Juglophen: a tetradentate non-innocent electron sponge naphthoquinone-imine ligand and its reduced and oxidized nickel complexes [Ni(jp)]−, 0, + . Issue 24 (7th June 2022)

• Record Type: Journal Article
• Authors: Schumann, Henrik; Klein, Marius; Prinzisky, Christian; Burghaus, Olaf; Sundermeyer, Jörg
• Is Part Of: Dalton transactions. Volume 51:Issue 24(2022)
• Page Start: 9348
• Page End: 9356
• Publication Date: 2022-06-07
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d1dt03927j
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The synthesis of new tetradentate dianionic N2 O2 ligand juglophen (H2 jp, 1 ), its nickel(ii ) complex [Ni(jp)] (2 ) as well as oxidized [Ni(jp)] + (3) and reduced [Ni(jp)] − (4) ionic species are reported. Abstract : The synthesis of new tetradentate dianionic N2 O2 ligand juglophen (H2 jp, 1 ) and its nickel(ii ) complex [Ni(jp)] (2 ) is reported. The unprecedented ligand synthesis is accomplished via oxidative coupling of 1, 5-dihydroxynapthalene and o -phenylenediamine by hypervalent phenyliodine(iii )-diacetate. Ligand 1 and complex 2 were characterized via NMR, IR, UV-Vis spectroscopy, mass spectrometry, cyclic voltammetry and by XRD analysis. In order to investigate the non-innocent character of ligand 1, [Ni(jp)] (2 ) was oxidized using AgPF6 to form [Ni(jp)] + [PF6 ] − (3 ) whereas one-electron reduction with [Cp2 Co] generated [Cp2 Co] + [Ni(jp)] − (4 ). The paramagnetic nature of the oxidized and reduced species 3 and 4 was validated via EPR spectroscopy and further investigated pursuing DFT calculations at the PBE-D3(BJ)/def2-TZVPP level of theory. Predominantly ligand-centered SOMOs of 3 and 4 are allowing insight towards a deeper understanding of the redox behavior of [Ni(jp)] (2 ).