Iodine‐ and ethynyl‐containing 'Kuhn'‐verdazyls, oxoverdazyls, and nitronyl nitroxides were investigated as building blocks for the preparation of multi‐spin systems via the Sonogashira reaction, and, as a result, eleven diradicals were prepared with fair yields. The reactivity of the building blocks indicates that oxoverdazyl iodides are effective starting components for the synthesis of diradicals via the Sonogashira coupling. The described one‐step protocol allows combining different spin units, thereby facilitating the design of tolane‐bridged diradicals and screening of their properties. The novel compounds were characterized by cyclic voltammetry, UV/Vis and electron spin resonance (ESR) spectroscopy. Although the electrochemical investigation and electronic spectra showed a negligible influence of radical moieties on each other, ESR data revealed a strong exchange interaction between two unpaired electrons. The prepared verdazyl‐nitronylnitroxide diradicals have high stability at storage and hold promise for further investigation and application.

<p>Verdazyl-nitroxide diradicals were synthesized using the palladium-catalyzed cross-coupling reaction of the corresponding iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields (up to 82%). The synthesized diradicals were found to be highly thermally stable and have a singlet (D<i>E</i>_ST » -64 cm^–1) or triplet ground state (D<i>E</i>_ST ³ 25 and 100 cm^–1), depending on which canonical hydrocarbon diradical type they belong to. Upon crystallization, triplet diradicals form unique one-dimensional (1D) spin <i>S</i> = 1 chains of organic diradicals with intrachain ferromagnetic coupling of <i>J</i>′/<i>k</i>_B from 3 to 6 K.</p>

Quartet verdazyl-nitronylnitroxide triradical was synthesized via palladium-catalyzed cross-coupling reaction of the corresponding diiodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex. The triradical is air-stable and possess good thermal stability with decomposition onset at ∼160 °C in an inert atmosphere. X-ray diffraction analysis of single crystals confirmed the presence of verdazyl and nitroxide radical centers. Magnetic properties were characterized by a SQUID magnetometry of polycrystalline powders and by EPR spectroscopy in different matrices. Collected data analyzed using of the high-level quantum chemical calculations confirmed that the triradical has high-spin ground states.<br>

Quantum-chemical analysis of fluorinated benzo-and naphthoquinones bearing nitronyl nitroxide function revealed that they upon one-electron reduction give triplet diradicals with the large gap of the tripletsinglet splitting (2J ≥ 430 cm-1) that comes from the non-disjoint nature of these diradicals. It was shown that the triplet-singlet splitting is highly sensitive to the number and arrangement of fluorine atoms in the quinone core. Therefore, it is aimed reasonable to synthesize the proposed triplet diradicals and to study the inherent magneto-structural correlations. It is a new synthetic challenge in the field of molecular magnetism.