Use of 1,3,5-trihydroxy-2,4,6-trinitrobenzene as a building block in crystal engineering

Abstract

U sklopu diplomskog rada pripravljeno je te strukturno i termicki okarakterizirano devetnaest soli i dva kokristala 1,3,5-trihidroksi-2,4,6-trinitrobenzen (trinitrofloroglucinol) s alifatskim i aromatskim aminima te heterociklickim spojevima. Trinitrofloroglucinola pripravljen je nitriranjem 1,3,5-trihidroksibenzena. Soli i kokristali trinitrofloroglucinola pripravljeni su sporom evaporacijom otapala iz otopina koje sadrže trinitrofloroglucinol i organski spoj u odgovarajucem stehiometrijskom omjeru. Produkti su analizirani difrakcijom rentgenskog zracenja na jedinicnom kristalu, razlikovnom pretražnom kalorimetrijom i spektroskopijom u infracrvenom podrucju. NaÒeno je da trinitrofloroglucinol može sudjelovati u velikom broju meÒumolekulskih vodikovih veza jer sadrži veliki broja akceptora vodikove veze s obzirom na broj atoma u molekuli. Unutarmolekulske vodikove veze izmeÒu protoniranih hidroksilnih skupina i susjednih nitro-skupina stabilizirane potpomognute su rezonancijom i delokalizacijom naboja te su slabi donori vodikove veze. To cini trinitrofloroglucinol odlicnim modelnim spojem za proucavanje utjecaja strukture molekule donora vodikove veze na strukturu kristala.Nineteen salts and two co-crystals of 1,3,5-trihydroxy-2,4,6-trinitrobenzene (trinitrophloroglucinol) with heterocyclic compounds, aliphatic, and aromatic amines, were prepared and structurally and thermically characterised. Trinitrophloroglucinol was prepared from 1,3,5-trihydroxybenzene by nitration. Salts and cocrystals were prepared by slow evaporation of solvent from a solution containing trinitrophloroglucinol and an organic compound in an appropriate stoichiometric amount. Resulting compounds were analyzed by diffraction of X-rays on single crystals, differential scanning calorimetry and infra-red spectroscopy. Trinitrophloroglucinol can participate in a great number of intermolecular hydrogen bonds because it contains a large number of hydrogen bond donors compared to the total number of atoms in the molecule. The protonated hydroxyl groups and adjacent nitro-groups are bonded by charge- and resonance-assisted hydrogen bonds and therefore are weak hydrogen bond donors. This makes trinitrophloroglucinol an ideal model compound for studying the effects of hydrogen bond donor molecule structure on crystal structure