25770-85-8Relevant academic research and scientific papers
Study of the properties of pyridine-2-azo-p-phenyltetramethylguanidine as a metal ion complexing agent
Leffek, Kenneth T.,Jarczewski, Arnold
, p. 1238 - 1244 (2007/10/02)
Pyridine-2-azo-p-phenyltetramethylguanidine (PAPT) was synthesized and the properties of this compound examined.The dissociation contants of the conjugate acids in H2O are pK'a H20 = 10.41 +/- 0.06, and pK"a H2O = 2.62 +/- 0.02 at 25 deg C at I = 0.1, and in acetonitrile are pK'a = 18.0 +/- 0.2 and pK"a = 10.4 +/- 0.2.The properties of metal-ligand chelates in acetonitrile have been examined and the stability constants for Ni2+, Co2+, and Zn2+ complexes measured.The rates of reaction of PAPT with Ni2+, Co2+, and Zn2+ in acetonitrile have been determined and the activation parameters measured for the complex formation of LNi2+.The stability constants for both complexing centres of PAPT have been calculated.The 13C NMR spectra for PAPT and LNi2+ are quoted.The expected enhancement of the metal ion complexing ability of PAPT due to the strongly electron-releasing nature of the tetramethylguanidinyl group was not found. Key words: metal ion complexes, pyridine-2-azo-p-phenyltetramethylguanidine, stability constants, pKa.
