Complexes of 1,2-bis(isopropylseleno)ethane with nickel(II) halides and thiocyanate

Abstract

The synthesis of the high-spin nickel(II) complexes L₂NiX₂ is described, where L is the bidentate selenium ligand 1,2-bis(isopropylseleno)ethane and X is Cl or Br. These pale-green complexes are considered to have a six-co-ordinate molecular structure on the basis of conductimetric, magnetic, and spectroscopic evidence. They react with the stoicheiometric amount of potassium thiocyanate to give a bright green, paramagnetic, square-planar isothiocyanato-complex LNi(SCN)₂; this, when heated in isopropyl alcohol under reflux affords a yellow complex LNi₂(SCN)₄ which is probably polymeric. With an excess of potassium thiocyanate the chloro-complex yields the pale blue compound K₄Ni(SCN)₆,2EtOH.