Synthesis, spectroscopy and electrochemistry of octaphenoxyphthalocyaninato silicon complexes

2001 ◽  
Vol 05 (07) ◽  
pp. 555-563 ◽  
Author(s):  
M. DAVID MAREE ◽  
TEBELLO NYOKONG
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Organic Solvents ◽  
High Yield ◽  
Cyclic Voltammograms ◽  
H Nmr ◽  
Axial Ligands ◽  
Convenient Route ◽  
Cyclic Voltammetry Data

A number of octaphenoxyphthalocyaninato silicon complexes containing a variety of axial ligands, represented by ( OPh )8 PcSi ( X )2 (where X = chloro 3, hydroxy 4, (4-carboxybenzene) acetato 5, isonicatinato 6, propionato 7, nitrophenoxy 8 and dimethylaminoxy 9) have been synthesized using a convenient route starting with the 4,5-diphenoxy-1,2-dicyanobenzene. 1 H NMR and UV/vis spectra, and the cyclic voltammetry of the complexes are reported. The complexes are obtained in high yield and are soluble in many organic solvents. Cyclic voltammetry revealed two reduction couples and one oxidation couple for these complexes. Analysis of the cyclic voltammograms showed that compounds 6 and 8 were easier to oxidize and more difficult to reduce than the rest. Also cyclic voltammetry data suggested that electron transfer was not governed only by diffusion.

A new fluorescence molecular switch incorporating TTF and tetraphenylporphyrin units

2007 ◽  
Vol 11 (10) ◽  
pp. 729-735 ◽  
Author(s):  
Yibo Liu ◽  
Chengyun Wang ◽  
Meijiang Li ◽  
Sufang Lv ◽  
Guoqiao Lai ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Excited State ◽  
Ground State ◽  
Photoinduced Electron Transfer ◽  
Intramolecular Charge Transfer ◽  
Molecular Switch ◽  
Target Compound ◽  
Chemical Methods ◽  
H Nmr

A donor-σ-acceptor compound incorporating tetrathiafulvalene and tetraphenylporphyrin units was synthesized. The structures of the target compound and its intermediates have been characterized by 1 H NMR, ESI MS, UV-vis, IR and mp. The results of UV-vis and cyclic voltammetry of the compound indicated negligible intramolecular charge transfer interaction in its ground state. The fluorescence and fluorescence lifetime of the compound were reduced, compared to tetraphenylporphyrin, which evidently indicated that photoinduced electron transfer occurred from the tetrathiafulvalene (TTF) unit to the tetraphenylporphyrin unit in the excited state. The fluorescence intensity of the compound could be reversibly modulated by sequential oxidation and reduction of the TTF unit using electrochemical and chemical methods. Therefore, a new fluorescence molecular switch based on TTF and porphyrin units was established.

scholarly journals Facile preparation and isolation of neutral organic electron donors based on 4-dimethylaminopyridine

2018 ◽  
Vol 96 (6) ◽  
pp. 522-525 ◽  
Author(s):  
Julien D. Martin ◽  
C. Adam Dyker
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Inert Atmosphere ◽  
Electron Donors ◽  
High Yield ◽  
Step Procedure ◽  
Organic Electron ◽  
Facile Preparation ◽  
Isolated Neutral

A number of new neutral bis-2-(4-dimethylamino)pyridinylidene electron donors featuring N-akyl groups of varying lengths (propyl, butyl, hexyl, dodecyl) have been prepared from 4-dimethylaminopyridine by means of a simple two-step procedure. Each derivative could be isolated in high yield and could be stored indefinitely under inert atmosphere. The electron donors were chemically oxidized to the corresponding bipyridinium ions, and all compounds were characterized by NMR spectroscopy and cyclic voltammetry. As an emerging class of electron transfer agents, the availability of the isolated neutral bispyridinylidenes should be beneficial for cases that are incompatible with generating the electron donor in situ.

scholarly journals Carbon Nanotube Yarn Microelectrodes Promote High Temporal Measurements of Serotonin Using Fast Scan Cyclic Voltammetry

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1173 ◽  
Author(s):  
Alexander Mendoza ◽  
Thomas Asrat ◽  
Favian Liu ◽  
Pauline Wonnenberg ◽  
Alexander G. Zestos
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Electrode Materials ◽  
Cyclic Voltammograms ◽  
Electron Transfer Kinetics ◽  
Fast Scan Cyclic Voltammetry ◽  
Peak Separation ◽  
Aspect Ratios ◽  
Carbon Fiber Microelectrodes

Carbon fiber-microelectrodes (CFMEs) have been the standard for neurotransmitter detection for over forty years. However, in recent years, there have been many advances of utilizing alternative nanomaterials for neurotransmitter detection with fast scan cyclic voltammetry (FSCV). Recently, carbon nanotube (CNT) yarns have been developed as the working electrode materials for neurotransmitter sensing capabilities with fast scan cyclic voltammetry. Carbon nanotubes are ideal for neurotransmitter detection because they have higher aspect ratios enabling monoamine adsorption and lower limits of detection, faster electron transfer kinetics, and a resistance to surface fouling. Several methods to modify CFMEs with CNTs have resulted in increases in sensitivity, but have also increased noise and led to irreproducible results. In this study, we utilize commercially available CNT-yarns to make microelectrodes as enhanced neurotransmitter sensors for neurotransmitters such as serotonin. CNT-yarn microelectrodes have significantly higher sensitivities (peak oxidative currents of the cyclic voltammograms) than CFMEs and faster electron transfer kinetics as measured by peak separation (ΔEP) values. Moreover, both serotonin and dopamine are adsorption controlled to the surface of the electrode as measured by scan rate and concentration experiments. CNT yarn microelectrodes also resisted surface fouling of serotonin onto the surface of the electrode over thirty minutes and had a wave application frequency independent response to sensitivity at the surface of the electrode.

scholarly journals The voltammetric study of the reduction of tetraalkylammonium perchlorate by Fe(TPP)2−

2007 ◽  
Vol 11 (07) ◽  
pp. 519-523 ◽  
Author(s):  
Michael D. Ryan ◽  
Chathra DeSilva
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Thin Layer ◽  
Alkyl Group ◽  
Activation Parameters ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
H Nmr ◽  
Voltammetric Study ◽  
Tetraethylammonium Ions

Tetraalkylammonium ions react with Fe ( TPP )2− to form Fe ( TPP )( R )− and trialkylamine. The tetrabutylammonium cation was verified to be the source of the alkyl group in the product, Fe ( TPP )( R )−, by using (1 H 5 C 2)3(2 H 5 C 2) N − as the cation and 2 H NMR. The reaction of Fe ( TPP )2− with Bu 4 N − was monitored by cyclic voltammetry and thin layer spectroelectrochemistry. The activation parameters were measured, and were most consistent with an electron transfer (ET) mechanism. The rate of the reaction of tetramethyl and tetraethylammonium ions with Fe ( TPP )2− was also examined. The rate constant decreased significantly as the carbon chain length decreased, which was also consistent with an ET mechanism.

Metallkomplexe mit Tetrapyrrol-Liganden, LII [1]. Synthetische und elektrochemische Untersuchungen an Praseodym-bis(octaethylporphyrinat)-Systemen / Metal Complexes with Tetrapyrrole Ligands, LII [1]. Synthetic and Electrochemical Investigations on Praseodymium-bis(octaethylporphyrinate) Systems

1988 ◽  
Vol 43 (11) ◽  
pp. 1371-1380 ◽  
Author(s):  
Johann W. Buchler ◽  
Martina Kihn-Botulinski ◽  
Bernd Scharbert
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectra ◽  
Mixed Valence ◽  
Electron Systems ◽  
H Nmr ◽  
Transfer Processes ◽  
Reversible Electron Transfer ◽  
Sandwich Type ◽  
Electron Transfer Processes ◽  
Cyclic Voltammetry Data

The preparation of sandwich-type praseodymium-bis(octaethylporphyrinate) systems [Pr(OEP)2]n with different charges -1 ≤ n ≤+1 is described. The following derivatives have been isolated: Praseodymium(III)-hydrogen-bis(octaethylporphyrinate). PrH(OEP)2** (1; n = -1 ) . bis(octaethylporphyrinato)praseodymium(III), Pr(OEP)2 (2; n = 0). and bis(octaethylporphyrinato) praseodymium(III) diiodoaurate(I), [Pr(OEP)2][AuI2] (3; n = +1). For n = 0 or +1, one or both of the porphyrin π-electron systems have defect electrons. The compounds are identified by UV/VIS/NIR, IR and 1H NMR spectra. The cyclic voltammetry data of the "mixed valence' species Pr(OEP)2 in N.N-dimethylformamide are interpreted in terms of three reversible electron transfer processes. The behaviour of PrH(OEP)2 is complicated by a deprotonation occurring during the electrochemical experiment.

Electrochemical oxidation of 6-propionyl-2-(N,N-dimethylamino)naphthalene (prodan) in acetonitrile on Pt electrodes: Reversible dimerization of prodan radical cations

2002 ◽  
Vol 80 (9) ◽  
pp. 1232-1241 ◽  
Author(s):  
Marcela Beatriz Moressi ◽  
María Alicia Zón ◽  
Héctor Fernández
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Diffusion Coefficient ◽  
Electrochemical Oxidation ◽  
Digital Simulation ◽  
Formation Rate ◽  
Radical Cations ◽  
Cyclic Voltammograms ◽  
Controlled Potential ◽  
Reversible Dimerization

The electrooxidation of 6-propionyl-2-(N,N-dimethylamino)naphthalene (prodan) has been investigated for the first time. It has been performed on both conventional size platinum electrodes and platinum ultramicroelectrodes in acetonitrile by cyclic voltammetry with convolution analysis and controlled-potential electrolysis. The voltammetric responses at room temperature are similar to those corresponding to a kinetically controlled anodic electron-transfer process. Cyclic voltammetry measurements were also carried out at different concentrations of prodan and at different temperatures. Chemical transformation of the radical monocation formed after the electrochemical oxidation of prodan, as deduced from reverse controlled potential bulk electrolysis and cyclic voltammetry measurements, gives evidence for the reversible dimerization of prodan radical cations. Both diagnostic criteria and digital simulation confirm that radical–radical coupling is the reversible chemical reaction coupled to the initial electron transfer step, to give the corresponding dimeric dication. The kinetic and thermodynamic parameters for the first electron transfer reaction and the dimerization process were estimated from digital simulation at 293 K. Values of 8.0 × 106 M–1 and 3.2 × 105 M–1 s–1 were determined for the dimerization reaction equilibrium constant and the dimer formation rate constant, respectively. The diffusion coefficient of prodan was determined from both limiting currents from convoluted cyclic voltammograms as well as limiting currents on ultramicroelectrodes. For such cases where the electron number exchanged in the electrode process is unknown, a method derived from the combination of data previously indicated is also proposed to obtain the diffusion coefficient of the electroactive species.Key words: prodan, cyclic voltammetry, reaction mechanism, reversible dimerization, electron transfer reactions, radical cation.

Studies on electrooxidation of lignin and lignin model compounds. Part 1: Direct electrooxidation of non-phenolic lignin model compounds

Holzforschung ◽  
2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Takumi Shiraishi ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Carbonyl Compounds ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Bulk Electrolysis ◽  
Lignin Model ◽  
Dimeric Compound ◽  
High Yields ◽  
Short Time

Abstract The direct anodic oxidation of non-phenolic lignin model compounds was investigated to understand their basic behaviors. The results of cyclic voltammetry (CV) studies of monomeric model, such as 1-(4-ethoxy-3-methoxyphenyl)ethanol, are interpreted as the oxidation for Cα-carbonylation did not proceed in the reaction without a catalyst, but a base promotes this reaction. Indeed, the bulk electrolyses of the monomeric lignin model compounds with 2,6-lutidine afforded the corresponding Cα-carbonyl compounds in high yields (60–80%). It is suggested that deprotonation at Cα-H in the ECEC mechanism (E=electron transfer and C=chemical step) is important for Cα-carbonylation. In the uncatalyzed bulk electrolysis of a β-O-4 model dimeric compound, 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether, the corresponding Cα-carbonyl compound was not detected but as a result of Cα-Cβcleavage 4-O-ethylvanillin was found in 40% yield. In the electrolysis reaction in the presence of 2,6-lutidine (as a sterically hindered light base), the reaction stopped for a short time unexpectedly. These results indicate the different electrochemical behavior of simple monomeric model compounds and dimeric β-O-4 models. The conclusion is that direct electrooxidation is unsuitable for Cα-carbonylation of lignin.

Synthesis and spectral characterization of bis(β-diketonato)zirconium(IV) and -hafnium(IV) phthalocyaninates

2002 ◽  
Vol 06 (02) ◽  
pp. 114-121 ◽  
Author(s):  
L. A. Tomachynski ◽  
V. Ya. Chernii ◽  
S. V. Volkov
Keyword(s):  
Organic Solvents ◽  
Elemental Analysis ◽  
Central Atom ◽  
Spectral Characterization ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Cl Atoms

The reaction of PcMCl 2 ( M = Zr , Hf ) with β-diketones is reported. 1 H NMR and elemental analysis suggest the substitution of two Cl atoms for two β-diketone fragments takes place as a result of this reaction and the complexes PcM(β-dik)2 are formed. All obtained complexes are stable and highly soluble in most organic solvents. The data from 1 H and 19 F NMR, and UV-vis spectroscopy suggest the coordination of two β-diketone ligands in a cis geometry about the central atom of the macrocycle. It was shown bis(β-diketonato)zirconium(IV) and hafnium(IV) phthalocyanines containing β-diketones with donor or acceptor groups or with bulky substituents can be obtained.

Molecular design and synthesis of fluorescence PET (photo-induced electron transfer) sensors for detection of water in organic solvents

RSC Advances ◽  
2013 ◽  
Vol 3 (45) ◽  
pp. 23255 ◽  
Author(s):  
Yousuke Ooyama ◽  
Koji Uenaka ◽  
Ai Matsugasako ◽  
Yutaka Harima ◽  
Joji Ohshita
Keyword(s):  
Electron Transfer ◽  
Organic Solvents ◽  
Molecular Design ◽  
Design And Synthesis ◽  
Photo Induced Electron Transfer
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