SYNTHESIS AND CHARACTERIZATION OF AMINE ADDUCTS OF TRI(4-TOLYL)BOROXINE AND TRI(3,5-XYLYL)BOROXINE - MOLECULAR-STRUCTURE OF (4-MEC(6)H(4))(3)B3O3-CENTER-DOT-CYCLOHEXYLAMINE

19 1:1 adducts of the triarylboroxines (4-MeC(6)H(4))(3)B3O3 (PTB) and (3,5-Me(2)C(6)H(3))(3)B3O3 (MXB) With N-donor ligands (cyclohexylamine, 4-picoline, 3-picoline, piperidine, morpholine, isobutylamine, methylamine, dimethylamine, isoquinoline and benzylamine) have been prepared by reaction of stoichiometric quantities of ligand and triarylboroxine in Et(2)O at room temperature. All 19 adducts have been characterized by elemental analysis, M pt, IR and H-1 and C-13 NMR. C6H11 NH2 . PTB has been characterized in the solid state by a single-crystal X-ray diffraction study. Solid-state B-11 MAS NMR results for PTB and its adducts with cyclohexylamine and isoquinoline are reported. In solution-variable temperature H-1 NMR of the morpholine, cyclohexylamine, isoquinoline and benzylamine adducts of PTB and MXB indicate that a ligand dissociation-recombination process is occurring with Delta G(double dagger) of ca 43-49 kJ mol(-1).