The preparation and crystal structure of acetatobis( l-arginine)zinc(II) acetate trihydrate, the first reported X-ray structure of a zinc(II)–arginine complex

• Published in: Inorganica Chimica Acta 2011-11, Vol.377 (1), p.185-187
• Main Authors: Alagha, Ahmed, Brown, David A., Elawad, Mohammed, Müller-Bunz, Helge, Nimir, Hassan, Yanovsky, Alexander I., Nolan, Kevin B.
• Format: Article
• Language: English
• Subjects: Acetato ligand; Salt bridged acetate; X-ray crystal structure; Zinc(II)–arginine complex
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2011.08.015

The X-ray crystal structure of [Zn(OAc)( l-Arg) 2]OAc·3H 2O, the first reported of a zinc(II)–arginine complex, shows that the metal ion lies in a square pyramidal environment containing two trans-N,O chelated l-arginine ligands in the basal plane with an axially coordinated acetate while a second acetate is salt-bridged to the δ and ω NH groups of the guanidinium side chain of one of the arginine ligands. [Display omitted] ► The first reported X-ray structure of a zinc(II)–arginine complex. ► Important in view of the physiological importance of arginine. ► Contains an acetate–guanidinium salt bridge. The synthesis and X-ray crystal structure of acetatobis( l-arginine)zinc(II) acetate trihydrate, [Zn(OAc)( l-Arg) 2]OAc·3H 2O is reported. In this structure, the first of a zinc(II)–arginine complex to be reported, the geometry around zinc(II) is distorted square-pyramidal containing two trans-N,O chelated l-Arg ligands in the basal plane and the acetato ligand in an axial position. The structure contains a second acetate which is salt-bridged to the δ and ω NH groups of the guanidinium side chain of an arginine ligand and also contains three hydrogen bonded water molecules.