Acephenanthrylenes from flash vacuum thermolysis of diarylmethylidenecycloproparenes
Upon flash vacuum thermolysis at 750°C fluorenylidenecyclopropa[b] naphthalene (1) undergoes opening of the three-membered ring and rearrangement to give a range of C24H14 polycyclic aromatic hydrocarbons. Dibenz[e.l]- and -[e.k]acephenanthrylene (7) and (12), respectively, have been identified while the plausible naphth[1,2-e]- and [2,3-e]acephenanthrylenes (9) and (14) were not detected. With diphenylmethylidenecyclopropa[b]naphthalene (2) cyclodehydrogenation and rearrangement also provide C24H14 polycycles; dibenz[e.k]acephenanthrylene (12) is identified and dibenz[a.e]aceanthrylene (15) is a proposed product.
Modular Design of Fluorescent Dibenzo- and Naphtho-Fluoranthenes: Structural Rearrangements and Electronic Properties
A library of 12 dibenzo- and naphtho-fluoranthene polycyclic aromatic hydrocarbons (PAHs) with MW = 302 (C24H14) was synthesized via a Pd-catalyzed fluoranthene ring-closing reaction. By understanding the various modes by which the palladium migrates during the transformation, structural rearrangements were bypassed, obtaining pure PAHs in high yields. Spectroscopic and electrochemical characterization demonstrated the profound diversity in the electronic structures between isomers. Highlighting the significant differences in emission of visible light, this library of PAHs will enable their standardization for toxicological assessment and potential use as optoelectronic materials.
Mohammad-Pour, Gavin S.,Ly, Richard T.,Fairchild, David C.,Burnstine-Townley, Alex,Vazquez-Molina, Demetrius A.,Trieu, Khang D.,Campiglia, Andres D.,Harper, James K.,Uribe-Romo, Fernando J.
p. 8036 - 8053
(2018/05/31)
Attempted synthesis of Fjord-region containing polycyclic fluoranthenes reveals a steric-driven double Wagner-Meerwein rearrangement
A double Wagner-Meerwein rearrangement takes place commonly in the synthesis of sterically hindered polycyclic fluoranthenes via cyclodehydration reactions and the extent of intramolecular steric crowding within the initially formed tertiary cationic intermediate controls the equilibrium between the expected and the rearranged product.