KH Larijani - Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
M Izadyar - Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
M Khavani - Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
M.R Housaindokht - Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran

Dipicolylamino ligand (DPA) is one of the most commonly employed ligands inchemosensors, providing a tridentate ligand with three nitrogen donors, which is selective toZn(II) ]1[. Theoretical studies play an important role in the design and improvement of thesetypes of biosensors. Because of the importance of the quantum chemistry descriptors indetermining the sensors efficiencies, we describe herein a fluorescent chemosensor by aphosphorylated peptide surface. This sensor consists of a sequence of a phosphorylatedpeptide and a receptor, bis(Zn-DPA)]2[. The optimized structure of this complex is shown inFigure 1. In order to study the ability of the peptide as a sensor, Natural Bond Orbital (NBO)analysis for charge transfer investigation between the peptide and DPA has been performed.