Synthesis of ONO-Ligated Tetrylenes Based on 2,6-bis(2-Hydroxyphenyl)pyridines: Influence of Ligand Sterics on the Structure of the Products

European Journal of Inorganic Chemistry. 2023. Vol. 26. No. 11. Article e202200690.

Mankaev B., Serova V., Syroeshkin M., Akyeva A., Sobolev A., Churakov A., Lermontova E., Minyaev M. E., Oprunenko Y., Zabalov M., Zaitsev K., Zaitseva G., Karlov S.

A series of novel tetrylenes based on three 2,6-bis(2-hydroxyphenyl)pyridines has been obtained by the reaction of Lappert’s tetrylenes E[N(SiMe3)2]2 (E=Ge, Sn) with corresponding tridentate pyridine-linked phenol-based ligands. It was found that the structure of the ligand and the size of the atom of the group 14 element drastically affect the structure of the reaction product. A ligand with a bulky tert-butyl group leads to monomeric tetrylenes, while ligands with less bulky groups lead to bis-ligand derivatives of M(IV) (M=Ge, Sn) and a coordination polymer. Also, derivatives of germanium (IV) and tin (IV) were obtained by the metathesis reaction of MCl4 (M=Ge, Sn) with lithium phenoxides. The compositions and structures of the novel compounds were established by elemental analysis and 1H, 13C, 119Sn, 1H DOSY  NMR spectroscopy, in the solid state by X-ray diffraction analysis (germylene, stannylene, Ge4+ compound, Sn4+ compound) and 119Sn Mössbauer spectrum of the tin complex. All the synthesized tetrylenes are monomeric. Tetrylenes were characterized by cyclic voltammetry. A study of the redox behavior by cyclic voltammetry on a glassy carbon working electrode in acetonitrile solution of 0.1 M Bu4NPF6 as a supporting electrolyte showed that these compounds can be both oxidized and reduced electrochemically in the accessible potential range.

Keywords: germanium, Tin, structure elucidation, Electronic structure, Ligand effects