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The Stability of Fused Rings in Metal Chelates. VII. Copper(II) Complexes of Schiff Bases Derived from 2-Acetylpyridine or Pyridine-2-aldehyde and Dipeptides Containing Glycine, β-Alanine and/or α-Aminoisobutyric Acid

1970; Oxford University Press; Volume: 43; Issue: 11 Linguagem: Inglês

10.1246/bcsj.43.3457

1348-0634

Yasuo Nakao, Hiroyuki Ishibashi, Akitsugu Nakahara,

Crystal structures of chemical compounds

Abstract Eight new copper(II) complexes of SchifF bases derived from 2-acetylpyridine or pyridine-2-aldehyde and dipeptides containing glycine, β-alanine and/or α-aminoisobutyric acid have been prepared, and their relative stability was discussed on the basis of numerical data obtained by spectrophotometric, polarographic and other measurements. As a result, it was found that the stability of fused-ring systems decreases in the order 5-5-6-\simeq5-6-5->5-5-5->5-6-6-system (the first number represents the number of ring members containing pyridine derivatives and the second and third numbers represent those of ring members containing dipeptide moieties). The conclusion proposed previously that SchifF base chelates of aldehydes are generally less stable than those of corresponding ketones, has been proved to be valid also for the copper(II) chelates. It was found that transamination reactions take place in the copper(II) chelates of Schiff bases with pyridine-2-aldehyde and glycylglycine or glycyl-β-alanine.