Synthesis and structures of Salen-supported borates containing siloxides

The ligand N,N"-bis(2-hydroxybenzylidene)diethylenetriamine (SalenN(3)H(3)) was used to prepare the compound SalenN(3)H{B(OMe2)}(2) (1) which could, in turn, be used in the formation of SalenN(3)H{B(OSiPh3)(2)}(2) (2). For comparative purposes, the compounds Salben{B(OSiPh3)(2)}(2) (3) (Salben = N,N'-butylenebis(2-hydroxybenzylideneamine), Salen(Bu-t){B(OSiPh3)(2)}(2) (4) (Salen(Bu-t) = N,N'-ethylenebis(3,5-di-tert-butyl-2-hydroxy-benzylideneamine) and Salben(Bu-t){B(OSiPh3)(2)}(2) (5) (Salben(Bu-t) = N,N'-butylenebis(3,5-di-tert-butyl-2-hydroxybenzylideneamine) were prepared. In reactions where the siloxide is (HO)(2)SiPh2, unique dimeric siloxide-bridged compounds result, [Salpten(Bu-t){B(O2SiPh2}](2) (6) and [SalenN(3)H{B(O2SiPh2)}](2) (7). Compound 6 possesses a zeolite-like cavity having a volume of 157 Angstrom(3). All Of the compounds were characterized by physical (mp, analyses) and spectroscopic techniques (H-1 and B-11 NMR, IR) and, in the case of 1, 3, 4, and 6, by X-ray crystallography.