Donor−Acceptor−Donor Tetrazines Containing a Ferrocene Unit:  Synthesis, Electrochemical and Spectroscopic Properties

Abstract

Donor-acceptor-donor tetrazines containing ferrocene moieties and phenyl unit as a pi-bridge have been synthesized and characterized. UV-vis spectroscopic and cyclic voltamperometric results indicate sizable intramolecular charge transfer interactions in the ground state when the ferrocene is directly bound to the tetrazine. On the other hand, the results show reduction of the electron-donor strength of ferrocene moieties when there is a phenyl linkage. Both tetrazines display a high reduction potential. The role of ferrocenyl groups appear to be detrimental to maximize the cubic hyperpolarizability gamma of tetrazines, as compared to purely organic groups such as thiophene. A possible explanation for this behavior may originate from metal-to-ligand charge transfer processes.

New pyridinium conjugated ferrocenes: Synthesis and electrochemical properties

“…Comparison with ferrocene indicates that the attracting power of a pyridinium core appears comparable and very slightly below the effect of a tetrazine ring (E 0 = 0.27 V vs. Fc for bisferrocenyltetrazine [15]), which is of interest, given that pyridinium is a charged species, whereas tetrazine is neutral, the former thus leading to an additional coulombic repulsion. Fig.…”

“…Therefore it often provides a molecular switch for many physical properties in the case of compounds containing ferrocenes linked to another active moiety [10][11][12][13], and especially a pyridinium [8,9,14]. This is especially true for the linear and nonlinear optical (NLO) properties, which could thus be triggered through the electrochemical conversion of the compounds, as suggested recently by one of us in the case of ferrocenetetrazines [15].…”

Rapid-scan time-resolved FT-IR spectroelectrochemistry – Study on the electron transfer of ferrocene-substituted thiophenes

“…These properties also make ferrocene-based complexes good candidates for the preparation of new materials which can be applied in organic synthesis, catalysis and materials science [1,2]. For decades, research into the synthesis and electronic properties of ferrocene complexes has been focused on [3][4][5][6][7] .…”

s‐Tetrazines as a New Electrode‐Active Material for Secondary Batteries

“…1,2,4,5‐Tetrazine, also known as s ‐tetrazine, is the most electron deficient six‐membered aromatic ring among the C−N heterocycles that is stable at room temperature . Because it has a high electron affinity and intriguing n–π* transition character with strong fluorescence, various s ‐tetrazine derivatives have been extensively studied as electron‐poor dienes in inverse‐demand cycloaddition reactions, fluorophores in chemosensors, and active materials in nonlinear optics (NLO), in transistors and in solar cells . In particular, s ‐tetrazine derivatives can undergo reversible reduction by accepting one electron to form very stable anion radicals owing to their strong electron deficient character (Figure a) .…”