Cocrystallization of perfluoroiodobenzenes with simple pyridine derivatives – comparative evaluation of classical halogen bond donors

Abstract

U sklopu disertacije pripravljeno je 37 novih kokristala jodperfluorbenzenâ i jednostavnih derivata piridina koji su strukturno i termički okarakterizirani. Po prvi puta su sustavno ispitana i uspoređena donorska svojstva komercijalnih jodperfluorbenzenâ i uočene su sličnosti i razlike u strukturama njihovih kokristala s jednostavnim derivatima piridina. Potvrđena je teza o 1,4-dijodtetrafluorbenzenu kao provjerenom i pouzdanom donoru halogenske veze koji tvori kokristale s 13 korištenih akceptora, dok je s 1,2-dijodtetrafluorbenzenom pripravljeno samo 5 kokristala. Ispitan je međuodnos geometrije molekula donora, iznosa elektrostatskih potencijala na donorskim atomima i prostornih ograničenja na nastajanje kokristala te njihov utjecaj na konačnu stehiometriju produkta. Također, bazičnost molekulâ akceptora istaknula se kao iznimno bitan faktor za pripravu kokristala s nešto slabijim donorima te kokristala s tritopičnim donorom halogenske veze, u kojemu su na molekulu donora vezane tri molekule akceptora.In this study, 37 novel cocrystals of iodoperfluorobenzenes and simple pyridine derivatives were prepared and structurally and thermally characterized. For the first time, donor properties of commercial iodoperfluorobenzenes were systematically examined and compared, and similarities and differences in their cocrystal structures with simple pyridine derivatives were observed. 1,4-diiodotetrafluorobenzene was proven as a reliable halogen bond donor with a total of 13 prepared cocrystals, while 1,2-diiodotetrafluorobenzene forms cocrystals with only 5 used acceptors. The relationship between the geometry of donor molecules, electrostatic potentials at the donor atoms and the steric effects on the formation of cocrystals was investigated as well as their influence on the final product stoichiometry. Additionally, the basicity of acceptor molecules has emerged as a highly important factor for the preparation of cocrystals with slightly weaker donors and for the synthesis of cocrystals with a tritopic halogen bond donor, in which three acceptor molecules are attached to the donor molecule