Naphthalene Dimer Research Articles

Effects of the higher electron correlation correction on the calculated intermolecular interaction energies of benzene and naphthalene dimers: comparison between MP2 and CCSD(T) calculations

Intermolecular interaction energies of parallel and T-shape benzene dimers and parallel naphthalene dimer were calculated with MP2, MP3, MP4(SDQ), MP4(SDTQ), CCSD and CCSD(T) electron correlation corrections using several basis sets. The MP2 calculations considerably overestimated the attraction compared to the CCSD(T) ones. The MP2 correlation interaction energies, the differences between the HF and MP2 interaction energies, were 21–38% larger than the corresponding CCSD(T) ones. The MP4(SDQ) and CCSD calculations substantially underestimated the attraction compared to MP4(SDTQ) and CCSD(T), which indicated the importance of triple excitation. The estimated CCSD(T) interaction energies of the three dimers with reasonably large basis sets were −1.74, −2.50 and −5.69 kcal/mol, respectively.

Time-Resolved EPR and Optical Studies of Intermoiety Interactions in the Lowest Triplet State of L-Shaped Dimers of Naphthalene: Conformation Dependence of Excitation Exchange Interaction

Time-resolved EPR (TREPR), transient absorption, and phosphorescence spectra have been measured in solid matrixes at 77 K for the covalently linked L-shaped dimers of naphthalene, in which the in-plane long axes of the two naphthalene moieties are parallel and the in-plane short axes make an angle. The zero-field splitting (ZFS) parameters obtained by simulation of the TREPR spectra are consistent with the dimer geometries, if it is assumed that excitation exchange interaction is responsible for the small D values of the dimers relative to the monomer. The tilt angle in the triplet state is significantly smaller for the dimers exhibiting excimeric phosphorescence than those exhibiting monomeric emission. Comparison of the spectral position and lifetime of phosphorescence from the L-shaped dimers with those from the sandwich dimers indicates that the excitation exchange interaction is substantially greater for the L-shaped dimers as compared to the sandwich dimers. The proposal that the preferred conformation of the triplet excimer of naphthalene is L-shaped, rather than sandwich, is supported by the measurements.

Transient Absorption Probe of Intermolecular Triplet Excimer of Naphthalene in Fluid Solutions: Identification of the Species Based on Comparison to the Intramolecular Triplet Excimers of Covalently-Linked Dimers

We report here the observation of the laser-induced transient absorption spectrum of intermolecular triplet excimers of naphthalene in fluid solution. This assignment is confirmed by comparison to the transient absorption spectra of the intramolecular triplet excimers of covalently linked dimers of naphthalene and quinoxaline.

Excitonic couplings and electronic coherence in bridged naphthalene dimers.

The electronic excitations of naphthalene and a family of bridged naphthalene dimers are calculated and analyzed by using the Collective Electronic Oscillator method combined with the oblique Lanczos algorithm. All experimentally observed trends in absorption profiles and radiative lifetimes are reproduced. Each electronic excitation is linked to the corresponding real-space transition density matrix, which represents the motions of electrons and holes created in the molecule by photon absorption. Two-dimensional plots of these matrices help visualize the degree of exciton localization and explain the dependence of the electronic interaction between chromophores on their separation.

Electronic Energy Transfer in Multichromophoric Arrays. A Sequential and Superexchange Dynamics Study

The dynamics of electronic energy transfer (EET) from a photoexcited donor to an acceptor connected by an intermediate bridge is investigated using the Haken, Strobl, and Reineker stochastic Liouville equations (HSR). The effects of the system−bath interaction on both the superexchange and sequential energy transfer mechanisms via the bridge are discussed and subsequently used to explain the role of the bridge in mediating EET. We examine the mechanisms of EET in a rigidly linked naphthalene dimer where the chromophores are separated by six σ bonds (DN-6). Experimental studies of EET using fluorescence anisotropy measurements indicate that the superexchange mechanism dominates in DN-6.

LIQUID CRYSTAL MODELING: ELECTROSTATIC AND VAN DER WAALS INTERACTION ENERGIES FOR MOLECULAR BUILDING BLOCKS FROM BENZENE TO CHOLESTEROL

Intermolecular interaction energies for molecular dimers of benzene, indene, naphthalene, phenanthrene, cholesterol and glycyrrhetinic acid have been calculated according to the CVFF empirical force field of the DISCOVER program. The parallel orientations (side by-side) turned out to be the energetically most favourable ones, in agreement with the parametrization of Gay–Berne potentials. The energies of the T-shape and in-plane (end-to-end) orientations of the entirely asymmetric molecules cholesterol and glycyrrhetinic acid depend strongly on the actual atomic positions. This shows the extent to which the shape and charges of molecules determine all possible orientations and interaction energies in molecular ensembles.

Monoamine oxidase inhibitory naphthoquinone and/or naphthalene dimers from Lemuni Hitam (Diospyros sp.), a Malaysian herbal medicine.

From the extract of a Malaysian herbal medicine, Lemuni Hitam (Diospyros sp.), which exhibited monoamine oxidase (MAO) inhibition, three new naphthoquinone and/or naphthalene dimers (lemuninols A-C, 1-3) were isolated together with 4,6-dihydroxy-5-methoxy-2-methyl-naphthalene (8) and six known monomers (4-7, 9 and 10). The structures were determined by spectroscopic methods including 2D-NMR techniques. Among them, lemuninol A showed 45% inhibition of MAO (mouse liver) at 5.0 x 10(-6) g/ml, and lemuninols B and C and a naphthoquinone (9) indicated weak activity. Some related quinones were also tested for their MAO inhibitory activities.

Electronic interactions in rigidly linked naphthalene dimers

Singlet state (S1) radiative and non-radiative decay rates and S1 polarisabilities have been determined for naphthalene dimers where the chromophores are separated by a rigid polynorbornane bridge of varying length corresponding to 2, 4 and 6 σ-bonds. The dramatic increase in S1 radiative rates and polarisabilities as interchromophore separation is reduced is attributed to the contribution of a `through-configuration' interaction (involving interchromophore charge-transfer states) to the electronic coupling.

Optical activity of electronically delocalized molecular aggregates: Nonlocal response formulation

A unified description of circular dichroism and optical rotation in small optically active molecules, larger conjugated molecules, and molecular aggregates is developed using spatially nonlocal electric and magnetic optical response tensors χ(r,r′,ω). Making use of the time dependent Hartree Fock equations, we express these tensors in terms of delocalized electronic oscillators. We avoid the commonly-used long wavelength (dipole) approximation k⋅r≪1 and include the full multipolar form of the molecule–field interaction. The response of molecular aggregates is expressed in terms of monomer response functions. Intermolecular Coulomb interactions are rigorously taken into account thus eliminating the necessity to resort to the local field approximation or to a perturbative calculation of the aggregate wave functions. Applications to naphthalene dimers and trimers show significant corrections to the standard interacting point dipoles treatment.

Observation of charge-resonance band of naphthalene dimer cation confined in cavities of faujasite zeolites. Near-IR diffuse reflectance laser photolysis study

The naphthalene dimer cation was formed on 266 nm nanosecond laser excitation of naphthalene adsorbed in faujasite zeolites at high loading levels and the charge-resonance band of the dimer cation was measured for the first time by use of diffuse reflectance laser photolysis with a near-infrared detection technique. The dimer cations were found to form exclusively inside the cage networks, not at the external surface of the zeolite and are expected to take a twisted form, conformation in which two naphthalene moieties are partially overlapped, enforced by the cage walls.

Coherent and incoherent hopping of triplet exciton in quinoxaline-annelated and naphthalene-annelated dimers

Both a quinoxaline-annelated dimer and a naphthalene-annelated dimer showed excimer-type fluorescence spectra. Excimer-type phosphorescence was observed for the quinoxaline dimer, while the phosphorescence of the naphthalene dimer was not much different from that of the monomer type. In contrast, the EPR spectra clearly showed delocoalization of the unpaired spins in the two chromophores for both molecules. The present results can be interpreted by the models of coherent supermolecule delocalization of the unpaired spins and incoherent hopping of triplet exciton for the quinoxaline and naphthalene dimers, respectively.

Cluster Ion Formation from a Liquid Surface of Solutions of Naphthalene. Photosensitization Effect of Naphthalene

An ethanol solution of naphthalene was introduced into vacuum as a continuous liquid flow (liquid beam) and was irradiated with a laser beam at the wavelength of 275 nm. Ions produced by multiphoton ionization in the liquid beam and ejected from it were analyzed by a reflectron time-of-flight mass spectrometer. The dominant ions produced were protonated ethanol cluster ions, H+(EtOH)n. In addition, naphthalene−ethanol cluster ions, Np+(EtOH)n, and a naphthalene dimer ion, Np2+, were observed. The ion species, Np+(EtOH)n and Np2+, are considered to be produced by multiphoton ionization of naphthalene followed by ejection from the liquid surface. In order to confirm the assignments of the ions from the liquid beam of the ethanol solution, the ions ejected from methanol and 1-propanol solutions of naphthalene were also observed. On the other hand, the formation of H+(EtOH)n, are explained in terms of proton transfer from a naphthalene ion to ethanol molecules, where naphthalene acts as a photosensitizer for ...

Through-Bond and Through-Space Coupling in Photoinduced Electron and Energy Transfer: An ab Initio and Semiempirical Study

Ab initio and semiempirical calculations of transfer integrals for electron transfer and energy transfer have been carried out on rigidly linked norbornane-bridged naphthalene dimers to gain insight into the relative importance of through-bond and through-space interactions on photoinduced energy and electron transfer processes. In the absence of direct through-space orbital overlap between the naphthalene moieties, through-bond interaction involving the linking polynorbornane bridge is found to significantly enhance the transfer integrals for electron transfer and triplet−triplet energy transfer. For singlet−singlet energy transfer direct through-space Coulombic interaction between the naphthalene moieties is non-negligible at the separations considered and acts to reinforce the through-bond interaction. The relationship between electron and energy transfer processes and the application of these results to the interpretation of recent experimental data are discussed.

Benzene, naphthalene and anthracene dimers and their relation to the observed crystal structures

Molecular packing in benzene, naphthalene and anthracene crystals is analyzed in terms of molecular dimer interaction. Intermolecular energies of the gas dimer molecules are calculated for various intermolecular distances and orientations using empirical (exp−6−1) potential-energy functions. The gas dimers are compared to pairs of molecules extracted from the observed crystal structures. Particular attention is given to intermolecular Coulombic interaction. Net atomic charges are obtained by the potential-derived method from 6-31G and 6-31G** level ab initio wavefunctions. In the benzene crystal there are strong edge-plane intermolecular Coulombic interactions. The edge-plane interaction becomes somewhat less important in naphthalene and anthracene and the van der Waals interaction increases in importance.

Exciton interactions in the spectrum of a dinaphthonorbornadiene

AbstractThe near‐ultraviolet spectrum of a dinaphthonorbornadiene is reported and is interpreted using simple exciton theory that treats this molecule as a dimer of naphthalene. It shows examples of weak, intermediate, and strong coupling for the interaction of the three observed bands of naphthalene.

Photochemical probe of the conformation of naphthalene triplet excimer: light-induced changes in the phosphorescence of Agosta pinacol dimer in rigid hydrocarbon glasses

The initial monomeric phosphorescence of Agosta pinacol dimer of naphthalene in hydrocarbon glasses at 77 K changes to an excimer-like phosphorescence of the corresponding diketone dimer upon irradiation. The close spectral resemblance between the diketone emission and the room-temperature excimer phosphorescence of naphthalene and 1,n-di-{alpha}-naphthylalkanes (n = 1-4) in fluid solutions provides compelling evidence for the stability of the naphthalene triplet excimer and enables us to address the question of its likely conformation.

Photocarboxylation of Naphthalene in the Presence of Carbon Dioxide and an Electron Donor

Abstract Naphthalene was carboxylated to naphthoic acids by the irradiation of naphthalene and a donor in the presence of carbon dioxide. The UV irradiation through Pyrex caused reactions of naphthalene, itself, giving a naphthalene dimer etc. Such undesirable reactions were partly depressed by using a CuSO4 filter solution; the selectivities of naphthoic acids and dihydronaphthalenecarboxylic acid increased from 2.2–9.8 to 12.2–23.0%. To avoid any direct irradiation to naphthalene and naphthoic acids was critical. Their high selectivities, up to 67%, were obtained upon visible light irradiation by using phenazine as a sensitizer. More than 90% of the naphthoic acids was 1-naphthoic acid, which was confirmed by GC and ms.

ChemInform Abstract: Conformations of Naphthalene Dimer Cation Radicals Studied by Laser Photolysis.

ChemInform Abstract: Conformations of Naphthalene Dimer Cation Radicals Studied by Laser Photolysis.

Conformations of naphthalene dimer cation radicals studies by laser photolysis

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformations of naphthalene dimer cation radicals studies by laser photolysisAkira Tsuchida, Yoshinobu Tsujii, Shinzaburo Ito, Masahide Yamamoto, and Yoshio WadaCite this: J. Phys. Chem. 1989, 93, 4, 1244–1248Publication Date (Print):February 1, 1989Publication History Published online1 May 2002Published inissue 1 February 1989https://doi.org/10.1021/j100341a015RIGHTS & PERMISSIONSArticle Views167Altmetric-Citations29LEARN 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 (670 KB) Get e-Alerts

Pulse radiolysis studies on the transient species of aromatic molecules in chlorinated hydrocarbon solutions

Pulse radiolysis has been carried out to identify the transient species produced by the pulsed electron irradiation for the several kinds of combination of the solutions of aromatic hydrocarbons (benzene, naphthalene and pyrene) in chlorinated hydrocarbons (CCl 4, CHCl 3, and CH 2Cl 2). Charge-transfer complex between aromatic ring and Cl atom has been observed for benzene solutions in above three solvents. Naphthalene monomer and dimer cation radicals have been observed for the solutions in CHCl 3 and CH 2Cl 2. Monomer cation radicals of pyrene has been observed for the solution of pyrene in CCl 4, and monomer and dimer cation radicals of pyrene have been observed for the solutions in CHCl 3 and CH 2Cl 2.