Langmuir−Blodgett Films of Amphiphilic Bis(tetrathiafulvalene) Macrocycles with Four Alkyl Chains

Abstract

Amphiphilic bis(tetrathiafulvalene) [bis(TTF)] macrocycles with four alkyl chains were fabricated as novel electrically active Langmuir-Blodgett (LB) films. Two TTF units were linked via [24]crown-8, [21]crown-7, and [18]crown-6 macrocycles, forming charge-transfer (CT) salts with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (F4-TCNQ) at the air-water interface and on solid substrates. The CT salt of the amphiphilic bis(TTF)-macrocycle having a [24]crown-8 ring system formed a uniform surface morphology on mica. Using single-crystal X-ray structural analysis, the layer structure between the hydrophobic chains and the one-dimensional pi-pi stack of the CT salt was confirmed. Our results show that the bis(TTF)-macrocycle was folded at the flexible [24]crown-8 moiety, forming intramolecular pi-pi dimer structures and one-dimensional intermolecular pi-pi stacks with F4-TCNQ dimers. The open-shell electronic structure of the LB films was determined by electronic spectra, electrical conductivity, and electron spin resonance analyses. Asymmetry was introduced into the bis(TTF)-macrocycle by changing the ring size from [24]crown-8 to [21]crown-7. The surface morphology of the CT salts with F4-TCNQ was established as two-dimensional round-shape domains on mica. Further reduction of the macrocyclic ring from [21]crown-7 to [18]crown-6 resulted in a CT salt of the bis(TTF)-macrocycle with F4-TCNQ with a leaf-shape domain morphology and a typical dimension of approximately 1 microm2 on mica. In general, decreasing the macrocyclic ring size from [24]crown-8 to [21]crown-7 or [18]crown-6 affected the inter- and intramolecular interactions and the surface morphologies of LB films.

Urethane tetrathiafulvalene derivatives: synthesis, self-assembly and electrochemical properties

“…The electrical conductivity of thin films obtained from the T 1 and T 2 samples with TCNQ (1:1 molar)/I 2 (30 min) were further evaluated. To eliminate the influence of contact resistance, the four-probe method was carried out instead of the two-probe method [ 29 – 30 ]. To prepare the thin films, a diluted ethyl acetate solution was dropcasted onto a glass substrates (20 mm × 20 mm) and dried overnight at 40 °C under vacuum.…”

Synthesis and electron donating property of novel porphyrazines containing tetrathiacrown ether-linked tetrathiafulvalene moieties

“…The FT-IR spectrum of 4 showed the nitrile stretch of the F 4 TCNQ radical anion at 2191 cm À1 compared to the neutral state of 2222 cm À1 . In addition, an electron paramagnetic resonance (EPR) spectrum of compound 4 in CH 2 Cl 2 at 25°C was centered around g = 2.008 and 2.002, which is in the region characteristic for both a TTF radical cation [36] and a F 4 TCNQ radical anion [37]. These results show that some CT takes place between the TTF unit(s) and F 4 TCNQ in solution (Fig.…”

Organic Nanodots of a Cation Radical Salt of Amphiphilic Bis-TTF Annulated Macrocycle

“…[4][5][6] Furthermore, size-controllable nanodots of a cation radical salt of ethylenedithio-substituted bis-TTF annulated macrocycle derivative (1 in Scheme 1) were successfully fabricated on substrate surface by using spin-coating technique. 7 When a 0.5 mM CHCl 3 : CH 3 CN (8 : 2) solution of 1 -(I 2 ) 2 was subjected to form spin-coat films, the diameter of nanodots was controllable in the diameter range from 20 to 1000 nm.…”