Structure and dynamics of methanol in water: a quantum mechanical charge field molecular dynamics study.
An ab initio quantum mechanical charge field molecular dynamics simulation was carried out for one methanol molecule in water to analyze the structure and dynamics of hydrophobic and hydrophilic groups. It is found that water molecules around the methyl group form a cage-like structure whereas the hydroxyl group acts as both hydrogen bond donor and acceptor, thus forming several hydrogen bonds with water molecules. The dynamic analyses correlate well with the structural data, evaluated by means of radial distribution functions, angular distribution functions, and coordination number distributions. The overall ligand mean residence time, τ identifies the methanol molecule as structure maker. The relative dynamics data of hydrogen bonds between hydroxyl of methanol and water molecules prove the existence of both strong and weak hydrogen bonds. The results obtained from the simulation are in excellent agreement with the experimental results for dilute solution of CH(3)OH in water. The overall hydration shell of methanol consists in average of 18 water molecules out of which three are hydrogen bonded.
Theoretical Chemistry Division, University of Innsbruck, Innsbruck, Austria.
Syed Tarique
ST
Moin
Thomas S
TS
Hofer
Bernhard R
BR
Randolf
Bernd M
BM
Rode
D006860:Hydrogen Bonding; D000432:Methanol / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D011789:Quantum Theory; D014867:Water / Q000737:chemistry
D014867:Water; D000432:Methanol