Au(III)-complexes of the alanyl-containing peptides glycylalanine and glycylalanylalanine – Synthesis, spectroscopic and structural characterization

As part of an investigation on the coordination ability of peptides, the dipeptide glycylalanine (H -Gly -Ala -OH ), tripeptide glycylalanylalanine (H -Gly -Ala -Ala -OH ) and their Au(III)-complexes have been characterized structurally. The quantum chemical calculations and linear-dichroic infrared (IR-LD) spectroscopy predict structures of the compound studied, which are compared with a single crystal X-ray diffraction of H -Gly -Ala -OH . The coordination processes with Au(III) are supported by data for 1H NMR, ESI-MS, HPLC–MS–MS, TGV and DSC methods. The [Au(Gly -Ala )H−1Cl] and [Au(Gly -Ala -Ala )H−2] · 2H2O complexes are formed via –NH2, N−amide/s and View the MathML sourceCO2- groups of the peptides. One Cl− ion is attached to the metal center as terminal ligand in the first complex. In both cases a near to square-planar geometry of the chromophors AuN2OCl and AuN3O is yielded.