Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Beiträge zur nickelorganischen Chemie

A study of rhodium(I)-catalyzed synthetic transformations involving selective breaking of the C−C bond α to the carbonyl group of cyclobutanones is described. Decarbonylation took place on treatment of a cyclobutanone with an equimolar amount of (Ph3P)3RhCl at reflux in toluene to afford the corresponding cyclopropane. The formation of the cyclopropane suggests that Rh(I) undergoes an insertion into the bond between the carbonyl carbon and the α-carbon in the initial step. Catalytic decarbonylation of cyclobutanone was also achieved. The mode and rate of the reaction depended greatly on the ligands of the rhodium(I) complex. When a cyclobutanone bearing a hydrogen atom at the 3-position was used, appropriate choice of the catalyst system led to the selective formation of either a cyclopropane or an alkene. Breaking of the carbon−carbon bond was next combined with hydrogenolysis. When cyclobutanone was treated under hydrogen pressure with a catalytic amount of a rhodium(I) complex having a bidentate diphos...

Breaking of the C−C Bond of Cyclobutanones by Rhodium(I) and Its Extension to Catalytic Synthetic Reactions

Rhodium(i)-catalyzed successive double cleavage of carbon-carbon bonds of strained spiro cyclobutanones

Remarkable Stability of Metallocenes with Superbulky Ligands: Spontaneous Reduction of SmIII to SmII

über die katalytische Umwandlung von Olefinen, II Zum Reaktionsablauf der Cyclotrimerisation von Butadien-(1.3)

Übergangsmetall‐Komplexe, II1) Reaktionen von Nickel(0) mit Radikalen

Das aus 2.2′-Dianthrylamin durch Umsetzung mit Schwefel zugangliche 8H-Dinaphtho-[2.3-c: 2′.3′-h]phenothiazin (1) liefert bei der Dehydrierung das stabile freie Radikal 4. Der Radikalgehalt betragt im Kristall nach ESR-Messungen 85%. Losungen von 4 liefern ein linienreiches ESR-Spektrum, das im Zusammenhang mit Huckel-Rechnungen diskutiert wird.



E.S.R. Investigation of the Dinaphtho[2.3-c:2′.3′-h]phenothiazinyl Radical



8H-Dinaphtho[2.3-c : 2′.3′-h]phenothiazine (1), obtained by reaction of di-2-anthrylamine with sulfur, yields the stable free radical 4 by dehydrogenation. For the solid state a free radical content of 85% has been determined by e. s. r. Solutions of 4 gave a complex e. s. r. spectrum which is discussed in connection with Huckel calculations.

ESR-Spektroskopische Untersuchung des Dinaphtho[2.3-c: 2′.3′-h]phenothiazinyl-Radikals

7H-Dibenzo[c.h]phenothiazin (1) liefert bei der Dehydrierung mit gelbem HgO das stabile freie Titel-Radikal 2. Der Radikalgehalt (Raumtemperatur) betragt nach ESR-Messungen in Losung 64%, im Kristall 6%. Das linienreiche Losungs-ESR-Spektrum wird im Zusammenhang mit Huckel-Rechnungen diskutiert. Ein 1:1-Addukt von 1 und 2 weist (im Kristall) einen Radikalgehalt von 72% (bezogen auf 2) auf. 2 und das fruher beschriebene Dinaphtho-[2.3-c : 2′.3′-h]phenothiazinyl1) (5) zeigen charakteristische UV-Spektren.



Synthesis and Properties of the Dibenzo[c.h]phenothiazinyl Radical



The stable free title radical 2 is obtained from 7H-dibenzo[c.h]phenothiazine (1) by dehydrogenation with yellow HgO. For 2 a free radical content of 64% in solution (room temperature) and 6% in the crystalline state has been determined by e.s.r. The complex e.s.r. spectrum of 2-solutions is discussed in connection with Huckel calculations. A 1:1-adduct of 1 and 2 in the crystalline state exhibit a radical content of 72% (referred to 2). 2 and the formerly described dinaphtho[2.3-c : 2′.3′hyphen;h]phenothiazinyl (5) display characteristic u.v. spectra.

Josef Brandt

Papers

über die katalytische Umwandlung von Olefinen, II Zum Reaktionsablauf der Cyclotrimerisation von Butadien-(1.3)

Übergangsmetall‐Komplexe, II1) Reaktionen von Nickel(0) mit Radikalen

ESR-Spektroskopische Untersuchung des Dinaphtho[2.3-c: 2′.3′-h]phenothiazinyl-Radikals

Darstellung und Eigenschaften des Dibenzo[c.h]phenothiazinyl‐Radikals

Use of a Computer in Nuclear Magnetic Resonance Spectroscopy