2 FORMS OF 5-DIMETHYL-4,7-DIAZADECANE-1,10-DIAMINE)NICKEL(II) DIPERCHLORATE

The title Ni(II) complex, [Ni(C10H26N4)](ClO4)2, crystallizes in yello w and orange forms. In both crystals, the stereochemistry and conforma tion of the complex cations are identical. Small differences arise fro m packing effects, differences in the orientations of the perchlorate groups and hydrogen bonding. The Ni(II) atom has square-planar coordin ation with the four tetraamine N atoms in equatorial positions. In eac h complex, the two chiral N-atom centres are in the (4RS,7RS) configur ation. The tetraamine binds to the Ni(II) atom in a relatively strain- free planar manner; the central six-membered ring exhibits a stable ch air conformation and the two terminal five-membered rings adopt stable skew forms.