Behavioral pattern exploration of single guest, hexadecane-1,16-diol and hexadecane in urea inclusion compounds via molecular dynamics simulation

Abstract

The urea inclusion compounds, a unique polar organic crystalline complex, are considered as a potential candidate for a molecular separator of long chain alkane molecule. A well-defined structure of the crystalline channel systems constructed from hydrogen bonding arrangement of the urea molecules, can be used to understand the fundamental aspects of the processes involving ions or molecules transportation. To do so, in our work, molecular dynamics approach is implemented to understand the behavioral pattern of the hexadecane-1,16-diol and hexadecane guests' related to translational and rotational orientation along the urea tunnel. Our obtained results reveal that high interaction of hexadecane-1,16-diol with urea host molecules offers a restricted environment inside urea tunnel, resulting in slowing down the guest movement. Hexadecane guest system, on the contrary, exhibits lower interaction whereby the translational and rotational movement is faster. Moreover, as the distance increases (along c-axis) in the urea tunnel, both guest systems favor a clockwise rotational orientation. Preference of the respected orientation indicates the influence of chiral urea tunnel on achiral guests that is clathrate inside the tunnel structure.