A Star-Shaped Supercrowded 2,3,4,5-Tetraferrocenylthiophene: Synthesis, Solid-State Structure, and Electrochemistry†

A straightforward method for the octafunctionalization of biphenylene based on the [2+2]-cycloaddition of an aryne intermediate has been developed. This enabled a "North-South" extension of biphenylene towards isomeric graphene nanoribbons composed of four-, six-, and eight-membered rings. This procedure furthermore allowed an "East-West" expansion to [n]phenylenes with different lengths. For the fabrication of isomeric nanongraphenes, octaarylbiphenylenes decorated with phenyl, pyrenyl, and thieno substituents were prepared. The subsequent oxidative cyclodehydrogenation provided an expanded helicene as a model compound.

Octafunctionalized Biphenylenes: Molecular Precursors for Isomeric Graphene Nanostructures

Electron Transfer Studies on Ferrocenylthiophenes: Synthesis, Properties, and Electrochemistry

Novel electron-transfer-induced intermolecular [2 + 2] cycloaddition reactions between an aliphatic cyclic enol ether and several unactivated olefins have been demonstrated on the basis of the aromatic “redox tag” strategy. The aromatic “redox tag” was oxidized during the formation of the cyclobutane ring, affording the relatively long-lived aromatic radical cation, which was then reduced to complete the overall reaction that constructed the corresponding [2 + 2] cycloadducts. The aromatic “redox tag” was also found to facilitate electron-transfer-induced cycloreversion reactions of cyclobutane rings.

Electron-Transfer-Induced Intermolecular [2 + 2] Cycloaddition Reactions Based on the Aromatic “Redox Tag” Strategy

In this review, the properties of the most significant examples of multi(ferrocenyl) cations containing a number of ferrocenyl units from two to six are discussed and the results are compared with the outcomes of some of our recent studies on conjugated ferrocenyl complexes, in order to give an overview of how the nature of the bridging ligand, the distance between the redox-active centres, and the medium affect the electronic and electrostatic properties of the molecules.

Key multi(ferrocenyl) complexes in the interplay between electronic coupling and electrostatic interaction

Syntheses, Structures, and Reactivity of Radial Oligocyclopentadienyl Metal Complexes: Penta(ferrocenyl)cyclopentadienyl and Congeners

The Thermal Retro[2+2+2]cycloaddition of Cyclohexane Activated by Triscyclobutenannelation: Concerted All-Disrotatory versus Stepwise Conrotatory Pathways to Fused [12]Annulenes

Radial (tetracyclopentadienyl)cyclobutadiene pentametals

Author(s): Cammack, J. Kevin; Amouri, Hani; Leonard, Philip W.; Myrabo, Randy L.; Vollhardt, Peter C.

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Philip W. Leonard

Papers

Syntheses, Structures, and Reactivity of Radial Oligocyclopentadienyl Metal Complexes: Penta(ferrocenyl)cyclopentadienyl and Congeners

The Thermal Retro[2+2+2]cycloaddition of Cyclohexane Activated by Triscyclobutenannelation: Concerted All-Disrotatory versus Stepwise Conrotatory Pathways to Fused [12]Annulenes

Radial (tetracyclopentadienyl)cyclobutadiene pentametals

Electron Exchange Along the Tercyclopentadienyltrimetallic Scaffold: Kinetics, Equilibria, and Bond Strengths