Sythesis, characterization and Pd(II) ions coordination equilibrium studies of a-octasubstituted octylthio- and dodecylthio-derivatsed phthalocyanines

Abstract

Two metal-free phthalocyanines, 1,4,8,11,15,18,22,25, octakis (octylthio)phthalocyanine (H₂OOPc) and 1,4,8,11,15,18, 22,25,- octakis (dodecylthio)phthalocyanine (H₂ODPc) were synthesized and characterized using Elemental analysis, IR, ¹H NMR, and UV/Vis absorption spectroscopies. The Pd(II) coordination extent and sequence were investigated for the two molecules at room temperature. The extent and nature of the two processes were different for the two molecules. The numbers of Pd(II) ions bound by H₂OOPc and H₂ODPc  were 5 and 4 respectively, showing significant contribution from variation in chain length. The longer chain H₂Pc  behaved differently by disallowing Pd(II) ion coordination in its cavity. There was also a direct correlation between the carbon chain length and equilibrium constants, with the longer chain showing a lower equilibrium constant of 1.1 x 10⁹ dm³ mol^-1.

Keywords: Equilibrium Constant, Phthalocyanines, Coordination, Octylthio, Dodecylthio, Palladium Ions