A Perspective on Synthesis and Applications of Fluorenones

Abstract

Fluorenones are important constituents in material, medical and chemical sciences with potential applications in various domains. The key factors responsible for the diverse usage of fluorenones in material sciences are their intriguing and tunable photo, as well as physico‐chemical properties. Besides this, the presence of conjugated poly‐(en)ynes in the fluorenones makes them molecules of interest in material sciences. Fluorenones show various biological activities like antibiotics, anticancer, antiviral, and neuromodulatory, etc. Organic chemists are developing various protocols for the synthesis of fluorenones. Despite several protocols developed for their synthesis since 1931, there is no review covering their entire synthetic protocols. This review includes several classical and novel synthetic approaches for the synthesis of fluorenones. Furthermore, we delineated the mechanism by which they have been synthesized.

Analytical Characterization of the Intercalation of Neutral Molecules into Saponite

“…Since the above analyses suggested a modification of the fluorene incorporated by the OP technique, this material has been further investigated. In fact, the harsh experimental conditions and the contemporaneous presence of aluminum isopropoxide, alcohol isopropyl, catalytic substrate (saponite) and basic environment (NaOH) are known to be able to promote fluorene alkylation and/or the formation of fluorenone which can actually take place under even milder oxidation conditions [ 41 , 42 , 43 , 44 ]. Possible fragments deriving from fluorene modification were searched for in the TGA-GC-MS profiles acquired in the full-scan mode of the sample CTA_FL_SAP_OP.…”

Nonlinear Optical Properties and Applications of Fluorenone Molecular Materials

“…[51,52] As one of the most important π-conjugated organic semiconductors, fluorenes have attracted considerable research attention in the past decades because of their intrinsic high quantum yields, excellent thermal, optical, and chemical stability, [53,54] as well as the diversity of molecular configurations and commercially availability. In particular, its oxidized materials, namely fluorenone and derivatives, have been recently explored as building blocks for very promising multifunctional materials, [55] that demonstrate both second-and third-order NLO responses, together with distinctive waveguiding properties. [8,56,57] Though these fluorenone derivatives have moderate ICT characteristics and permanent dipole moments that are oriented perpendicularly to the long molecular axis, they favor synergistic non-covalent interactions such as hydrogen bonds and CH•••π interactions, which could overcome the dipoledipole interactions.…”

The Trityl Cation Embedded into a [7]Helicene-Like Backbone: Preparation and Application as a Lewis Acid Catalyst

“…The carbenium ion is embedded into a [7]helicene-like backbone. To access this motif, a novel carbonylative annulation 15,17 for the synthesis of -extended fluorenones was developed. The helically chiral trityl cation derivative is a Lewis acid that catalyzes several model reactions equally effectively as the parent compound.…”

“…Our approach relies on an unprecedented palladium-catalyzed carbonylative annulation. 15 Nozaki and co-workers used a (Chen 1997 similar strategy for the preparation of oxygen-and nitrogen-containing hetero [7]helicenes through palladium catalysis. 14 Scheme 2 Planned synthesis of the [7]helicene-based trityl cation…”