Salen-supported dinuclear and trinuclear boron compounds

Abstract Six boron compounds have been synthesized through the combination of phenylboronic acid and various Salen ( N , N ′-ethylenebis(2-hydroxy)benzylidenimine) ligands. They contain seven- and eight-membered heterocycles with a bridging oxygen and have the formula: L[(PhB) 2 (μ-O)] (L=Acmen ( 1 ), Salen( t Bu) ( 2 ), Sal(2-OH)pen ( 3 ), Salpen( t Bu) ( 4 ), Acpen ( 5 )) and L[B 2 (μ-O)(O 2 BPh)] (L=Acen ( 6 ), Salmen ( 7 )). Compounds 6 and 7 are interesting trinuclear boron derivatives with two four-coordinate and one three-coordinate boron atoms. The compounds have been characterized by MP, MS, IR, EA and 1 H- and 11 B-NMR, by 11 B-MAS for 6 and 7 and by X-ray crystallography for 2 , 4 – 7 .