Istraživanje prirode π-interakcija nearomatskih sustava metodama elektronske gustoće i kristalografije pri ekstremnim uvjetima

doctoral thesis

• Title (english): Study of the nature of π-interactions between non-aromatic systems by x-ray charge density and crystallography under extreme conditions
• Author: Valentina Milašinović
• Mentor: Krešimir Molčanov (mentor)
• Committee member: Marijana Đaković (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2021-06-18, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Glavni cilj doktorske disertacije je detaljno istražiti prirodu π-interakcija nearomatskih prstenova kombinacijom naprednih difrakcijskih metoda. Vrste π-interakcija objašnjene i opisane u ovome radu su multicentrične veze s djelomičnim kovalentnim karakterom između semikinonskih radikala (palačinka-veze), te interakcija anion–π između kinoidnih prstenova i jodidnih aniona. Priroda π-interakcija nearomatskih prstenova istražena je određivanjem eksperimentalne elektronske gustoće rendgenskom difrakcijom u monokristalu i elektronske gustoće metodom prenošenja multipola, zatim kombinacijom temperaturno ovisne rendgenske difrakcije i rendgenske difrakcije pri visokom tlaku. Analizom elektronske gustoće u tri proučavana semikinonska sustava dokazana je prisutnost multicentrične veze s djelomičnim kovalentnim karakterom, a kontakt jodid···kinon je utvrđen kao elektrostatska interakcija. Visoka temperatura utjecala je na rast parametra jedinične ćelije i udaljenosti među ravninama prstenova, odnosno udaljenosti jodid···kinon. Visoki tlak povećao je kovalentni karakter multicentričnih veza u oba proučavana sustava te uzrokovao fazne pretvorbe.

Abstract (english)

The main goal of the Ph.D. thesis is detailed study of the nature of π-interactions of the non-aromatic rings by a combination of advanced diffraction methods. π-Interactions explained and described in this work are partially covalent multicentric bond between semiquinone radicals (pancake bonds) and an anion–π interaction between quinone rings and iodide anions. The nature of π-interactions of the non-aromatic systems was investigated by experimental X-ray charge density, X-ray charge density by transferrable aspherical atom model, and high-pressure and variable-temperature single-crystal X-ray diffraction. Charge density analyses were revealed existence of partially covalent multicentric bond in all of three studied semiquinoid systems. Iodide···quinone contact was defined as an electrostatic interaction. The unit-cell parameters, distances between ring planes and iodide···quinone distances were increased with increasing temperature. The covalent component of the multicentric interaction of two studied systems was increased with high pressure and the phase transitions were caused.

• Keywords: elektronska gustoća; π-interakcije; kristalografija; multicentrične veze; nearomatski sustavi; visoki tlak
• Keywords (english): charge density; crystallography; high pressure; π-interactions; multicentric bonding; non-aromatic rings
• Language: croatian
• URN:NBN: urn:nbn:hr:217:014854
• Promotion: 2021
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 160 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-07-01 12:18:10