The Ionization Energies of Tetrazinodi(heteroarenes)

Abstract

The ionization energies of four [I ,2,4,5]tetrazinodi(heteroarenes) of C,, symmetry have been measured by PE spectroscopy. It is found that the first ionization energy is very low (6.2 eV to 6.4 eV) and rather independent of the size and/or topology of the molecules. This is explained, by comparison with the results of a simple MO treatment, as being due to the strong localization of the HOMO (of A , symmetry) on the [1,2,4,5]tetrazino moiety of the molecules. The PE-spectroscopic data are shown to be in agreement with the UVjVIS-and electrochemical-oxidation data published previously.Introduction. -Recently, we have reported the synthesis, the electronic spectra [I], and the oxidation potentials [2] of a series of tetrazinodi(heter0arenes). These molecules are of interest as electron donators in charge-transfer complexes and as redox catalysts. In this connection, the ionization energies of these electron donators are important quantities, which now have been determined for four key molecules, using PE spectros-COPY.

Annelated[1,2,4,5]Tetrazines

“…Similar treatment of 1-amino-2-(4-chlorobenzoyl)quinolinium perchlorate 153b with sodium hydroxide methanol was reported to give 154 via methanolysis of the initially formed dimer (Scheme 42) [66]. [53][54][55].…”

“…Treatment of the latter with base, resulted in the generation of the 1,3 dipole 221, which dimerizes to give cycloadduct 222. Dehydrochlorination of the latter occurs in situ to give the end product 223 (Scheme 63) [53][54][55].…”

Radical Cations of Tetrazinodi(heteroarenes): An ESR and ENDOR Study

“…are listed in the Table. The coupling constants aNp and a,, are arranged in such a way that values for nuclei in topologically similar positions p of the n-systems are placed in the same line. The assignments to individual positions are based on Huckel-McLachlan calculations [8] using the conventional parameters for hetero-n-centers and adjacent bonds [5] [9] [lo]; a further guidance for these assignments was provided by the consistency of the data within the series 1''-5+. and 6+'-8+..…”

Tetrazinodiheteroarene: ‘Charge‐Transfer’‐Komplexbildung mit Akzeptorverbindungen

“…In fruheren Publikationen wurden die Synthesen einiger Tetrazinodiheteroarene beschrieben [ 11, ihre elektrochemischen Eigenschaften untersucht [2] und ihre Ionisierungsenergien gemessen [3]. Mit Akzeptorverbindungen wie TCNQ (Tetracyanochinodimethan = 2,2'-(Cyclohexa-2,5-dien-l,4-diyliden)bis[propandinitril]; 9), TCNE (Tetracyanoethylen = Ethylentetracarbonitril; 11) und I, lassen sich tiefschwarze, kristalline Komplexverbindungen herstellen [4].…”