Evidence of cluster formation of pyrrole with mixed silver metal clusters, Agx-My (x = 4,5, y = 2/1 and M = Au/Ni/Cu) using DFT/SERS analysis

Abstract

Interaction between biologically active compounds and metal clusters are of immense theoretical and experimental interest due to its wide range of applications including drug delivery. We conducted a comprehensive analysis of the electronic characteristics of pyrrole interacting with metal atoms by combining DFT simulations with a literature review. Adsorption behavior of pyrrole (PYR) functionalized bimetallic clusters (PYR-Agx-My (x = 4/5, y = 2/1 and M = Au/Ni/Cu) is reported in the present study. In Ag4 and Ag5 systems, AgAu-PYR and AgNi-PYR systems have highest interaction energies. Mulliken charges and HOMO-LUMO energy can be utilized to determine the stability of molecule–metal interactions as well as the reactivity of PYR after they have interacted with metals. Study of noncovalent interactions indicates better interaction is between Ag4-Ni2 and PYR. It is found that electrons are localized over the PYR residue in the cluster.