Search results for "s-Set"
showing 10 items of 30 documents
Photochemistry of 1,2,4-oxadiazoles. A DFT study on photoinduced competitive rearrangements of 3-amino- and 3-N-methylamino-5-perfluoroalkyl-1,2,4-ox…
2006
The photoinduced competitive rearrangements of 5-perfluoroalkyl-3-amino(N-alkylamino)-1,2,4-oxadia- zoles have been investigated by DFT calculations and UV-vis spectroscopy. The observed product selectivity depends on the number of hydrogen atoms present in the amino moiety and involves two or three possible routes: (i) ring contraction-ring expansion (RCRE), (ii) internal-cyclization isomerization (ICI), or (iii) C(3)-N(2) migration-nucleophilic attack-cyclization (MNAC). UV absorption and fluorescence spectra of the reactants, and vertical excitation energy values, calculated by time dependent DFT, support the involvement of a neutral singlet excited state in the photoexcitation process. …
Derivatives not first return integrable on a fractal set
2018
We extend to s-dimensional fractal sets the notion of first return integral (Definition 5) and we prove that there are s-derivatives not s-first return integrable.
Computational determination of the dominant triplet population mechanism in photoexcited benzophenone
2014
In benzophenone, intersystem crossing occurs efficiently between the S-1(n pi(star)) state and the T-1 state of dominant n pi(star) character, leading to excited triplet states after photoexcitation. The transition mechanism between S-1(n pi(star)) and T-1 is still a matter of debate, despite several experimental studies. Quantum mechanical calculations have been performed in order to assess the relative efficiencies of previously proposed mechanisms, in particular, the direct S-1 -> T-1 and indirect S-1 -> T-2(pi pi(star)) -> T-1 ones. Multiconfigurational wave function based methods are used to discuss the nature of the relevant states and also to determine minimum energy paths a…
An Henstock-Kurzweil type integral on a meausure metric space
2014
We consider an Henstock-Kurzweil type integral defined on a complete measure metric space $X=(X, d)$ endowed with a Radon measure $\mu$ and with a family $\F$ of ``intervals" that satisfies, besides usual conditions, the Vitali covering theorem. In particular, for such integral, we obtain extensions of the descriptive characterization of the classical Henstock-Kurzweil integral on the real line, in terms of $ACG_*$ functions and in terms of variational measures. Moreover we show that, besides the usual Henstock-Kurzweil integral on the real line, such integral includes also the dyadic Henstock-Kurzweil integral, the $GP$-integral and the $s$-HK integral. For this last integral we prove a be…
The Henstock-Kurzweil-Stieltjes type integral for real functions on a fractal subset of the real line
2011
The aim of this paper is to introduce an Henstock-Kurzweil type integration process for real functions on a fractal subset E of the real line.
Gold(I) Complexes of Ferrocenyl Polyphosphines: Aurophilic Gold Chloride Formation and Phosphine-Concerted Shuttling of a Dinuclear [ClAu···AuCl] Fra…
2016
International audience; A smart steric control of the metallocene backbone in bis- and poly(phosphino)ferrocene ligands favors intramolecular aurophilic interactions between [AuCl] fragments in polynuclear gold(I) complexes. We synthesized and characterized by multinuclear NMR and X-ray diffraction analysis mono-, di-, and polynuclear gold complexes of constrained ferrocenyl diphosphines, which bear either bulky tert-butyl groups or more flexible siloxane substituents at the cyclopentadienyl rings. The complexes meso-1,1'-bis-(diphenylphosphino)-3,3'-di-tert-butylferrocene (4-m), rac-1,1'-bis[bis-(5-methy1-2-furyl)phosphino]-3,3'-di-tert-butyfferrocene (5-r), and rac-1,1'-bis ( diphenylphos…
Pressure-Driven Isostructural Phase Transition in InNbO4: In Situ Experimental and Theoretical Investigations
2017
[EN] The high-pressure behavior of technologically important visible-light photocatalytic semiconductor In.NbO4, adopting a monoclinic wolframite-type structure at ambient conditions, was investigated using synchrotron-based X-ray diffraction, Raman spectroscopic measurements, and first-principles calculations. The experimental results indicate the occurrence of a pressure-induced isostructural phase transition in the studied compound beyond 10.8 GPa. The large volume collapse associated with the phase transition and the coexistence of two phases observed over a wide range of pressure shows the nature of transition to be first-order. There is an increase in the oxygen anion coordination num…
Excited State N−H Tautomer Selectivity in the Singlet Energy Transfer of a Zinc(II)-Porphyrin-Truxene-Corrole Assembly
2017
International audience; An original corrole-containing polyad for S-1 energy transfer, in which one zinc(II)-porphyrin donor is linked to two free-base corrole acceptors by a truxene linker, is reported. This polyad exhibits a rapid zinc(II)-porphyrin*free-base corrole transfer (4.83x10(10)s(-1); 298K), even faster than the tautomerization in the excited state processes taking advantage of the good electronic communication provided by the truxene bridge. Importantly, the energy transfer process shows approximately 3-fold selectivity for one corrole N-H tautomer over the other even at low temperature (77K). This selectivity is due to the difference in the J-integral being effective in both t…
Metal Dependence on the Bidirectionality and Reversibility of the Singlet Energy Transfer in Artificial Special Pair-Containing Dyads
2017
International audience; The demetalation of a precursor dyad, 3, built upon a zinc(II)-containing artificial special pair and free-base antenna, leads to a new dyad, 4, for singlet energy transfer composed of cofacial free-base porphyrins (acceptor), [Fb](2) bridged by a 1,4-C6H4 group to a free-base antenna (donor), [Fb]. This dyad exhibits the general structure [M](2)-C6H4-[Fb], where [M](2) = [Fh](2), and completes a series reported earlier, where [M](2) = [Mg](2) (2) and [Zn](2) (3). The latter dyads exhibit a bidirectional energy-transfer process at 298 K for 2 and at 77 K for 3. Interestingly, a very scarce case of cycling process is observed for the zinc-containing dyad at 298 K. The…
When the Grafting of Double Decker Phthalocyanines on Si(100)-2 × 1 Partly Affects the Molecular Electronic Structure
2016
International audience; A combined X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and density functional theory (DFT) study has been performed to characterize the adsorbate interaction of lutetium biphthalocyanine (LuPc2) molecules on the Si(100)-2 × 1 surface. Large molecule–substrate adsorption energies are computed and are found to compete with the molecule–molecule interactions of the double decker molecules. A particularly good matching between STM images and computed ones confirms the deformation of the molecule upon the absorption process. The comparison between DFT calculations and XP spectra reveals that the electronic distribution in the two plateaus …