2,9-Diazadibenzoperylene and 2,9-Dimethyldibenzoperylene-1,3,8,10-tetratriflates: Key to Functionalized 2,9-Diazaperopyrenes

Rapid Synthesis of Highly Substituted 1,6-Naphthyridines Via Heteroaryl Ditriflates

We report the discovery of a convenient and efficient method for the synthesis of highly substituted 1,6-naphthyridines. A tandem nitrile hydration/cyclization procedure was developed to access 1,6-naphthyridine-5,7-diones under mild conditions. Subsequently, we have found that ditriflation of these intermediates provides 1,6-naphthyridine-5,7-ditriflates which are bench-stable but highly reactive intermediates that can be engaged in one-pot difunctionalization reactions leading to diverse drug-like products in rapid fashion.

Peri-Decoration of a Tetraazaperylene with Urea Units: Chiral Octaazaperopyrenedioxides (OAPPDOs) and Their Optical and Chiroptical Properties

Octaazaperopyrenedioxides (OAPPDOs) are a new class of fluorescent polycyclic aromatic hydrocarbons based on a tetraazaperylene core that is formally condensed with N-substituted urea units in the two opposite peri positions. Here, we report the synthesis of series of substituted OAPPDO derivatives with different N-substitution patterns (H, alkyl, benzyl) in the peri positions, including bay-chlorinated OAPPDOs. Starting from the latter, a series of bay-arylated OAPPDOs was synthesized by Suzuki cross coupling, which resulted in the formation of helically chiral OAPPDO derivatives. The electrochemical and photophysical properties were investigated by UV/Vis and fluorescence spectroscopy as well as cyclic voltammetry. The P and M enantiomers of a phenylated OAPPDO were separated by semipreparative HPLC and further analyzed by CD spectroscopy. The frontier orbital energies, the mechanism of the isomerization, the electronic excitation and the CD spectrum (TD-DFT) were computed and compared to the experimental data. The reversible 1e^- oxidation of the OAPPDOs generates the corresponding radical cations, one of which was characterized by EPR spectroscopy. The reversible oxidation process was also systematically investigated by spectro-electrochemistry.

Rylene- and diaza-rylene-derived cobalt clusters for solid-state pyrolysis towards undoped and N-doped carbon nanoparticles

2,7-Diazapyrene and 2,9-diazaperopyrene tetraalkynes (12 and 13) as well as related non-N-doped pyrene and peropyrene tetraalkynes (14 and 15) of the same shape were used as polyaromatic templates in their metalation by [Co₂(CO)₈]. Isolated cobalt-rich [(12, 13, 14, 15)Co₈(CO)₂₄] clusters were characterized by means of NMR, IR, UV-Vis spectroscopy and X-ray crystallography. Their thermogravimetric behaviour and products of solid-state pyrolysis (SSP) were investigated by TGA, DSC, and scanning electron microscopy (SEM). Despite the same precursor shape, different carbon nanoparticles and nanotubes were formed depending on the extension of the π-system and nitrogen content of the precursors. Diazapyrene and diazaperopyrene complexes formed cauliflower-shaped nanoparticles, and the pyrene complex formed spherical nanoparticles and the peropyrene complex led to multi-walled carbon nanotubes. These results elucidate that the carbon to cobalt ratio and the nitrogen dopant in the precursor have a significant impact on the products of the pyrolysis reaction.

Reductive O-triflylation of naphthalene diimide: access to alkyne- and amine-functionalized 2,7-diazapyrenes

A reductive one-pot triflylation and silylation of naphthalene diimide is presented. Post-functionalization of the 1,3,6,8-tetratriflato key compound leads to so far non-accessible UHV processable tetraalkynyl and tetraaminyl 2,7-diazapyrenes.