Thermodynamics of Alkaline-earth Metal Cation Complexation with Calix[4]arene Ketone Derivative. The Alkaline Earth Metals.

U okviru istraživačkog dijela rada ispitana je termodinamika kompleksiranja zemnoalkalijskih kationa s ketonskim derivatom kaliks[4]arena (L) u acetonitrilu i metanolu. Entalpija otapanja spoja L u acetonitrilu određena je kalorimetrijski. Ligand L iznimno je učinkovit receptor zemnoalkalijskih kationa u acetonitrilu i vrlo slab u metanolu. Reakcije kompleksiranja u acetonitrilu su egzotermne, osim u slučaju Mg2+ čija je entalpija kompleksiranja pozitivna. Entropijski doprinos standardnim reakcijskim Gibbsovim energijama vezanja svih kationa je pozitivan i znatno pridonosi stabilnosti produkata. Spoj L najjače veže veličinom najprikladniji ion Ca2+. Znatan utjecaj otapala na istražene reakcije može se protumačiti razlikama u solvataciji slobodnih kationa i nastalih kompleksnih vrsta. U metodičkom dijelu rada naslova „Zemnoalkalijski metali“ izrađene su metodičko-didaktičke pripreme za učenike trećih razreda gimnazije prema Planu i programu iz 1995. i za učenike drugih razreda gimnazije prema Kurikulumu za nastavni predmet Kemija za osnovne škole i gimnazije iz 2019. Predloženi su nastavnThe complexation of alkaline-earth metal cations with ketone lower rim calix[4]arene derivative was explored in acetonitrile and methanol. The explored calix[4]arene bound the cations efficiently in acetonitrile with peak affinity for calcium, wheras the binding in methanol was extremely poor. The complexation in acetonitrile was exothermic in all cases except magnesium. The entropic contribution to standard complexation Gibbs energies was considerable and favourable for all explored cations. The solvent effect on the complexation equilibria could be rationalized by considering the solvation of free cations and the products. The methodic part of thesis entitled „ Alkaline-earth metal “ involved the drafting of didactic preparations for third grade (1995 gymnasium program) and second grade gymnasium students (2019 subject curriculum for chemistry). The learning through discovery principle was attempted by envisioning two-hour teaching sessions which linked the experimental observations with aimed learning outcomes