Thiol-yne chemistry of diferrocenylacetylene: from synthesis and electrochemistry to theoretical studies

The thiol-yne coupling chemistry of diferrocenylacetylene (FcCCFc) 1, bearing two electron rich and redox-active ferrocenyl units (Fc = Fe(η⁵-C₅H₄)(η⁵-C₅H₅)) and an internal triple bond, has been investigated for the first time. In order to determine whether steric limitations might affect hydrothiolation, a model reaction using a functionalized monothiol was tested, namely 2-mercaptoethanol I. The thiol-diferrocenylacetylene reactions were initiated either thermally (in toluene with AIBN) or by UV light irradiation (in THF and in the presence of DMPA as the photoinitiator). The outcomes of these thiol-yne reactions showed a strong dependence on the initiation method used, with the thermally initiated one being the most efficient. These thiol-diferrocenylacetylene reactions mainly afforded the (Z)-stereoisomer of the newly obtained vinyl thioether sulfide FcCHC(Fc)S-(CH₂)₂OH (2), unlike the more common (E)-vinyl sulfides found in other additions to alkynes. The hydrothiolation of the internal -CC- bond in 1 was successfully extended to dithiol 2,2'-(ethylenedioxy)diethanethiol II, leading to the formation of the (ZZ)-isomer, with four ferrocenyl units, as the major product. According to the electrochemical studies, the new asymmetrical ferrocenyl-vinyl sulfides show iron-iron electronic and electrostatic interactions. Theoretical results for the (Z)-stereoisomer (2) suggest that adiabatic oxidation would lead to the loss of almost one electron on the ferrocenyl subunit closer to the thioether chain. Furthermore, the thiol-yne chemistry of the internal -CC- bond in diferrocenylacetylene has been compared to the external triple bond in ethynylferrocene, the theoretical results of which helped us to rationalize the very different reactivities observed in both metallocenes.

Crystal structure of 1-ferrocenyl-2-(4-nitro-phen-yl)ethyne

The title ferrocene derivative, [Fe(C5H5)2(C8NO2)], including an alkyne bonded to a para-nitro-phenyl substituent, which was synthesized from a copper-free Sonogashira cross-coupling reaction between ethynylferrocene and 4-bromo-1-nitro-benzene, crystallizes in the P21/n space group. In the ferrocene unit, the penta-dienyl (Cps) rings are in an eclipsed conformation. The angle of rotation between the substituted cyclo-penta-dienyl ring and the p-nitro-phenyl group is 6.19 (10)°, yielding a quasi-linear extension of the ferrocenyl substitution. Important inter-molecular inter-actions arise from π-π stacking between the Cp rings and the p-nitro-phenyl, from corners of the Cp rings that are perpendicularly aligned, and between the O atoms from the nitro substituent and carbons at the corners of the Cp rings, propagating along all three crystallographic axes.

o-Carborane, Ferrocene, and Phthalocyanine Triad for High-Mobility Organic Field-Effect Transistors

An unsymmetrical zinc phthalocyanine with ferrocenylcarborane linked to the phthalocyanine ring through a phenylethynyl spacer was designed for organic field-effect transistor (OFET). The unsymmetrical phthalocyanine derivatives were characterized using a wide range of spectroscopic and electrochemical methods. In particular, the ferrocenylcarborane structure was unambiguously revealed based on the single-crystal X-ray diffraction analysis. In-depth investigations of the electrochemical properties demonstrated that the ferrocenylcarborane insertion extended the electrochemical character of ferrocenylcarborane-substituted phthalocyanine (7). Moreover, in the anodic potential scans, the oxidative electropolymerization of etynylphthalocyanine (6) and 7 was recorded. To clarify the effect of the insertion of ferrocenylcarborane (2) on the field-effect mobility, solution-processed films of 2, 6, and 7 were used as an active layer to fabricate the bottom-gate top-contact OFET devices. An analysis of the output and transfer characteristics of the fabricated devices indicated that the phthalocyanine derivative functionalized with ferrocenylcarborane moiety has great potential in the production of high-mobility OFET.

Ferrocene amphiphilic D–π–A dyes: synthesis, redox behavior and determination of band gaps

We reported the synthesis, optical and redox behavior of six ferrocenyl D–π–A dyes. Optical and electrochemical band gaps were determined and corroborated by TD-DFT calculations. Compounds4exhibit the smallest band gap of this series.

Synergistic effect of donors on tetracyanobutadine (TCBD) substituted ferrocenyl pyrenes

The ferrocenyl substituted pyrenes 2, 3a–3c, 4a and 4b were designed and synthesized using Suzuki and Sonogashira cross-coupling, and [2+2] cycloaddition–retroelectrocyclization reactions.

Star shaped ferrocenyl substituted triphenylamines

This manuscript reports design and synthesis of star shaped ferrocenyl substituted triphenylamine conjugates (Fc-TPA) 3a–3c by the Pd-catalyzed Sonogshira cross-coupling reaction.