Norbornadiene

About: Norbornadiene is a research topic. Over the lifetime, 2389 publications have been published within this topic receiving 38603 citations.

Use of Norbornadiene in Solar Energy Storage: Theoretical Study of a Copper(I) Photosensitizer for the Norbornadiene−Quadricyclane Transformation

Abstract: Density functional calculations with the hybrid B3LYP functional have been used to study the ground state of norbornadiene bound to the photosensitizer [Cu(8-oxoquinolinato)]. The main bonding interaction between the ligand and the metal is π back-donation, metal to ligand, which reduces the π−π* band gap in norbornadiene. CIS calculations performed on free norbornadiene and on the system where norbornadiene interacts with the photosensitizer have shown that the photosensitizer reduces the excitation energy to promote the system to the first excited singlet state. In terms of wavelength, this difference implies that light with λ almost 100 nm longer can be used to photoactivate the norbornadiene with respect to free norbornadiene.

Cycloaddition of Dialkylalumanyl Anion toward Unsaturated Hydrocarbons in (1+2) and (1+4) Modes.

Abstract: The reactivity of dialkylalumanyl anion (1) towards naphthalene, anthracene, diphenylacetylene, and (E)/(Z)-stilbenes was investigated. The compound 1 reacts with naphthalene and anthracene through (1+4) cyclization, giving Al-containing norbornadiene derivatives. In the reaction of 1 with diphenylacetylene and (E)/(Z)-stilbenes, (1+2) cyclization proceeded to form Al-C-C three-membered rings. Cyclization toward (E)- or (Z)-stilbenes solely gave a trans-cycloadduct. DFT calculations revealed that the cycloaddition of 1 with (Z)-stilbene proceeds via a single transition state with a carbanion character, which results in the selectivity towards the trans-cycloadduct.

Mechanistic approach to the sensitization process of aromatic ketones in the isomerization between norbornadiene and quadricyclane.

Abstract: The quantum yields for norbornadiene(N)→quadricyclane(Q) and Q→N isomerization were determined in acetonitrile using several substituted benzophenones (BPs) as triplet sensitizers. For the N→Q isomerization, BPs with electron-donating substituents exhibited higher quantum efficiency (0.4–0.6) than BPs with electronaccepting substituents. The quantum yields for Q→N isomerization increased with electron-accepting ability of the substituents on BPs, but were lower than 0.1. The rate constants for quenching of triplet BPs by N and Q were also determined in acetonitrile by means of laser flash photolysis. The rate constants for N were not dependent on the triplet energies (ET) of BPs but dependent on electronic properties of the substituents on BPs. On the contrary, those for Q increased with decreasing ET of BPs and with increasing Hammett’s σ constants of the substituents of BPs. Based on these observations an addition-elimination process is proposed for the N→Q isomerization, and an electron transfer proces...

Highly enantioselective hydrogenation of 1-alkylvinyl benzoates: a simple, nonenzymatic access to chiral 2-alkanols.

Abstract: Going chiral! Highly enantioselective catalytic hydrogenations of enol esters 1 by using a Rh catalyst bearing a P-OP ligand are described (see scheme; NBD=norbornadiene). The catalytic system has a broad scope and allows the preparation of a wide range of chiral esters 2 bearing diverse alkyls or a benzyl group with high enantioselectivities. These esters can easily be converted in highly enantioenriched 2-alkanols.