《The Conveyor Belt Umbrella Sampling (CBUS) Scheme: Principle and Application to the Calculation of the Absolute Binding Free Energies of Alkali Cations to Crown Ethers》 was published in Journal of Chemical Theory and Computation in 2020. These research results belong to Hahn, David F.; Zarotiadis, Rhiannon A.; Hunenberger, Philippe H.. Product Details of 33100-27-5 The article mentions the following:
We recently introduced a method called conveyor belt (CB) thermodn. integration (TI) for the calculation of alchem. free-energy differences based on mol. dynamics simulations. In the present work, the CBTI approach is generalized to conformational free-energy changes, i.e., to the determination of the potential of mean force (PMF) along a conformational coordinate ξ of interest. The proposed conveyor belt umbrella sampling (CBUS) scheme relies on the parallel simulation of K replicas k = 0,1, …, K – 1 of the system, with K even. For each replica k, the instantaneous value of ξ is restrained to an anchor value λk. The latter anchor points are equally spaced along a forward-turn-backward-turn path (i.e., a CB) between two extreme values defining the ξ-range of interest. The rotation of the CB is controlled by a variable Λ (range from 0 to 2π) which evolves dynamically along the simulation. The evolution of Λ results from the forces exerted by the restraining potentials on the anchor points, taken equal and opposite to those they exert on the replicas. Because these forces tend to cancel out along the CB, the dynamics of Λ is essentially diffusive, and the continuous distribution of ξ-values sampled by the replica system is automatically close to homogeneous. The latter feature represents an advantage over direct counting (DCNT) and traditional umbrella sampling (TRUS), shared to some extent with replica-exchange umbrella sampling (REUS). In this work, the CBUS scheme is introduced and compared to the three latter schemes in the calculation of 45 standard absolute binding free energies. These correspond to the binding of five alkali cations to three crown ethers in three solvents. Different free-energy estimators are considered for the PMF calculation, and the calculated values are also compared to those of a previous study relying on an alchem. path, as well as to exptl. data. In the experiment, the researchers used many compounds, for example, 1,4,7,10,13-Pentaoxacyclopentadecane(cas: 33100-27-5Product Details of 33100-27-5)
1,4,7,10,13-Pentaoxacyclopentadecane(cas: 33100-27-5) is a member of crown ether Ligands. Crown-ethers are macrocyclic polyethers capable of forming host-guest complexes, especially with inorganic and organic cations. Crown-ethers can incorporate protonated primary amine compounds by formation of ion-dipole bonds with the oxygen atoms of the chiral selector. Crown-ethers have been widely used for the separation of several pharmaceuticals both in aqueous and non-aqueous media. Product Details of 33100-27-5
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem