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Synthetic Evolution of the Multifarene Cavity from Planar Predecessors
Author(s) -
Swamy P Chinna Ayya,
Solel Ephrath,
Reany Ofer,
Keinan Ehud
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201803189
Subject(s) - thiourea , thiocarbamates , vicinal , chemistry , urea , planar , crystallography , carbonylation , graphene , intramolecular force , thioether , stereochemistry , organic chemistry , materials science , nanotechnology , catalysis , computer graphics (images) , carbon monoxide , computer science
The stepwise evolution of curved multifarene structures from planar precursors is demonstrated, highlighting three architectural design elements: 1) employment of various aromatic units, 2) changing the hybridization of the linking atoms from sp 2 to sp 3 , and 3) rigidification of the system by the introduction of five‐membered rings. Similar design elements have been employed to transform graphene sheets into curved carbon structures. Specifically, the stepwise synthetic evolution of multifarene[2+2], which has a curved, quite rigid structure, begins with a planar, tetraimine precursor, conversion to pairs of vicinal diamines, and the transformation of these pairs to cyclic thiourea groups. This process was probed by NMR spectroscopy and X‐ray crystallography. Since varying the carbonylation conditions resulted in carbamates or thiocarbamates rather than the urea or thiourea isomers, the isomeric interconversion was studied both experimentally and by DFT computations. The carbamate versus urea preference was found to reflect either kinetic or thermodynamic control, respectively.