Dipole moments of some diazaarenes

Cation-Promoted Hierarchical Formation of Supramolecular Assemblies of Self-Organized Helical Molecular Components

“…Herein we describe a new type of oligomeric strand composed of alternating pym and napy heterocycles ( A , Scheme ), where the interheterocyclic transoid conformational preference of 2,2′‐bipyridine‐like units may be expected to enforce helix formation 7. In view of the large dipole moment of napy (4.1 D in benzene, 25 °C),11 the helical entity A should present a very polar interior and be able to bind a variety of cationic species, which themselves could thereafter promote helix aggregation. Acyclic and macrocyclic structures containing rigidly maintained napy units have been described and found to bind guanidinium ions 12…”

Naphthyridine-Based Helical Foldamers and Macrocycles: Synthesis, Cation Binding, and Supramolecular Assemblies

“…Using the 1,8-naphthyridine (napy) groups as two fused pyridines instead of one, would be expected to yield helices presenting external and internal diameters in the order of 15 and 3.8 Å, respectively, large enough to accommodate small ions. In addition to enlarging the internal cavity, the introduction of such napy units, whose electric dipole is nearly twice that of pyridine, was also anticipated to affect the electrostatic features of the oligomer. This should affect (i) the conformational bias of the oligomer as well as (ii) its electrostatic interactions with cations.…”

Chemistry and biological activities of 1,8-naphthyridines

“…438 The electric dipole moment of 1,8-naphthyridine in benzene was determined (4.10 D). 439 The ESR spectrum of hexahydro-1,8naphthyridinetetrazole was measured. 440 Homonuclear 2D J-resolved 1 H NMR spectra of 2-(2-pyridyl)-1,8-naphthyridine were measured and a complete assignment of the resonances was made.…”