Norbornadiene

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

η2-Alkene Complexes of [Rh(PONOP-iPr)(L)]+ Cations (L = COD, NBD, Ethene). Intramolecular Alkene-Assisted Hydrogenation and Dihydrogen Complex [Rh(PONOP-iPr)(η-H2)].

Abstract: Rhodium-alkene complexes of the pincer ligand κ3-C5H3N-2,6-(OPiPr2)2 (PONOP-iPr) have been prepared and structurally characterized: [Rh(PONOP-iPr)(I2-alkene)][BArF4] [alkene = cyclooctadiene (COD), norbornadiene (NBD), ethene; ArF = 3,5-(CF3)2C6H3] Only one of these, alkene = COD, undergoes a reaction with H2 (1 bar), to form [Rh(PONOP-iPr)(I2-COE)][BArF4] (COE = cyclooctene), while the others show no significant reactivity This COE complex does not undergo further hydrogenation This difference in reactivity between COD and the other alkenes is proposed to be due to intramolecular alkene-assisted reductive elimination in the COD complex, in which the I2-bound diene can engage in bonding with its additional alkene unit H/D exchange experiments on the ethene complex show that reductive elimination from a reversibly formed alkyl hydride intermediate is likely rate-limiting and with a high barrier The proposed final product of alkene hydrogenation would be the dihydrogen complex [Rh(PONOP-iPr)(I2-H2)][BArF4], which has been independently synthesized and undergoes exchange with free H2 on the NMR time scale, as well as with D2 to form free HD When the H2 addition to [Rh(PONOP-iPr)(I2-ethene)][BArF4] is interrogated using pH2 at higher pressure (3 bar), this produces the dihydrogen complex as a transient product, for which enhancements in the 1H NMR signal for the bound H2 ligand, as well as that for free H2, are observed This is a unique example of the partially negative line-shape effect, with the enhanced signals that are observed for the dihydrogen complex being explained by the exchange processes already noted

Photochemical isomerization of norbornadiene‐containing polytriazoles obtained by click chemistry polyaddition

Abstract: Polyesters and polyethers containing norbornadiene (NBD) and 1,2,3-triazole units in the main chain are prepared by step growth polymerization of diester or diether NBD-based dialkynes with different aromatic diazides using copper-catalyzed azide–alkyne cycloaddition. The solubility and the physical properties of the resulting polytriazoles are investigated by differential scanning calorimetry, thermogravimetric analysis, size exclusion chromatography, and 1H NMR spectroscopy, and are discussed taking into account of the chemical structures of the monomers. All of them are amorphous with glass transition temperatures ranging from 51 to 117 °C, number average molecular weight (Mn) values from 16 to 43 kDa and thermal degradation (Td10) values from 175 to 292 °C. The photochemical valence isomerization (PVI) of the NBD units into quadricyclanes (QC) is investigated using UV–vis spectroscopy of polymer films spin-coated onto quartz substrates. For the first time the PVI of NBD into QC is demonstrated by 1H NMR spectroscopy. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 223–231

Synthesis of 4,5,9,10-tetradehydroadamantan-2-one

Abstract: On prepare le compose du titre en 10 etapes a partir du norbornadiene et de l'acrylonitrile