This critical review is devoted to semiconducting and high spin polymers which are of great scientific interest in view of further development of the organic electronics and the emerging organic spintronic fields. Diversified synthetic strategies are discussed in detail leading to high molecular mass compounds showing appropriate redox (ionization potential (IP), electron affinity (EA)), electronic (charge carrier mobility, conductivity), optoelectronic (electroluminescence, photoconductivity) and magnetic (magnetization, ferromagnetic spin interactions) properties and used as active components of devices such as n- and p-channel field effect transistors, ambipolar light emitting transistors, light emitting diodes, photovoltaic cells, photodiodes, magnetic photoswitches, etc. Solution processing procedures developed with the goal of depositing highly ordered and oriented films of these polymers are also described. This is completed by the description of principal methods that are used for characterizing these macromolecular compounds both in solution and in the solid state. These involve various spectroscopic methods (UV-vis-NIR, UPS, pulse EPR), electrochemistry and spectroelectrochemistry, magnetic measurements (SQUID), and structural and morphological investigations (X-ray diffraction, STM, AFM). Finally, four classes of polymers are discussed in detail with special emphasis on the results obtained in the past three years: (i) high IP, (ii) high |EA|, (iii) low band gap and (iv) high spin ones.

Polymers for electronics and spintronics

The strong electron-donation and the steric bulk of trialkylphosphines renders them as very useful ligands for palladium-catalyzed cross coupling reactions. This critical review reports on the synthesis of two families of trialkylphosphines (diadamantylalkylphosphines, fluorenyldialkylphosphines) and the properties of the respective palladium complexes in various cross coupling reactions, which evolved as alternatives to the classical Pd/PtBu3 system. In contrast to the latter phosphine the new classes of ligands are characterized by a highly flexible ligand design, which allows the fine tuning of catalytic properties to the specific needs of certain substrates and also enables the attachment of additional tags to impart certain useful properties onto the respective phosphines (179 references).

Sterically demanding trialkylphosphines for palladium-catalyzed cross coupling reactions—alternatives to PtBu3

Organic molecules with high-spin ground states, besides being fundamentally interesting, possess numerous potential applications in diverse fields such organic magnetism, MRI contrast agents, and spintronics. Such molecules, once thought to exist only as highly reactive intermediates, can be rationally designed to have adequate stability for organic synthesis and characterization. This Synopsis provides an overview of the factors that lead to high-spin ground states as well as recent progress in the design and synthesis of high-spin organic molecules.

High-spin organic molecules

https://pubs.rsc.org/en/content/articlepdf/2013/gc/c2gc36900a

Evaluation of alternative solvents in common amide coupling reactions: replacement of dichloromethane and N,N-dimethylformamide

High spin (S = 1) organic diradicals may offer enhanced properties with respect to several emerging technologies, but typically exhibit low singlet triplet energy gaps and possess limited thermal s...

/pdf/thermally-and-magnetically-robust-triplet-ground-state-130nf5bikk.pdf

Thermally and Magnetically Robust Triplet Ground State Diradical.

N-Benzyl substituted aza[1n]metacyclophanes (n = 4, 6, 8, and 10) were prepared in overall 40% isolated yields via Pd-catalyzed aminations. Analyses of the reaction mixtures showed that aza[14]metacyclophane and the related polymer were the primary products (∼60% overall yield); aza[1n]metacyclophanes up to n = 14 and linear oligomers with up to 20 nitrogen atoms (with at least three types of end groups) were detected. Macrocyclic structures for n = 4, 6, and 10 were confirmed by X-ray crystallography. 1,3-Alternate (D2d) and 1,3,5-alternate (S6) conformations in solution on NMR time scale at low temperatures were found for macrocycles with n = 4 and n = 6, respectively; the barrier for ring inversion was considerably lower for the larger macrocycle.

Synthesis, Structure, and Conformation of Aza[1n]metacyclophanes

Hydrocarbon diradical 1, a new stable, 3-fold symmetric analogue of trimethylenemethane (TMM) with no heteroatom perturbation, is prepared and studied. Such diradicals should provide new building blocks for high-spin hydrocarbon polyradicals with very strong net ferromagnetic coupling. Magnetic studies (SQUID) and EPR spectroscopy indicate that 1 in tetrahydrofuran-d8 (THF-d8) possesses a triplet (S = 1) ground state, with strong ferromagnetic coupling. After annealing at room temperature, the EPR spectra of 1 (∼0.02 M in frozen THF-d8) consist of a single narrow resonance (ΔHpp < 1 G), and intermolecular antiferromagnetic coupling is increased by 1 order of magnitude. This behavior is consistent with the presence of exchange narrowing, thus suggesting aggregation of 1 in THF-d8. Blue solutions of 1 in THF-d8 possess a strong UV−vis absorption band at λmax ≈ 640 nm. Diradical 1 in THF-d8 is stable (or persistent) at room temperature, with no detectable decomposition for at least 2 days.

Stable hydrocarbon diradical, an analogue of trimethylenemethane.

A low temperature method, in which the progress of the oxidation of secondary diarylamines with DMDO at low temperatures is monitored by magnetic resonance spectroscopy (EPR and NMR) and magnetic studies by a Superconducting Quantum Interference Device (SQUID), is developed for preparation of the first m-phenylene based diarylnitroxide diradical. EPR spectroscopy and magnetic studies (SQUID) indicate that the diradical in the dichloromethane matrix predominantly adopts anticonformation (2A-anti) and possesses triplet ground state. Similar oxidation experiments for conformationally constrained aza[14]metacyclophane provide evidence for the formation of small amounts of the corresponding diarylnitroxide diradical. Both diarylnitroxide diradicals could only be detected at low temperatures (−80 °C and below).

Diarylnitroxide diradicals: low-temperature oxidation of diarylamines to nitroxides.

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Synthesis, Structure, and Conformation of Aza[1n]metacyclophanes

Stable hydrocarbon diradical, an analogue of trimethylenemethane.

Diarylnitroxide diradicals: low-temperature oxidation of diarylamines to nitroxides.