Binuclear Salan borate compounds with three-coordinate boron atoms

A series of binuclear boron compounds supported by Salan(tBu)H4 ligands have been prepared. They are of the general formula Salan(tBu)[B(OR)]2. The compounds are Salean(tBu)(BOR)2 [Salean(tBu) = (N,N′-ethylenebis(3,5-di-tert-butyl-salicylamine)), R = Me (1), SiMe3 (4)], Salban(tBu)(BOR)2[Salban(tBu) = (N,N′-butylenebis(3,5-di-tert-butyl-salicylamine)), R = Me (2), SiMe3 (5)], and Salhan(tBu)(BOR)2 [Salhan(tBu) = (N,N′-hexylenebis(3,5-di-tert-butyl-salicylamine)), R = Me (3)]. All of the compounds were characterized by spectroscopic (1H NMR, 11B NMR, IR) and physical (mp, EA) techniques. Also, 1, 2 and 4 were structurally characterized by single crystal X-ray diffraction studies.

Graphical abstractSalan(tBu)H4 ligands react with B(OMe)3 or B(OSiMe3)3 to form Salan(tBu)(BOMe)2 (shown) or Salan(tBu)(BOSiMe3)2 containing three-coordinate boron.Figure optionsDownload full-size imageDownload as PowerPoint slide