Structural investigations of nickel(II) complexes of isonitrosoacetylacetone

An olive-green and a violet form of Ni(C 5 H 6 NO 3 ) 2 , a pyridine adduct Ni(C 5 H 6 NO 3 ) 2 . 2Py and orange-red Ni(C 5 H 7 N 2 O 2 ) 2 have been prepared from Ni(II) salts and isonitrosoacetylacetone in addition to the Ni(CH 3 COO)(C 5 H 7 N 2 O 2 ) and Ni(C 5 H 7 N 2 O 2 ) 2 already reported in the literature. Magnetic and spectral measurements reveal that the two forms of Ni(C 5 H 6 NO 3 ) 2 , Ni(C 5 H 6 NO 3 ) 2 . 2Py and Ni(CH 3 COO).(C 5 H 7 N 2 O 2 ) have octahedral or pseudooctahedral structures, whereas the two varieties of Ni(C 5 H 7 N 2 O 2 ) 2 have square-planar configurations. PMR studies suggest that at least three structural isomers of Ni(C 5 H 2 N 2 O 2 ) 2 exist in CDCl 3 solution.