Search results for "Donor acceptor"
showing 10 items of 17 documents
Synthesis of an Acceptor–Donor–Acceptor Multichromophore Consisting of Terrylene and Perylene Diimides for Multistep Energy Transfer Studies
2016
Motivated by the results obtained from the investigation of singlet–singlet annihilation in a linear multichromophore comprising terrylene diimides (TDI) and perylene diimide (PDI) in 2010, we report the detailed process toward the successful synthesis of a TDI–PDI–TDI dyad. Ineffective synthetic pathways, which were necessary for the understanding of the step-by-step construction of the complex multichromophore, are described, leading toward a universal synthetic plan for multicomponent systems containing rylene diimides separated by rigid oligophenylene spacers.
Strong donor–acceptor couplings in a special pair-antenna model
2010
A special pair model composed of two cofacial zinc porphyrins (acceptor) linked to a free base (donor) acts as an energy transfer dyad. Despite the absence of conjugation, ππ*/charge transfer excited states and ultrafast energy transfer (∼5 ps) are noted.
Large Quadratic Hyperpolarizabilities with Donor–Acceptor Polyenes Exhibiting Optimum Bond Length Alternation: Correlation Between Structure and Hype…
1997
Donor-acceptor polyenes of various lengths, and that combine aro- matic electron-donating moieties with powerful heterocyclic electron-withdraw- ing terminal groups, have been synthe- sized and characterized as efficient non- linear optical (NLO) chromophores. Their linear and nonlinear optical proper- ties have been investigated, and variations in these properties have been related to ground-state polarization (dipole p) and structure. In particular, unprecedented quadratic hyperpolarizabilities (p) have been achieved (up to p(0) =I500 x 10-30esu) by reduction of the bond- length alternation (BLA) in the polyenic chain. In each series of homologous com-
Oligo(phenylenvinylene) mit terminaler Donor-Acceptor-Substitution
2002
¿Conjugated? Copolymers from a Pechmann Dye Derivative
2016
ChemInform Abstract: Comparative G2(MP2) Molecular Orbital Study of B3H7XH3 and H3BXH3 Donor-Acceptor Complexes (X: N, P, and As).
2010
B3H7XH3 and H3BXH3 (X = N, P, and As) have been studied as donor−acceptor complex type at the G2(MP2) level of theory. Both single- and double-bridged structures of B3H7 Lewis acid are taken into account. Although the double-bridged structure is energetically favored in the isolated state, the coordination prefers the single-bridged one. The monoborane adducts adopt the staggered arrangement with C3v symmetry. The energetic analysis by natural bond orbital theory shows that the decrease of hyperconjugative contribution upon complexation in the B3H7 moiety has, as consequence, a loss of symmetry for B3H7XH3 (X= P and As) complexes. In the two series, the coordination is the result of two opp…
A G2 study of H3BXHn (X=N, O, F, P, S, and Cl) donor–acceptor complexes
1999
Abstract Complexation energies of H3BXHn complexes (X=N, O, F, P, S, and Cl; n=1, 2, 3) have been computed at the G2 level of theory. G2 results show that the H3BXH3 (X=N, P) complexes are more stable than H3BXH2 (X=O, S) and H3BXH (X=F, Cl) ones. This stability was related completely either to the nature of donor compounds, and to the pyramidalization of the monoborane. Two linear correlations were established. The first one is between experimental proton affinity of the XHn donor compounds, and complexation energies of the H3BXHn complexes. The second correlation is between the ∠HBH bond angles and the complexation energies of the H3BXHn complexes calculated at the G2 level of theory.
Synthesis of oxaspiranic compounds through [3 + 2] annulation of cyclopropenones and donor–acceptor cyclopropanes.
2014
The Sc(OTf)3-catalyzed [3 + 2]-annulation reaction between cyclopropenones and donor–acceptor cyclopropanes is described. The process leads directly to the formation of 4-oxaspiro[2.4]hept-1-ene derivatives in good to excellent reaction yields. Density functional theory calculations suggest that the [3 + 2]-annulation pathway is strongly preferred over the possible [3 + 3]-process.
Comparative G2(MP2) molecular orbital study of [H 3 AlX(CH 3 ) 2 ] − (X=N, P, and As) and H 3 AlY(CH 3 ) 2 (Y=O, S, and Se) donor–acceptor complexes
2001
Abstract [H3AlX(CH3)2]− (X=N, P, and As) and H3AlY(CH3)2 (Y=O, S, and Se) donor–acceptor complexes have been studied using G2(MP2) level of theory. The coordination mode, the structural and the methyl substitution effects upon complexation are analyzed. The interaction of the alane with the donor ligand is stronger in the anionic complexes than in the neutral ones and the methylated complexes are more stable than the hydrogenated ones. The coordination is ensured by tow interactions having a reverse character: interaction between a′ symmetry fragment molecular orbital (stabilizing) and interaction between a″ symmetry occupied molecular orbital (destabilizing) of the two fragments. A linear …