Doctor of Philosophy (PhD)
The overall goal of this dissertation research is to design, synthesize, and study new Pt(II) and Re(I) complexes relevant to biomedical applications. One of the projects involves the assessment of the interactions of bulky tridentate carrier ligands with a bound guanine nucleobase derivative (G) in platinum complexes, with a goal of developing chemistry potentially relevant to active anti-cancer Pt drugs. In another project, the fac-[ReI(CO)3]+ core is used to prepare novel Re(I) complexes with the purpose of developing new linking chemistry relevant to 99mTc and 187Re radiopharmaceuticals. This research explores the use of three different types of linear carrier-ligands in approaches directed toward achieving the stated goals.
The first type of linear tridentate carrier ligand employed (N(R)1,1′-Me2dma, when R = H, bis(1-methyl-2-methylimidazolyl)amine) is terminated by imidazolyl rings and has a central N-donor with an NH or an N−C bond. High in-plane steric bulk in monofunctional Pt(II) complexes is a feature associated with increased anti-cancer activity. Therefore, understanding carrier-ligand steric effects is crucial in designing new platinum drugs. For that purpose, the new N(R)1,1′-Me2dma ligands were utilized to synthesize [Pt(II)(N(R)1,1′-Me2dma)Cl]Cl complexes. The chemical behavior of adducts of simple purine derivatives (G) made with these monofunctional Pt(II) complexes was studied. The ligands and complexes were characterized using NMR spectroscopy, single-crystal X-ray crystallography and ESI mass spectrometry. Solution NMR spectroscopy was used as the primary tool to study the Pt(II)(N(R)1,1′-Me2dma)G adducts. During this work, the 3′-GMP mono adduct of [Pt(N(H)1,1′-Me2dma)Cl]Cl complex was crystallized, allowing the first crystallographic molecular structure determination for a 3′-GMP platinum(II) complex.
The other two types of linear tridentate ligands have the central N donor in a sulfonamide linkage. New ligands terminated with either two pyridyl rings (second type, N(SO2R)3,3′,5,5′-Me4dpa and N(SO2R)6,6′-Me2dpa, derivatives of 2-dipicolylamine) or with two imidazolyl rings (third type, N(SO2R)1,1′-Me2dma) were prepared. Pt(II) and Re(I) complexes of these new ligands were synthesized and their chemical properties studied.
Pilana Vithanage, Himali Kokila Ranasinghe, "New Platinum(II) and Rhenium(I) Complexes of "Linear" Chelate Ligands Terminated with Pyridyl or Imidazolyl N-Donor Groups" (2018). LSU Doctoral Dissertations. 4641.