1,1′‐Diaryl‐Substituted Ferrocenes: Up to Three Hinges in Oligophenyleneethynylene‐Type Molecular Wires

Abstract

Molecular wires of the oligophenyleneethynylene (OPE)‐type are potentially rigid entities. The idea of the work reported herein was to replace some, not all, of the phenylene moieties with ferrocene units, thereby introducing limited conformational flexibility with the ferrocene units acting as hinges as a consequence of the facile rotation around the Cp–Fe–Cp axis. In this context, the syntheses of a number of 1,1′‐diaryl‐disubstituted ferrocene building blocks are described. The new terminal diynes 22 and 24 were used to construct the first representatives of ferrocene‐based molecular wires with three ferrocene hinges. The study includes an X‐ray structure analysis of the thiophene‐based diyne 24 as well as cyclovoltammetric analyses of a number of the compounds prepared.

Improved Syntheses of 1,2‐Disubstituted Ferrocenes

“…Its stability against heat and air, its three‐dimensional shape, and its redox activity are most striking. Such properties facilitate the formation of planar‐chiral derivatives and the exploitation of the facile rotation of the cyclopentadienyl ligands as a “hinge” in larger structures, for example in extended π‐systems In addition, ferrocene finds applications in many areas such as catalysis, materials sciences, bioorganometallic chemistry, and electroanalytical methods . These fields and many others have been reviewed in recent monographs ,…”

Tricyclic Quinazoline Alkaloids Conjugated to Ferrocene: Synthesis, Structure, and Redox Behavior of Ferrocenylmethylene‐Substituted 7H‐Deoxyvasicinones

“…[39,40] The structure has an approximate C 2 symmetry, with the 3-deoxyvasicinone moieties and the ferrocene cyclopentadienyl ligands adopting almost coplanar conformations (C3- Figure 5. Cyclic voltammograms of 10 (top) and 18 (bottom).…”

(Di‐tert‐butylphosphanylethyl)cyclopentadienylnickel Chelates with Alkyl, Alkenyl, Aryl, and Alkynyl Ligands: Hints to Cumulenylidene Resonance Forms

“…Compound 32: GP2; {1,1′‐bis[(4‐trimethylsilyl)ethynyl]phenyl}ferrocene (100 mg, 0.3 mmol) was added to 5 (170 mg, 0.5 mmol) and copper(I) iodide (3 mg, 0.03 mmol) in triethylamine (8 mL), and the mixture was stirred for 72 h. After workup, chromatographic purification (10 × 1 cm, SiO 2 , petroleum ether/diethyl ether, 2.5:3) afforded 32 (124 mg, 0.1 mmol, 74 %) as a brown solid (m.p. 155 °C, dec.).…”