Synthesis and crystal structure of two metal complexes involving reduced imino nitroxides

Two novel complexes, [Co(mal)(IMH2py) 2 ]ClO 4 (1) and [Mn(mal)(IMH2py) 2 ]·H 2 O (2), have been synthesized and their crystal structures determined by X-ray diffraction methods. The imino nitroxide 1-oxy-2-(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1 H -imidazole (IM2py) is reduced during reaction to yield 1-hydroxy-2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole (IMH2py); mal is the malonate anion. Complexes 1 and 2 crystallize in the monoclinic space group C 2 space group with a =17.004(9), b =10.753(5), c =9.207(5)Å, =113.856(8)° and Z =2 for 1, and a =16.721(5), b =10.897(5), c =9.253(3)Å, =120.807(6)° and Z =2 for 2. Each metal ion is six-coordinated by two imino nitrogen atoms of two iminohydroxylamine groups, two nitrogen atoms of two pyridyl groups and two oxygen atoms of the malonate ion.