Infrared (IR) excitation of vibrations that participate in the reaction coordinate of an otherwise thermally driven chemical reaction are believed to lead to its acceleration. Attempts at the practical realization of this concept have been hampered so far by competing processes leading to sample heating. Here we demonstrate, using femtosecond IR-pump IR-probe experiments, the acceleration of urethane and polyurethane formation due to vibrational excitation of the reactants for 1:1 mixtures of phenylisocyanate and cyclohexanol, and toluene-2,4-diisocyanate and 2,2,2-trichloroethane-1,1-diol, respectively. We measured reaction rate changes upon selective vibrational excitation with negligible heating of the sample and observed an increase of the reaction rate up to 24%. The observation is rationalized using reactant and transition-state structures obtained from quantum chemical calculations. We subsequently used IR-driven reaction acceleration to write a polyurethane square on sample windows using a femtosecond IR pulse.
The molecular binding mechanisms for the adsorbed phosphate at the goethite–water interface have been explored via a joint experimental/theoretical study. This study involved performing sorption experiments, characterization by FT-IR spectroscopy, and performing periodic DFT calculations.
The available phosphorus for plants is mainly affected by the strong binding of phosphates to soil mineral surfaces. Here, we have investigated the molecular mechanisms for this binding process at the surface–water interface by QM/MM MD simulations.
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