NEW TETRAAZA MACROCYCLIC COMPLEXES OF PALLADIUM(II) AND PLATINUM(II) FORMED BY THE SELF-CONDENSATION OF 5-AMINO-3-METHYL-1-PHENYLPYRAZOLE-4-CARBALDEHYDE IN THE PRESENCE OF METAL-IONS - ALPHA-AMINO ETHER AND CARBINOLAMINE DERIVATIVES OF THE MACROCYCLIC SCHIFF-BASE METAL-COMPLEX

The self-condensation of 5-amino-3-methyl-1-phenylpyrazole-4-carbaldeh yde (AMPC) in the presence of Pd-II and Pt-II ions yields the Pd-II an d Pt-II complexes, [M(TAAP)]Cl-2, of the fully cyclized tetradentate m acrocyclic ligand tetrapyrazolo[1,5,9,13]tetraazacyclohexadecine, (TAA P). Metathetical displacement of the chloride has led to isolation a s eries of complexes of the type [M(TAAP)]X-2, (X = I, ClO4 and BF4), th e formulation of which is supported by elemental analysis, molar condu ctance and magnetic susceptibility measurements, and i.r. and u.v.-vis . spectra. Spectroscopic and other analytical results reveal that the complexes have square-planar stereochemistry with four donor nitrogen atoms coordinated to the metal ion in a planar array. The reaction whi ch produces this new cyclic ligand is assumed to include the metal ion acting as a template for the condensation. Thus the probable mechanis tic implications for the coordination template hypothesis are discusse d to explain the formation of these new macrocyclic chelate compounds. Both Pd-II and Pt-II complexes appear to be sensitive to nucleophilic attack at the methine carbon, which is reversible upon acidification. The reaction of [Pt(TAAP)](2+) or [Pd(TAAP)](2+) with MeO- or EtO- io ns results in the formation of partially solvolysed inner complexes co ntaining two ionized alpha-amino ether functions, stabilized by the ma crocyclic chelate ring. Attempts to prepare discrete alpha-carbinolami ne derivatives were unsuccessful.