Using Density Functional Theory to Rationally Design Ru(II)-Polypyridyl Complexes for Nitrile Ligand Loss
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Chemistry and Biochemistry Honors Theses; 2017
Photodynamic therapy (PDT) is an emerging cancer therapy that utilizes photoactive drug molecules, which can be activated with low energy light but are otherwise inactive. Previous studies show that ruthenium(II) complexes with ancillary nitrile ligands are a promising tool in PDT due to their rapid photodissociative properties, which allows for selective delivery of therapeutic agents. If the dissociative nature of this bond can be tuned, these compounds could serve in the development of novel oncological treatments. This study aims to analyze the effects of various bidentate ligands on the bond strength of acetonitrile bound to a ruthenium(II) metal center and to determine which parameters most account for efficient nitrile ligand loss. A series of six ruthenium(II)-polypyridyl complexes, each with a different bipyridyl derivative, were subjected to singlet and triplet state geometry optimizations using B3LYP functional and a combination of the 6-31G* and SDD basis sets. The Mayer bond orders and bond lengths of the nitrile bond and the percent metal character in each derivative were calculated and compared to assess which bidentate ligand results in the greatest destabilization of the acetonitrile bond. It was determined that nitrile ligand loss occurs from the triplet state, and that complexes with more metal-centered character in the excited state will likely undergo more efficient nitrile ligand loss, but further studies are required.
Academic Major: Chemistry
NIH (1RO1 EB016072)