Primary hydrogen-bond interactions

Scheme 22 The primary hydrogen-bond interaction in the 1 1 cociystal benzoic acid carbamazepine.

FIGURE 1.4 Ligand-binding plots showing hydrogen-bonding interactions and distances and hydrophobic contacts for (a) the sucrose molecule in the A. maxima OCP structure and (b) the 3 -hydroxyechinenone molecule. Residues labeled in bold are absolutely conserved in the primary structure of the OCP. (From Wallace, A.C. et al., Protein Eng., 8, 127, 1995.)... 

The protonated endo-endo isomers of the diazabicycloalkanes, catapinands, were among the first macrocycles found to be capable of incorporating halide anions (78).54 Electrostatic and hydrogen bond interactions are undoubtedly the primary driving forces for complex stability. The crystal structure of the chloride catapinate of (78) has confirmed the inclusion nature of the complex and... 

Figure 1.18 (a) Primary and secondary hydrogen bond interactions between guanine and cytosine... 

Primary interest goes to the surface hydroxyls found after modification. Unreacted Q3 and Q4 sites are detected. Concurrent with the silanol number before reaction, also the number of surface silanols after reaction decreases with increasing pretreatment temperature. From the general reaction scheme, these bands may be attributed either to surface silanols in hydrogen bonding interaction with amine groups, or to unreacted surface groups. 

There are many kinds of capsules but few have the capacity to position co-guests in predictable orientations. We used the ability of 1.24.1 to do so, and applied it to evaluate hydrogen-bonding interactions between boronic acids, carboxylic acids, and primary amides [52], The phenyl boronic acids are useful as components of covalently self-assembled systems [53], and we found that the p-methyl, methoxy, ethyl, and isopropyl derivatives all fit as symmetrical dimers inside I.24.I. The structure of the boronic acid dimer has been debated but a recent theoretical study found the doubly hydrogen-bonded exo/endo conformer (Fig. 10) to be lowest in... 

Having discussed the primary structure of DNA and RNA, we now consider how the nucleotide sequence is reproduced or transcribed into another molecule. This information transfer takes place by an interesting hydrogen-bonding interaction between specific pairs of bases. 

Noguchi, T., Inoue, Y., and Tang, X-S. (1999) Hydrogen bonding interaction between primary quinone acceptor Qa and a histidine side chain in Photosystem II as revealed by Fourier transform infrared spectroscopy, Biochemistry 38, 399403. 

The interest in chiral crown ethers arises not only from their ability to differentiate between the enantiomers of racemic substrates8 containing substituted primary ammonium centres by virtue of N-H- -O hydrogen bonding interactions, but also because they can behave as chiral reagents or catalysts when enantioselective reactions are performed on appropriate substrates.8,9... 

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