Host-guest compounds: structure and thermal behaviour

Abstract

Inclusion compounds of two hydroxyl hosts with a variety of guests have been investigated. These host compounds are bulky molecules and have the ability to interact with smaller organic guests to form new compounds. The host 9-(1-naphthyl)-9H-xanthen-9-ol (H1), forms inclusion compounds with pyridine (PYR), N,N-dimethylacetamide (DMA), morpholine (MORP) and N-methyl-2-pyrrolidinone (NMP). The crystal structures of H1•NMP, H1•DMA and H1•MORP1 were successfully solved in the triclinic space group PĪ, whereas the inclusion compound H1•PYR crystallised in the monoclinic space group P21/c. A different inclusion compound involving morpholine, H1•MORP2 resulted from dissolution of H1 in a 1:1 molar ratio of MORP: DMA. H1•MORP2 crystallised in the space group PĪ. All of the abovementioned inclusion compounds demonstrated a host: guest ratio of 1:1 except for H1•MORP1 (host: guest ratio = 1: ). H1 interacts with pyridine and morpholine guests via (Host)O-H•••N(Guest) hydrogen bonds and via (Host)OH•••O(Guest) hydrogen bonds with N-methyl-2-pyrrolidinone and N,N-dimethylacetamide.