Electron affinities and Marcus reorganization energies. A correlation between gas phase electron affinities and solution phase redox potentials

1989 ◽  
Vol 67 (1) ◽  
pp. 171-175 ◽  
Author(s):  
Dennis D. Tanner ◽  
Natasha Deonarian ◽  
Abdelmajid Kharrat

Redox potentials determined by cyclic voltammetry were used in conjunction with published electron affinities to determine the solvation energies for series of three classes of compounds: substituted benzoquinones, substituted nitrobenzenes, and polynuclear aromatic hydrocarbons. Excellent linear correlations were obtained between the measured electron affinities and the E0 of the substrates. The calculated electron affinities, EA (E0), were computed using the average solvation energies for the three classes of compounds, and were found to be in excellent agreement with the measured values. The nitrobenzenes and quinones had one solvation energy, while the aromatic hydrocarbons were correlated with a significantly different value. The solvation energy of a variety of compounds could also be related to their Marcus reorganization energiesλ(0), by a linear plot with a high correlation coefficient. From simple electrochemical measurements of similar compounds, either electron affinities or Marcus λ(0) values can be estimated. Keywords: electron affinities, Marcus reorganization energies, cyclic voltammetry.

1989 ◽  
Vol 67 (10) ◽  
pp. 1628-1631 ◽  
Author(s):  
Glen W. Dillow ◽  
P. Kebarle

Electron affinities for aza-substituted polycyclic aromatics were determined from measurements of electron transfer equilibria in the dilute gas phase with a pulsed electron high pressure mass spectrometer (PHPMS). These are (in kcal/mol): quinazoline (12.7), quinoxaline (15.8), cinnoline (16.0), acridine (20.3), benzo[c]cinnoline (20.6), pyrido[2,3-b]pyrazine (22.5), phenazine (29.5). Solvation energies of the corresponding radical anions in acetonitrile and dimethylformamide are derived from the gas phase data and literature on electron reduction potentials in solution. An observed linear relationship between the electron affinities and the reduction potentials allows estimates of electron affinities to be made for 12 aza compounds whose EA's are too low to be measured with the present method. Keywords: aza-substituted aromatic hydrocarbons, electron affinities, electron transfer, radical anions, reduction potentials, solvation energies of radical anions, stabilities of radical anions.


Author(s):  
M. E. Snook ◽  
R. F. Severson ◽  
R. F. Arrendale ◽  
H. C. Higman ◽  
O. T. Chortyk

AbstractThe methyl, multi-methyl, and ethyl derivatives of the polynuclear aromatic hydrocarbons (PAH) of cigarette smoke condensate (CSC) were isolated from the neutrals by silicic acid chromatography, solvent partitioning and gel chromatography. The procedure yielded a relatively pure PAH isolate amenable to further identifications. The multi-alkylated PAH were concentrated in the early gel fractions with parent and higher ring PAH found in subsequent gel fractions. It was shown that CSC is very rich in alkylated PAH, and their successful identification required extensive use of gas and liquid chromatography and ultra-violet and GC - mass spectrometric techniques. High-pressure liquid chromatography (HPLC) separated individual isomers of the alkylated PAH in complex GC peaks. PAH from indene to pentamethylchrysene were found. This report concludes our identification studies on the PAH of CSC and complements our two previous reports in this journal. Collectively, our studies have identified approximately 1000 PAH of cigarette smoke condensate and have led to the development of methods for the routine quantitation of PAH in smalI quantities of cigarette smoke condensate.


2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>


2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>


1991 ◽  
Vol 26 (1) ◽  
pp. 1-16 ◽  
Author(s):  
T.P. Murphy ◽  
H. Brouwer ◽  
M.E. Fox ◽  
E. Nagy

Abstract Eighty-one sediment cores were collected to determine the extent of coal tar contamination in a toxic area of Hamilton Harbour. Over 800 samples were analyzed by a UV spectrophotometric technique that was standardized with gas chromatography/mass spectrometry analysis. The coal tar distribution was variable. The highest concentrations were near the Stelco outfalls and the Hamilton-Wentworth combined sewer outfalls. The total concentration of the 16 polynuclear aromatic hydrocarbons (PAHs) in 48,300 m3 of near-surface sediments exceeded 200 µg/g.


Sign in / Sign up

Export Citation Format

Share Document