Studies on the structural characteristics of various complexes formed with amino acid derivatives and the cu (ii) - ninhydrin reagent

Cu(II) - ninhydrin reagent is used to screen a variety of small peptides and amino acid derivatives by developing color on paper. Amino acids produce a pink color and their carboxyl derivatives produce a yellow color with this reagent. All compounds which produce a yellow color have been classified as Cu(II) - ninhydrin positive compounds. These compounds include amino acid esters, amino acid amides and small peptides containing upto 5 amino acids. Even though we have proposed a minimum structural requirement for the production of a yellow chromophore with these compounds, we are interested in elucidating a structural model for these compounds. In this report, we have proposed a square planar structural model for these complexes.