Hirshfeld surface analysis of the intermolecular interaction networks in cellulose Iα and Iβ

Due to the high crystallinity and natural abundance, the crystal structures of native cellulose allomorphs have been theoretically studied until today, but some details remain to be deciphered. In this work, research was extended on the visualization and quantification of intermolecular interactions related to hydrogen bonds and van der Waals interactions in cellulose crystals Iα and Iβ based on previous studies. For each allomorph, the crystal structure has been described by two models of hydrogen bonding networks designated here as (A) and (B). This network diversity is due to the location of the hydrogen atoms of two disordered positions in the hydroxyl groups O6 and O2. Hirshfeld surface analysis (3D) was used to visualize the fidelity of intermolecular interactions O-H⋯O (involving O2 and O6) in the different cellulosic structural models Iα and Iβ. Two-dimensional fingerprint plots were used to identify the individual type of intermolecular contact and its impact on crystal packaging by graphical representation. A crystal contact study using the enrichment ratio was performed to investigate the tendency of intermolecular interactions to form the crystalline packing. The control of O-H⋯O inter-chain interactions in each type of network shows that hydrogen bonding is more favored in the model (A) than in the model (B).