Complex Formation and Ligand Substitution Reactions of (2-Picolylamine)palladium(II) with Various Biologically Relevant Ligands. Characterization of (2-Picolylamine)(1,1-cyclobutanedicarboxylato)palladium(II).

The influence of a 2-picolylamine (pic) ligand on the reactivity of Pd(II) complexes was investigated by detailed equilibrium and kinetic studies. Reactions of [Pd(pic)(H(2)O)(2)](2+) with chloride, 1,1-cyclobutanedicarboxylic acid (CBDCAH(2)), inosine (ino), and inosine 5'-monophosphate (5'-IMP) were studied. A significantly higher reactivity for the first reaction step involving the displacement of one coordinated solvent molecule on [Pd(pic)(H(2)O)(2)](2+) was observed for the nucleoside inosine (k(10)( degrees )(C) = 25 400 +/- 200 M(-)(1) s(-)(1)) than for the nucleotide 5'-IMP (k(10)( degrees )(C) = 7100 +/- 300 M(-)(1) s(-)(1)) and for CBDCAH(-) (k(25)( degrees )(C) = 5380 +/- 70 M(-)(1) s(-)(1); DeltaH() = 54 +/- 2 kJ mol(-)(1); DeltaS() = 10 +/- 4 J K(-)(1) mol(-)(1); DeltaV() = -0.2 +/- 0.7 cm(3) mol(-)(1)). The results are compared and discussed in reference to data reported for closely related systems in the literature. The molecular structure of [Pd(pic)(CBDCA)] in solution and in the solid state was resolved. [Pd(pic)(CBDCA)].2H(2)O crystallizes in the space group P2(1)/c (monoclinic, a = 5.659(5) Å, b = 18.320(5) Å, c = 14.027(5) Å, beta = 97.748(5) degrees, V = 1440.94(14) Å(3), Z = 4).