Molecular structure of N,N?-diphenylformamidine

Polymers containing formamidine groups. VI. Structural influences on the formation of cyclic trimers

“…In the case of the phenyl moiety ( 1a , 2a ), this steric hindrance causes high‐energy barriers at τ = 0 and 180° resulting in a nonplanar conformation in which the aromatic rings are turned out of the amidine plane. A nonplanar conformation of the aromatic rings was also found in diphenylformamidine by means of X‐ray analysis 28. In this conformation, cyclization is practically impossible.…”

Solution Chemistry of N,N’‐Disubstituted Amidines: Identification of Isomers and Evidence for Linear Dimer Formation

“…: “Steric effects determine the isomer”), with a slight preference for the N Mes over the NH Mes substituent (i.e., Z‐anti over E‐syn ). Compared to the E‐anti isomer, which may form cyclic homodimers as seen in N , N’ ‐bisarylformamidines, this repulsion effectively shields one of the nitrogen atoms from being available for hydrogen bonding. Hence, for the E‐syn and Z‐anti isomers only heterodimers are possible, with the E‐syn and Z‐anti isomers acting as hydrogen‐bond donor and acceptor, respectively.…”

“…Provided that there is at least one proton bound to a nitrogen atom, the formation of dimers or polymers through intermolecular hydrogen bonding networks was noticed several times . Accordingly, for example, cyclic dimers of the E‐anti isomer, linear chains of amidines, or complexes with solvent molecules or carboxylic acids have been detected. The extent to which intermolecular association occurs mostly depends on the nature of the substituents and the substitution pattern, temperature, concentration, and the solvent .…”

“…The extent to which intermolecular association occurs mostly depends on the nature of the substituents and the substitution pattern, temperature, concentration, and the solvent . In the solid state, intermolecular association of amidines has been occasionally observed by means of X‐ray crystallography …”

Crystallographic studies and physicochemical properties of π-electron systems. 21. Structure of N,N'-bis(p-chlorophenyl)formamidine

“…Amidine derivatives have recently been extensively studied both chemically (Oszczapowicz & Ciszkowski, 1987;Gilli & Bertolasi, 1979;H/ifelinger, 1975) and crystallographically (Bellucci, 0108-2701/90/112121-03503.00 Bertolasi, Ferretii & Gilli, 1985;Norrestam, 1984a,b;Alcock, Barker & Kilner, 1988;Kratochvil, Ondracek, Krechl & Hasek, 1987;Ciszak, Gdaniec & Kosturkiewicz, 1987;Tykarska, Jask61ski & Kosturkiewicz, 1986a,b;Oszczapowicz, Tykarska, Jask61ski & Kosturkiewicz, 1986) to investigate their chemical (Shriner & Neumann, 1944;Schwenker & B6sl, 1969) and in particular biological (Grout, 1975) properties. One particular feature of some amidine derivatives is their tautomerism (Oszczapowicz & Ciszkowski, 1987Hfifelinger, 1975) and this paper is a continuation of our studies (Anulewicz, Krygowski & Pniewska, 1987;Anulewicz, Krygowski, Jaroszewska-Manaj & Pniewska, 1989). Geometrical analysis of the amidine skeleton seems to be of great interest because of its dependence on the hydrogen bonding in dimers of formamidine derivatives.…”