The role of coordinative bonds and π-π interactions in the formation of supramolecular architecture in the crystals of copper coordination compounds. X-ray study
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StatusThe thesis was presented on the 26 July, 2022Approved by NCAA on the 30 September, 2022 Abstract – 2.09 Mb / in romanianThesisCZU [538.9:546.56]:548(043.2)
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Keywords
Cu(II) coordination compounds, aromatic ligands, metallocycle, crystalline and electronic structure, π-π stacking interactions, spectroscopic measurementsSummary
Thesis structure: introduction, 5 chapters, conclusions and recommendations, bibliography of 360 references, 139 pages of basic text, 8 tables, 86 figures and 12 annexes. The results obtained were disseminated in 28 scientific papers.
The purpose of the thesis: Study of π-π-stacking interactions in the crystal structures of mono-, di- and polynuclear Cu(II) coordination compounds with aromatic ligands and elucidation of the role of the metallocycle in these interactions based on a number of new materials.
Research objectives: design and identification of methods for the preparation of Cu(II) coordination compounds with aromatic ligands; characterization of compounds by X-ray diffraction analysis; identification of π-π stacking intermolecular interactions involving the metallocycle and their statistical analysis; establishing the contribution of π-π stacking interactions in the construction of supramolecular motifs; evaluation of the energy of these interactions and spectroscopic properties.
Novelty and scientific originality: consists in determining the crystal structure of 37 new Cu(II) compounds with aromatic ligands and revealing the chelating effect on π-π stacking interactions. For the first time, for these systems, the particularities of the electronic structure were calculated, which explains the nature of π-π stacking interactions.
The results obtained that contribute to solving an important scientific problem: the creation of model crystals of compounds with aromatic ligands coordinated to the metal, the study of their structure and intermolecular interactions allowed to reveal and evaluate the effect of enhancement of π-π stacking interactions due to coordination. The possibility of predicting and using such interactions in the design of new crystals has been established, which expands the crystal engineering paradigm based on weak interactions to create new materials.
Theoretical significance: The concept of enhancing π-π stacking interactions by coordinating the aromatic ligand to the metal, the theoretical evaluation of the factors influencing the stacking interactions and the energy calculations of such interactions in the crystals of Cu(II) coordination compounds with aromatic ligands demonstrates the significant contribution of π-π stacking interactions to stabilize supramolecular motifs and the need to take them into account when modeling new materials.
Practical importance: the stability of the π-π stacking interactions revealed in Cu (II) structures with aromatic ligands offers the possibility of their use in crystal engineering and for modeling the mechanisms of intercalation of bioactive molecules in biological systems.
Implementation of the scientific results: the process of obtaining the dinuclear coordination compound of Cu(II) with π-π intra- and intermolecular π-π stacking interactions (32) formed by in situ condensation of 2,3-bis (2-pyridyl) pyrazine and acetylacetone can be used to create new bioactive compounds. The result is protected by the patent of the Republic of Moldova.
Oficial Reviewers
- Leonid Culiuc
doctor habilitat, professor, Institute of Applied Physics of the - Olga Şikimaka
doctor, professor, Institute of Applied Physics of the
Council's Members
- Veaceslav Ursachi, president
doctor habilitat, associate professor (docent), Institute of Applied Physics of the - Elena Condrea, secretary
doctor, associate professor (docent) - Vasile Lozan, member
doctor habilitat, associate professor (docent) - Sofia Clochişner, member
doctor habilitat, professor - Irina Filippova,
doctor
Theses
