| Abstract | U okviru ove disertacije istražena su svojstva aminskih, ureidnih i tioureidnih derivata dehidracetne kiseline (3-acetil-2-hidroksi-6-metil-4H-piran-4-on, DHA) te kaliks[4]arena s triptofanskim podjedinicama na donjem obodu kaliksarenskog prstena kao receptora različitih vrsta u otopinama. Reakcije kompleksiranja istražene su potenciometrijskim, spektrofotometrijskim, mikrokalorimetrijskim i konduktometrijskim titracijama te NMR spektroskopijom. Proučene su reakcije niza anorganskih aniona (Cl, NO3, ClO4-, PF6, SbF) s aminskim derivatima DHA u metanolu. Istraženo je i kompleksiranje nekoliko dikarboksilnih kiselina (maleinska, fumarna, ftalna, izoftalna, jantarna) sa simetričnim monoaminskim receptorom. Također je provedeno istraživanje protonacijskih svojstava tih kiselina te aminskih receptora zasnovanih na DHA. U slučaju anorganskih aniona nije zamijećena selektivnost proučavanih receptora, što je posljedica njihove fleksibilnosti. S druge strane, uočena je selektivnost simetričnog monoaminskog receptora za maleinsku, odnosno ftalnu kiselinu. Određeni su termodinamički parametri reakcija nastajanja kompleksa nekoliko aniona (H2PO4, HSO4, AcO, Cl) s (tio)ureidnim derivatima dehidracetne kiseline u acetonitrilu i dimetilsulfoksidu. Utvrđeno je da ti spojevi tvore anionske komplekse stehiometrije 1:1 (anion:receptor), osim u slučaju dihidrogenfosfata u acetonitrilu, gdje nastaje i kompleks stehiometrije 2:1. Dimerizacija dihidrogenfosfatnog aniona također je kvantitativno istražena u oba otapala. Derivat kaliks[4]arena s triptofanskim podjedinicama pokazao se selektivnim za fluoridni anion te je ispitana njegova mogućnost vezanja parova iona u acetonitrilu. Utvrđeno je da nastaju ionski asocijati između fluoridnog aniona i kationa ispitanih metala koji imaju značajan utjecaj na ravnoteže reakcija kompleksiranja te je s tim u vezi potenciometrijski određena konstanta ravnoteže nastajanja Na+F. Svi dobiveni rezultati diskutirani su s obzirom na svojstva aniona, strukturne značajke receptora, a u obzir je uzet i utjecaj otapala na proučavane ravnoteže. |
| Abstract (english) | Complexation of various species by amine, urea, and thiourea derivatives of dehidroacetic acid (3acetyl-2-hydroxy-6-methyl-4H-pyran-4-one, DHA), as well as by calix[4]arene derivative bearing tryptophan units at the lower rim, has been studied using NMR spectroscopy, potentiometric, spectrophotometric, microcalorimetric, and conductometric titrations. Complexation reactions of a series of inorganic anions (Cl, NO3, ClO4) with amine derivatives of DHA were studied in methanol. In addition, complexation of several dicarboxylic acids (maleic, fumaric, phthalic, isophthalic, and succinic) by the symmetrical monoamine DHA derivative was investigated. The protonation properties of the acids and the aminebased DHA receptors were also studied. In the case of inorganic anions, no selectivity was observed. In contrast, it was found that the symmetrical monamine receptor was selective for maleic and phthalic acid among the investigated dicarboxylic acids. The thermodynamic parameters for complex formation of (thio)urea derivatives with several anions (H2PO4, HSO4, AcO Cl,) in acetonitrile and dimethyl sulfoxide were determined. The complexes were found to be of 1:1 (anion:receptor) stoichiometry, with the exception of dihydrogen phosphate anion, which formed both 1:1 and 2:1 complexes. It was found that the extent of the dimerisation of dihydrogen phosphate was significant in both solvents used. Hence, this reaction was also quantitatively studied, and was taken into account in the course of the anion-binding studies. Calix[4]arene derivative with tryptophan subunits was shown to be selective for fluoride anion among the other halide anions investigated (Cl, Br, I).The possibility of ion-pair binding by this derivative was also explored, whereby the ion-association process, i.e. formation of M species (M stands for metal), was found to play an important role. The equilibrium constant for the formation of Na+F, PF associate was determined potentiometrically. The gathered results were discussed with respect to anion and receptor structural properties. The solvent effect on the studied equilibria was also addressed in detail. |
