Synthesis and Structure of Potassium and Barium Complexes With Diphenylphosphinothioicamido Ligand Containing Ba-S Direct Bonds

GRAPHICAL ABSTRACT

Abstract

We report the syntheses and structures of homoleptic diphenylphosphinothioicamido potassium and barium complexes of the molecular formula [{K(THF)₂Ph₂P(S)N(CHPh₂)}₂] (2)] and [Ba(THF)₂{Ph₂P(S)N(CHPh₂)}₂] (3)], respectively. The potassium complex 2 can be obtained in good yield by the treatment of diphenylphosphinothioicamine [Ph₂P(S)NH(CHPh₂)] (1) and potassium bis(trimethylsilyl)amide in tetrahydrofuran (THF). However, the barium complex 3 was prepared by two synthetic routes; first by the silylamide route where the barium bis-trimethylsilyl amide [Ba{N(SiMe₃)₂}₂(THF)₂] was treated with 1 in 1:2 molar ratio in THF to afford 95% of the product via the elimination of hexamethyldisilylamine. In the second method, potassium complex 2 was treated with barium diiodide in THF to yield the same product 3 in 85% yields. In the solid state, the potassium complex 2 is dimeric and form highly strained polymetallacyclic motif through the coordination of nitrogen, phosphorus, and sulfur atoms of the diphenylphosphinothioicamido moieties. The solid state structures of 2 and 3 were established by single-crystal X-ray diffraction analysis. In the molecular structure of barium complex 3, the barium adopts a pseudo-octahedral geometry and a direct barium sulfur bond is observed.

Keywords:

• Diphenylphosphinothioicamine
• metallacycle
• potassium
• barium
• sulfur

Additional information

Funding

This work was supported by the Department of Science and Technology India (DST) under the SERC Fast Track Scheme (SR/FT/CS-74/2010) and start-up grant from IIT Hyderabad. R.K.K. and K.N. would like to thank UGC, India, and S.A. would like to thank CSIR, India, for their PhD fellowship. Generous support from K. Mashima, Osaka University, Japan is gratefully acknowledged.