Aya Tanatani, K. Yamaguchi, I. Azumaya
Jun 17, 1998
Citations
1
Influential Citations
63
Citations
Journal
Journal of the American Chemical Society
Abstract
The crystal structures of N,N‘-diphenylguanidine (1) and its N-methylated derivatives were investigated, and the conformational properties of these molecules were utilized to construct water-soluble oligomers with multilayered aromatic structures. N,N‘-Diphenylguanidine (1) afforded two types of crystals, chiral (P212121) and racemic (P21/c), upon recrystallization from EtOH. In both crystals, 1 exists in the (E,Z) conformation, in which one C−N bond (length: 1.28−1.30 A) attached to a phenyl ring shows double-bond character. In contrast, N,N‘-dimethyl-N,N‘-diphenylguanidine (4a) exists in the (Z,Z) conformation with the two aromatic rings facing each other. As judged from the crystal structures of several N-methylated compounds, the conformational preferences of diphenylguanidines appear to be related to those of aromatic anilides. N,N,N‘,N‘‘-Tetramethyl-N‘,N‘‘-diphenylguanidinium iodide (6) afforded chiral crystals, like 1 and N-methyl-N,N‘-diphenylguanidine (2). The absolute structure of each enantiom...