Electron Affinity of the Acceptor Molecule in Charge-Transfer Complexes

Nature ◽  
1961 ◽  
Vol 191 (4789) ◽  
pp. 702-703 ◽  
Author(s):  
M. E. PEOVER
Keyword(s):  
Charge Transfer ◽  
Electron Affinity ◽  
Charge Transfer Complexes ◽  
Acceptor Molecule

Introduction

2003 ◽  
Author(s):  
Toshiaki Enoki ◽  
Morinobu Endo ◽  
Masatsugu Suzuki
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Ionization Potential ◽  
Molecular Orbital ◽  
Electron Affinity ◽  
Basic Unit ◽  
Charge Transfer Complexes ◽  
Vacuum Level ◽  
2D System ◽  
Lowest Unoccupied Molecular Orbital

There are two important features in the structure and electronic properties of graphite: a two-dimensional (2D) layered structure and an amphoteric feature (Kelly, 1981). The basic unit of graphite, called graphene is an extreme state of condensed aromatic hydrocarbons with an infinite in-plane dimension, in which an infinite number of benzene hexagon rings are condensed to form a rigid planar sheet, as shown in Figure 1.1. In a graphene sheet, π-electrons form a 2D extended electronic structure. The top of the HOMO (highest occupied molecular orbital) level featured by the bonding π-band touches the bottom of the LUMO (lowest unoccupied molecular orbital) level featured by the π*-antibonding band at the Fermi energy EF, the zero-gap semiconductor state being stabilized as shown in Figure 1.2a. The AB stacking of graphene sheets gives graphite, as shown in Figure 1.3, in which the weak inter-sheet interaction modifies the electronic structure into a semimetallic one having a quasi-2D nature, as shown in Figure 1.2b. Graphite thus features a 2D system from both structural and electronic aspects. The amphoteric feature is characterized by the fact that graphite works not only as an oxidizer but also as a reducer in chemical reactions. This characteristic stems from the zero-gap-semiconductor-type or semimetallic electronic structure, in which the ionization potential and the electron affinity have the same value of 4.6 eV (Kelly, 1981). Here, the ionization potential is defined as the energy required when we take one electron from the top of the bonding π-band to the vacuum level, while the electron affinity is defined as the energy produced by taking an electron from the vacuum level to the bottom of the anti-bonding π*-band. The amphoteric character gives graphite (or graphene) a unique property in the charge transfer reaction with a variety of materials: namely, not only an electron donor but also an electron acceptor gives charge transfer complexes with graphite, as shown in the following reactions: . . .xC + D → D+ C+x. . . . . .(1.1). . . . . .xC + A → C+x A−. . . . . .(1.2). . . where C, D, and A are graphite, donor, and acceptor, respectively.

Elementorganische Verbindungen mit ö-Phenylenresten, XI [1] 3:l-Komplexe von Hexachlor-dibenzo-p-dioxin-2,3-chinon mit 2,3,7,8-Tetramethoxythianthren und -selenanthren / Organometallic Compounds with o-Phenylene Substituents, Part XI [1] 3:1 Complexes of Hexachloro-dibenzo-p-dioxin-2,3-quinone with 2,3,7,8-Tetram ethoxythianthrene and Selenanthrene

1986 ◽  
Vol 41 (9) ◽  
pp. 1133-1141 ◽  
Author(s):  
Winfried Hinrichs ◽  
Peer Berges ◽  
Günter Klar
Keyword(s):  
Charge Transfer ◽  
Organometallic Compounds ◽  
Charge Transfer Complexes ◽  
Acceptor Molecule ◽  
Front Side ◽  
Concentrated Solutions ◽  
The Mean ◽  
Dark Blue

Abstract The title com pounds can be isolated from concentrated solutions of 2,3,7,8-tetramethoxy thianthrene or selenanthrene and tetrachloro-o-benzoquinone as dark blue crystals. Bond distances and bond and folding angles of the components indicate these com pounds to be charge transfer complexes in which the tetramethoxy thianthrene or selenanthrene molecules act as donors (D), the hexachloro-dibenzo-p-dioxin-2,3-quinone molecules as acceptors (A). In the asymmetric units of the two isostructural complexes an acceptor, a donor and another acceptor molecule are arranged parallel to each other. A third acceptor molecule is placed at the front side of the A1 ,D ,A2-arrangement. In the crystal the A1, D, A2,(A3) units are connected by centres of symmetry leading to A1 ,D ,A2 , A1',D',A2', . . . stacks in which the aryl rings of the halves of the molecules are equidistant and parallel to each other. The mean distances between the rings are 340 and 345 pm, respectively

Charge-transfer Complexes with Nitrate Esters as Electron Acceptors

1972 ◽  
Vol 50 (20) ◽  
pp. 3340-3349 ◽  
Author(s):  
T. Urbański ◽  
B. Hetnarski ◽  
W. Południkiewicz
Keyword(s):  
Charge Transfer ◽  
Electron Affinity ◽  
Electron Acceptors ◽  
Stable Complex ◽  
Charge Transfer Complexes ◽  
Polar Solvents ◽  
Nitrate Esters ◽  
High Enthalpy ◽  
Unstable Complex

Nitrate esters of alcohols, containing from one to six O-nitro groups, react with tetramethyl-p-phenylenediamine (TMPD) in non-polar solvents to yield Wurster cation. The number of O-nitro groups necessary to produce 1 mol of Wurster cation is at least three. This is now explained in terms of the enthalpy of the reaction related to the electron affinity of nitrate esters; esters with five to six O-nitro groups show a relatively high enthalpy manifested by their ability to form charge-transfer complexes. Initially an unstable complex A is formed which then gives Wurster cation, both reactions being fast. A slow transformation then occurs into more stable complex B having the composition: 1 mol TMPD–2 mol of pentanitrates or 1 mol TMPD–1 mol of hexanitrate. TMPD in complex B was transformed into tetramethyl-p-quinonediimine dication.That all nitrate esters with one to four O-nitro groups do not form complexes A and B may be due either to their relatively low enthalpy (and electron affinity), or to more favorable structures of complexes A and B of pentanitrates of D-xylitol and penta- and hexanitrates of hexitols with TMPD.

Nickel(IV) Bis-(3)-1,2-dicarbollide as an Acceptor Molecule in the Synthesis of Electrically Conducting Charge Transfer Complexes

1995 ◽  
Vol 14 (2) ◽  
pp. 666-675 ◽  
Author(s):  
Peter A. Chetcuti ◽  
Walther Hofherr ◽  
Andre Liegard ◽  
Grety Rihs ◽  
Guenther Rist ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complexes ◽  
Acceptor Molecule ◽  
Electrically Conducting

Charge-Transfer Complexes of Some Heteroarylthiourea Derivatives with π-Acceptors

1993 ◽  
Vol 58 (12) ◽  
pp. 2846-2852
Author(s):  
Maher M. A. Hamed ◽  
Hassan M. A. Salman ◽  
Elham M. Abd-Alla ◽  
Mohamed R. Mahmoud
Keyword(s):  
Molecular Structure ◽  
Charge Transfer ◽  
Spectral Data ◽  
Stability Constants ◽  
Electron Affinity ◽  
Ionization Potentials ◽  
Charge Transfer Complexes ◽  
Ct Complexes

Charge-transfer complexes of some heteroarylthiourea derivatives with π-accptors have been studied spectrophotometrically in CH2Cl2. Spectral data, stability constants and enthalpies of complexation are reported. From the energies of the CT transition, ionization potentials of the donors have been obtained. Effects of donor molecular structure, π-acceptor electron affinity and nature of solvent on KCT of complexes are investigated and discussed. It is deduced that the formed CT complexes are of n-π kind and of 1 : 1 stoichiometry.

Magnetic properties of new charge-transfer complexes based on manganese porphyrins

1997 ◽  
Vol 90 (3) ◽  
pp. 407-413
Author(s):  
MARC KELEMEN ◽  
CHRISTOPH WACHTER ◽  
HUBERT WINTER ◽  
ELMAR DORMANN ◽  
RUDOLF GOMPPER ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Transfer ◽  
Charge Transfer Complexes ◽  
Manganese Porphyrins
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