Synthesis and fluorine-mediated interactions in methanol-encapsulated solid state self-assembly of an isatin-thiazoline hybrid

An exciting isatin-thiazoline hybrid molecule 2 having -C=N-N=C- linkage has been synthesized in 88% yield by the reaction of 5-fluoroisatin with N-(4-fluorophenyl)hydrazinecarbothioamide followed by condensation of the resultant isatin-thiosemicarbazone intermediate with p-chlorophenacyl bromide. The solid state self-assembly of this hybrid molecule was studied by X-ray crystallographic technique. A layered assembly composed of 1D-chains with methanol molecules encapsulated between every two chains is obtained, making a bi-chain sandwich like structure. The supramolecular forces involved in the stabilization of this structure are importantly fluorine-mediated interactions (C-H center dot center dot center dot F, F center dot center dot center dot S and F center dot center dot center dot pi) along with others i.e. N-H center dot center dot center dot O, O-H center dot center dot center dot O, C-H center dot center dot center dot O, Cl center dot center dot center dot pi, C-H center dot center dot center dot pi and pi center dot center dot center dot pi interactions. To the best of our knowledge, this is the first example of solid state fluorine-mediated C-H center dot center dot center dot F, F center dot center dot center dot S and F center dot center dot center dot pi interactions found in a family of isatin-based compounds. (C) 2015 Elsevier B.V. All rights reserved.