Amides H-bonding

Because of the weaker nature of the H-bonds between amines and alcohols, compared with more polar amidic H-bonds, supraminols are compatible with hydrophobic environments when crystallized, although this is not a requirement. The supraminol helical trans-l,2-diaminocyclohexane-C02 complex can be recrystallized from aqueous ethanol [51]. 

The coordination of four n-butylnicotinamide ligands to a Pt(II) center provides access to organized amide H-bond... 

Walter, J. A. and Wright, L. C., C— N. spin-spin coupling constants of amides H-bonding effects in a cyclohexapeptide. Tetrahedron Lett. 41, 3909-3912 (1979). 

The aforementioned trends are noted at either SCF or MP2 levels, and apply not only to the electronic segment of the binding energy, but also to AH where vibrational contributions have been considered. The authors conclude that a single amide-amide H-bond is similar in strength to that between an amide and a water molecule. If one is interested in a binary complex, there is a preference for the syn geometry of NMA, as it then becomes possible to form more than one H-bond. 

Fig. 16 Heterogeneous catalysis of the esterification of benzyl alcohol with 1-hexanoic acid using a cross-linked Hn-phase sulfonic acid resin formed by amide H-bond-assisted LLC phase formation...

N1 Neutral flat NH, e.g. amide H-bond donor probe... 

The Szumna and Jurczak group reported a pyridine-based tetraamide macrocycle, 20. NMR titration studies in DMSO- ie suggested that this receptor should be suitable for fluoride (K = 830 M ) (Table 2). The crystal structure of the fluoride complex (Figure 8a), indicates that the anion is coordinated by four amide H-bonds with an average N- - -F distance of 2.78 The fluoride sits almost in the plane... 

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