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A symmetric hydrogen bond is a special type of hydrogen bond in which the proton is spaced exactly halfway between two identical atoms. The strength of the bond to each of those atoms is equal. It is an example of a three-center four-electron bond. This type of bond is much stronger than a "normal" hydrogen bond.
Number of atoms from 20 to 70 (includes H-bond donors [e.g. OHs and NHs] and H-bond acceptors [e.g. Ns and Os]) Veber's Rule further questions a 500 molecular weight cutoff. The polar surface area and the number of rotatable bonds has been found to better discriminate between compounds that are orally active and those that are not for a large ...
Nucleic acid tertiary structure is the three-dimensional shape of a nucleic acid polymer. [1] RNA and DNA molecules are capable of diverse functions ranging from molecular recognition to catalysis. Such functions require a precise three-dimensional structure. While such structures are diverse and seemingly complex, they are composed of ...
The thiourea hydrogen bonds to the nitro group and stabilizes the incoming negative charge, while the amine acts a specific base to activate the nucleophile. This is an example of bifunctional catalysis. Hydrogen-bond catalysis is a type of organocatalysis that relies on use of hydrogen bonding interactions to accelerate and control organic ...
Secondary structure is defined by hydrogen bonding, so the exact definition of a hydrogen bond is critical. The standard hydrogen-bond definition for secondary structure is that of DSSP, which is a purely electrostatic model. It assigns charges of ±q 1 ≈ 0.42e to the carbonyl carbon and oxygen, respectively, and charges of ±q 2 ≈ 0.20e to ...
The chemical basis for Markovnikov's Rule is the formation of the most stable carbocation during the addition process. The addition of the hydrogen ion to one carbon atom in the alkene creates a positive charge on the other carbon, forming a carbocation intermediate. The more substituted the carbocation, the more stable it is, due to induction ...
A Low-barrier hydrogen bond (LBHB) is a special type of hydrogen bond. LBHBs can occur when the pKa of the two heteroatoms are closely matched, which allows the hydrogen to be more equally shared between them. This hydrogen-sharing causes the formation of especially short, strong hydrogen bonds. [1]
Hansen solubility parameters were developed by Charles M. Hansen in his Ph.D thesis in 1967 [1][2] as a way of predicting if one material will dissolve in another and form a solution. [3] They are based on the idea that like dissolves like where one molecule is defined as being 'like' another if it bonds to itself in a similar way.