Facile Metal-Directed Synthesis and Crystal Structure of a New Amino Acid Ester, Methyl 3-[(2-Aminoethyl)amino]-2-[(2-aminoethyl)aminomethyl]propionate, as the Copper(II) Complex

Abstract

Condensation of bis (ethane-1,2-diamine) copper(II) perchlorate with formaldehyde and diethyl malonate in basic methanol generates the new amino acid ester complex (ethyl hydrogen bis [(2-aminoethyl ) aminomethyl ] malonate )copper(II) perchlorate, [Cu(1)] (ClO₄)₂. Base- catalysed ester hydrolysis and decarboxylation in methanol of[Cu(1)]²⁺ yields, with reesterification, (methyl 3-[(2-aminoethy )amino]-2-[(2-aminoethyl) aminomethyl ]propionate)copper(II) perchlorate, [Cu(2)](ClO₄)₂. This complex crystallizes in the monoclinic space group P2₁/c, a 12.763(6), b 9.176(2), c 16.32(2)Ǻ, β 112.49 (6)°, Z 4, R 0.054 for 2626 independent 'observed' reflections. The copper ion lies in a near plane of four nitrogens with perchlorates occupying axial sites.