Tt hydrogen bonds

Fig. 12.2 The benzene-hydrogen fluoride complex connected through F-H—tt hydrogen bonding...

That having been said, their deliberate application in crystal design and specifically in inorganic crystal design has been much more limited. There are nevertheless some interesting examples of D-H tt hydrogen bonds in inorganic systems... 

We have found the novel structure by which phenol complexes with the acetonitrile molecule. Such a structure has an absolutely different hydrogen bonding pattern, which certainly makes it less favourable on comparison with the conventional one attributed to the <7-type hydrogen bonding. A phenol-acetonitrile complex formation via tt hydrogen bonding between the OH group of phenol and the C=N bond should be ruled out affirmatively. 

When a solute is dissolved in a pure hydrogen-bond donor solvent, such as water or alcohol, all acceptor sites are involved in the solvation phenomenon. For example, the partition of phenols between water and organic phases now depends both on the oxygen and on the tt hydrogen-bond basicities, because of the excess of water molecules. From sets of water-solvent partition coefficients, Abraham has constructed a scale of effective or summation hydrogen-bond basicity, for about 350 solutes, of which... 

Weak H-bonds are for instance tt hydrogen bonds that have acceptors that are not atoms with nonbonding orbitals, but a set of atoms with polarizable orbitals such as Tr-orbitals... 

As mentioned above, the asymmetric unit also contains one molecule of chloroform. This molecule is linked to one of the phenyl rings via a weak CH-tt hydrogen bond (see Figure 5.32). In addition, the CHCI3 molecule is disordered approximately about the C-H- 7r-axis. Figure 5.19 shows this disorder. 

An interesting novel approach to anion binding is the use o/NH-tt hydrogen bonds. It has to be emphasized that this type of receptor rests on neutral hydrogen bonding, a seldom-encountered situation in the field of anion coordination. In Compound 21 (Fig. 21). it can be seen that the amide hydrogens are orientated toward the inside of the cavity ard are able to interact with the tt electron system of an anion. Crystal structure of the acetate complex reveals that the anion is bound within the cavity. ... 

Gotch AJ, Zwier TS (1990) The spectroscopy and dyntunics of tt hydrogen-bonded complexes benzene-HCl/Da and toluene-HO/DCl. J Chem Phys 93 6977-6986... 

Grabowski SJ, Ugalde JM (2010) Bond paths show preferable interactions ab initio and QTAIM studies on the X-H- tt hydrogen bond. J Phys Chem A 114 7223-7229... 

In 2007, Cassol et al., found that the selectivity on the extraction of a specific aromatic compound is influenced by anion volume, hydrogen bond strength between the anion and the imidazohum cation and the length of the l-methyl-3-alkylimidazolium alkyl side chain. The interaction of alkylbenzenes and sulfur heterocyles with the IL is preferentially through CH-tt hydrogen bonds and the quantity of these aromatics in the IL phase decreases with the... 

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