PLATINUM(IV) COMPLEXES OF A TETRAAZA MACROCYCLE WITH PENDENT DICHLOROAMINE OR AMMONIUM GROUPS

Reaction of the platinum(II) complex of the pendent-arm macrocycle 6,13-diammonio-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane with chlorine in aqueous solution does not lead simply to oxidation of the platinum(II) complex to a trans-dichloroplatinum(IV) complex. Instead, complete chlorination of the pendent primary amines occurs also, producing the trans-dichloroplatinum(IV) complex of a bis(dichloroamino) macrocycle. The dichloroamino complex was characterized by a crystal structure analysis, the first X-ray crystal structure of a dichloroamine; the perchlorate salt of trans-[Pt(2)Cl2](ClO4)2 crystallized in the P2(1)/n space group, with Z = 2, a = 10.612 (5) angstrom, b = 10.280 (3) angstrom, c = 12.792 (4) angstrom, and beta = 110.56 (3)-degrees. Inequivalent N-Cl bond lengths (1.718 (12) and 1.779 (12) angstrom) were observed. In aqueous acid, slow dechlorination occurs to produce the trans-dichloroplatinum(IV) complex of the precursor macrocycle, also characterized by a crystal structure analysis. The complex of the precursor macrocycle, trans-[Pt(1)Cl2]Cl2(ClO4)2.4H2O, crystallized in the P1BAR space group, with Z = 1, a = 7.308 (2) angstrom, b = 10.448 (2) angstrom, c = 10.672 (2) angstrom, alpha = 103.89 (1)-degrees, beta = 104.50 (1)-degrees, and gamma = 103.90 (1)-degrees.