Acid-Base Behavior of Substituted Hydrazone Complexes Controlled by the Coordination Geometry

作者：Chang Mee; Horiki Hiroyuki; Nakajima Kiyohiko; Kobayashi Atsushi; Chang Ho Chol; Kato Masako^*

来源：Bulletin of the Chemical Society of Japan, 2010, 83(8): 905-910.

DOI：10.1246/bcsj.20100065

A new series of substituted hydrazone complexes, [Cu(Hpbph)I] (1), [Cu(Hpbph)PPh3]PF6 (2-PF6), [NiCl-(Hpbph)]Cl (3-Cl), [PtCl(Hpbph)]ClO4 (4-ClO4), and [PtCl(pbph)] (4b) (Hpbph = 2-(diphenylphosphino)benzaldehyde 2-pyridylhydrazone) have been synthesized and characterized. X-ray crystallography revealed that the copper(1) complexes adopt pseudo-tetrahedral geometry, while the nickel(II) and platinum(II) complexes provide square-planar forms. All the complexes exhibit distinct color changes on the basis of the deprotonation/protonation on the ligand although their acid/base behaviors are largely different. The acidity constants (pK(a)) in methanol were determined to be 11.4 (1), 12.5 (2), 7.7 (3), and 6.7 (4). The results indicate that the dissociation of the proton on the ligand strongly depends on the ligand deformation controlled by the coordination geometry of the complexes and ancillary ligands also somewhat affect the acidity.

• 出版日期2010-8-15