Study of the properties of pyridine-2-azo-p-phenyltetramethylguanidine as a metal ion complexing agent

Autor:	Arnold Jarczewski, Kenneth T. Leffek
Rok vydání:	1991
Předmět:	Azo compound Organic Chemistry Inorganic chemistry General Chemistry Nuclear magnetic resonance spectroscopy Catalysis Dissociation constant chemistry.chemical_compound Reaction rate constant chemistry Pyridine Chemical stability Chelation Conjugate
Zdroj:	Canadian Journal of Chemistry. 69:1238-1244
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v91-185
Popis:	Pyridine-2-azo-p-phenyltetramethylguanidine (PAPT) was synthesized and the properties of this compound examined. The dissociation constants of the conjugate acids in H2O are [Formula: see text] and [Formula: see text] at 25 °C at I = 0.1, and in acetonitrile are [Formula: see text] and [Formula: see text]. 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.
Databáze:	OpenAIRE
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