Reversible Carbon–Carbon Bond Breaking and Spin Equilibria in Bis(pyrimidinenorcorrole). Issue 42 (6th October 2016)

• Record Type: Journal Article
• Authors: Liu, Bin; Yoshida, Takuya; Li, Xiaofang; Stępień, Marcin; Shinokubo, Hiroshi; Chmielewski, Piotr J.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 42(2016)
• Page Start: 13142
• Page End: 13146
• Publication Date: 2016-10-06
• Subjects: biradicals -- free-radical dimerization -- norcorrole -- porphyrinoids -- spin equilibria; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201607237
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Reversible homolytic dissociation of the bis(pyrimidinenorcorrole) σ‐dimer was elucidated by means of variable temperature ESR and 1 H 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 : Porphyrinoid metal complexes : Amination of the nickel(II) complex of norcorrole under mild conditions resulted in C(sp 3 )–C(sp 3 )‐linked bis(pyrimidinenorcorrole)1 which in solution exists in equilibrium with a monomeric radical (see picture). After dehydrogenation1 shows a conformation‐dependent singlet–triplet equilibrium.