Phase transitions and self-assemblies of lower diamondoids and derivatives

TL;DR

This study uses ab initio calculations and molecular dynamics simulations to explore the self-assembly and phase transitions of lower diamondoids, their derivatives, and organometallic molecules, revealing how density influences phase transition points.

Contribution

It provides new insights into the phase behavior and self-assembly of diamondoids and derivatives through comprehensive simulations and analysis.

Findings

Clear phase transitions observed in all molecules.

Higher aggregation temperatures for derivatives.

Density increases lead to higher phase transition points.

Abstract

Applying ab initio calculation and molecular dynamics simulation methods, we have been calculating and predicting the essential self-assemblies and phase transitions of two lower diamondoids (adamantane and diamantane), three of their important derivatives (amantadine, memantine and rimantadine), and two organometallic molecules that are built by substituting one hydrogen ion with one sodium ion in both adamantane and diamantine molecules (ADM-Na and Optimized DIM-Na). To study their self-assembly and phase transition behaviors, we built seven different MD simulation systems, and each system consisting of 125 molecules. We obtained self-assembly structures and simulation trajectories for the seven molecules. Radial distribution function studies showed clear phase transitions for the seven molecules. Higher aggregation temperatures were observed for diamondoid derivatives. We also studied the density dependence of the phase transition which demonstrates that the higher the density - the higher the phase transition points.