1,2,4,5‐Tetrakis(dimethylamino)benzene, a New Electron Donor with Unusual Properties

A product consisting of two vinylogous amidinium ions is formed when the title compounds gives up two electrons to iodide. The resulting salt forms diamagnetic, blackish‐violet crystals. The two mesomeric π‐electron systems are almost planar; the sixmembered ring in 1 has a twist‐conformation

New proton sponges, 13. - syntheses, structures and basicities of 1,2,4,5-tetrakis(dimethylamino)benzene and 2,3,6,7-tetrakis(dimethylamino)naphthalene

1,2,4,5-Tetrakis(dimethylamino)benzene (4) and 2,3,6,7-tetrakis (dimethylamino)naphthalene (5) were prepared and structurally determined. Electron-donor functions, protonation, and the geometry of intramolecular hydrogen bonds are discussed. By oxidation of 4 to its dication the benzenoid aromaticity is cancelled in favour of two independent units as determined by X-ray structure aromaticity is cyanine-type analysi

1,2,4,5‐Tetrakis(dimethylamino)‐benzol, ein neuer Elektron‐Donor mit ungewöhnlichen Eigenschaften

In ein Gebilde aus zwei vinylogen Amidinium‐Ionen wandelt sich die Titelverbindung bei der Abgabe von zwei Elektronen an Iod um. Das dabei entstehende Salz 1 bildet diamagnetische, schwarzviolette Kristalle. Die beiden mesomeren π–Elektronensysteme sind etwa planar; der Sechsring in 1 hat Twist‐Konformation

Radical cations of 1,2,4,5-tetrakis(dimethylamino)benzene and 2,3,6,7-tetrakis(dimethylamino)naphthalene: an ESR and ENDOR study

The title radical cations, 2.+ and 3.+, were generated by oxidation of the parent compounds with tris(4-bromophenyl)aminium hexachloroantimonate, iodine or lead tetraacetate, and were characterized by ESR and ENDOR. For 2.+ a restricted rotation about the C(aryl)N bond is found at low temperature (≤ 230 K). The remarkably low a(HCH3)/a(N) ratios of 2.+ and 3.+ point to an increase in the average degree of bending at nitrogen

Protonation of 1,2,4,5-tetrakis(dimethylamino)benzene

1,2,4,5-Tetrakis(dimethylamino)benzene () forms diprotonated salts like the bis(tetrafluoroborate) and the dibromide . For -dihydrate an -X-ray structure revealed the presence of ‘bifurcated hydrogen bonds’. and the protonated species derived therefrom are discussed with regard to the sterical requirements of ‘proton sponges’. Protonation of 1,2,4,5-tetrakis(dimethylamino)benzene yields only the diprotonated dication the molecular structure of which is discussed on the basis of X-ray structure analysis

Entwicklung von fluessigkristallinen Polymeren als Mantelmaterial fuer elektronische Bauelemente

A joint research project was directed towards the investigation into the feasibility of substituting currently used thermosetting resins for the encapsulation of electronic components by mouldable thermoplasts. Materials based on liquid crystalline polymers (LCP) appeared to be favourable in view of their excellent flow characteristics, inherent inflammability and mouldability. Initially tested materials derived from BASF developmental LCP exhibited sufficient thermal conductivity and low ion content levels. The additional requirements of stability towards hydrolysis and soldering as well as good welding line strength, however, were met only by blends of LCP with poly(aryletherketone)s (PAEK). Adherence of these materials to lead frame metal surfaces was investigated by a team of the Fraunhofer Institute of Applied Materials Research (FhG-IFAM). A minimised temperature difference between thermoplast melt and mould was recognised to be decisive for good adherence. The structural stability was significantly enhanced by introducing a polyimide layer between thermoplast and lead frame. The developmental materials were evaluated by SIEMENS for direct and indirect (premoulded packaging) sheathing. With direct sheathing using the LCP/PAEK blends ''wire sweeps'' were unavoidable. Promising results were obtained with the same materials under conditions of premoulded packaging techniques, among which heated tool welding proved to be the best suited welding process. High potential of the developed blends in system packaging is expected providing new prospects for the electronics industryAvailable from TIB Hannover: F93B1281+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman