channel mobility has been enhanced from 826 to 1,144 cm²/Vs. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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1918 KiB

Open AccessArticle

Stain Resistance of Cotton Fabrics before and after Finishing with Admicellar Polymerization

by Srinivas Hanumansetty, Jayanta Maity, Rod Foster and Edgar A. O’Rear

Appl. Sci. 2012, 2(1), 192-205; https://doi.org/10.3390/app2010192 - 5 Mar 2012

Cited by 18 | Viewed by 9533

Abstract

Environmental concerns related to perfluoroctanoic acid (PFOA) led to a re-examination of the methods for imparting stain resistance and stain repellency to textiles. Non-PFOA fluoropolymer finishes have been formed on cotton knits by admicellar polymerization, a surface analogue of emulsion polymerization. Fabric samples [...] Read more.

Environmental concerns related to perfluoroctanoic acid (PFOA) led to a re-examination of the methods for imparting stain resistance and stain repellency to textiles. Non-PFOA fluoropolymer finishes have been formed on cotton knits by admicellar polymerization, a surface analogue of emulsion polymerization. Fabric samples were characterized by a drop test, contact angle measurements, SEM, elemental analysis and durability studies. Stain resistance and stain release properties were assessed by reflectance and AATCC tests with results comparing favorably with swatches from commercially available garments. Admicellar polymerization enabled the formation of durable finishes that exhibited high performance in stain resistance and stain repellency. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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1655 KiB

Open AccessArticle

Self-Assembled Fluorinated Organogelators for Surface Modification

by Anilkumar Raghavanpillai and Vincent A. Franco

Appl. Sci. 2012, 2(1), 175-191; https://doi.org/10.3390/app2010175 - 1 Mar 2012

Cited by 11 | Viewed by 8022

Abstract

A new class of alkyl- and perfluoroalkyl-containing urea and amide derivatives was synthesized from amino acid derivatives. Most of these compounds showed excellent gelation behavior in organic solvents at low concentrations. A few organogelators selected from the initial screening were used for surface [...] Read more.

A new class of alkyl- and perfluoroalkyl-containing urea and amide derivatives was synthesized from amino acid derivatives. Most of these compounds showed excellent gelation behavior in organic solvents at low concentrations. A few organogelators selected from the initial screening were used for surface modification of fibrous substrates to create hydrophobic and oleophobic composites. The hydrophobic and oleophobic behaviors of these composites were ascribed to a combination of increased surface roughness and the alkyl/fluorinated functionalities present in the gelator backbone. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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346 KiB

Open AccessArticle

Computational Study on the Acid Catalyzed Reactions of Fluorine-Containing 2,4-Dialkoxy-3,4-dihydro-2H-pyrans with Aromatic Compounds

by Norio Ota, Yasuhiro Kamitori, Ryusuke Shirai, Mizuki Hatakenaka and Etsuji Okada

Appl. Sci. 2012, 2(1), 129-138; https://doi.org/10.3390/app2010129 - 24 Feb 2012

Cited by 3 | Viewed by 7082

Abstract

The reaction of 2,4-diethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyran (1) with aromatic compounds in refluxing acetonitrile in the presence of p-toluenesulfonic acid gave the mixture of 4-aryl-2-trifluoromethyl-4H-pyrans (3) and 6-aryl-1,1,1-trifluorohexa-3,5-dien-2-ones (4). In contrast, the same reaction carried [...] Read more.

The reaction of 2,4-diethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyran (1) with aromatic compounds in refluxing acetonitrile in the presence of p-toluenesulfonic acid gave the mixture of 4-aryl-2-trifluoromethyl-4H-pyrans (3) and 6-aryl-1,1,1-trifluorohexa-3,5-dien-2-ones (4). In contrast, the same reaction carried out in trifluoroacetic acid at ambient temperature afforded 4-aryl-2-ethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyrans (2) selectively. These two types of reactions giving quite different products under each condition were studied on the basis of DFT calculations. Moreover, the proposed mechanism for the reaction of 5-trifluoroacetyl-6-trifluoromethyl-3,4-dihydro-2H-pyran (5) with aromatic compounds affording butadiene derivatives (6) exclusively was also discussed based on the calculations and comparison with the reactivity of pyrylium intermediate (7). Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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391 KiB

Open AccessArticle

A Study of Fluorinated β-Nitrostyrenes as Antimicrobial Agents

by King Lo, Hugh Cornell, Gina Nicoletti, Neale Jackson and Helmut Hügel

Appl. Sci. 2012, 2(1), 114-128; https://doi.org/10.3390/app2010114 - 23 Feb 2012

Cited by 18 | Viewed by 7132

Abstract

The effect of variously fluorine-substituted β-methyl-β-nitrostyrenes on their antimicrobial activity was investigated. Their efficacy was determined by minimum inhibition concentration (MIC) in cultures of Gram positive and Gram negative bacteria and a fungus. Highest activity against the Gram negative bacterium, E.coli, was [...] Read more.

The effect of variously fluorine-substituted β-methyl-β-nitrostyrenes on their antimicrobial activity was investigated. Their efficacy was determined by minimum inhibition concentration (MIC) in cultures of Gram positive and Gram negative bacteria and a fungus. Highest activity against the Gram negative bacterium, E.coli, was achieved with 4-fluorine-aryl substituted β-methyl-β-nitrostyrenes, while most compounds gave excellent results against gram positive bacteria. Importantly, the addition of the β-methyl group profoundly enhanced the antibacterial activity of the compounds tested. The comparative K_D values for the most potent compounds against E.coli were much lower than those required for the gram positive and fungus counterparts. This investigation illustrated that fluorine substituted nitropropenylarenes have enhanced antimicrobial activity suitable for antibiotic applications. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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645 KiB

Open AccessArticle

Novel Fluorinated Indanone, Tetralone and Naphthone Derivatives: Synthesis and Unique Structural Features

by Joseph C. Sloop, Paul D. Boyle, Augustus W. Fountain, Cristina Gomez, James L. Jackson, William F. Pearman, Robert D. Schmidt and Jonathan Weyand

Appl. Sci. 2012, 2(1), 61-99; https://doi.org/10.3390/app2010061 - 1 Feb 2012

Cited by 7 | Viewed by 9197

Abstract

Several fluorinated and trifluoromethylated indanone, tetralone and naphthone derivatives have been prepared via Claisen condensations and selective fluorinations in yields ranging from 22–60%. In addition, we report the synthesis of new, selectively fluorinated bindones in yields ranging from 72–92%. Of particular interest is [...] Read more.

Several fluorinated and trifluoromethylated indanone, tetralone and naphthone derivatives have been prepared via Claisen condensations and selective fluorinations in yields ranging from 22–60%. In addition, we report the synthesis of new, selectively fluorinated bindones in yields ranging from 72–92%. Of particular interest is the fluorination and trifluoroacetylation regiochemistry observed in these fluorinated products. We also note unusual transformations including a novel one pot, dual trifluoroacetylation, trifluoroacetylnaphthone synthesis via a deacetylation as well as an acetyl-trifluoroacetyl group exchange. Solid-state structural features exhibited by these compounds were investigated using crystallographic methods. Crystallographic results, supported by spectroscopic data, show that trifluoroacetylated ketones prefer a chelated cis-enol form whereas fluorinated bindone products exist primarily as the cross-conjugated triketo form. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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682 KiB

Open AccessArticle

Nanoimprint Resist Material Containing Ultraviolet Reactive Fluorine Surfactant for Defect Reduction in Lithographic Fabrication

by Satoshi Takei and Atsushi Sekiguchi

Appl. Sci. 2012, 2(1), 24-34; https://doi.org/10.3390/app2010024 - 16 Jan 2012

Cited by 16 | Viewed by 7516

Abstract

The generated resist based defects on the template in addition to the presence of particles and contaminants is critical for ultraviolet curing of nanoimprint lithographic fabrication. This procedure is proven to be suitable for advanced resist material design under the process conditions. Nanoimprint [...] Read more.

The generated resist based defects on the template in addition to the presence of particles and contaminants is critical for ultraviolet curing of nanoimprint lithographic fabrication. This procedure is proven to be suitable for advanced resist material design under the process conditions. Nanoimprint resist material containing an ultraviolet reactive fluorine surfactant was developed to modify the fundamental surface interactions between resists and the template for defect reduction in nanoimprint patterning replication. The developed acrylate type nanoimprint resist material containing 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-2-hydroxyundecyl acrylate as an ultraviolet reactive fluorine surfactant, indicated excellent patterning dimensional accuracy by minimizing surface free energy, and having the effect of improving the generated resist based defect numbers on the template, with a 500 nm contact hole and 2 μm line patterns, in the replication of 20 nanoimprint process cycles. This desirable concept using an ultraviolet reactive fluorine surfactant with an acrylate group in the acrylate type nanoimprint resist material is one of the most promising processes ready to be incorporated into mass fabrication in the next generation of electronic devices. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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Review

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217 KiB

Open AccessReview

Overview of the Development of the Fluoropolymer Industry

by Hongxiang Teng

Appl. Sci. 2012, 2(2), 496-512; https://doi.org/10.3390/app2020496 - 29 May 2012

Cited by 232 | Viewed by 27102

Abstract

The present review briefly describes the development of the fluoropolymer industry in the past 70 years. Discussed are industrial fluoropolymers including polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidenefluoride, polyvinylfluoride, ETFE, ECTFE, FEP, PFA, THV, Teflon AF and Cytop. Nafion is included as a special functional fluoropolymer material. [...] Read more.

The present review briefly describes the development of the fluoropolymer industry in the past 70 years. Discussed are industrial fluoropolymers including polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidenefluoride, polyvinylfluoride, ETFE, ECTFE, FEP, PFA, THV, Teflon AF and Cytop. Nafion is included as a special functional fluoropolymer material. These industrial fluoropolymers are introduced in the order of their discovery or time of first production, included are their chemical structures, thermal properties, mechanical properties, electrical and electronic properties, optical properties, chemical resistance, oxidative stabilities, weather stabilities, processabilities and their general applications. The main manufacturing companies for the different types of fluoropolymer products are also mentioned. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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521 KiB

Open AccessReview

An Environmentally Friendly Class of Fluoropolyether: α,ω-Dialkoxyfluoropolyethers

by Menghua Wu, Walter Navarrini, Gianfranco Spataro, Francesco Venturini and Maurizio Sansotera

Appl. Sci. 2012, 2(2), 351-367; https://doi.org/10.3390/app2020351 - 11 Apr 2012

Cited by 15 | Viewed by 7813

Abstract

The α,ω-dialkoxyfluoropolyethers (DA-FPEs) characterized by the structure R_HO(CF₂CF₂O)_n(CF₂O)_mR_H have been developed as a new class of environmentally friendly hydrofluoroethers (HFEs) suitable as solvents, long-term refrigerants, cleaning fluids, and heat transfer [...] Read more.

The α,ω-dialkoxyfluoropolyethers (DA-FPEs) characterized by the structure R_HO(CF₂CF₂O)_n(CF₂O)_mR_H have been developed as a new class of environmentally friendly hydrofluoroethers (HFEs) suitable as solvents, long-term refrigerants, cleaning fluids, and heat transfer fluids. Synthetic methodologies for DA-FPEs described here consist of radical-initiated oxypolymerization of olefin, peroxy-elimination reaction in peroxidic perfluoropolyethers (P-PFPEs) and further chemical modification of α,ω-diacylfluoride PFPE. The physical properties of selected α,ω-dimethoxyfluoropolyethers (DM-FPEs) have been evaluated and compared with analogous hydrofluoropolyethers (HFPEs) having -OCF₂H as end-groups. Atmospheric implications and global warming potentials (GWPs) of selected DA-FPEs are also considered. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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628 KiB

Open AccessReview

Silicon-[¹⁸F]Fluorine Radiochemistry: Basics, Applications and Challenges

by Carmen Wängler, Alexey Kostikov, Jun Zhu, Joshua Chin, Björn Wängler and Ralf Schirrmacher

Appl. Sci. 2012, 2(2), 277-302; https://doi.org/10.3390/app2020277 - 28 Mar 2012

Cited by 43 | Viewed by 13119

Abstract

Silicon-[¹⁸F]fluorine (Si-¹⁸F) radiochemistry has recently emerged alongside other unconventional approaches such as aluminum-¹⁸F and boron-¹⁸F based labeling strategies, reshaping the landscape of modern ¹⁸F-radiochemistry. All these novel methodologies are driven by the demand for [...] Read more.

Silicon-[¹⁸F]fluorine (Si-¹⁸F) radiochemistry has recently emerged alongside other unconventional approaches such as aluminum-¹⁸F and boron-¹⁸F based labeling strategies, reshaping the landscape of modern ¹⁸F-radiochemistry. All these novel methodologies are driven by the demand for more convenient ¹⁸F-labeling procedures to further disseminate one of the most sophisticated imaging technologies, Positron Emission Tomography (PET). The PET methodology requires special radionuclides such as ¹⁸F (one of the most prominent examples) to be introduced into bioactive molecules. Si-¹⁸F radiochemistry contributed greatly towards the development of new radiopharmaceuticals for PET imaging. Herein, we describe the radiochemical basics of Si-¹⁸F bond formation, the application of Si-¹⁸F tracers for PET imaging, and additionally, the inherent chemical intricacies of this methodology. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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1250 KiB

Open AccessReview

Nucleic Acid Based Fluorinated Derivatives: New Tools for Biomedical Applications

by Christel Dolain, Amit Patwa, Guilhem Godeau and Philippe Barthélémy

Appl. Sci. 2012, 2(2), 245-259; https://doi.org/10.3390/app2020245 - 23 Mar 2012

Cited by 24 | Viewed by 12801

Abstract

Nucleic acid-based fluorinated derivatives, e.g., nucleosides or oligonucleotides connected to highly fluorinated chains or labeled with one or more fluorine atoms, have been investigated recently due to their high potential for biomedical applications. This review deals with recent works on nucleoside and oligonucleotide [...] Read more.

Nucleic acid-based fluorinated derivatives, e.g., nucleosides or oligonucleotides connected to highly fluorinated chains or labeled with one or more fluorine atoms, have been investigated recently due to their high potential for biomedical applications. This review deals with recent works on nucleoside and oligonucleotide fluorocarbon amphiphiles as well as with properties and applications of fluorine-labeled oligonucleotide analogues. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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5398 KiB

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Oxyfluoride Chemistry of Layered Perovskite Compounds

by Yoshihiro Tsujimoto, Kazunari Yamaura and Eiji Takayama-Muromachi

Appl. Sci. 2012, 2(1), 206-219; https://doi.org/10.3390/app2010206 - 6 Mar 2012

Cited by 75 | Viewed by 17792

Abstract

In this paper, we review recent progress and new challenges in the area of oxyfluoride perovskite, especially layered systems including Ruddlesden-Popper (RP), Dion-Jacobson (DJ) and Aurivillius (AV) type perovskite families. It is difficult to synthesize oxyfluoride perovskite using a conventional solid-state reaction because [...] Read more.

In this paper, we review recent progress and new challenges in the area of oxyfluoride perovskite, especially layered systems including Ruddlesden-Popper (RP), Dion-Jacobson (DJ) and Aurivillius (AV) type perovskite families. It is difficult to synthesize oxyfluoride perovskite using a conventional solid-state reaction because of the high chemical stability of the simple fluoride starting materials. Nevertheless, persistent efforts made by solid-state chemists have led to a major breakthrough in stabilizing such a mixed anion system. In particular, it is known that layered perovskite compounds exhibit a rich variety of O/F site occupation according to the synthesis used. We also present the synthetic strategies to further extend RP type perovskite compounds, with particular reference to newly synthesized oxyfluorides, Sr₂CoO₃F and Sr₃Fe₂O_5+xF₂₋_x (x ~ 0.44). Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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357 KiB

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Enhancement of Brillouin Scattering Signal in Perfluorinated Graded-Index Polymer Optical Fibers

by Yosuke Mizuno and Kentaro Nakamura

Appl. Sci. 2012, 2(1), 46-60; https://doi.org/10.3390/app2010046 - 31 Jan 2012

Cited by 3 | Viewed by 7558

Abstract

Perfluorinated graded-index polymer optical fibers (PFGI-POFs), fabricated by replacing the hydrogen atoms of standard polymethyl methacrylate-based POFs with fluorine atoms, have been extensively studied due to their relatively low propagation loss even at telecommunication wavelength. Recently, Brillouin scattering, which is one of the [...] Read more.

Perfluorinated graded-index polymer optical fibers (PFGI-POFs), fabricated by replacing the hydrogen atoms of standard polymethyl methacrylate-based POFs with fluorine atoms, have been extensively studied due to their relatively low propagation loss even at telecommunication wavelength. Recently, Brillouin scattering, which is one of the most significant nonlinear effects in optical fibers, has been successfully observed in PFGI-POFs at 1.55-μm wavelength. The Brillouin Stokes signal was, however, not large enough for practical applications or for detailed investigations of the Brillouin properties. In this paper, we review our recent work on Stokes signal enhancement. First, we induce stimulated Brillouin scattering based on the so-called pump-probe technique, and discuss its applicability to temperature sensors. Then, we investigate the influence of the core diameter and length of PFGI-POFs on Stokes signal, and observe the Brillouin linewidth narrowing effect. We believe our work is an important technological step toward the implementation of practical Brillouin-based devices and systems including distributed strain and temperature sensors. Full article

(This article belongs to the Special Issue Organo-Fluorine Chemical Science)

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