Solvolitsko ponašanje fenilferocenilmetilnih butanoata u 60%-tnom vodenom acetonu

master's thesis

• Title (english): Solvolytic behaviour of ferrocenylphenylmethyl butanoates in 60% aqueous acetone
• Author: Margareta Paulić
• Mentor: Sandra Jurić (mentor)
• Committee member: Sandra Jurić (predsjednik povjerenstva)
• Committee member: Biljana Nigović (član povjerenstva)
• Committee member: Jasna Jablan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of organic chemistry); Zagreb
• Defense date and country: 2022-09-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Konstante brzine solvolize k izmjerene su različito supstituiranim fenilferocenilmetilnim butanoatima 60%-tnom vodenom acetonu. Konstruiran je graf ovisnosti log k o parametru elektrofugalnosti Ef te je dobivena odlična linearna ovisnost (R2 > 0,99) što opravdava korištenje LFER modela log k = sf ( Nf + Ef ) i potvrđuje izmjerene vrijednosti parametra Ef korištenih elektrofuga. Iz korelacijskog pravca izračunati su parametri nukleofugalnosti za butanoat u 60%-tnom vodenom acetonu koji iznose Nf = -4,54 i sf = 0,99. Dobiveni parametri uspoređeni su s vrijednostima parametara za butanoate u 80%-tnom vodenom acetonu koji upućuju na povećanje nukleofugalnosti povećanjem količine vode u otapalu zbog boljih solvatacijskih efekata za negativno nabijene izlazne skupine. Nukleofugalnost butanoata u 60%-tnom vodenom acetonu uspoređena je s drugim izlaznim skupinama (kloridna, benzoatna, acetatna) te je zaključeno da je butanoat vrlo slab nukleofug. Razmotren je utjecaj različitih susptituenata na fenilnom prstenu fenilferocenilmetilnih supstrata usporedbom Ef vrijednosti te korištenjem Hammet-Brownove jednadžbe. Niske apsolutne vrijednosti Hammet-Brownovog parametra ρ+ za različito supstituirane fenilferocenilmetil-butanoate upućuju na to da se u prijelaznom stanju reakcije solvolize razvija mala količina pozitivnog naboja i potvrđuju prevladavajući elektron-donirajući utjecaj ferocena na reakcijski centar koji zasjenjuje utjecaj supstituenata na fenilnom prstenu. Istaknuta je mogućnost primjene ljestvica elektrofugalnosti i nukleofugalnosti u predviđanju konstanti brzine solvolize različitih kombinacija elektrofuga i nukleofuga u danom otapalu te korištenje slabih izlaznih skupina kao što su butanoati u određivanju elektrofugalnosti jakih elektrofuga, primjerice različito supstituiranih fenilferocenilmetilnih kationa.

Abstract (english)

Solvolysis rates k were measured for differently substituted ferrocenylphenylmethyl butanoates in 60% aqueous acetone. Graph depicting log k vs. parameter of electrofugality Ef was plotted and great linear correlation (R2>0,99) was obtained, which then justifies the use of LFER model log k = sf (Nf + Ef) and confirms measured Ef values of used electrofuges. Nucleofugality parameters were calculated using the correlation graph for butanoate in 60% aqueous acetone which amount to Nf = -4,54 and sf = 0,99. The obtained values were compared to the nucleofugality parameters of butanoates in 80% aqueous acetone which display that the increase of the amount of water in the solvent causes the nucleofugality parameters to increase due to better solvatation effects. Nucleofugality of butanoate in 60% aqueous acetone was compared to other leaving groups (chloride, benzoate, acetate) with the conclusion that butanoate is a very weak nucleofuge. The impact of different substituents on the phenyl ring of ferrocenylphenylmethyl substrates was reviewed by comparing Ef values and using Hammet-Brown equation. Low absolute values of Hammet-brown parameter ρ+ for differently substituted ferrocenylphenylmethyl butanoates indicate that the generation of the positive charge in the transition state of solvolysis reaction is considerably reduced which confirms the strong electron-donating ability of the ferrocenyl group overshadowing the phenyl substituents' impact. The possibility of applying the electrofugality and nucleofugality scales in the prediction of solvolysis rates for different electrofuge-nucleofuge combinations in given solvents as well as using weak leaving groups like butanoates in determining electrofugality of strong electrofuges, like differently substituted ferrocenylphenylmethyl cations, was pointed out.

• Keywords: ferocen; nukleofugalnost; butanoat; solvoliza
• Keywords (english): ferrocene; nucleofugality; butanoate; solvolysis
• Language: croatian
• URN:NBN: urn:nbn:hr:163:886919
• Study programme: Title: Pharmacy; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-09-13
• Created on: 2022-09-14 13:04:24