Nickel(II) complexes with [2(4).3(1)]Adamanzane, 1,4,7,10-tetraazabicyclo[5.5.3]pentadecane

Nickel(II) complexes with the bicyclic tetraamine L=[2(4).3(1)]adamanzane ( 1,4,7,10-tetraazabicyclo[5.5.3]pentadecane) have been synthesized. The reac tion of NiBr2 with [2(4).3(1)]adz in dimethylformamide gives a dibromo-brid ged dinuclear complex [{Ni(L)}(2)(mu-Br)(2)] Br-2. From this crude product pure [{Ni(L)}(2)(mu-Br)(2)](ClO4)(2) and [{N1(L)}(2)(mu-Cl)(2)](ClO4)(2) ha ve been obtained. In aqueous solution these dinuclear species hydrolyse to the parent mononuclear diaqua species, which was isolated as [Ni(L)(H2O)(2) ]S2O6 . 2H(2)O. The reaction of the diaqua complex with nitrile gives [Ni(L )(NO2)]ClO4 or [Ni(L)(NO2)]PF6 and with nitrate [Ni(L)(NO3)]ClO4 is obtaine d. Equilibrium studies of the formation of the nitrito and nitrate complexe s are reported. The structures of [{Ni(L)}(2)(mu-Cl)(2)](ClO4)(2), [Ni(L)(H 2O)(2)]S2O6 . 2H(2)O, [Ni(L)(NO2)]PF6 and [Ni(L)(NO3)]ClO4 have been determ ined by X-ray diffraction techniques. The coordination geometry about the n ickel(II) ion is a distorted octahedron in all the structures.