Studies of Some Tetraazacyclopentadecadiene Complexes of Nickel(II). The Crystal and Molecular-Structure of (1RS,8SR)-(5,7,7,13,15,15-Hexamethyl-1,4,8,12-Tetraazacyclopentadeca-4,1 2-Diene)Nickel(II) Perchlorate Hydrate