A synthetic co-crystal prepared by cooperative single-crystal-to-single-crystal solid-state Diels–Alder reaction

Abstract

A single-crystal-to-single-crystal solid-state reaction involving the 2 : 1 charge-transfer complex of 9-bromoanthracene and bis(N-cyclobutylimino)-1,4-dithiin leads to a synthetic co-crystal composed of the Diels–Alder cycloadduct and unreacted 9-bromoanthracene molecules. Analysis of close contacts in the product crystal and DFT energy calculations indicate an ordered arrangement of product and unreacted molecules due to cooperative effects during the reaction.