Siegel der Universität zu Köln
 
University of Cologne
Faculty of Mathematics and Natural Sciences
Department of Chemistry - Inorganic Chemistry
Dr. rer. nat. Michael Neugebauer
email: uni*delete this part*@neugebauer-koeln.de
homepage: uni.neugebauer-koeln.de

main research: PhD thesis:
Beiträge zur Chemie des Platins mit Nukleobasen und weiteren biorelevanten Liganden
ISBN: 978-3-86853-276-0

abstract:
The present dissertation deals with syntheses and investigations of new platinum(II) complexes with nucleobases and further biorelevant ligands. The [Pt(dien)(R)] 14 VE complex fragment binds to biorelevant ligands (dien = 1,5-cyclooctadiene (cod), norbornadiene (nbd), 1,5-hexadiene (1,5-Hex); R = methyl (Me), neosilyl (neoSi, Trimethylsilylmethyl), neopentyl (neop, 2,2-dimethyl-1-propyl), benzyl (Bzl) und neophyl (neoPh, 2-Methyl-2-phenyl-1-propyl); L = guanine, uracil, cytosine, caffeine, ...) forming square-planar 16 VE complexes [Pt(dien)(R)(L)]n+. The solubility of these compounds in aprotic solvents allows their characterisation by multiple (1H, 13C, 195Pt) NMR spectroscopy and also facilitates their crystallisation for crystal structure analysis. Prominent findings in NMR spectroscopy are the cytosine bridged binuclear complex [(cod)(Me)Pt(N3-cytosinate-N1)Pt(Me)(cod)][SbF6] and the penta-coordiation in [Pt(cod)(Me)(bpy)]+ (bpy = 2,2′-bipyridyl). The new complexes are stable under standard conditions and air. The neosilyl group in [Pt(cod)(neoSi)Cl] is sensitive to fluorine containing anions such as [SbF6]-. It decomposes under formation of trimethylfluorsilane (Me3SiF) and conversion of the platinum bound methylene group to methyl. The bulky ligand in [Pt(cod)(neoPh)Cl] undergoes a cyclometallation after abstraction of the chloride forming [Pt(cod)(neoPh′)] (neoPh′ = 2-Methyl-2-phenyl-1-propyl-1,2′-η2-diyl). The exchange rate of dien replacement by diimine ligands (1,4-diisopropyl-1,4-diazabuta-1,3-diene, Dipyrido[3,2-a:2′,3′-c]phenazine, 3,4,7,8-Tetra-methyl-1,10-phenanthroline) depends on the dien′s bite angle and flexibility.
Cytotoxicity experiments on HT-29 colon carcinoma cell lines and MCF-7 breast cancer cell lines revealed promising anti-prolific activities for selected platinum cod complexes.