Don't forget poly(disulfide)s. There is a rich literature pointing out the advantages of the dynamic nature of single disulfide bridges to explore self-sorting, biomolecular engineering, biomembrane analysis, and so on. Disulfide bonds between polymer chains are essential for protein folding, materials properties and the stabilization of various supramolecular architectures. However, poly(disulfide)s with disulfide bonds in the main chain are rarely used today to create interesting structures or functions. To attract attention and outline scope and limitations of poly(disulfide)s to build modern supramolecular systems, the rather eclectic recent literature on the topic is summarized. The review is moving from fascinating basic studies including photoinduced metathesis, polycatenanes and polyrotaxanes to applications in biosupramolecular systems such as micelles, membranes, tubes, gels, carriers, pores, sensors, catalysts and photosystems.

Poly(disulfide)s

A series of benzothiadiazole oligothiophene and oligo(thienylene vinylene) donor–acceptor (D–A) copolymers were synthesized and characterized. These low optical band gap materials (∼1.5 eV) are capable of absorbing photons in the range of 400–800 nm and exhibit good thermal stability. Their hole mobilities, determined using an organic field-effect transistor (OFET) architecture, vary over a range of 3 orders of magnitude and strongly correlate with the molecular ordering and morphology of the respective thin films. Spin-coated films of the poly(benzothiadiazole-sexithiophene) PBT6, which exhibits a highly crystalline lamellar π–π stacked edge-on orientation on the OFET substrate, possesses a hole mobility of ca. 0.2 cm2/V·s. Vinylene-containing analogs PBT6V2 and PBT6V2′ are amorphous and exhibit very low mobilities. The molecular weight of PBT6 has a strong influence on the electronic properties: a sample with a lower molecular weight exhibits a mobility approximately 1 order of magnitude lower than the ...

High Charge Carrier Mobility, Low Band Gap Donor–Acceptor Benzothiadiazole-oligothiophene Based Polymeric Semiconductors

We report the synthesis and characterization of new alkyl-substituted 1,4-di(thiophen-2-yl)buta-1,3-diyne (R-DTB) donor building blocks, based on the −C≡C–C≡C– conjugative pathway, and their incorporation with thienyl-diketopyrrolopyrrole (R′-TDPP) acceptor units into π-conjugated PTDPP-DTB polymers (P1–P4). The solubility of the new polymers strongly depends on the DTB and DPP solubilizing (R and R′, respectively) substituents. Thus, solution processable and high molecular weight PDPP-DTB polymers are achieved for P3 (R = n-C12H25, R′ = 2-butyloctyl) and P4 (R = 2-ethylhexyl, R′ = 2-butyloctyl). Systematic studies of P3 and P4 physicochemical properties are carried using optical spectroscopy, cyclic voltammetry, and thermal analysis, revealing characteristic features of the dialkynyl motif. For the first time, optoelectronic devices (OFETs, OPVs) are fabricated with 1,3-butadiyne containing organic semiconductors. OFET hole mobilities and record OPV power conversion efficiencies for acetylenic organic ma...

Buta-1,3-diyne-Based π-Conjugated Polymers for Organic Transistors and Solar Cells

Analysis of Conjugated Polymers Conductivity by in situ Electrochemical‐Conductance Method

Oligothiophene-substituted 1,1,4,4-tetracyanobutadienes (TCBDs) have been synthesized by [2 + 2] cycloaddition reactions between tetracyanoethylene and oligothiophene alkynes. The TCBD moiety is compared to other electron acceptors attached to dibutylterthiophene including dicyanovinyl (DCV) and tricyanovinyl (TCV). These donor−acceptor molecules (TCBD-3T, DCV-3T, and TCV-3T) show red-shifted absorption spectra relative to the unsubstituted oligothiophene as a result of intramolecular charge-transfer (ICT). Monosubstituted terthiophenes bearing the electron acceptors show both oxidation and reduction processes as characterized by cyclic voltammetry. Density functional theory (DFT) calculations are used to explain the electronic and redox properties of the materials. Electrochemical oxidation of a bis(terthienyl)-substituted TCBD molecule (3T-TCBD-3T) yields a conducting polymer exhibiting balanced ambipolar redox conduction with similar values for the oxidized and reduced states of the polymer (1 × 10−3 S...

Oligothiophene Tetracyanobutadienes: Alternative Donor−Acceptor Architectures for Molecular and Polymeric Materials†

Electrochemical oxidation of bis-terthienyl-B (B = ethane, disulfide, diacetylene, acetylene, ethylene) has been investigated. Monomers without and with 3,3′′-dialkylsubstitution are regularly coupled to polymers alternating sexithiophene and B moieties. The corresponding terthienyl homopolymers have also been produced for comparison. The polymers obtained are characterized by cyclic voltammetry, EQCM, UV−vis, and FTIR spectroscopy, in situ ESR and in situ conductivity. The conductivities of p-doped polymers with ethane or disulfide bridges fall in a narrow range (1−5 × 10−2 S cm−1) and are practically the same as those of α,ω-dimethylsexithiophene (1 × 10−2 S cm−1), suggesting that conduction proceeds without the help of the links via a direct redox hopping between sexithiophene blocks of adjacent polymer chains. In the cases of diacetylene and acetylene, conduction changes from redox to bipolaron-type but only in the case of ethylene the conductivity jumps to high values (1−5 S cm−1) corresponding to th...

Electrochemical, Magnetic, and Electrical Properties of α,ω-Capped Sexithiophene Films. Part 3. Conduction in Poly(bis-terthienyl-B)s (B = Ethane, Disulfide, Diacetylene, Acetylene, Ethylene)

M. Pasini

Papers

Electrochemical, Magnetic, and Electrical Properties of α,ω-Capped Sexithiophene Films. Part 3. Conduction in Poly(bis-terthienyl-B)s (B = Ethane, Disulfide, Diacetylene, Acetylene, Ethylene)