ABSTRACT
A series of new complexes of general formula [AuIII(N^N)Br2](PF6) (N^N = 2,2'-bipyridine and 1,10-phenanthroline derivatives) were prepared and characterized by spectroscopic, electrochemical, and diffractometric techniques and tested against Gram-positive and Gram-negative bacterial strains (Staphylococcus aureus, Streptococcus intermedius, Pseudomonas aeruginosa, and Escherichia coli), showing promising antibacterial and antibiofilm properties.
Subject(s)
2,2'-Dipyridyl , Anti-Bacterial Agents , 2,2'-Dipyridyl/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Phenanthrolines/pharmacology , Phenanthrolines/chemistry , Escherichia coli , Biofilms , Microbial Sensitivity TestsABSTRACT
The reaction of the complex [Au(phen)Br2](PF6) (phen = 1,10-phenanthroline) with molecular dibromine afforded {[Au(phen)Br2](Br3)}∞ (1). Single crystal diffraction analysis showed that the [Au(phen)Br2]+ complex cations were bridged by asymmetric tribromide anions to form infinite zig-zag chains featuring the motif ···Au-Br···Br-Br-Br···Au-Br···Br-Br-Br···. The complex cation played an unprecedented halogen bonding (XB) donor role engaging type-I and type-II XB noncovalent interactions of comparable strength with symmetry related [Br3]- anions. A network of hydrogen bonds connects parallel chains in an infinite 2D network, contributing to the layered supramolecular architecture. DFT calculations allowed clarification of the nature of the XB interactions, showing the interplay between orbital mixing, analyzed at the NBO level, and electrostatic contribution, explored based on the molecular potential energy (MEP) maps of the interacting synthons.
