Synthesis and structure of heavier group 2 metal complexes with diselenoimidodiphosphinato ligand containing Sr–Se and Ba–Se direct bonds

•Mononuclear diselenoimidodiphosphinato strontium and barium complexes have been synthesized.•In the solid state, strontium adopts distorted octahedral and barium adopts pentagonal bipyramidal geometry.•In solid state, strontium and barium have direct metal selenium contact.

We report the mononuclear diselenoimidodiphosphinato strontium and barium complexes of the molecular formula [{η2-N(PPh2Se)2}2Sr(THF)2] (2) and [{η2-N(PPh2Se)2}2Ba(THF)3] (3) which can be obtained by two routes, either by the treatment of metal bis(trimethylsilyl)amide and diselenoimidodiphosphine (1) via the elimination of silylamine or salt metathesis reaction involving metal diiodide and potassium salt of diselenoimidodiphosphine. In the solid state structures of 2 and 3, each of the metal atom is ligated by four selenium atoms from two diselenoimidodiphosphinato ligand moieties and two (for 2) and three (for 3) THF molecules to adopt a distorted octahedral geometry around the strontium atom and distorted pentagonal bipyramidal geometry for barium ion. In the complexes 2 and 3, a direct metal selenium contact is observed. Additionally we also report the synthesis and structure of lithium complex [η2-N(PPh2Se)2Li(THF)2] (4) which was synthesized by using 1 and LiCH2SiMe3 in THF solution.

Graphical abstractDiselenoimidodiphosphinato ligand supported strontium and barium complexes of the molecular formula [{η2-N(PPh2Se)2}2Sr(THF)2] (2) and [{η2-N(PPh2Se)2}2Ba(THF)3] (3) were obtained by two synthetic routes. In the solid state structures of both the complexes which were established by X-ray diffraction analysis, a direct metal selenium contact is observed.Figure optionsDownload full-size imageDownload as PowerPoint slide