Synthesis and luminescent studies of ruthenium(II) polypyridines and palladium(II) porphyrins
Abstract
Compounds with the general formula Ru(4'-R-T)(dmeb)CN +, where 4'-R-T is a substituted tridentate terpyridine ligand and dmeb is dimethyl 2,2'-bipyridine-4,4'-dicarboxylate, were synthesized and their photophysical properties studied. The π-accepting ligand, dmeb, was held constant, but the R group of the terpyridine ligand was varied to examine the effects on the emission and lifetime (where R = H (trpy), dimethylamino (dma-T), phenyl (Ph-T), and N-pyrrolidinyl (pyrr-T)). In addition, by varying the solvent polarity the energy of the metal to ligand charge transfer (MLCT) can be adjusted and thus the emitting wavelength be tuned. Lifetimes were found to be optimized by finding a balance between two deactivating pathways. The lifetimes were found to maximize at 185 nanoseconds by finding a balance between the 3d-d state and the Energy Gap Law. Cationic porphyrins and their interactions with DNA are of importance due to potential applications for photodynamic, anticancer and antiviral therapies. Porphyrin's binding to DNA was followed by absorbance, emission and circular dichroism (CD). Palladium porphyrins are of specific importance do to their long lived triplet excited state. The excited state interacts with oxygen in solution by energy transfer to produce singlet oxygen. This study works with both externally bound and intercalated porphyrins to gain insight to how interactions with DNA can affect oxygen's access to the chromophore.
Degree
Ph.D.
Advisors
McMillin, Purdue University.
Subject Area
Inorganic chemistry
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