U ovoj disertaciji predstavljena je i primijenjena nova klaster-kontinuum metoda za opis solvatacije. U odnosu na postojeće, ova metoda uvodi novi pristup generiranju klastera na način da se solutu ...dodaju najvažnije molekule otapala. Pristup se temelji na konceptu solvatacijskih sfera funkcionalnih skupina. Radijusi solvatacijskih sfera dobivaju se analizom radijalnih funkcija raspodjele molekula otapala oko funkcionalnih skupina soluta, što omogućuje eliminaciju molekula otapala koje nisu potrebne za točan opis solvatacije. Nakon toga, daljnja analiza vrši se usporedbom interakcijskih energija preostalih molekula otapala. Predstavljena metoda omogućuje jednostavno, efikasno i nepristrano dobivanje geometrija s određenim brojem molekula otapala. Testiranje metode provedeno je na dva modelna sustava u vodi. Analizom dobivenih geometrija identificirani su obrasci vezanja nabijenih i neutralnih vrsta s molekulama vode, dok su dobivene energije, utežene Boltzmannovom raspodjelom, dale vrijednosti termodinamičkih veličina u odstupanju od 1 kcal/mol od eksperimentalnih. Nakon toga, metoda je iskorištena za istraživanje mogućih reakcijskih mehanizama hidrolize acetil-klorida.
In this dissertation, a new cluster-continuum solvation modeling method is presented and applied. The most important feature of this method is a novel approach for the generation of clusters, in which only important solvent molecules are added to the solute. This approach is based on the concept of functional group solvation spheres. Solvation sphere radii are defined by analyzing radial distribution functions of solvent molecules around solute functional groups, which enables the elimination of molecules unperturbed by the solute. Also, the presented method implements a procedure for simple, effective and unbiased generation of geometries with a selected number of solvent molecules. This is achieved by sorting the solvent molecules according to their interaction energy. The method was tested on two model systems, using water as the solvent. The patterns of solvent-solute bonding for neutral and charged molecules were identified by analysis of obtained geometries, while the calculated Boltzmann weighted Gibbs energies gave values of thermodynamic quantities with an average deviation of 1 kcal/mol when compared to experimental data. After that, the method was used for the investigation of acetyl-chloride hydrolysis reaction mechanisms.
Sintetizirano je sedam novih fluorescentnih derivata kaliks4arena s fenantridinskim (13) i difenilantracenskim (47) supstituentima na donjem obodu kaliksarenskog prstena. Spojevi su pripravljeni ...konvencionalnom organskom i mikrovalovima potpomognutom sintezom te su uspoređena reakcijska vremena i iskorištenja. Okarakterizirani su na temelju podataka dobivenih 1H i 13C NMR, FTIR spektroskopijom, elementnom analizom kao i spektrometrijom masa. Spektrofotometrijskim, fluorimetrijskim, potenciometrijskim i 1H NMR titracijama istraženo je kompleksiranje dobivenih liganada s alkalijskim kationima u smjesama otapala acetonitril/diklormetan i metanol/diklormetan ( fi= 0,5). Pri tome su određene konstante stabilnosti odgovarajućih kompleksa stehiometrije 1:1 (kation:ligand). Istraženo je i nastajanje ionskih parova u istim smjesama otapala, budući da ono također utječe na proces kompleksiranja. Kao što je očekivano s obzirom na izbor supstituenata, svi ligandi vežu alkalijske katione uz smanjenje afiniteta prema metalnim ionima s porastom njihova radiusa. Opaženo je da otapalo znatno utječe na stabilnost kompleksa, pri čemu je afinitet liganada prema kationima znatno veći u smjesi diklormetana s acetonitrilom nego onoj s metanolom. Može se zaključiti da bi pripravljeni kaliksarenski derivati mogli poslužiti kao osjetljivi fluorimetrijski senzori za alkalijske katione.
In the framework of this work seven fluorescent calix4arene derivatives with phenanthridine (13) and diphenylanthracene (47) substituents at the lower calixarene rim were synthesized. Compounds were prepared by conventional organic synthesis as well as by microwave-assisted synthesis, and the reaction times and yields were compared. The compounds were characterized by means of FTIR, 1H and 13C NMR spectroscopies, elemental analysis as well as by mass spectrometry. The complexation of these ligands with alkali-metal cations was studied by spectrophotometric, fluorimetric, potentiometric, and NMR titrations in acetonitrile/dichloromethane and methanol/dichloromethane solvent mixtures ( phi= 0.5). The stability constants of the corresponding 1:1 (cation:ligand) complexes were determined. Ion association in these solvent mixtures was also investigated because this phenomenon can considerably affect the complexation process. The ligands were proven to bind the alkali-metal cations rather strongly with lowering of their binding abilities with the increase of the cation radius. It was found that solvent considerably affected the stability of the complexes, whereby the ligands showed significantly higher affinities for cations in acetonitrile than in methanol/dichloromethane mixture. It could be concluded that the prepared calixarene ligands could serve as sensitive fluorimetric sensors for alkali-metal cations.
