Synthesis and crystal structures of bis[1-oxopyridin-2-olato(1−)]bis(pentafluorophenyl)silicon(IV)–tetrahydrofuran–pentane (2/1/1), bis[1-oxopyridin-2-olato(1−)]bis(p-tolyl)silicon(IV), and dimesitylbis[1-oxopyridin-2-olato(1−)]silicon(IV)

Abstract

The neutral organosilicon(IV) complex, (C6F5)2Si(OPO)2 (OPO = 1-oxopyridin-2-one, C5H4NO2), was synthesized from (C6F5)2Si(OCH3)2 and 2 equiv. of 1-hydroxypyridin-2-one in tetrahydrofuran (THF). Single crystals grown from the diffusion of n-pentane into a THF solution were identified as a THF hemisolvate and an n-pentane hemisolvate, (C6F5)2Si(OPO)2·0.5THF·0.5C5H12 (1). p-Tolyl2Si(OPO)2 (2) and mesityl2Si(OPO)2 (3) crystallized directly from reaction mixtures of 2 equiv. of Me3Si(OPO) with p-tolyl2SiCl2 and mesityl2SiCl2, respectively, in acetonitrile. The oxygen-bonded carbon and nitrogen atoms of the OPO ligands in 1, 2, and 3 were modeled as disordered indicating co-crystallization of up to three possible diastereomers in each. Solution NMR studies support the presence of exclusively the all-cis isomer in 1 and multiple isomers in 2. Poor solubility of 3 limited its characterization in solution.

Keywords

• crystal structure
• silicon
• pyridinone
• pyridine n-oxide