Polycyclic Aromatic Hydrocarbons Containing A Pyrrolopyridazine Core

Abstract

Polycyclic aromatic azomethine ylides (PAMYs) are versatile building blocks for the bottom‐up construction of unprecedented nitrogen‐containing polycyclic aromatic hydrocarbons (N‐PAHs). Here, we demonstrate the 1,3‐dipolar cycloaddition between PAMY and 1,4‐diphenylbut‐2‐yne‐1,4‐dione and the subsequent condensation reaction with hydrazine, which led to unique N‐PAHs with a phenyl‐substituted pyrrolopyridazine core (PP‐1 and PP‐2). The molecular structures of pristine PP‐1 and tert‐butyl‐substituted PP‐2 were verified by NMR spectroscopy and mass spectrometry. Moreover, the structure of PP‐2 was unambiguously elucidated by X‐ray single crystal analysis. The optoelectronic properties were investigated by solvent‐dependent UV‐Vis absorption and fluorescence emission spectroscopy as well as cyclic voltammetry. Additionally, density functional theory (DFT) calculations showed that PP‐1 and PP‐2 exhibit push–pull behavior. Furthermore, in situ EPR/UV‐Vis‐NIR spectroelectrochemistry allowed the detailed insight into the spectroscopic properties and spin distribution of radical cation species of PP‐2.

[3 + n] Cycloaddition Reactions: A Milestone Approach for Elaborating Pyridazine of Potential Interest in Medicinal Chemistry and Optoelectronics

“…Richter et al [ 44 , 45 ] performed an in-depth study concerning the optoelectronic properties of and obtaining some polycyclic aromatic hydrocarbons with pyrrolopyridazine core 74a , b , as shown in Scheme 18 .…”

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

“…216.2a , b were then condensed with hydrazine to yield the final compounds 216.3a , b as yellow solids. 409 The cycloaddition reaction of PAMY 216.1b with ortho -1,2-naphthoquinone and the following oxidation gave the intermediate 216.4 , which provided the helicene-like 216.5 upon condensation with ortho -benzenediamine. The same synthetic method was used to obtain larger fused frameworks by cycloaddition of PAMY to anthracene-1,2,6,7-tetraketone, acting as a single or double dipolarophile.…”

“… Reagents and conditions: (a) 409 (1) 1,4-diphenylbut-2-yne-1,4-dione, DCM, 5 min, rt, (2) DDQ, toluene, rt, 3 h; (b) hydrazine, ethanol, overnight, 80 °C; (c) 410 (1) 1,2-naphthoquinone, DCM, TEA, rt, 5 min, (2) DDQ, toluene, rt, 3 h; (d) HOAc, toluene, 100 °C, 72 h; (e) 413 Pd(dppf)Cl 2 , Na 2 CO 3 , DMSO, 100 °C, 16 h; (f) PdCl 2 (PPh 3 ) 2 , PPh 3 , K 2 CO 3 , DMF/H 2 O, 90 °C, 24 h; (g) hν (254 nm), decalin, 100 °C, 2 h; (h) 411 (1) i -Pr 2 NEt, CsF, DMSO, 160 °C, 12 h, (2) DDQ, DCM, rt, 20 min; (i) Pd(AcO) 2 , P( t -Bu) 2 Me·HBF 4 , DBU, DMA, 160 °C, 12 h. …”

“…In 2019, Bunz, Feng, and Berger et al reported ullazine derivatives ( 216.3 – 7 ) obtained through cycloaddition reactions of the previously reported polycyclic aromatic azomethine ylides (PAMYs, Scheme ). , Intermediates 216.2a , b were initially obtained via 1,3-dipolar cycloaddition of PAMYs, generated in situ from the corresponding salts 216.1a , b by addition of triethylamine (TEA), followed by dehydrogenation with DDQ. 216.2a , b were then condensed with hydrazine to yield the final compounds 216.3a , b as yellow solids .…”

Modular Nitrogen‐Doped Concave Polycyclic Aromatic Hydrocarbons for High‐Performance Organic Light‐Emitting Diodes with Tunable Emission Mechanisms**

“…Notably, seminal works on the pyrrole-embedded curved PAHs 5 a and 5 b were independently reported by Nozaki [18] and Shinokubo; [19] whereas further modifications of this scaffold were explored by Ito [20,21] and Feng. [22] More recently, Zhang and co-workers reported PAHs containing acridone (6 and 7) [23][24][25] and phenothiazine (8) [26] , as suitable building blocks to ensure the desired curvature for the construction of concave and boat-like conformations, respectively. Moreover, the Gryko research group demonstrated the utility of pyrrolo [3,2-b]pyrrole in forming a buckybowl-like system, with inverse Stone-Thrower-Wales defects, first through "on surface", [27] and subsequently "in solution" [28] approaches (Figure 1b, 9).…”