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A novel series of trans and cis enediyne-cored dendrimers bearing naphthalenes at the periphery were synthesized and their photochemical properties were examined. The trans/cis isomer ratio in the photostationary state was dependent on the excitation site in the dendrimers. When the enediyne core was selectively excited, the trans/cis isomer ratio in the photostationary state was either around 50/50 or a cis-rich mixture in all dendrimers due to the larger molar extinction coefficient of the trans-enediynes. On the other hand, when naphthalene was excited, a trans-rich mixture was unexpectedly obtained in higher generation dendrimers even though the energy transfer efficiency was almost quantitative in the trans dendrimers. These results could be explained by the energy transfer process, which was different depending on the geometric isomerism of the enediyne core.Key words: dendrimers, energy transfer, photoisomerization.Nous avons synthétisé une nouvelle série de dendrimères à noyau central ènediyne, trans et cis, portant des groupements naphtalène en périphérie et nous avons examiné leurs propriétés photochimiques. Le rapport isomérique trans/cis à l'état photostationnaire était dépendant du site d'excitation dans les dendrimères. Lorsque le noyau central ènediyne était excité sélectivement, soit le rapport isomérique trans/cis à l'état photostationnaire se situait autour de 50/50, soit il dénotait un mélange riche en isomère cis, et ce, pour tous les dendrimères en raison du plus grand coefficient d'extinction molaire des ènediynes trans. En revanche, lorsque les groupes naphtalène étaient excités, nous avons obtenu contre toute attente un mélange riche en isomère trans pour les dendrimères de haute génération, même si l'efficacité du transfert énergétique dans les dendrimères trans était presque quantitative. Ces résultats pourraient s'expliquer par le processus de transfert d'énergie, qui différait selon l'isomérisme géométrique du noyau central ènediyne. [Traduit par la Rédaction]Mots-clés : dendrimères, transfert d'énergie, photo-isomérisation., IntroductionLight harvesting and energy transfer in dendrimers have been studied extensively. (1,2) In particular, energy transfer between the chromophoric units within dendrimers has been the focus of many researchers because [...]

Abstract: The reaction mechanisms of PAH formation from phenyl radical ([C.sub.6][H.sub.6]) to naphthalene via [C.sub.2][H.sub.3] ([C.sub.2][H.sub.3]-Path) and [C.sub.4][H.sub.4] ([C.sub.4][H.sub.4]-Path) were investigated by the G3(MP2, CC) method. The hydrogen abstraction, ring [...]

The energetics of all the possible isomers of the didehydronaphthalene (naphthalyne or naphthyne) diradical has been examined using the reduced multi-reference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest size MR CISD wave function as an external source of the most important (primary) triples and quadruples to account for nondynamic correlation effects in the presence of quasi-degeneracy, as well as by its perturbatively corrected version for the secondary triples, the RMR CCSD(T) method. The resulting energies are compared with those obtained by the standard single-reference (SR) CCSD and CCSD(T) approaches. In all cases, we used both the cc- pVDZ basis set, as well as its restricted version cc-[pVDZ.sub.*] with deleted p-functions on hydrogens. Once the optimal geometry for each isomer was found, we computed the energy of the lowest-lying singlet and triplet states using the above mentioned CC methods, as well as the implied singlet-triplet splittings. These results enabled us to classify the isomers into three groups according to their stability and to determine, whenever possible, the spin multiplicity of the ground state. Finally, we point out the relationship between the extent of the diradical character of naphthyne isomers, the degree of their MR nature, the distance separating the radical centers, and, finally, the size of the largest doubly-excited cluster amplitude in their CC wave functions. Key words: didehydronaphthalenes (naphthalynes, naphthynes), coupled-cluster methods, quasi-degeneracy, singlet-triplet splitting, diradicals. On a examine les energetiques de tous les isomeres possibles du biradical du didehydronaphtalene (naphtalyne ou naphtyne) en faisant appel a la methode des agregats couples (AC) a multireference reduite (MRR) avec des simples et des doubles (MRR ACSD) qui utilise une fonction d'onde de taille modeste (MR CISD) comme source externe des triples et quadruples les plus importants (primaires) afin de tenir compte des effets de correlation non dynamique en presence de quasi-degenerescence; on a aussi fait appel a sa version corrigee d'un point de vue des perturbations pour les triples secondaires, la methode MRR ACSD(T). On a compare les energies ainsi obtenues avec celles obtenues par les approches a reference simple ACSD (RS) et ACSD(T). Dans tous les cas, on a utilise l'ensemble de base cc-pVDZ ainsi que la version restreinte cc-[pVDZ.sub.*] desquelles les fonctions p de l'hydrogene ont ete eliminees. Une fois que la geometrie optimale de chaque isomere a ete trouvee, on a calcule les etats singulet et triplet de plus basse energie en utilisant les methodes d'agregats couples mentionnees plus haut et on a aussi calcule la separation des niveaux de singulet et triplet qu'ils impliquent. Ces resultats permettent de classifier les isomeres en trois groupes suivant leur stabilite et de determiner, lorsque cela est possible, la multiplicite de spin de l'etat fondamental. Enfin, on signale la relation entre le degre du caractere biradicalaire des isomeres du naphtyne, le degre de leur nature de multireference, la distance qui separe les centres radicalaires et enfin la taille de l'amplitude de l'agregat doublement excite le plus gros dans leurs fonctions d'onde d'agregat couple. Mots-cles: didehydronaphtalene (naphtalynes, naphtynes), methodes des agregats couples, quasi-degenerescence, couplage singulet-triplet, biradicals. [Traduit par la Redaction], Introduction Arynes, or didehydroarenes, and their heteroanalogues and derivatives, represent transient species of great interest in view of their participation in a wide variety of organic reactions, and thus belong [...]

Naphthalene sublimation experiments were conducted to study heat transfer for flow through blockages with holes in an internal cooling passage near the trailing edge of a gas turbine airfoil. The cooling passage was modeled as two rectangular channels whose heights decreased along the main flow direction. The air made a right-angled turn before passing through two blockages with staggered holes in each channel and left the channel through an exit that was partially blocked by periodic lands with rounded leading edges. There were ten holes along each blockage and all of the holes had rounded edges. Local heat (mass) transfer was measured and overall heat (mass) transfer results were obtained, on the exposed surfaces of one of the walls downstream of the two blockages, for Reynolds numbers (based on the hydraulic diameter of the channel at the upstream surface of the first blockage) between 5000 and 36,000. The results showed that the blockages with the larger hole-to-channel cross-sectional area ratio in one of the two test sections enhanced the heat (mass) transfer downstream of the blockages more than the blockages with the smaller open area ratio in the second test section. For the geometric configurations and flow conditions studied, the average heat (mass) transfer was higher downstream of the second blockage than downstream of the first blockage. The configurations of the inlet channel and the exit slots considered in this study did not significantly affect the local heat (mass) transfer distributions or the average heat (mass) transfer downstream of the blockages. Keywords: turbine blade trailing edge cooling, naphthalene sublimation, mass transfer, blockages with holes

A concise synthesis of naphthalene compounds for incorporation into a synthetic sequence for the rubromycin family of natural products is presented. These highly substituted naphthalenes generated from 2,4,5-trimethoxybenzaldehyde can be used to generate variety of coupling partners.

A [2]rotoxane is presented that has featured succinamide and naphthalene diimide hydrogen-bonding stations for a benzylic amide macrocycle that can shuttle and switch its net position both in solution and in a monolayer. The analysis of the electrochemical behavior of the molecular shuttle monolayers has shown that the redox-switched shuttling is maintained in this environment, occurring on the millisecond timescale.

The heat/mass transfer in a rotating smooth channel with bleed flow by a naphthalene sublimation method is investigated. The tripping flow induced by the bleed flow enhances and influences the heat/mass transfer.

We tested the hypothesis that during metabolism of naphthalene and other substrates by Pseudomonas sp. strain As1 oxidative stress arises and can be reduced by antioxidant enzymes. Our approach was to prepare plasmid constructs that conferred expression of two single antioxidant enzymes [Fpr (ferredoxin-[NADP.sup.+] reductase) and SOD (superoxide dismutase)] and the pair of enzymes SOD plus AhpC (alkyl hydroperoxide reductase). The fpr, soda and ahpC genes were placed under the transcriptional control of both the constitutive lac promoter and their respective native promoters. Both HPLC and growth-rate analyses showed that naphthalene metabolism was enhanced in the recombinant strains. All antioxidant-overexpressing recombinant strains, with the exception of one with an upregulated sodA gene due to the lac promoter [strain As1 (sodA)], exhibited resistance to the superoxide generating agent paraquat (PQ). The growth of strain As1 (sodA) was inhibited by PQ, but this growth defect was rapidly overcome by the simultaneous overproduction of AhpC, which is a known hydrogen peroxide scavenger. After PQ-induced oxidative damage of the [Fe-S] enzyme aconitase, recovery of enzyme activity was enhanced in the recombinant strains. Reporter strains to monitor oxidative stress in strain As1 were prepared by fusing gfp (encoding green fluorescent protein, GFP) to the fpr promoter. Growth on salicylate and naphthalene boosted the GFP fluorescent signal 21- and 14-fold, respectively. Using these same oxidative stress reporters, overexpression of fpr and sodA was found to considerably reduce PQ-induced stress. Taken together, these data demonstrate that the overproduction of Fpr or SodA contributes to oxidative tolerance during naphthalene degradation; however, elevated SOD activity may trigger the generation of excess hydrogen peroxide, resulting in cell death.

An ab initio and Rice-Ramsperger-Kassel-Marcus (RRKM) study is conducted of 9-H-fulvalenyl ([C.sub.5][H.sub.5]-[C.sub.5][H.sub.4]) radical rearrangements is conducted. The analysis helps in explaining the formation of naphthalene, azulen, and fulvalene from cyclic [C.sub.5] species in combustion.

A novel multicomponent reaction of arynes, [beta]-keto sulfones and Michael-type acceptors has provided an efficient method for the synthesis of polysubstituted naphthols and polysubstituted naphthalenes. It is shown that the tandem reaction might proceed via a sequential nucleophilic attack to arynes, intramolecular nucleophilic substitution followed by a Michael addition and a ring closure-elimination process.

The anti-resonance phenomenon and the excited electronic states of naphthalene molecules are explored by using the deduced formulas and a time-dependent density functional theory. The direct evaluation approach might provide a method of predicting anti-resonance and studying its origin.

A study of the enolization of the [alpha], [beta]-unsaturated, bicyclic ketone [DELTA.sup.9,10]-octal-1-one (3, 4, 5, 6, 7, 8-hexahydro-1(2H)-naphthalenone), which can form the s-cis, endocyclic and s-trans, exocyclic dienolates, both of which have similar patterns of alkyl substitution at the [beta], [gamma] double bond is presented. The results have shown that the exocyclic dienolate is more stable than its endocyclic counterpart.

The molecular and crystal structure of 1,8-thianaphthalene is determined and compared with other single-atom peribridged naphthalenes (SAPN). The accurate ring strain energies are obtained and its effect on the electronic structure of the aromatic system is elucidated.

Abstract: A novel thioureido naphthalene derivative was synthesized and characterized. The compound proved itself as an effective fluoride sensor with respect to selectivity and sensitivity. In acetonitrile, the fluorescence intensity [...]

Molecular and thermal diffusion coefficients of binary mixtures of normal decane-normal alkanes and methylnaphthalene-normal alkanes are measured at atmospheric pressure and T=25 degree Celcius. Results present a significant effect of molecular shape and size on thermal and molecular diffusion coefficients and it shows a monotonic behavior in both aromatic-normal alkane and normal decane-normal alkane mixtures.

A measurable difference found in the heat released by the well-known Birch reduction of naphthalene and of its perdeuteriated analogue is reported. The results are coupled with the known enthalpy of electron transfer between naphthalene and its perdeuteriated analogue, implying that the heat of hydrogenation of naphthalene is decreased upon perdeuteriation of the naphthalene.

A mechanism is proposed for the ultrafast nonradiative relaxation from the second excited state ([D.sub.2]) down to the ground ([D.sub.0]) of naphthalene radical cation [N.sup.} to explain its photostability. The results reveal an ultrafast, unimolecular, radiationless decay mechanism between the optically active second excited state and the ground state of the naphthalene radical cation by internal conversion through two consecutive sloped conical intersections.

An analysis of the primary processes of germanorbornadiene (GNB) phototransformation was done using pulse photolysis The scheme of GNB photocleavage can be used where the triplet excited 1,2,3,4-tetraphenylnaphthalene (TPN) originated from the triplet state of biradical through cleavage of the second C-Ge bond, the latter being generated form the excited singlet state of the initial GNB after the cleavage of the first C-Ge bond.

The synthesis, structure determination and sorption properties ([H.sub.2], C[O.sub.2], C[H.sub.4], and [N.sub.2]) of the metal-naphthalene-1,4,5,8-tetracarboxylate complex [Cr.sub.3.sup.III]O[([H.sub.2]O).sub.2]F[{[C.sub.10][H.sub.4][(C[O.sub.2]).sub.4]}.sub.1.5].6[H.sub.2]O, containing trivalent chromium (MIL-102) are described. MIL-102 is a new example of a porous chromium carboxylate that has a trimeric inorganic subnetwork, shows zeolite behavior with no pore contraction and has a small hydrogen storage capacity.

A study used ultraviolet absorption spectra, NMR spectra, and phosphorescence measurements to confirm that [alpha]-cyclodextrin (CD) and 2-bromo-6-[beta]-D-glucopyranosidylnaphthalene (BGN) form only a binary complex and to characterize its properties. The binding constant for the Cd-BGN complex is found to be 886 plusmn 24 [M.sup.-1] and 770 plusmn 110 [M.sup.-1] from NMR and UV absorbance measurements, respectively.

X-ray and neutron diffraction are used to examine the single crystals of [h.sub.8]-naphthalene over a wide range of temperatures and the anisotropic displacement parameters (ADPs) of carbons and hydrogens are measured. A considerable reduction is seen in the ratio of number of adjustable parameters/numbers of independent observations by applying the treatment to multi-temperate diffraction data.

The parallelized version of the Gibbs ensemble (PGE) method was implemented in order to predict low-temperature vapor-liquid equilibria 1- and 2-methylnaphthalene modeled by anisotropic united atom potentials. The reason behind the parallelization is to bypass the physical transfer of complex molecules between boxes representing different phases computing the chemical potential in a canonical ensemble for which a number of sophisticated methods are developed.

The kinetic data on triplet (T1) sensitization of singlet oxygen by two series of biphenyl and naphthalene sensitizers in solvents of strongly different polarity is analyzed and the rate constants and the efficiencies of singlet oxygen formation are quantitatively reproduced by a model that assumes the competition of a noncharge transfer (nCT) and a CT deactivation channel. The quantitative model has represented a realistic and general mechanism for the quenching of pipi(super star) triplet states by O2.

Highly substituted 1H-isochromenes, isobenzofurans and pyranopyridines are prepared by allowing o-(1-alkynyl)arenecarboxaldehydes and ketones to react with I2, ICl, NIS, Br2, NBS, p-O2NC6H4SCl or PhSeBr and different alcohols or carbon-based nucleophiles at room temperature. Naphthyl ketones and iodides can be prepared by the reaction of 2-(1-alkynyl)arenecarboxaldehydes with I2 and simple olefins or alkynes.

A demonstration of two-dimensional heterocorrelation analysis between spectrally resolved and temporally resolved fluorescene is presented to investigate the decay dynamics of the 8-anilino-1-naphthalenesulfonate-(ANS-) apomyoglobin complex. The relative decay dynamics across the emission spectra are resolved without measuring fluorescence lifetime at each wavelength as in the approach of decay-associated spectra.

A study was conducted to provide evidence that ring fusion to an arene promotes the oxidative addition to H(sub 2) to a metal center through facilitating an eta(super 6)-to-eta(super 4) haptotropic shift. Density functional theory calculations indicate that the increased facility of naphthalene and anthracene to adopt eta(super 4)-coordination modes compared to that of benzene is a consequence of the fact that the Mo-(eta(super 4)-ArH) bonding interaction increases in the sequence benzene < naphthalene < anthracene, while the Mo-(eta(super 8)-ArH) bonding interaction follows the sequence benzene > naphthalene > anthracene.

A significantly improved procedure that provides efficient access to a highly congested 1,8-diacridylnaphthalene fluorosensor is reported. Screening of palladium-catalyzed Negishi, Kumada, Suzuki, Hiyama, and Stille coupling methods showed that the latter affords highly congested 1,8-diarylnapthalenes in superior yields.

The distance-dependent current-voltage (I-V) spectroscopy of the base-free naphthalo-cyanine (planar) and tin-naphthalocyanine (nonplanar) on a comparatively weak interacting substrate as highly oriented pyrolytic graphite (HOPG) is studied. The current-voltage curves show an unsymmetrical diode-like nature especially at large tip-sample distance in both cases.

A description is provided on the circular dichroism (CD) spectrum modulation and a chiral molecular switch based on a binaphthalene skeleton with two tetrathiofulvalene (TTF) units. This process is performed by reversible oxidation and reduction of tetrathiofulvalene units.

The reactions of vinylidencyclopropanes with diphenyl diselenide in the presence of AIBN produced the corresponding products in moderate to good yields under mild conditions. The transformation of the corresponding products to methylenecyclopropanes (MCPs) can be further converted to the corresponding naphthalene derivatives by treatment with 30 mol % of TfOh in dichloromethane.

A synthesis is presented of 2a,8a-syn tricyclic guanidines corresponding to the originally proposed relative configuration of these units of batzelladine F. A description is provided on the preparation of analogous 2a,8a-syn tricyclic guanidines and the evolution of the strategy for the total synthesis of linked tricyclic guanidines corresponding to the proposed constitution and revised relative configuration of batzelladine F.

The total synthesis of (-)-colombiasin A and (-)-elisapterosin B was achieved. The key step is a C-H functionalization process, the combined C-H activation/cope rearrangement, between methyl (E)-2-diazo-3-pentenoate and 1-methyl-1,2-dihydronaphthalenes.

The time-resolved fluorescence profiles of the anthracene chromophore after excitation of the naphthalene chromophore at 285 nm have allowed the kinetics of the energy-transfer process to be evaluated. A comparison of the experimentally determined EET rate constant with those modeled via a direct Coulombic (Forster-type) interaction between the two chromophores indicated excellent agreement for both [ZnL(super 3)](super 2+) and [ZnL(super 4)](super 2+).

A combination of Schwesinger's phosphazene base concept and the idea of the disubstitued 1,8-naphthalene spacer, yields a superbase, 1,8-bis(hexamethyltriaminophosphazenyl)naphhalene (HMPN), which is the most basic representative of 'proton sponges'. The high basicity of HMPN is a consequence of the high energy content of the base in its initial neutral state and the intramolecular hydrogen bonding in the resulting conjugate acid with contributions to proton affinity.

An efficient method for the synthesis of cis-2-alkyl- or allyl-1,2-dihydronaphythalenes through a nickel-catalyzed highly regio- and stereoselective ring-opening addition of alkyl- or allylzirconium reagents to 7-oxabenzonorbornadienes is described. The alkylative ring-opening products from 7-oxabenzonorbornadienes underwent dehydration readily with HCl to afford the corresponding naphthalene derivatives in excellent yields.

The study addresses the nature of electron trapping in polar-solvated zeolites with emphasis on the zeolite NaX and NaY. The result points out the conditions under which Na(sub 4)(super 4+) is active as an electron trap in polar-solvated zeolites (PSZ) and that water must be present in the sodalite DPYRENE.

Benzalacetone analogues of naphth[1,2-a]azulene, naphth[a]azulenes and naphth [2,3-a]azulene were synthesized from 2-(5-methyl-2-furyl)-1-tropylionaphthalene, 1-(5-methyl-2-furyl)-2-tropylionaphthalene and 2-(5-methy-2-furyl)-3-tropylionaphthalene respectively. Single-crystal X-ray work on the napth[1,2-a]azulene derivative revealed that its tetracyclic system exhibited deformation from planarity similar to that of benzo-[c]phenanthrene.

The model of ionization and large electron kinetic energy is used to study the electron-recollision-induced fragmentation and double ionization more precisely. It is concluded that the fragmentation originated in the unstable nature of the highly charged molecular ion itself and in the Coulomb explosion in the case of naphthalene.

A variety of biaryl quinone methides have been photogenerated with a range of efficiencies from biaryl precursors 4-6 and 8, 10, and 11, all having hydroxyl and hydroxymethyl substituents on alternate rings. These novel biaryl quinone methides, which cannot be readily generated via thermal chemistry, are trapped by added nucleophiles such as MeOH and ethanolamine; two that cannot undergo electrocyclic ring closure (from 8 and 11) are readily observable by nanosecond laser photolysis, with long wavelength maxima ([λ.sub.max]) of 600 and 520 nm, respectively. Photogenerated o,o'-biaryl quinone methides undergo electrocyclic ring closure to give the corresponding chromene (pyran) products in high yield. Since the precursor biaryl alcohols have highly twisted structures in the ground state (dihedral angle of up to 90° by molecular mechanics calculations), a significant twisting motion to planarity is required to achieve reaction. Using steady-state fluorescence studies, we present evidence to suggest that the mechanism of quinone methide formation may occur via one of the following mechanisms: (i) dissociation of the proton from ArOH that precedes twisting; or (ii) ArOH dissociation and twisting taking place either simultaneously or in quick succession. Key words: biaryl quinone methide, photosolvolysis, photodeprotonation, photocyclization. Resume : Un certain nombre de biaryl quinone methides diverses a ete photogenere avec des efficacites variables a partir des precurseurs biaryles 4-6, 8, 10 et 11 qui portent tous des substituants hydroxyle et hydroxymethyle sur les autres cycles. Ces nouveaux biaryl quinone methides, qui ne peuvent pas etre generes facilement par le biais de la chimie thermique, peuvent etre pieges par l'addition de nucleophiles tel que le methanol et l'ethanolamine; deux d'entre eux qui ne peuvent pas subir des fermetures electrocycliques de cycles (obtenus a partir de 8 et 11) peuvent facilement etre observes par photolyse laser nanoseconde avec des longueurs d'onde maximales ([λ.sub.max]) de 600 et 520 nm respectivement. Les o,o'-biaryl quinone methides photogenerees subissent des fermetures electrocycliques de cycle conduisant a la formation des chromenes (pyran) correspondants, avec des rendements eleves. Puisque les structures de chaque alcool precurseur biaryle sont de nature fortement deformee a l'etat fondamental (angle diedre allant jusqu'a 90° sur la base de calculs de mecanique moleculaire), la reaction ne peut se faire qu'a la suite d'un mouvement de deformation important pour atteindre un etat planaire. Faisant appel a des etudes de fluorescence en etat stationnaire, on a obtenu des donnees qui permettent de suggerer que le mecanisme de formation de la quinonemethide peut impliquer l'une des voies suivantes: (i) une dissociation de proton a partir du ArOH qui precede la deformation ou (ii) une dissociation du ArOH et une deformation qui se produisent soit de facon simultanee soit en succession rapide. Mots cles : biaryl quinone methide, photosolvolyse, photodeprotonation, photocyclisation. [Traduit par la Redaction], Introduction The moderate to highly twisted ground-state structures of biaryls (as measured by the dihedral angle between the two phenyl rings) are known, in general, to become more planar when [...]

Spin-unrestricted calculations and time-dependent DFT are used to characterize structure and reactivity of 1-methyl-8-nitronaphthalene in the triplet state. The results are discussed in relation to mechanisms of photoinduced rearrangements of peri-substituted nitronaphthalenes that could be used to develop novel photolabile protecting groups.

A new method of synthesis of meso-tetraaryltetranaphtho[2,3]porphyrins (Ar4TNP) is developed. Ar4TNPs with peripheral functional groups are obtained by oxidative aromatization of meso-tetraarylporphyrins, in which pyrrole units are fused with octahydro- and dihydronaphthalene moieties.

Novel 1,5-bis(diarylamino)naphthalene derivatives (1-9), which have potential as hole-transporting materials for electroluminescent devices, were obtained through palladium-catalyzed coupling of diarylamines and 1,5-dibromonaphthalene. The thermal, electrochemical, and photophysical properties of these compounds were examined and the effects of the N-aryl substituents on these properties were investigated. These materials possess glass transition temperatures ([T.sub.g]) that range from 70-131 [degrees]C and these values are related to the identity of the aryl substituents. Cyclic voltammetric measurements demonstrated that these compounds possess two reversible oxidation processes and were further used to estimate the HOMO energy levels of these materials by comparison with the ferrocene/ferrocenium couple. The intramolecular charge mobility, as gauged by the difference between the two oxidation potentials, indicates that compounds 1-8 have a similar degree of delocalization as meta-diaminobenzene derivatives while that of 9 is similar to TPD. Compounds 1-9 emit in the blue-green region and optical absorption and emission data for these materials can be rationalized in terms of the electronic donating properties of the aryl substituents. This data when combined with the electrochemically determined HOMO energies allowed estimation of the LUMO energy levels. Key words: hole transport materials, diaminonaphthalene, thermal analysis, palladium-catalyzed arylation. Faisant appel a un couplage catalyse par le palladium de diarylamines et de 1,5-dibromonaphtalene, on a prepare des 1,5-bis(diarylamino)naphtalenes (1-9), qui ont le potentiel de transporter des trous pour les appareils electroluminescents. On en a examine les proprietes thermiques, electrochimiques et photophysiques et on a etudie les effets des substituants N-aryles sur ces proprietes. Ces materiaux possedent des temperatures de transition de verre ([T.sub.g]) qui s'etalent de 70 a 131 [degrees]C et on a pu etablir une correlation entre cette propriete et l'identite des substituants aryles. Des mesures de voltamperometrie cyclique demontrent que ces composes possedent deux processus d'oxydations reversibles qui ont, de plus, ete utilisees pour evaluer les niveaux d'energie de l'orbitale moleculaire haute occupee de ces composes par comparaison avec le couple ferrocene/ferrocenium. La mobilite de la charge intramoleculaire, telle qu'evaluee par la difference entre les deux potentiels d'oxydation, indique que les composes 1-8 possedent un degre de delocalisation semblable a celui des derives du meta-diaminobenzene alors que celle du compose 9 est semblable a celle du TDE Les composes 1-9 emettent dans la region du bleu-vert et les donnees d'absorption et emission optique de ces composes peuvent etre rationalisees en termes du caractere electrodonneur des substituants aryles. Lorsque ces donnees sont combinees avec les energies de l'orbitale moleculaire haute occupee determinee electrochimiquement, il est possible d'evaluer les niveaux d'energie de l'orbitale moleculaire basse vacante. Mots cles : materiaux pouvant transporter des trous, diaminonaphtalene, analyse thermique, arylation catalysee par le palladium. [Traduit par la Redaction]

A series of heteroleptic rare-earth sandwich complexes [M(Nc)(OEP)]( where M= La, Nd, Eu , Dy and Lu; Nc=2,3-naphthalocyaninate; OEP= octaethylporphyrinate] is investigated by electronic absorption and magnetic circular dichroism (MCD) spectroscopy. The electronic absorption spectra of the neutral forms show two characteristic transitions in the near-IR region, both of which were systematically shifted depending on the size of their central metal.

Calculations were performed using strictly atomic benzene-p-orbitals and p-orbitals that are allowed to delocalize, on naphthalene, acenaphthylene, pyracylene and many organic compounds. The results show that cyclopenta-fusion does not extend the pie system in the ground state and the five-membered rings act as peri-substituents.

The study selected 1-methyl-naphthalene as a surrogate for aromatic hydrocarbons (PAHs) found in tropospheric aerosols. It determined mass accommodation coefficients (alpha) on 1-methylnaphthalene as a function of temperature for gas-phase m-xylene, ethylbenzene, butylbenzene, alpha-pinene, gamma-terpinene, p-cymene, and 2-methyl-2-hexanol.

A report that generation of the naphthylmethyl radical, produced through the naphthymethyl-oxygen (C-O) bond cleavage, can be controlled by two- or three-laser irradiations through the higher triplet excited states (Tn) is presented. The results revealed that acenaphthene was produced as the final product during the stepwise C-O bond cleavage of 1,8-(BPOCH2)2Np and 1,8-(PhOCH2)2Np.

The femtosecond fluorescence upconversion and transient absorption experiments were performed to monitor the photoinduced electronic, geometry, and solvent relaxation dynamics of 1,8-bis(dimethylamino)naphthalene dissolved in methycyclohexane and acetonitrile. It is concluded that the solvent relaxation and vibrational cooling in the lpi* state cannot be seperated in polar solvents, but in apolar solvents a distinct vibrational cooling process in the lpi* state is discerned.

A study was carried out on titanocene 1,8-dithiolato-naphthalene and its oxidized relatives that may be readily prepared by oxidative addition of the appropriate S--S bonded precusor with Cp2Ti(CO)2. The effect of using pro-ligands where the sulfur atom is mono-oxidized and di-oxidized is studied and an interesting oxygen elimination reaction is observed for the S(triple bond)O fragments but not for the SO2 groups.

An efficient synthesis of highly substituted alpha-arylnaphthalene analogues is developed utilizing Lewis acid-promoted regicontrolled benzannulation of aryl(aryl')-2,2-dichlorocyclopropylmethanols. Application of the method to the total synthesis for unsymmetrically substituted natural lignan lactones, justicidin B, retrojusticidin B, dehydrodesoxypodophyllotoxin, and a related analogue, 5'-methoxy-retrochinensin, was demonstrated.