INTERMEDIATE PRODUCTS OF THE REACTION OF (4,4,9,9-TETRAMETHYL-5,8-DIAZADODECANE-2,11-DIONE DIHYDRAZONE)NICKEL(II) WITH BUTANE-2,3-DIONE - THE STRUCTURE OF EXAAZACYCLOHEXADECA-1(16),4,6-TIEN-3-OL)NICKEL(II) PERCHLORATE TRIHYDRATE

Intermediate products have been isolated from the reaction of (4,4,9,9 -tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone)nickel(II) perch lorate with butane-2,3-dione which finally yields the macrocyclic prod uct -hexaazacyclohexadeca-2,4,6,16-tetraene)nickel(II) perchlorate, [N i(omht)] (ClO4)2. An initial violet product is assigned a structure wi th the macrocyclic ligand hyl-1,2,4,5,9,12-hexaazacyclopentadeca-5,15- diene. In water this converts into an equilibrium mixture of the tauto meric cations blue aazacyclohexadeca-1(16),4,6-trien-3-ol)nickel(II), cis-[Ni(L2)(H2O)]2+, and orange hyl-4,5,9,12-tetraazahexadeca-3,5-dien e-2,15-dione 15-hydrazone)nickel(II), [Ni(L3)]2+. The rates at 25-degr ees-C of the forward and reverse reactions of this tautomerism, and of the slower conversion of the equilibrium mixture to [Ni(omht)](ClO4)2 , are reported. The structure of cis-[Ni(L2)(H2O)](ClO4)2.3H2O has bee n determined by X-ray diffractometry (monoclinic, space group P2(1)/n, a 9.694(8), b 19.218(14), c 16.652(9) angstrom, beta 94.88(1)-degree, R 0.079 for 3254 reflections). This has Ni(II) in octahedral coordina tion by secondary amine nitrogen atoms 10 and 13, hydrazone nitrogen a toms 1 and 6, and the carbinolamine oxygen substituent at position 3 o f the pentadentate macrocyclic ligand L2, with a water molecule coordi nated cis to the hydroxy group. Compounds of the tautomeric cations [N i(L2)]2+ and [Ni(L3)]2+ with coordinated thiocyanate, azide, nitrite, oxalate and acetate are described.