714-53-4

Upstream product

• 947-57-9 dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate 
• 30715-39-0 tetracyclo[3.2.0.0^2,7.0^4,6]heptane-1,5-dicarboxylic acid 
• 77-78-1 dimethyl sulfate 

Relevant academic research and scientific papers

SINGLET SENSITIZATION OF THE NORBORNADIENE REARRANGEMENT: EXCITATION ENERGY CASCADE POTENTIALLY INVOLVING TRIPLET EXCIPLEXES.

Valence isomerization of dimethyl bicyclohepta-2,5-diene-2,3-dicarboxylate is induced on quenching the fluorescence of a variety of sensitizers.Quantum efficiencies for rearrangement depend on the triplet energy of the sensitizer.

A Radical Ion/Triplet Mechanism for Sensitized Valence Photoisomerization of a Norbornadiene

Quenching of the fluorescence of a series of electron donor aromatic hydrocarbons in acetonitrile by dimethyl bicyclohepta-2,5-diene-2,3-dicarboxylate results in isomerization of the norbornadiene with varying efficiency.Quantum yield, CIDNP, and flash photolysis results are consistent with a rearrangement mechanism involving electron transfer from the sensitizer, intersystem crossing of resultant radical-ion pairs, and ion recombination to give norbornadiene triplets followed by rearrangement to the valence isomer.Where energetic factors are favorable, the isomerization quantum yield is as high as 0.39 and the efficiency of formation of norbornadiene triplets via ion recombination as high as 65 percent.

Effects of photophysical properties of 1,4-cyclohexadiene derivatives on their [2 + 2] photocycloaddition reactivities: Experimental and theoretical studies

To study the relationship between the [2 + 2] photocycloaddition reactivities of 1,4-cyclohexadiene derivatives (1,4?CHDs) and their structures, photophysical properties of a series of 1,4?CHDs were studied experimentally and by performing theoretical calculations. Specifically, UV–vis absorption spectra of these compounds in diluted solutions were acquired and the theoretical calculations were performed at the density functional theory (DFT) level. Their UV–vis absorption maxima were found to be related to the substituents on the 1,4-cyclohexadiene ring. To describe the [2 + 2] photocycloaddition reactivities of the 1,4?CHDs, time-dependent density functional theory (TDDFT) was used to optimize their ground- and excited-state structures, and their electronic excitation energies were calculated at the M062X/def-TZVP level. Frontier molecular orbitals and electron-hole distribution analyses were used to illustrate the electron transition modes of the 1,4?CHDs. The differences between the ground- and excited-state structures of the different 1,4?CHDs were characterized by carrying out a root-mean-square-deviation (RMSD) analysis. The results showed that the photophysical properties of 1,4?CHDs are meaningful for explaining their [2 + 2] photocycloaddition reactivities.

Photocalorimetry. 6. Enthalpies of Isomerization of Norbornadiene and of Substituted Norbornadienes to Corresponding Quadricyclenes

The enthalpies of isomerization of norbornadiene and of several substituted norbornadienes to the corresponding quadricyclenes have been determined by the method of photocalorimetry.This method also gives f, the percent of adsorbed light energy of a given wavelength that is stored chemically as a consequence of the photoinduced isomerization.The results for 25 deg C are as follows (compound, solvent, ΔH in kcal mol-1, fwavelength, nm): norbornadiene, cyclohexane, 14.0 +/- 1, f313 = 15.0 +/- 1percent: 2,3-bis(carbomethoxy)norbornadiene, acetonitrile, 25.2 +/- 3.5, f313 = 12.4 +/- 2.2percent; 2,3-dicyanonorbornadiene, acetonitrile, 22.0 +/- 2.3, f313 = 11.2 +/- 1.9percent; 1,2,3-trimethyl-5,6-dicyanonorbornadiene, acetonitrile, 21.0 +/- 2.0, f366 = 15.5 +/- 1.7percent.The position of the first absorption band shifts progressively to longer wavelengths in the above sequence, and the results show that such shifting toward the solar insolation region does not impair the energy storage ability of the system.For the parent, norbornadine system, it was necessary to use acetophenone as sensitizer, and it is possible that minor secondary photolysis effects led to the relatively low ΔH value; the value has the merit that it is the practical one for conditions relevant to actual solar energy storage.

HIGHLY EFFICIENT VALENCE ISOMERIZATION BETWEEN NORBORNADIENE AND QUADRICYCLANE DERIVATIVES UNDER SUNLIGHT

3-Phenylcarbamoyl-2,5-norbornadiene-2-carboxylic acid (1b) undergoes a facile and quantitative isomerization into the corresponding quadricyclane derivative (2b) under sunlight.The back isomerization of 2b to 1b proceeds quantitatively by the use of catal