Synthesis and diverse crystal packing in o-, m- and p-bis(carbonylthioureido)benzenes containing bisferrocenes.

Abstract

Three bisferrocene-based bis(acylthiourea) positional isomers, namely, 1,2-bis(ferrocenylcarbonylthioureido)benzene (1), 1,3-bis(ferrocenylcarbonylthioureido)benzene (2) and 1,4-bis(ferrocenylcarbonylthioureido)benzene (3), all [Fe₂(C₅H₅)₂(C₂₀H₁₆N₄O₂S₂)], have been synthesized via facile nucleophilic addition reactions of 2.3 equivalents of ferrocenoyl isothiocyanate with o-, m- and p-phenylenediamine, respectively. The structures of the three new synthesized isomers were fully characterized by ¹H NMR, ¹³C NMR, IR and UV-Vis spectroscopy, elemental analyses and cyclic voltammetry. In addition, the structures of acetone monosolvated compound 1 (1·CH₃COCH₃), as well as compounds 2 and 3, have been determined by single-crystal X-ray diffraction. A combination of intermolecular N-H...S and C-H...S hydrogen bonds connects the components of compound 1·CH₃COCH₃ into infinite helix chains. Two pairs of different N-H...S and C-H...S intermolecular hydrogen bonds, as well as N-H...O and C-H...π co-operating interactions, link the molecules of compound 2 into a two-dimensional network. In contrast, compound 3 displays a one-dimensional double-chain array via two intermolecular C-H...S hydrogen bonds. Therefore, the three reported positional isomers present unique individual crystal assemblies.