Cyclopentannulated Dihydrotetraazapentacenes

Abstract

The transition-metal-catalyzed cyclization of bissilylethynylated N,N'-dihydrotetraazapentacene (TIPS-TAP-H 2 ) into bissilylated cyclopenta[fg,qr]pentacenes is reported. Depending on the catalyst either none, one or two silyl groups migrate and change their positions in the formed five-membered rings. The optoelectronic properties are quite similar, whereas the packing motifs differ dramatically. Control experiments and quantum chemical calculations were performed to investigate the mechanism of the reaction and the selectivity of the silyl shift.

A Symmetrically π‐Expanded Carbazole Incorporating Fluoranthene Moieties

“…Experimental optoelectronic and electrochemical data of compounds 4, 8, 9, 10, and 11 as well as calculated HOMO and LUMO energies. (9), 360 (10), 293 nm (11).…”

“…In this context, the incorporation of π‐conjugated cyclopentadiene moieties has been established as a particularly potent strategy to modulate the electronic and structural properties of the polycyclic frameworks [9] . This approach has so far resulted in a number of interesting compounds with unusual properties including cyclopentannulated acenes [10] and their nitrogen‐containing counterparts [11] . The cyclopentannulated carbazole derivative 1 was reported by Wang and coworkers to exhibit intense blue fluorescence (Figure 1).…”

Versatile access to nitrogen-rich π-extended indolocarbazolesviaa Pictet–Spengler approach

“…Until recently, appropriate starting materials necessary for the bidirectional PSR were difficult or impossible to synthesize. Fortunately, we lately developed a versatile gold-catalyzed [51][52][53][54][55][56][57][58][59] method for the building of benzodipyrroles and therein showed the example of bis(2-aminophenyl)-substituted benzodipyrrole 1 (Scheme 2). 60 This substrate is accessible starting from 1,4-diiodo-2,5-dimethoxybenzene in a straightforward four step synthesis and should be suitable for the synthesis of BBPQs via the PSR.…”

Substituted Cyclopentannulated Tetraazapentacenes

“…Recently, we developed a transition metal-catalyzed cycloisomerization of bissilylethynylated N,N'-dihydrotetraazapentacene (C). [6] We disclosed a catalyst-dependent (gold [7] and palladium) silyl shift furnishing three different regioisomers of the annulated tetraazapentacenes (D) with similar photophysical properties but dramatic differences in crystal packing. Within that work, a detailed experimental and computational mechanistic investigation was conducted to explain the observed difference in the shift-behavior between gold and palladium catalysts.…”

“…Recently, we developed a transition metal‐catalyzed cycloisomerization of bissilylethynylated N , N’ ‐dihydrotetraazapentacene ( C ) [6] . We disclosed a catalyst‐dependent (gold [7] and palladium) silyl shift furnishing three different regioisomers of the annulated tetraazapentacenes ( D ) with similar photophysical properties but dramatic differences in crystal packing.…”