Characteristic Features of Fixation of Ammonia by Copper(II), Nickel(II), and Cobalt(II) Ions in Pivalates

The reaction of adduct Cu 2 (OOCBu t ) 4 (thf) 2 with polynuclear nickel(II) pivalate (prepared from NiCl 2 , HOOCBu t , and KOH) or cobalt(II) pivalate (prepared by thermolysis of Co(II) acetate with excess acid at 160°C) in THF with a large excess of aqueous ammonia at room temperature leads to the formation of the mononuclear molecular complex Cu(OOCBu t ) 2 (NH 3 ) 2 , the ionic complex [Ni(NH 3 ) 6 ](OOCBu t ) 2 , and unusual mixed-valence trinuclear complex {Co II (OOCBu t ) 2 (NH 3 ) 2 [(µ-OH)Co III (NH 3 ) 5 ] 2 }(OOCBu t ) 4 (H 2 O) 2 . The products were investigated by chemical analysis, X-ray diffraction, and IR spectroscopy.