Influence of Topology on the Long-Range Electron-Transfer Phenomenon

A Molecular Multiproperty Switching Array Based on the Redox Behavior of a Ferrocenyl Polychlorotriphenylmethyl Radical

“…In accordance with their distinct colors, the optical absorption spectra of the three species 1 , 1 + , 1 − show strikingly differences (Figure 2 and Supporting Information). Thus, radical 1 shows besides the characteristic absorptions of conjugated PTM radicals8 at 385 nm, 497, and 656 nm a broad intervalence charge‐transfer (IVCT) absorption band in the NIR region, centered at 1520 nm which is associated with an intramolecular electron transfer from the ferrocene donor unit to the radical acceptor unit (the PTM unit). The maximum of this IVCT band shifts from 1360 nm in n ‐hexane to 1540 nm in THF indicating a positive solvatochromism with increasing solvent polarity.…”

“…The synthesis of radical 1 was performed following a multistep synthetic methodology (see Supporting Information). A Wittig–Horner–Emmons reaction between the polychlorotriphenylmethane phosphonate derivative8 and the nonamethylated ferrocene carboxaldehyde9 gave the trans isomer of 1 ‐H. Then 1 ‐H was deprotonated to the carbanion 1 − , which was isolated as the [K([18]crown‐6)] salt in 89 % yield.…”

Ein molekularer, multifunktioneller Schalter auf der Basis des Redoxverhaltens eines Ferrocenyl‐Polychlortriphenylmethyl‐Radikals

“…Das Radikal 1 wird durch eine mehrstufige Synthese erhalten (Schema S1, siehe Hintergrundinformationen): Eine Wittig‐Horner‐Emmons‐Reaktion von Nonamethylferrocencarbaldehyd8 mit dem entsprechenden Phosphonat9 ergibt das trans ‐Isomer von 1 ‐H, aus dem durch Deprotonierung das Carbanion 1 − hergestellt und in 89 % Ausbeute als [K([18]Krone‐6)] + ‐Salz isoliert werden kann. Anschließende Oxidation ergibt das Radikal 1 in guter Ausbeute (57 %).…”

Induced Self‐Assembly of a Tetrathiafulvalene‐Based Open‐Shell Dyad through Intramolecular Electron Transfer

“…The ESR signal of dyad 1 in CH 2 Cl 2 at 300 K consists of an unstructured line at a g value of 2.0025 which becomes partially resolved into three lines when the temperature is decreased (see Figure S5 for ESR experimental and simulated spectra of dyad 1 at two extreme temperatures and Figure S6 for spectra at other temperatures). The three lines observed at low temperatures are assigned to the coupling of the unpaired electrons of the resulting species with two equivalent protons with a coupling constant of a H =1.1 G. This hyperfine coupling together with the temperature behavior resemble those exhibited by some PTM diradical derivatives incorporating a p ‐phenylenevinylene or a 1,1′‐ferrocenylendivinylene bridges between the two PTM subunits which are magnetically coupled through the bridges 10. 13b, 18 Therefore, the observation of the three‐lines signal at low temperatures suggests the presence of a fast equilibrium between the neutral molecule 1a and the homodimer π‐dimer 1a (Scheme ), which is driven by the known tendency of neutral TTFs to dimerize at low temperature in solution, that here may be enhanced by the dipolar character of 1 4…”

“…Dyad 1 was synthesized in three steps with a good yield (Scheme ). Compound 4 was first obtained through a Horner–Wadsworth–Emmons reaction9 of the protonated PTM derivative 2 10 functionalized with a phosphonate group and the 2‐formyltetrathiafulvalene 3 11 using potassium tert ‐butoxide as a base. Subsequent deprotonation of 4 with potassium hydroxide in the presence of [18]‐crown‐6 yielded 5 .…”