Functional groups hydrogen bonds

Finally, since besides the inductive effect of the sulfoxide and the sulfone functional groups, hydrogen bonding, field effects and steric effects to solvation may or may not work in the same direction, the pKx values can be useful in assigning configurations of suitable pairs of stereoisomeric sulfoxide and sulfone carboxylic acids291. 

In addition, polar functional groups hydrogen bond with each other (not just water), and amino acids with charged side chains like - COO and - NH3 can stabilize tertiary structure by electrostatic interactions. 

This equation assumes that the carboxylic acid group is not ionized in the polymer bulk and functions by hydrogen-bonding to the ester groups. For a small number of chain scissions, both the ester and water concentrations may be considered constants, and Eq. 4 simplifies to Eq. 5. 

New monosubstituted cobaltocenium derivatives functionalized with hydrogen-bonding amine groups (Fig. 39) have been prepared and the... 

The 4 position is normally a keto or amino group. Hydrogen bonds involving these functions do appear to contribute to binding the normal nucleotides but they are not crucial. A 4-thio function still provides a substrate. 

Don t think, though, that the C - C and C - H o bonds are unimportant. They form the carbon backbone or skeleton to which the functional groups are bonded. A functional group usually behaves the same whether it is bonded to a carbon skeleton having as few as two or as many as twenty carbons. For this reason, we often abbreviate the carbon and hydrogen portion of the molecule by a capital letter R, and draw the R bonded to a particular functional group. 

The experiments have demonstrated that the hydroxyl groups at C-4, C-8 and C-9 of sialic acid are important for binding, whereas the 7-OH is not necessary [33]. Most likely, these beneficial OH groups function as hydrogen-bond donors to the siglec, while the hydroxyl group at C-7 appears not to be in contact with the protein, according to the crystal structure [25]. 

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