One longstanding question about water’s intermolecular interactions, and notably hydrogen bonding, is the extent and importance of charge transfer (CT),which can have important implications for the development of our site reliable model potentials for water chemistry, among other applications.
The weakly bound adducts, Inhibitors,Modulators,Libraries commonly regarded as pure van der Waals systems, formed by H2O, H2S, and NH3 with noble gases or simple molecules such as H-2, provide an interesting case study for these interactions. Their binding energies are approximately 1 or 2 kJ/mol at most, and CT effects in these systems are thought to be negligible. Our laboratory has performed high-resolution molecular-beam scattering experiments that probe the (absolute scale) Inhibitors,Modulators,Libraries intermolecular potential of various types of these gas-phase binary complexes with extreme sensitivity.
These experiments have yielded surprising and intriguing quantitative results. The key experimental measurable is the “”glory”" quantum interference shift that shows Inhibitors,Modulators,Libraries a systematic, anomalous energy stabilization for the water complexes and clearly points to a significant role for CT effects.
To investigate these findings, we have performed very accurate theoretical calculations and devised a simple approach to study the electron displacement that accompanies gas-phase binary intermolecular interactions in extreme detail. These calculations are based on a partial progressive integration of the electron density changes. The results unambiguously show that water’s intermolecular interactions are not typical van der Waals complexes.
Instead, these interactions possess a definite, strongly stereospecific CT component, even when very weak, where Inhibitors,Modulators,Libraries a water molecule may act as electron donor or acceptor depending on its orientation. CT is mediated by an asymmetric role played by the two hydrogen atoms, which causes strong orientation effects. The careful comparison of these calculations with the experimental results shows that the stabilization energy associated to CT is approximately 2-3 eV per electron transferred and may make up for a large portion of the total interaction energy. A simple electron delocalization model helps to validate and explain these findings.”
“Fashioned through billions of years of evolution, biological molecular machines, such as ATP synthase, myosin, and kinesin, use the intricate relative motions of their components to drive some of life’s most essential processes.
Having control Drug_discovery over the motions in molecules is imperative for life to function, and many chemists have designed, synthesized, and investigated artificial molecular systems that also express controllable motions within molecules. Using bistable mechanically interlocked molecules (MIMs), based on donor-acceptor recognition motifs, we selleck chemicals Trichostatin A have sought to imitate the sophisticated nanoscale machines present in living systems.