Synthesis and characterization of sterically encumbered aluminum thiolato complexes with rare Al/S/halide structural motifs

The reaction of the bulky lithium terphenyl thiolates LiSArMe6 (ArMe6 = C6H3-2,6-(C6H2-2,4,6-Me3)2) and LiSAriPr4 (AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2) with AlBr3 in PhMe or Et2O resulted in the formation of two new lithium aluminum thiolate salts LiAl(SArMe6)2Br2·PhMe 1, [LiAl(SArMe6)Br3]22, and the etherate Al(SAriPr4)Br2(OEt2) 3. Compounds 1–3 were structurally characterized and analyzed by 1H, 13C NMR and IR spectroscopy. In further investigations the reduction of 1 and 2 with KC8 or Rieke’s magnesium in different solvent systems afforded the compounds KAl(SArMe6)3H·2PhMe 4 and LiAl(SArMe6)Br0.36I1.64(2THF)·PhMe 5. All of the compounds described herein contain four-coordinate aluminum atoms with distorted tetrahedral geometries.

The terphenyl thiolato aluminates LiAl(SArMe6)2Br2·PhMe, LiAl(SArMe6)Br3 (ArMe6 = C6H3-2,6(C6H2-2,4,6-Me3)) and the neutral Al(SArPri4)Br2(OEt2) (ArPri4 = C6H3-2,6(C6H3-2,6-iPr2)2) were obtained by the reactions of the lithium thiolates with AlBr3. Their reduction with KC8 or Rieke’s magnesium afforded aluminum thiolates/hydrides or the incorporation of iodine in place of bromine but no Al–Al bond formation.Figure optionsDownload as PowerPoint slide