Photochemistry of Aryltert-Butyl Ethers in Methanol:  The Effect of Substituents on an Excited State Cleavage Reaction

Whereas direct irradiation (2537 Å) of 5,6-dihydro-4,6,6-trimethyl-2(1H)-pyridone 1 (1a) produced almost exclusively the cleavage products 2 and 3, the acetophenone sensitized reaction (3500 Å) gave a single cyclobutane dimer. In contrast, direct (2537 Å) or sensitized (acetophenone, 3500 Å) irradiation of the homo derivative 7 of compound 1 gave approximately the same mixture of two cyclobutane dimers. It was thus demonstrated that dimer formation proceeded by way of a triplet excited state and that the cleavage reaction most probably occurred via an excited singlet state.A structure for each cyclobutane dimer in the seven-membered series was proposed on the basis of its spectral properties.

Download Full-text

Effect of Substituents at the 4,7-Positions on the Structural Change Dynamics of Cu(I) Bis(phenanthroline) Complexes in the MLCT Excited State

Chemistry Letters ◽

10.1246/cl.151018 ◽

2016 ◽

Vol 45 (2) ◽

pp. 167-169 ◽

Cited By ~ 5

Author(s):

Munetaka Iwamura ◽

Fumiaki Kobayashi ◽

Koichi Nozaki

Keyword(s):

Excited State ◽

Structural Change ◽

Effect Of Substituents ◽

Change Dynamics

Download Full-text

Effect of Substituents on the Equilibrium between Trans and Perpendicular Conformers in the Triplet Excited State of Substituted Styrylpyrenes

Chemistry Letters ◽

10.1246/cl.1993.833 ◽

1993 ◽

Vol 22 (5) ◽

pp. 833-836 ◽

Cited By ~ 6

Author(s):

Yoshihiko Kikuchi ◽

Hiroaki Okamoto ◽

Tatsuo Arai ◽

Katsumi Tokumaru

Keyword(s):

Excited State ◽

Triplet Excited State ◽

Effect Of Substituents

Download Full-text

The Effect of Substituents on the Polarity in the First Excited Singlet State of Some trans-Styryl-Methyl-Sulfones

Zeitschrift für Naturforschung A ◽

10.1515/zna-1989-1205 ◽

1989 ◽

Vol 44 (12) ◽

pp. 1163-1166

Author(s):

A. Kawski ◽

A. Kubicki ◽

J. Czajko

Keyword(s):

Dipole Moment ◽

Excited State ◽

Electron Donor ◽

Ground State ◽

Singlet State ◽

Excited Singlet State ◽

Excited Singlet ◽

Hammett Constant ◽

Effect Of Substituents ◽

Donor Power

Abstract The effect of substituents R (R=N(CH3)2, OCH3, CH3, H, Cl, Br, CN) on the polarity of trans-styryl-methyl-sulfones in the first excited singlet state is investigated. Linear relations are found between the dipole moment in the excited state, μe, and the Hammett constant, σp+ , and also between μe and the dipole moment in the ground state, μg. On increasing the electron-donor power of R, μe grows faster than μg.

Download Full-text

Renilla Bioluminescence: A Morphologic Approach to the Location of Photocytes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051050 ◽

1974 ◽

Vol 32 ◽

pp. 208-209

Author(s):

Ben O. Spurlock ◽

Milton J. Cormier

Keyword(s):

Excited State ◽

Ground State ◽

Molecular Basis ◽

Light Emission ◽

Chemical Basis ◽

Electronic Excited State ◽

Colonial Form ◽

The Common ◽

Eighteenth And Nineteenth Centuries ◽

Catalyzed Oxidation

The phenomenon of bioluminescence has fascinated layman and scientist alike for many centuries. During the eighteenth and nineteenth centuries a number of observations were reported on the physiology of bioluminescence in Renilla, the common sea pansy. More recently biochemists have directed their attention to the molecular basis of luminosity in this colonial form. These studies have centered primarily on defining the chemical basis for bioluminescence and its control. It is now established that bioluminescence in Renilla arises due to the luciferase-catalyzed oxidation of luciferin. This results in the creation of a product (oxyluciferin) in an electronic excited state. The transition of oxyluciferin from its excited state to the ground state leads to light emission.

Download Full-text

Integration of Core-Edge Spectroscopy Methods for the Study of Polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016323x ◽

1996 ◽

Vol 54 ◽

pp. 154-155

Author(s):

E. G. Rightor

Keyword(s):

Excited State ◽

Polymer Blends ◽

Gas Phase ◽

Spatial Resolution ◽

High Spatial Resolution ◽

Electronic States ◽

Core Electron ◽

Bulk Solids ◽

Development Application

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.

Download Full-text

Examining the degradation of environmentally-daunting per- and poly-fluoroalkyl substances from a fundamental chemical perspective

Physical Chemistry Chemical Physics ◽

10.1039/d0cp02445g ◽

2020 ◽

Vol 22 (31) ◽

pp. 17659-17667 ◽

Cited By ~ 2

Author(s):

Antonio H. da S. Filho ◽

Gabriel L. C. de Souza

Keyword(s):

Excited State

In this work, ground and excited-state properties were used as descriptors for probing mechanisms as well as to assess potential alternatives for tackling the elimination of per- and poly-fluoroalkyl substances (PFAS).

Download Full-text