Intermolecular Exciplex Formation Research Articles

1,4-ジシアノナフタレン－N,N-ジメチルアニリン連結Dyadの結晶状態における分子間エキシプレックス生成

1,4-ジシアノナフタレン－N,N-ジメチルアニリン連結Dyadの結晶状態における分子間エキシプレックス生成

Intermolecular exciplex formation and photoinduced electron transfer of 1,8-naphthalimide dyads in methylated benzenes

In methylated benzene (MB) solvents, 1,8-naphthalimide (NI) derivatives showed markedly red-shifted emission, which originated from an intermolecular exciplex formation between NI and MB in the singlet excited state. The exciplex emission shifted to longer wavelength according to an increase of the oxidation potential of MB. The Stokes shift of the exciplex emission obeyed Lippert–Mataga theory. On the other hand, the exciplex emission of 1,8-naphthalimide-linker-phenothiazine (NI-L-PTZ) dyads was markedly quenched by the linked PTZ. The transient absorption measurements were carried out to investigate the fast quenching process on NI-L-PTZ dyads in p-XYL/CH 3CN. The NI radical ion is predominantly generated from the photoinduced electron transfer (PET) between the singlet excited NI and PTZ. The quantum yields for PET of NI-L-PTZ dyads in p-XYL/CH 3CN were smaller than those in pure CH 3CN. This indicates that the exciplex formation of NI-L-PTZ dyads with MB competitively occurs with the PET process.

Thermal Effect and Quenching of Exciplex Fluorescence of Polystyrene Derivatives by Dimethyl Terephthalate in Solid Films

The effects of added dimethyl terephthalate to the fluorescence emission of poly(4-ethoxystyrene), poly(4-methoxystyrene), poly(4-methoxy α-methyl styrene) and poly(4-methoxyphenyl-styrene) were studied in solid films and in dichloromethane solution. A quenching of the excimer emission was accompanied with the appearance of a strong exciplex emission in solid films. In dichloromethane solution, only quenching of the excimer emission was noticed, but no exciplex emission was detected. Increase in the temperature of solutions or solid films of these polymers caused a decrease in the intensity of exciplex and an increase in the polymer emissions. This thermal effect was attributed to the thermal distraction of the formed exciplex chromophores that can enhance excimer emission. The thermostability of these polymers depends on electronic nature of substituent and their ability to stabilize radicals forming on chain scission. A kinetic model is proposed to account for these observations concerning the singlet excited state of polymers. The activation energies of intermolecular exciplex formation were calculated.

Nanolayered Heterojunctions of Donor and Acceptor Conjugated Polymers of Interest in Light Emitting and Photovoltaic Devices: Photoinduced Electron Transfer at Polythiophene/Polyquinoline Interfaces

Four new nanolayered heterojunctions of electron-donating poly(3-hexylthiophene-2,5-diyl) and poly(3-octylthiophene-2,5-diyl) with two electron-accepting polyquinolines have been prepared, and the photophysical processes occurring at the polymer/polymer interfaces were investigated by photoluminescence (PL) spectroscopy and picosecond time-resolved PL decay dynamics. Observed nearly complete quenching of the steady-state photoluminescence and a factor of 160 shortening of the fluorescence lifetime of the polyquinolines suggested photoinduced electron transfer from polythiophene to polyquinoline at the polyquinoline/polythiophene interfaces. A new, weak and red shifted, emission band centered at 630 nm and reduced lifetimes show the formation of intermolecular exciplexes at the polyquinoline/polythiophene interfaces. This is the first example of intermolecular exciplex formation between two π-conjugated polymers. Exciton diffusion lengths in the polyquinolines were estimated to be 17−22 nm. These results suggest that nanolayered polythiophene/polyquinoline heterojunctions are promising new material systems for the development of photovoltaic devices and for model studies of the photophysics of multicomponent conjugated polymers.

Photochemistry and photopolymerization activity of a novel 3,4-dimethyl-2(3- N, N-dimethylaminopropoxy)thioxanthone initiator

The photochemistry and photopolymerization activity of a novel initiator, 3,4-dimethyl-2-(3- N, N-dimethyl)-n-propoxythioxanthone, has been compared with that of the non-aminated molecule, 3,4-dimethyl-2-n-propoxythioxanthone. Using photodilatometry, the rate of photopolymerization of n-butyl methacrylate is significantly greater for the aminated derivative in the absence or in the presence of a tertiary amine co-synergist. In the former case, luminescence spectroscopy indicates that lower fluorescence quantum yields are consistent with higher rates of intersystem crossing giving correspondingly higher phosphorescence quantum yields. Here the solvent must be competing with any intra- or intermolecular hydrogen bonding between the amine functionality and carbonyl groups. On conventional micro-second flash photolysis, strong transient absorptions are observed due to both the ketyl radical and radical anion species in a non-reductive polar solvent acetonitrile. In this solvent system, intra- and intermolecular exciplex formation is evidently involved in radical formation. Using second order derivative absorption spectroscopy, the thioxanthone chromophore is identified in the structure of poly(methyl methacrylate) prepared using the aminated derivative so confirming that the alkylamino radical is involved in the initiation of polymerization.

Synthesis and exciplex formation of diethyl 2-(9-anthrylmethyl)-2-( p- N, N-dimethylamino-benzyl)malonate in a polymer matrix

A new bichromophoric compound, diethyl 2-(9-anthrylmethyl)-2-( p- N, N-dimethylaminobenzyl)malonate ( 1), was prepared by condensation of diethyl 2-( p- N, N-dimethylaminobenzyl)malonate with 9-chloromethyl anthracene. The corresponding model compound, diethyl 2-(2-anthryl methyl)malonate ( 2), was synthesized by condensation of diethyl malonate with 9-chloromethylanthracene. Exciplex formation was observed both in fluid media and a polymer matrix. The relative exciplex fluorescence intensity in the polymer matrix was strongly dependent on the concentration of compound 1, suggesting intermolecular exciplex formation of 1 in the polymer matrix at concentrations above 10 −3 M. Exciplex formation in fluid media was independent of concentration. The exciplex emission of 1 in the polymer matrix was considerably shifted towards shorter wavelengths (by about 30 nm) as compared with the maximum wavelength of exciplex emission measured in fluid media; this indicates that the interaction between chromophores is enhanced in a solid matrix.

Intermolecular exciplex formation between 1-pyrenylalanine and chiral amines

Steady state and transient fluorescence techniques were applied to investigate the intermolecular exciplex formation of the optically pure enantiomers of 1-pyrenylalanine (A1PME) with chiral p- l-alanino- N,N-dimethylaniline ( l-pAlDMA) and S-α-phenethyl- N,N-dimethylamine ( S-PhEA). The effect of the solvent polarity on the photophysics of these exciplexes was studied. The chiral discrimination in the exciplex formation is very weak. The steric effect of the alanine chain on the structure of the A1PME-pAlDMA exciplex is discussed.

ChemInform Abstract: INTERMOLECULAR EXCIPLEX FORMATION BETWEEN PYRENE DERIVATIVES AND 1,2‐DIMETHYLINDOLE

Chemischer InformationsdienstVolume 16, Issue 15 Physical Organic Chemistry ChemInform Abstract: INTERMOLECULAR EXCIPLEX FORMATION BETWEEN PYRENE DERIVATIVES AND 1,2-DIMETHYLINDOLE J. P. PALMANS, J. P. PALMANSSearch for more papers by this authorM. VAN DER AUWERAER, M. VAN DER AUWERAERSearch for more papers by this authorA. M. SWINNEN, A. M. SWINNENSearch for more papers by this authorF. C. DE SCHRYVER, F. C. DE SCHRYVERSearch for more papers by this author J. P. PALMANS, J. P. PALMANSSearch for more papers by this authorM. VAN DER AUWERAER, M. VAN DER AUWERAERSearch for more papers by this authorA. M. SWINNEN, A. M. SWINNENSearch for more papers by this authorF. C. DE SCHRYVER, F. C. DE SCHRYVERSearch for more papers by this author First published: April 16, 1985 https://doi.org/10.1002/chin.198515047AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue15April 16, 1985 RelatedInformation

Photochemistry of 1-cyanonaphthalene/triethylamine van der Waals complex: Intermolecular exciplex formation under collision free conditions

The van der Waals complex of 1-cyanonaphthalene with triethylamine exhibits fluorescence from the intermolecular exciplex upon electronic excitation. The efficiency of exciplex formation is strongly excitation energy dependent. The excitation of the complex into the origin band shows resonant emission, while excitations into vibronic bands with excess vibrational energies >400 cm−1 lead to the exciplex formation. The exciplex formation efficiency is also dependent on isotopic substitution in 1-cyanonaphthalene. The barrier to the exciplex formation is larger for the deuterated complex. The fluorescence excitation spectrum of the exciplex reveals that the exciplex formation process is favored over other intramolecular relaxation processes over the excess energy range 700–1500 cm−1. These results suggest that van der Waals complexes can be important intermediates in the intermolecular exciplex formation in the vapor phase.

Intermolecular exciplex formation between pyrene derivatives and 1,2-dimethylindole

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntermolecular exciplex formation between pyrene derivatives and 1,2-dimethylindoleJ. P. Palmans, M. Van der Auweraer, A. Swinnen, and F. C. De SchryverCite this: J. Am. Chem. Soc. 1984, 106, 25, 7721–7728Publication Date (Print):December 1, 1984Publication History Published online1 May 2002Published inissue 1 December 1984https://doi.org/10.1021/ja00337a014RIGHTS & PERMISSIONSArticle Views318Altmetric-Citations34LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (865 KB) Get e-Alerts Get e-Alerts

Exciplex formation in aromatic copolymers and photoinduced electron transfer from exciplex to acceptor

AbstractThe exciplex formation in 9‐vinylphenanthrene‐p‐N,N‐dimethylaminostyrene copolymers, its characteristics, and the electron transfer process in polar solvents were studied. The copolymer exhibited a more intense intramolecular exciplex fluorescence than the low‐molecular‐weight model system, phenanthrene‐N,N‐dimethylaniline, in which the intermolecular exciplex formation occurred. Intensities of the exciplex fluorescence, which were unchanged regardless of the copolymer composition, led us to speculate that the efficient energy migration takes place from an excited phenanthrene unit to an exciplex forming site on the polymer chain. The electron transfer in the copolymer‐p‐dicyanobenzene system was studied in polar media. The formation of p‐dicyanobenzene anion radical was measured by flash photolysis and electron spin resonance (ESR). p‐Dicyanobenzene anion radical was generated by the electron transfer process via exciplex and the direct electron transfer process from the excited phenanthrene unit in the copolymer.

The Formation and Electronic Relaxation of Intermolecular Exciplex in the Vapor Phase

Abstract The intermolecular exciplex formation and electronic relaxation of 1,4-dicyanonaphthalene (DCN) with pentamethylbenzene (PMB) in the vapor phase have been studied by means of nanosecond fluorescence spectroscopy. The exciplex formation and decay-rate constants were independent of the excitation energy, while the decay-rate constants of DCN fluorescence was dependent on the excitation energy. The rate constants of the exciplex formation and decay kinetics were discussed in comparison with the collisional relaxation rate of the upper vibrational states.

ChemInform Abstract: THERMODYNAMIC AND KINETIC ASPECTS OF THE INTERMOLECULAR EXCIPLEX FORMATION BETWEEN 2‐METHYLNAPHTHALENE AND ALIPHATIC AMINES

Chemischer InformationsdienstVolume 11, Issue 36 Physical Organic Chemistry ChemInform Abstract: THERMODYNAMIC AND KINETIC ASPECTS OF THE INTERMOLECULAR EXCIPLEX FORMATION BETWEEN 2-METHYLNAPHTHALENE AND ALIPHATIC AMINES F. MEEUS, F. MEEUSSearch for more papers by this authorM. VAN DER AUWERAER, M. VAN DER AUWERAERSearch for more papers by this authorF. C. DE SCHRYVER, F. C. DE SCHRYVERSearch for more papers by this author F. MEEUS, F. MEEUSSearch for more papers by this authorM. VAN DER AUWERAER, M. VAN DER AUWERAERSearch for more papers by this authorF. C. DE SCHRYVER, F. C. DE SCHRYVERSearch for more papers by this author First published: September 9, 1980 https://doi.org/10.1002/chin.198036045AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume11, Issue36September 9, 1980 RelatedInformation

Study of Reactivity of a Chain-Bound Molecular Moiety by Intermolecular Exciplex Formation

Abstract The effect of chain-binding on the reactivity of naphthyl groups towards intermolecular exciplex formation with triethylamine has been investigated. Polyamides of 2,6-bis(N-methyl methyl-amino)naphthalene with the diacid chlorides ClOC(CH2)x COCl (x = 2, 4, 6, and 8), designated P-2, P-4, P-6 and P-8, and 2,5-bis(n-methyl N-acetyl methylamino)naphthalene (MC) have been studied. Fluorescence spectra of dilute solutions of the poly-amides and their model compound have been obtained in the presence of varying amounts of triethylamine (TEA) as a quencher. The variations of exciplex monomer fluorescence intensity ratio, IE/IM, with quencher concentration indicates the following reactivity order: MC > P-8 > P-6 ± P-4 > P-2, which reflects the relative diffusion rate and accessibility of the naphthalene moiety. This order also represents the relative chain flexibilities of the polyamides studied. Monomer fluorescence quenching is explained in terms of a scheme involving formation of an exciplex, and a n...

Thermodynamic and kinetic aspects of the intermolecular exciplex formation between 2-methylnaphthalene and aliphatic amines

Thermodynamic and kinetic aspects of the intermolecular exciplex formation between 2-methylnaphthalene and aliphatic amines

Exciplex Formation and Electron Transfer in a Vinyl Copolymer

Studies have been made on the exciplex formation in a vinyl copolymer, its characteristics, and the electron-transfer process in polar solvents using a p-N,N-dimethylaminostyrene-p-cyanostyrene copolymer. The copolymer was found to exhibit a much more intense intramolecular exciplex fluorescence than the model N,N-dimethylaniline–cyanobenzene system where the intermolecular exciplex formation occurs. The copolymer system has an advantage over the model system in the exciplex formation process but suffers a disadvantage in the process of ionic dissociation in polar solvents. The ionic dissociation for the copolymer system, however, was attained in the presence of a stronger electron acceptor, p-dicyanobenzene, in polar solvents. The results of flash photolysis and exciplex quenching indicated that the p-dicyanobenzene, anion radical was generated by successive electron transfer from the cyanobenzene anion radical portion in the copolymer to p-dicyanobenzene. That is, in the copolymer system, the interaction between the pendant donor and acceptor groups is favored even in the presence of a stronger electron acceptor.

Structural effects in the intermolecular exciplex formation of 2‐methylnaphthalene and tertiary amines

AbstractThe quenching rate constant of 2‐methylnaphthalene (2 MN) with triethylamine (TEA) and N‐methylpiperidine (NMP) in a polar protic solvent is found to be less than diffusion controlled. In a non polar solvent the exciplex stabilisation and entropy of formation indicate a tighter bound complex for the 2 MN‐TEA system than for 2 MN‐NMP. Both observations are interpreted as arising from geometric restrictions in the approach of the amine to the excited 2‐methylnaphthalene.

Intermolecular exciplex formation between benzene and some olefinic compounds

Intermolecular exciplex formation between benzene and some olefinic compounds

Intramolecular exciplex formation in some compounds containing condensed aromatic hydrocarbon and NN-dimethylaniline moieties

Effects of the geometrical restrictions on intramolecular exciplex formation have been studied for some systems containing anthracene or pyrene and NN-dimethylaniline moieties, and it is concluded that a parallel sandwich structure may be favourable but not necessary for intra- and inter-molecular exciplex formation.