Ubiquitous Presence of Intermolecular CH…O Hydrogen Bonds in As-synthesized Host-Guest Zeolite Materials

Abstract

CH⋅⋅⋅O hydrogen bonds (HBs) are ubiquituous in silica zeolite crystals hosting cationic Organic Structure Directing agents (OSDAs). This new finding is notably supported by a correlation between experimental C−O distances and COSi angles’ distributions of two series of 19 and 11 available structures. The correlation enables to asses the directionality of the CH…O intermolecular interactions and to extrapolate a geometrical model for the hydrogen bonded moeities. DFT−D3 calculations on representative structures further confirmed the presence of these HBs and their geometry on the basis of H−O distances, CHO angles and electron density. The reported insights demonstrate also the particularities of these intermolecular interactions in terms of charge distribution and electrostatic potentials. Further, multiple hydrogen bonding is evidenced between OSDAs and zeolites’ channels and cages, opening new perspectives in the study of zeolite-OSDA host-guest interactions.