Synthesis of a Hemispherical Geodesic Phenine Framework by a Polygon Assembling Strategy
Tatsuru Mio, Koki Ikemoto, Sota Sato, Hiroyuki Isobe
Abstract
Abstract A synthetic strategy to construct large geodesic structures of phenine (1,3,5‐trisubstituted benzene) was devised. In this strategy, five pentagons were assembled on an omphalos pentagon, and bridging peripheral pentagons furnished five additional hexagons. Thirty phenine units were synthetically assembled to afford a large C 220 H 180 molecule with a phenine framework isoreticular to a hemispherical, bisected segment of C 60 . Although a hemispherical structure of the phenine framework was suggested by solution‐phase NMR spectra, crystallographic analysis revealed an oval‐like deformation of the molecular shape. In‐depth structural analyses, including theoretical calculations, showed that structural fluctuations observed as variations in the biaryl torsion angles allowed structural deformations and, at the same time, that the dynamic fluctuations resulted in the spectroscopic observation of a hemisphere as a time‐averaged structure.