Synthesis, Properties, and Intermolecular Interactions in the Solid States of π-Congested X-Shaped 1,2,4,5-Tetra(9-anthryl)benzenes

A Negishi coupling based synthesis of 1,2,4,5-tetra(9anthryl)benzene derivatives, possessing X-shaped molecular structures, is described. The results of X-ray crystallographic analysis show that two-dimensional highly ordered packing structure of the crystalline state of the unsubstituted derivative is a consequence of intermolecular p-p and CH-p interactions between anthracene units. Photoirradiation of the unsubstituted derivative as a precipitated solution promotes intramolecular [4+4] photocycloaddition reactions between both adjacent pairs of anthracene units to produce a crystalline polycyclic product having a unique 1.700 angstrom long carbon-carbon single bond. Furthermore, charge-transfer complexes, displaying near-infrared absorption and emission, are generated by co-crystallization of the X-shaped unsubstituted member of the group with electronacceptor molecules.

Automated summary

A Negishi coupling based synthesis of 1,2,4,5-tetra(9-anthryl)benzene derivatives with X-shaped molecular structures is described. X-ray crystallographic analysis reveals that the two-dimensional highly ordered packing structure of the unsubstituted derivative is a result of intermolecular interactions between anthracene units. Photoirradiation of the unsubstituted derivative promotes intramolecular [4+4] photocycloaddition reactions, leading to the formation of a crystalline polycyclic product featuring a unique long carbon-carbon single bond. Additionally, charge-transfer complexes exhibiting near-infrared absorption and emission are formed by co-crystallization with electron acceptor molecules.