University of Jyväskylä

Dissertation: 18.12 Nitrogen-containing ligands and their platinum and gold complexes (Chernyshev)

Start date: Dec 18, 2014 12:00 AM

End date: Dec 18, 2014 03:00 PM

Location: Ylistönrinne, KEM4

Alexander Chersnyshev. Kuvaaja: Margarita BulatovaM.Sc. Alexander Chernyshev defends his doctoral dissertation ”Nitrogen-Containing Ligands and Their Platinum (IV) and Gold (III) Complexes: Investigation of Basicity and Nucleophilicity, Luminescence, and Aurophilic Interactions". Opponent  Prof. Armando Pombeiro (Technical University of Lisbon) and custos Professor Matti Haukka (University of Jyväskylä). The event is in English.

Abstract

In the present thesis the properties of the nitrogen-containing ligands and their PtIV and AuIII complexes are investigated. The project can be virtually divided into three parts arising from one another. The research was initially focused on the investigation of the patterns and specificity of metal-mediated coupling of weak (H)N-nucleophiles, namely isomeric nitroanilines and 2,2’-dipyridylamine, with propionitrile coordinated to PtIV and AuIII metal centers. The dependency of the reaction pathway on the strength of nucleophile and the nature of the metal center was determined. The reactivity of the obtained amidine complexes at the elevated temperatures was also investigated. It was established that structure of the initial complex, as well as presence or absence of the traces of moisture in the reaction mixture can direct the reaction towards cyclometalation or elimination of propionitrile. The synthesized compounds can potentially possess the antitumor activity.

As it turned out, 2,2’-dipyridylamine hydrochloride, which was synthesized as a byproduct of one of the steps of the previous project, possesses an intense luminescence in the blue region of the spectrum. To study the nature of the luminescence of the 2,2’-dipyridylamine cation the targeted synthesis of a set of its salts with halides and halogen-containing anions was carried out. As it was shown theoretically and experimentally, the luminescence of 2,2’-dipyridylamine cation arises from the existence of weak intramolecular and intermolecular interactions in crystals of its salts, which blocks the radiationless decay of the excited state through mechanical motion of parts of the cation, thus being an aggregation-induced emission. Furthermore, it was found that the luminescence persists in a chloroform solution and disappears in methanol solution. The reason for this phenomenon is the different solvation ability of the solvents. Thus, chloroform (weakly solvating solvent) promotes the formation of emissive aggregates, which are structurally similar to crystals, whereas methanol (strongly solvating solvent) stimulates their splitting. The obtained luminescent materials are prospective for OLEDs.

During the course of the first part of the project two complexes of PtIV and AuIII with 2,2’-dipyridylamine were structurally characterized. These compounds were found to have a number of interesting weak intermolecular interactions that lead to the formation of chain-like supramolecular structure of the PtIV complex and dimeric structure of the AuIII complex. The study of the weak interactions in AuIII complexes was continued, and as a result a series of AuIII double salts with nitrogen-containing chelating ligands were synthesized and weak interactions in their structures were characterized with focus on the aurophililic contacts.

The amidines synthesized in the course of the present project can be potentially applied as the anticanser agents.

The dissertation is published in the series Kemian laitos, Jyväskylän yliopisto, Research Report Series number 179, ISSN 0357-346X, ISBN 978-951-39-6009-4.

  • Further information:

Alexander Chersnyshev, alexander.n.chernyshev@jyu.fi

Communications intern Birgitta Kemppainen, tiedotus@jyu.fi, 040 805 4483