Diphenylmethane moiety

A range of cyclophanes (compounds containing a bridged aromatic ring - for a full discussion of cyclophane chemistry see Section 6.5) with protonated nitrogen functionalities have been used with great success as anion binding hosts. In particular, the diphenylmethane moiety is commonly used... 

The polymethylene linkers between the two diphenylmethane moieties are very flexible leading to a poorly preorganised host. Spacers that are more rigid should result in greater selectivity. 

A closer inspection of the chemical structures of these compounds shows that they contain a modification of the diphenylmethane moiety, a diphenylamine. 

The diphenylmethane moieties open and preorganize a cavity lined by benzene rings that are nearly orthogonal to the mean molecular plane. 

Cyclophanes Endoacidic, Endobasic, and Endolipophilic Cavities, p. 424 Dendrimers. p. 432 The Diphenylmethane Moiety, p. 452 Enzyme Mimics, p. 546... 

Cucurbituril, Its Homologues, and Derivatives, p. 390 The Diphenylmethane Moiety, p. 452 Interpenetration, p. 735 Macrocycle Synthesis, p. 830 Rotaxanes and Pseudorotaxanes. p. 1194 Self-Assembly Definition and Kinetic and Thermodynamic Considerations, p. 1248 Self-Assembly Terminology, p. 1263 Strict Self-Assembly and Self-Assembly with Covalent Modifications, p. 1372 The Template Effect, p. 1493... 

Perhaps the most dramatic effect of the hydrophobic group on the association characteristics is to be found in the small group of amphiphiles with aromatic hydrophobic regions. An appreciable number of drug molecules are based on a diphenylmethane moiety and associate in solution in a typically micellar manner. 

When the two phenyl rings of the diphenylmethane moiety of adiphenine are linked together in the form of a rigid fluorene group as in pavatrine hydrochloride (I), the association pattern no longer conforms to that of a monodisperse micellar system [22]. The concentration dependence of the light-scattering intensity of pavatrine exhibits no such inflection as that detected in the curve of adiphenine (Fig. 4.8) and cannot be simulated by the mass-action theory. 

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