No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Influence of Sequential Nitrogen Substitution on the Redox Properties of Bis(thiazolylidene)hydrazine and on the Charge Transfer of TCNQ Complexes
Abstract
Various extended π-donor molecules incorporating an azino spacer between two heterocyclic moieties, either dithiole or thiazole rings, are described. As evidenced by cyclic voltammetric studies, the donor ability of these derivatives can be modulated depending on the nature of the two heterocycles. Three similar crystalline complexes were obtained with TCNQ and the donors 4, 7 and 8. Crystal structures and magnetic susceptibility data of these complexes are presented and the degree of charge transfer within these complexes has been correlated with the redox properties.
... For general background, see: Yoshita et al. (1983); Moore et al., (1998); Taniguchi et al. (2003). For useful properties of related compounds, see: Andreu et al., (2004); Guerin et al. (2002). For the synthesis of the starting material, 2-methylthio-1,3-dithiolium iodide, see: Challenger et al. (1953). ...
... Within the field of molecular conductors, tetrathiafulvalene and its π-derivatives have played a leading role in the formation of organic charge-transfer complexes (Yoshita et al. 1983;Moore et al., 1998;Taniguchi et al. 2003). One of the important strategies for the molecular design is to incorporate the nitrogen atom instead of carbon atoms to the conjugated spacer to modulate electron-donating properties (Andreu et al., 2004;Guerin et al., 2002). As a π-extended tetrathiafulvalene, we synthesized the title compound by incorporation an azino spacer between two 1,3-dithiole units. ...
The title molecule, C6H4N2S4, has a crystallographically imposed centre of symmetry located at the mid-point of the N—N single bond. The molecule is essentially planar: the two five-membered rings form a dihedral angle of 0.17 (6)°. The crystal packing exhibits short intermolecular S...S contacts of 3.549 (2) Å.
... A very simple route to generate azines involves the nucleophilic attack of hydrazine (NH2NH2.H2O) on heterocyclic quaternary salts 12 possessing a good leaving group such as OR, SR or halogen at position two of thiazole/benzothiazole. Guerin et al. 13 in 2002 reported two strategies (Scheme 1) for the synthesis of azine 7 which includes (i) the direct refluxing half equivalent of hydrazine with thiazolium salt or (ii) in a two-step procedure by first preparing an intermediate (hydrazino derivative) using an excess of hydrazine from the reaction of thiazolium salt 6. Moreover, the authors also reported the synthesis of unsymmetrical azine 8 by treating the intermediate with a dithiolium salt. ...
Azines are organic molecules which carry the C=N–N=C functional unit. In the recent past, azines received increased attention due to the recognition of their biological, chemical and material properties. Azines are conventionally synthesized by the condensation of hydrazine with ketones and aldehydes, many alternate routes are also available. The conjugation (or lack of it) in azines was investigated with the help of computational studies and crystal structure analysis. The tautomerism in azines is a topic of contemporary interest. Herein, we present a review of recent advances in the structure and electronic structure properties of azines along with information on the modern methods of their synthesis and application as precursors in generating heterocycles in organic synthesis and in medicinal chemistry. A few applications of azines in generating covalent organic frameworks (COF), metal organic frameworks (MOF), energetic material and chemosensors are also included.
The interaction between 4, 7, 13, 16, 21, 24 - hexaoxa-1,10 - diazabicyclo [8.8.8] hexacosane (C222) and 7,7,8,8- teracyanoquinodimethane (TCNQ) has been studied in chloroform at 25°C. The results indicate a two step mechanism. At the first step, two adducts (assign as P1 and P2) are formed through equilibrium reactions. In continue and through nonequilibrium reactions the adducts are converted to a final product (assign as P3). Based on the comparison of the spectra of C222-TCNQ mixture with that of Na-18C6-TCNQ mixture, the C222+TCNQ, C222+TCNQ- TCNQ° and (C222 +)2(TCNQ-)2 are suggested as the P1, P2, and P3, respectively. IR specra of C222 and TCNQ are compared with the spectrum of solid 1:1 TCNQ-C222 complex and the effect of complexation on absorption bands are discussed.
The unique properties of radical anion salts and charge transfer complexes formed by tetracyanoquinodimethane and other strong π-electron acceptors are analyzed. Their ability to form fusible conductive materials and magnetically ordered structures, including ferromagnetic ones with high Curie temperatures, spin ladders and quasi-two-dimensional organic conductors and superconductors is considered. Particular attention is given to the possible areas of application of these radical anion salts in electronic industry as nanomaterials, materials for the fabrication of field effect transistors, photodiodes and ion selective electrodes.
The bibliography includes 421 references.
The synthesis of a series of dimers containing two redox active moieties, such as azino-chalcogenoazafulvalenes, connected through one or two non conjugated spacer group is reported. Various heterocycles have been used to build these donor molecules incorporating an azino spacer group between two thiazole moieties or a thiazole core and a selenazole one or two selenazole cores or a thiazole and a dithiole moiety. Cyclic voltammetry experiments have evidenced the influence of the nature of the heterocycle on the donating ability of these dimers. Moreover, sizable intramolecular interactions between the two electroactive moieties are observed depending on the length and the number of the non conjugated spacer group.
The phosphoramidate-like reaction of 1,3-dithiole derived N-(diethoxyphosphinyl)hydrazones with formyl derivatives of 1,3-dithiole affords the longest aza-analogues of extended tetrathiafulvalenes with a polyenic spacer reported to date. Their structural and electrochemical properties are discussed.
The synthesis and the redox behaviour of electroactive donor molecules incorporating an azino spacer group between a benzoselenazole core and another heterocyclic moiety, either a benzoselenazole one or a thiazole one, are reported. Neutral complexes were obtained with TCNQ and, for the first time with dithiadiazafulvalene or diselenadiazafulvalene derivatives, cation radical salts by electrocrystallization. Crystal structures data of these complexes are presented and their geometries compared with those deduced from theoretical calculations.
The title mol-ecule, C(6)H(4)N(2)S(4), has a crystallographically imposed centre of symmetry located at the mid-point of the N-N single bond. The mol-ecule is essentially planar: the two five-membered rings form a dihedral angle of 0.17 (6)°. The crystal packing exhibits short inter-molecular S⋯S contacts of 3.549 (2) Å.
The title compound, C16H14N4S2, crystallizes in symmetry group C2. The molecule is planar with C2h symmetry, with the inversion centre at the mid-point of the hydrazine N-N bond, and it has an N-N s-trans conformation and a Z,Z configuration. The particular crystal examined was a racemic twin, as suggested by the Flack parameter of 0.41 (2) [Flack (1983). Acta Cryst. A39, 876-881].
Bridged and methylated bithiazolium salts have been prepared by alkylation of 2,2′-bithiazole. The electronic absorption spectra and reduction potentials have been measured and stable radical cations of the di- and trimethylene bridged species have been prepared.
Die Benzthiazoliumsalze (Ia) werden mit Triäthylamin in DMF bei 25°C über die bei 0°C auch isolierbaren Intermediärstufen (IIa) zu den Dimeren (IIIa) umgesetzt.
The properties of new 2,2'-ethanediylidene(1,3-dithiole) derivatives 5, 6, and 8-11 are reported, Cyclic voltammetric studies establish that they are efficient donor molecules, with the extended conjugation resulting in stabilization of dications, relative to tetrathiafulvalene TTF (1). Radical cations are generated by oxidation of the neutral compounds with trifluoroacetic acid or anhydrous silver perchlorate in dichloromethane, and their ESR and proton ENDOR spectra are reported. The bulk. of the spin population resides in the central S2C=C-CC=CS2 part of the pi-system. The X-ray crystal structure of donor 6 reveals that the 2,2'-ethanediylidene(1,3-dithiole) framework is planar. Donor 6 forms a crystalline 1:1 charge-transfer complex with TCNQ, the X-ray crystal structure of which shows a mixed stack structure. A solution of this complex in acetonitrile exhibits ESR spectra of both radical ions, 6(.+) and TCNQ(.-). Static susceptibility data are reported for TCNQ complexes of some of these donors.
N-Methylbenzoxazolium, N-methylbenzothiazolium, and benzimidazolium salts were reacted with triethylamine, potassium t-butoxide or dimsyl sodium to give corresponding ketospiran derivatives. Several other products were also characterized and possible mechanisms of these reactions were discussed briefly.
Communication: A quasi-planar dithiadiazafulvalene (DTDAF) with high electrondonating properties is reported. The chemical synthesis of a phenyl-N,N'-bridge DTDAF (the Figure shows an ORTEP drawing of the DTDAF(+.) cation radical) is described together with the preparation of a charge-transfer salt by in situ trapping and investigations of the structural and magnetic properties of this salt. Evidence for mixed valence states is presented.
Mescionic thiazoles are starting materials for the preparation of oxygen sensitive dithiadiazafulvalenes, which can be reacted in situ with acceptor derivatives to give the corresponding charge transfer complexes while their reaction with oxygen leads to a ten-membered macrocycle.
3-Substituted 2-nitrosoimino-2,3-dihydrobenzothiazoles (1) were reduced with lithium aluminum hydride to give the corresponding thiazolone azines and bis[o-(N-substituted N-formylamino)phenyl] disulfides as major products. Reactions of 1 with some substituted diazomethanes gave the corresponding unsymmetrical azine N-monoxides (16) or azines (17) depending on the structure of the diazomethane.
The synthesis and electrochemical redox properties of a series of symmetrical, highly conjugated bis(benzo-1,3-dithiole) and bis(benzothiazole) derivatives (8)–(24) are described. The heterocyclic end-groups are linked by a conjugated framework that incorporates the following groups: (a) phenyl, (b) naphthyl, (c) thienyl, (d) biphenyl, (e) anthracenyl, and (f) benzanthracenyl. Compounds (13) and (16)–(19) display two, single-electron redox waves in the cyclic voltammogram, while compounds (8)–(12), (14), (15), (20), (21), (23), and (24) display a single, two-electron redox wave. The redox potentials of these molecules can be correlated with the increased stability of the redox state of the system in which the central, bridging ring is aromatic.
Diazadithiafulvalenes act as excellent electron donors to arenediazonium salts. The diazadithiafulvalenium radical cations trap primary carbon radicals successfully. However, the diazadithiafulvalenium salts which form, undergo rapid ring fragmentation in contrast to their tetrathia counterparts.
The synthesis and solution electrochemistry of ten new ethanediylidene-2,2′-bis(1,3-dithiole) derivatives (7)–(16) is described; charge-transfer complexes have been obtained with tetracyano-p-quinodimethane (TCNQ).
Die vinylogen Verbindungen N1–3, O1–2, S1–3 sowie ihre Azaderivate N2a2 und S2a4 erweisen sich als zweistufige Redoxsysteme, deren Semichinonbildungskonstante Ksem mit wachsender Kettenlänge stark fällt (ca. 105 → 101). Für die planaren vinylogen Systeme gilt log KSem ˜ JSemmm (Coulombsches Repulsionsintegral). Azasubstitution erhöht KSem stark und verschiebt den gesamten Potentialbereich positiv. N3a4, O3a4 und S3a4 zeigen keine reversible Oxidationswelle. Die schwach basischen Amidrazone AS und ASe bilden bei der elektrochemischen Oxidation Tetrazene (z. B. S2a4). Soweit möglich, werden die Elektronenspektren der Redoxsysteme mitgeteilt. Nur die Radikalkationen zeigen einen Vinylensprung von 100–140 nm.Two Step Redox Systems, XVI1). – Spectroscopy and Polarography of Vinylogous Bibenzimidazoles, Bibenzoxazoles and Bibenzothiazoles and their Aza DerivativesThe vinylogous compounds N1–3, O1–3, S1–3 and their aza derivatives N2a2 and S2a4 prove to be two step redox systems of which the semiquinone formation constant KSem decreases drastically with growing chain length (circa 105 → 101). For the planar vinylogous systems a linear correlation between log KSem and JSemmm (Coulomb repulsion integral) is found. On aza substitution all potentials are shifted positively and KSem is strongly enhanced. N3a4, O3a4 and S3a4 display no reversible oxidation waves. The weakly basic amidrazones AS and ASe form tetrazenes during electrochemical oxidation (e. g. S2a4). Wherever possible the electronic spectra of the redox systems are given. The radical cations only show vinylene shifts of 100–140 nm.
This review describes the synthesis of 1,3- and 1,2-tetrachalcogenafulvalenes, the chemical transformation of substituents, reactions of the ring system, and the synthesis of polymers with 1,3-tetrathiafulvalene units in the backbone and in the side chain. For selected charge-transfer complexes of tetrachalcogenafulvalenes, the relation between molecular structure and solid-state structure, respectively, and electric conductivity are discussed. Superconducting properties of some charge-transfer complexes with tetrachalcogenafulvalenes as donor are reported.Preparations of important starting compounds for the synthesis of tetrachalcogenafulvalenes (such as 1,2- and 1,3-dithiole, 1,3-thiaselenole, and 1,3-diselenole derivatives) have been considered in this review.Selected properties (melting point, UV-Vis absorption data and oxidation potentials) of 1,2- and 1,3-tetrachalcogenafulvalenes are summarized in appropriate tables.
A new type of electron donors in the charge-transfer complex formation, ethanediylidene-2,2′-bis(1,3-dithiole)′s, have been synthesized by the reaction of (1,3-dithiolidene)phosphoranes with 2-formylmethylene-1,3-dithioles and their properties have been discussed.
Efficient syntheses are described for five new vinylogous pi-electron donors, viz. 5, 6, and 8-10, which are related to bis(ethylenediseleno)tetrathiafulvalene (3): symmetrical and unsymmetrical systems, containing mixed alkylseleno and alkylthio groups, have been obtained. The solution electrochemical redox properties, studied by cyclic voltammetry, establish that these molecules undergo two, single-electron, oxidations at low potentials. The single-crystal X-ray structure of 4,5-bis(methylseleno)-4',5'-bis(methylthio)-2,2'-ethanediylidene(1,3-dithiole) (6) is reported. Semiconducting complexes of the new donors with tetracyano-p-quinodimethane have been obtained.
Two new pi-donors related to bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF, 2) have been synthesized. These are the vinylogue 5 of BEDT-TTF and the mixed-vinylogue 4 related to TTF and BEDT-TTF.
Several dithiadiazafulvalenes, which are potent electron donors, were isolated as pure compounds for the first time. Solid charge-transfer complexes with TCNQ and also cation-radical and dication salts with perchlorate gegenions were obtained. Two of the TCNQ complexes are moderately conductive at room temperature (0.083 and 0.011 S/cm). A solution EPR study, combined with theoretical calculations, allowed the determination of the relative equilibrium cation-radical and anion-radical concentrations.
Dithiadiazafulvalenes (DTDAF) can be formed either chemically or electrochemically. Electrochemical investigations have been carried out on 2-ethylthio-1,3-thiazolium salts to determine the redox behavior of dithiadiazafulvalenes formed by cathodic coupling. Using an in situ method, the donor has been trapped in the medium and a crystalline charge-transfer salt with TCNQ has been isolated. The crystal structure and magnetic susceptibility data of this 1:3 complex established that the DTADF is in the dicationic state.
Aus Benzo- und Naphthothiazolium-Salzen (1) werden durch HX-Abspaltung mittels Triäthylamins über Carbene (Typ 3) die Dimeren 2 erhalten. Deren Reaktionen mit Sauerstoff (zu den Spiranen 7 und 8 bzw. zum Cyclodecan-Derivat 10), mit Wasserstoffperoxid (zum Thiazolon 20) und mit Wasser (zu 23) werden beschrieben. Die Additionsprodukte 24 von Methanol an 2 lassen sich vorteilhaft anstelle der Dimeren einsetzen. In Gegenwart von Pyridin entstehen aus den Salzen 1 mit Schwefel Thione 25. Über in situ erzeugte Carbene werden Azine (28 und 29) hergestellt. – NMR-Spektren und Reaktionsmechanismen werden diskutiert.
- P Cava
- R M Metzger
- J Becher
P. Cava, R. M. Metzger, and J. Becher, J. Org. Chem. 56, 2720 (1991);
- S H Unig
- D Scheutzow
- M Schlaf
- H Putter
- Liebigs Ann
S. H.
unig, D. Scheutzow, M. Schlaf, and H. Putter, Liebigs Ann.
Chem. 1436 (1974).
- W Coffin
- M R Clegg
- A J Bryce
- B K Moore
- R Tanner
- W Whitehead
- F Clegg
- A Gerson
- S Lamprecht
- Pfenninger
Coffin, and W. Clegg, J. Org. Chem. 57, 1696 (1992); (f) M. R. Bryce,
A. J. Moore, B. K. Tanner, R. Whitehead, W. Clegg, F. Gerson,
A. Lamprecht, and S. Pfenninger, Chem. Mater. 8, 1182 (1996).
- N Bellec
- D Lorcy
- A Robert
- R Carlier
- A Tallec
- C Rimbaud
- L Ouahab
- R Clerac
- P Delhaes
N. Bellec, D. Lorcy, A. Robert, R. Carlier, A. Tallec, C. Rimbaud,
L. Ouahab, R. Clerac, and P. Delhaes, Adv. Mater. 9, 1052 (1997).
- N Bellec
- D Lorcy
- K Boubekeur
- R Carlier
- A Tallec
- Sz
- W Los
- M Pukacki
- L Trybula
- A Piekara-Sady
- Robert
N. Bellec, D. Lorcy, K. Boubekeur, R. Carlier, A. Tallec, Sz. Los,
W. Pukacki, M. Trybula, L. Piekara-Sady, and A. Robert. Chem.
Mater. 11, 3147 (1999).
- N Goulle
- S Chirayil
N. Goulle, S. Chirayil, and R. P. Thummel, Tetrahedron Lett. 31,
1539 (1990).
- Liebigs Steinmaus
- Ann
Steinmaus, Liebigs Ann. Chem. 708, 155 (1967); (b) A. Takamizawa,
K. Hirai, and Y Hamashima, Chem. Pharm. Bull. 17, 1462 (1969);
- M Bssaibis
- A Robert
- P Le Maguer Es
- L Ouahab
- R Carlier
- A Tallec
M. Bssaibis, A. Robert, P. Le Maguer" es, L. Ouahab, R. Carlier,
and A. Tallec, J. Chem. Soc. Chem. Commun. 601 (1993).
- T Yoshida
- H Kawase
- I Awaji
- Sugimoto
(a) Z. Yoshida, T. Kawase, H. Awaji, and I. Sugimoto, Tetrahedron
Lett. 24, 3469 (1983); (b) T. K. Hansen, M. V. Lakshmikantham, M.
- J Kennedy
- Murphy
Kennedy, and J. Murphy, J. Chem. Soc. Perkin Trans. 1, 3637 (1999).
- R Carlier
- J Simonet
R. Carlier and J. Simonet, Bull. Soc. Chim. Fr. 831 (1988).
- T J Kistenmacher
- T J Emge
- A N Bloch
- D O Cowan
T. J. Kistenmacher, T. J. Emge, A. N. Bloch, and D. O. Cowan,
Acta. Crystallogr. B 38, 1193 (1982).