The Use of Halide‐Substituted Anilines for the Formation of Magnesium Imides

Abstract

Abstract The equimolar reactions of the halide‐substituted anilines 2,4,6‐trichloroaniline (Ar Cl NH 2 ) and 2,3,4,5,6‐pentafluoroaniline (Ar F NH 2 ) with Bu 2 Mg in the appropriate solvent system results in the formation of the magnesium imide compounds [(Ar Cl NMg · thf) 4 · tol] ( 4 ), [(Ar Cl NMg · diox) 4 · 3diox] ( 5 ), [(Ar F NMg · thf) 6 · 3C 6 H 6 ] ( 6 ) and [(Ar F NMg · diox) 6 ] ( 7 ). Single‐crystal X‐ray diffraction analyses show that 4 and 5 adopt tetrameric cubane arrangements in the solid state, whereas 6 and 7 form prismatic hexameric aggregates. In comparison, reaction of 2 mol‐equiv. of Ar F NH 2 with Bu 2 Mg produces the trimeric primary amide species [{(Ar F NH) 6 Mg 3 · (thf) 6 } · 2tol · thf] ( 9 ). In addition, the serendipitous synthesis of the decametallic imide [(Ar F N) 9 (F) 2 Mg 10 (thf) 6 · 1.25tol] ( 8a ) and the structural isomer [(Ar F N) 9 (F) 2 Mg 10 (thf) 6 · 4.5tol] ( 8b ) were discovered during the attempted synthesis of 6 . It is presumed that the formation of these unusually large cage compounds results from the partial decomposition of the imide ligand by C–F bond cleavage. The compounds 8a and 8b have similar core‐cage structures, but the orientation of their aryl groups and coordinated solvent molecules vary. The 20‐vertex Mg 10 N 9 F aggregates utilize one fluoride ion as a vertex, with a second fluoride ion encapsulated within the cage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)