The interactions of metal ions with poly(N-acryloyl N'-methyl piperazine) in the solid state were studied. The Cu(II) and Zn(II) compounds were prepared and characterized by means of elemental analysis, FT-IR, electronic spectroscopies, and thermogravimetric analysis. PM3 semiempirical calculations on the polymer conformations and the Zn(II) complex have been performed. The piperazine group in the polymer shows the conformations, namely, the chair and a distorted chair conformation. Both structures differ by just ca. 10 kcal/mol. In the compounds MCl4(PAPH)(2), the MCl42- complex ion presents a distorted tetrahedral geometry. The electronic spectrum of the yellow Cu(II) coordination compound shows a band at 894 nm. In the IR spectra, an absorption band at 3020 cm(-1) has been assigned to the v(N-H) stretching mode of the NH+ group. The protonated nitrogen atom is the one bonded to the methyl group due to the larger basicity according to the calculated electronic charge density and to the lower steric hindrance. The interaction of the MCl42- anion and the polymer is achieved by hydrogen bonding at the NH+ group and the chloride with N-H...Cl distances lying betwen 1.7 to 3.3 Adegrees.