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Research Letters in Materials Science
Volume 2009, Article ID 484172, 4 pages
Research Letter

The Studies of Conditions for Inducing Chirality to Cu(II) Complexes by Chiral Zn(II) and Ni(II) Complexes with Schiff Base

Department of Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kazurazaka, Shinjuku-ku, Tokyo 162-8601, Japan

Received 16 February 2009; Accepted 1 April 2009

Academic Editor: Luigi Nicolais

Copyright © 2009 Takashiro Akitsu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Recently, we have discovered that some chiral Schiff-base nickel(II) complexes induced d-d bands of CD spectra of some achiral copper(II) complexes. However, the novel phenomenon could be observed only a few systems of hybrid materials or limited conditions so far. In order to test conditions about copper(II) ions, we investigated model systems (1) metal-dendrimer (Cu-PAMAM; G4-N H 2 terminal) containing relatively small amount of copper(II) ions (4.5 equivalent to PAMAM) for modeling separated systems of achiral copper(II) complex from chiral Schiff-base nickel(II) or zinc(II) complexes, Bis( 𝑁 - 𝑅 -1-naphtylethyl-3,5-dichlorosalicydenaminato)nickel(II) or zinc(II) by polymer matrix. (2) equilibrium of copper(II) 𝑁 -ethylethylenediamine complexes to measure absorption spectra of d-d band, pH, and electron conductivity during titration of copper(II) ions. The results showed that (1) 4.5Cu-PAMAM could not be induced their d-d bands by the chiral nickel(II) or zinc(II) complexes, which suggested that separation by polymers prevented from inducing CD peaks. (2) Although 36Cu-PAMAM was known, uncoordinated copper(II) ions excess to ligands mainly attributed to increase electron conductivity by remained ions in methanol solutions, which was not associated with intermolecular interaction or dipole moments being effective for the induced CD mechanism by using molecular recognition between neutral molecules of metal complexes.