3,6-Di- tert -Butyl-2-Hydroxy-4-Pyridinylphenolate and Tin(IV) Complexes it Forms: Synthesis and Structure Details and S
- PDF / 1,317,781 Bytes
- 10 Pages / 612 x 792 pts (letter) Page_size
- 28 Downloads / 172 Views
Di-tert-Butyl-2-Hydroxy-4-Pyridinylphenolate and Tin(IV) Complexes It Forms: Synthesis and Structure Details and Solvatochromic Effect A. V. Piskunova, *, K. I. Pashanovaa, K. A. Mart’yanova, K. V. Arsen’evaa, and A. V. Cherkasova a
Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Nizhny Novgorod, Russia *e -mail: [email protected] Received May 22, 2020; revised July 17, 2020; accepted July 20, 2020
Abstract—Two synthetic approaches were developed for the preparation of 3,6-di-tert-butyl-2-hydroxy-4pyridinylphenolate (LH), a new zwitter-ionic redox-active diolate type ligand. Two heteroligand five-coordinate tin(IV) derivatives were prepared with this ligand: 3,6-di-tert-butyl-2-oxy-4-pyridinylphenolato(triphenyl)tin(IV) (I) and 3,6-di-tert-butyl-2-oxy-4-pyridinylphenolato(diphenyl)chlorotin(IV) (II). The molecular structures of the ligand LH ∙ 0.5Py and complex I ∙ CH3CN were determined by X-ray diffraction (CIF files CCDC nos. 1974166 (LH), 1974165 (I)). It was shown that the ligand LH and the tin(IV) compound exhibit solvatochromism, which consists in a considerable blue shift with increasing solvent polarity. Keywords: diolate ligand, zwitter-ion, tin(IV), X-ray diffraction, ESR spectroscopy, electronic absorption spectroscopy, solvatochromism DOI: 10.1134/S1070328420120064
INTRODUCTION o-Benzoquinone type compounds are of considerable interest for organoelement and coordination chemistry [1], as they are redox-active ligands that can occur in the metal coordination sphere in three oxidation states: dianion (catecholate), radical anion (semiquinone), and neutral states. Organic ligands of this type are of particular interest for the preparation of main group metal compounds, as they markedly expand the redox properties of derivatives of main group elements [2, 3]. The metal complexes containing ligands of this type in the paramagnetic state are of obvious interest from the standpoint of both intra- and intermolecular magnetic exchange interactions [4]. In addition, the unique ability of benzoquinone derivatives, as redoxactive compounds in a metal coordination environment, to undergo reversible interconversions between oxidation states makes it possible to observe the phenomenon of valence tautomerism [5] and to design the electronic structure of metal compounds via redox transformations [6]. The redox reactions of redoxactive ligands linked to the complexing ion find use in a number of stoichiometric and catalytic reactions that are not accompanied by a change in the oxidation state of the central ion [7–11]. Notably, most of the known coordination compounds with ligand systems of this type are formed by singly and doubly reduced redox forms, whereas the range of metal complexes based on
neutral ligands [12] is scarce. There are also only few metal benzoquinone derivatives with a mixed coordination mode in which the redox-active ligand is bound to the complexing ion by both covalent and donoracceptor bonds [13, 14]. This study reports the synthesis of 3,6-di-tertbutyl-2-hydroxy-4-p
Data Loading...
