Linearly Extended π-Conjugated Dithiafulvene Polymer Formed Soluble Charge-Transfer Complex with 7,7,8,8-Tetracyanoquinodimethane

Abstract

ABSTRACT:A soluble charge-transfer (CT) complex of ff-conjugated donor polymer with 7,7,8,8-tetracyanoquinodimethane (TCNQ) was formed when TCNQ was added to a dimethyl sulfoxide (DMSO) solution of a ll'-conjugated poly(dithiafulvene) (2). In DMSO, 2 reacted with TCNQ to produce a dark green solution. After the precipitated TCNQ was filtered, the filtrate was evaporated to obtain a dark green powder. The resulting CT complex was soluble in acetonitrile, DMSO, N, N-dimethylformamide (DMF), acetone, and MeOH, and partially soluble in tetrahydrofuran (THF). The UV-Vis absorption spectra suggested a formation of the CT complex containing about 1 : 1 ratio of dithiafulvene unit to TCNQ. The UV-Vis absorption and FT-IR analyses indicated that the anion radical ofTCNQ was initially formed by the charge-transfer reaction when TCNQ was added to the solution of 2, and the remaining TCNQ was interacted with 2 as a partially charge-transferred form. In the 1 H NMR spectra, the broad peak attributed to the benzylidene proton of 2 was shifted to a lower magnetic field proportional to the TCNQ feed ratio against the dithiafulvene unit of 2. The CT complex has a conductivity of2 X 10--4 S cm-- The formation of CT complexes by chemical oxidation can be accomplished only if the redox potentials of the donors and acceptors are carefully balanced. The electrical conductivity of the solid state ofTTF-TCNQ along the stacking direction is about three orders of magnitude higher than that in the perpendicular direction, and therefore TTF-TCNQ behaves as a quasi-one-dimensional metal. Such low-dimensional conductors have been predicted by Peierls to undergo a lattice distortion at low temperatures resulting in a metal-insulator transition.

Oxidative Polymerization of Silylthioketene Dimer

“…In the UV‐vis spectrum of the CT complex in DMSO, the absorptions for TCNQ anion radicals were observed at around 400 nm (anion radical and neutral TCNQ) and between 600 and 900 nm (see Supporting Information). This indicates the effective charge transfer between the 1,3‐dithietane unit and TCNQ 20…”

Organic π-type thermoelectric module supported by photolithographic mold: a working hypothesis of sticky thermoelectric materials

“…Overall, we had expected Au vapor deposition to give low contact resistance but it turns out to be a poor match with the important factors for the legs’ performance optimizations, such as having DMSO addition to PEDOT:PSS and the ball-milled TTF-TCNQ without PVC. This result suggests that we need to explore non-volatile additives to PEDOT:PSS [18] and polymer-based n-type materials soluble to common solvents [19].

10.1080/14686996.2018.1487239-F0008Figure 8.Schematic of the Au penetrated π-type TE module.

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Layer‐by‐layer films based on charge transfer interaction of ϕ‐conjugated poly(dithiafulvene) and incorporation of gold nanoparticles into the films

“…PDF was synthesized by the cycloaddition polymerization of bis(aldothioketene) with its alkynethiol tautomer derived from 1,4-diethynylbenzene according to our previous reports. 14,15 The number-average molecular weight (M n ) of PDF was 3400, determined by 1 H NMR. Comparison of the intensities of the absorption of the dithiafulvene protons in the repeating units with those of the absorptions of the terminal thioamide protons results in the estimation of number-average degree of polymerization.…”