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Abstract: Fused benzene rings to antiaromatic compounds generally improve their stability but attenuate their antiaromaticity. The opposite case is now reported. NiII benzonorcorroles were synthesized and the effect of benzo‐fusion on the antiaromaticity was elucidated. The benzo‐fusion resulted in significant decrease of the HOMO–LUMO gaps and enhancement of the paratropic ring current effect. Furthermore, the introduction of the benzo groups induced singlet diradical character in the antiaromatic porphyrinoid. [ABSTRACT FROM AUTHOR]

The synthesis of a bowl-shaped antiaromatic molecule was achieved through the deformation of a planar antiaromatic porphyrinic π-conjugation system by insertion of palladium into the small cavity of a metal-free norcorrole. The bowl-to-bowl inversion dynamics of the antiaromatic Pd-coordinated norcorrole was determined by variable-temperature 1H NMR spectroscopy. The metal-free norcorrole was prepared from acid-induced demetalation of a copper norcorrole, which was obtained from the intramolecular coupling of a bis(diiododipyrrin) copper complex with copper thiophenecarboxylate. [ABSTRACT FROM AUTHOR]

Reversible homolytic dissociation of the bis(pyrimidinenorcorrole) σ-dimer was elucidated by means of variable temperature ESR and 1H NMR spectroscopy, mass spectrometry, and optical spectrocopy. Dehydrogenation of the σ-dimer yielded another dimer displaying a singlet-triplet equilibrium in solution, strong NIR absorption (1570 nm), and a narrow electrochemical HOMO-LUMO gap (0.74 V). [ABSTRACT FROM AUTHOR]

Treatment of antiaromatic nickel(II) norcorrole with potassium cyanide provided nickel(II) 3-cyanonorcorrole with perfect regioselectivity without the help of a catalyst. The reaction of the nickel(II) norcorrole with phenol or thiophenol in the presence of a base also yielded substitution products. The antiaromatic 16π conjugation system in the norcorrole core was preserved in the functionalized products. Introduction of phenylthio groups significantly decreased the HOMO-LUMO gap and enhanced the near IR absorption property. [ABSTRACT FROM AUTHOR]

3-Pyridyl-5,15-diazaporphyrin nickel(II) serves as a bidentate metalloligand for platinum(II), ruthenium(II), and rhenium(I) metal centers. Single-crystal X-ray diffraction analysis of these metal complexes unambiguously reveals the presence of a dative bond between the outer metal center and the meso-nitrogen atom. The UV/Vis absorption spectra of the complexes show substantially red-shifted bands which are perturbed by outer-metal coordination. This is due to the contribution of metal-to-ligand charge transfer interactions. [ABSTRACT FROM AUTHOR]

Although aromatic compounds occupy a central position in organic chemistry, antiaromatic compounds have demonstrated little practical utility. Herein we report the application of an antiaromatic compound as an electrode-active material in rechargeable batteries. The performance of dimesityl-substituted norcorrole nickel(II) complex (NiNC) as a cathode-active material was examined with a Li metal anode. A maximum discharge capacity of about 207 mAhg−1 was maintained after 100 charge/discharge cycles. Moreover, the bipolar redox property of NiNC enables the construction of a Li metal free rechargeable battery. The high performance of NiNC batteries demonstrates a prospective feature of stable antiaromatic compounds as electrode-active materials. [ABSTRACT FROM AUTHOR]

The treatment of an antiaromatic norcorrole NiII complex with a kinetically stabilized silylene provided ring-expansion products in excellent yields through the highly regio- and stereoselective insertion into the β-β pyrrolic CC bonds. The resultant NiII porphyrinoid monoinsertion product exhibited relatively strong near-IR absorption bands due to the small HOMO-LUMO gap in spite of the disrupted cyclic π-conjugation by the silicon atom. [ABSTRACT FROM AUTHOR]

Hab Acht! Ein [32]Octaphyrin(1.0.1.0.1.0.1.0) ‐ Dipalladium(II) ‐ Komplex wird selektiv und ohne Bildung des Norcorrols durch intermolekulare Homokupplung eines α,α′ ‐ Dibromdipyrrin ‐ Palladium(II) ‐ Komplexes unter Metalltemplatisierung erhalten. Das schwach antiaromatische achterförmige [32]Octaphyrin(1.0.1.0.1.0.1.0) ‐ System wurde spektroskopisch und mithilfe von Dichtefunktionalrechnungen untersucht. [ABSTRACT FROM AUTHOR]