Termodinamika kompleksiranja derivata benzena s beta-ciklodekstrinom i kukurbit[7]urilom

master's thesis

• Title (english): Complexation thermodynamics of benzene derivates with beta-cyclodextrin and cucurbit[7]uril
• Author: Tea Babić
• Mentor: Josip Požar (mentor)
• Committee member: Josip Požar (predsjednik povjerenstva)
• Committee member: Vladimir Stilinović (član povjerenstva)
• Committee member: Nikola Cindro (član povjerenstva)
• Committee member: Nikola Bregović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

U okviru rada istražena je termodinamika kompleksiranja benzena te njegovih mono- i
1,4-disupstituiranih derivata s kukurbit[7]urilom (CB7) i β-ciklodekstrinom (β-CD), pomoću
titracijske mikrokalorimetrije i NMR spektroskopije u vodi. Vrijednosti logK° istraženih
kompleksa s CB7 su u rasponu od 6,32 (benzen) do 3,13 (hidrokinon), a kompleksiranje je u
svim slučajevima entalpijski kontrolirano. Razlike u afinitetima prema istraženim gostima
mogu se pojasniti razlikama u hidrataciji gostiju, elektron-donorskim (-akceptorskim)
svojstvima supstituenata te položajem funkcionalnih skupina na benzenu. Kompleksi derivata
funkcionaliziranih s elektron-donorskim skupinama primarno su stabilniji zbog egzotermnijeg
kompleksiranja. Slično, veći afinitet CB7 prema istraženim gostima u usporedbi s β-CD
posljedica je povoljnije reakcijske entalpije. Istraživanja termodinamike kompleksiranja u
širem temperaturnom području ukazuju na značajnu temperaturnu ovisnost ΔrH° i ΔrS°, koje je
u svim slučajevima rezultiralo entalpijsko-entropijskom kompenzacijom. Navedena činjenica
ukazuje na ispravnost klasičnog (iceberg) modela hidratacije gosta pri nižim temperaturama.

Abstract (english)

The complexation of mono- and 1,4-disupstituted derivatives of benzene with cucurbit[7]uril
(CB7) and β-cyclodextrin (β-CD) was explored in water by means of titration microcalorimetry
and NMR spectroscopy. Determined logK° values of the CB7 complexes were in the range of
6,32 (benzene) to 3,13 (hydroquinone), while the complexation reactions were always
enthalpically controlled. The differences in complexation affinities could be rationalized by
considering the guest hydration, electron-donor (-acceptor) properties of the substituents and
their position. Complexes of the derivatives functionalized with electron-donor groups were
more stable due to more favourable complexation energetics. The β-CD affinity for each guest
was always lower than that of CB7 because of less exothermic inclusion. Investigations in a
wider temperature range revealed significant temperature dependence of the ΔrH° and ΔrS°
which resulted in almost complete enthalpy-entropy compensation. This fact supports classic
(iceberg) model of hydrophobic hydration at lower temperatures.

• Keywords: β-ciklodekstrin; derivati benzena; hidrofobni efekt; inkluzijski kompleks; kukurbit[7]uril; termodinamika kompleksiranja
• Keywords (english): benzene derivatives; β-cyclodextrin; complexation thermodynamics; cucurbit[7]uril; hydrophobic effect; inclusion complex
• Language: croatian
• URN:NBN: urn:nbn:hr:217:683848
• Project: Number: IP-2019-04-9560; Title: Koordinacijske reakcije makrocikličkih liganada u otopini; Title: Coordination Reactions of Macrocyclic Ligands in Solution; Acronym: MacroSol; Leader: Vladislav Tomišić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-09-28
• Created on: 2022-10-21 12:50:16