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 (cyclohexylamin e, 4-picoline, 3-picoline, piperidine, morpholine, isobutylamine, meth ylamine, dimethylamine, isoquinoline and benzylamine) have been prepar ed by reaction of stoichiometric quantities of ligand and triarylborox ine in Et(2)O at room temperature. All 19 adducts have been characteri zed 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-ra y diffraction study. Solid-state B-11 MAS NMR results for PTB and its adducts with cyclohexylamine and isoquinoline are reported. In solutio n-variable temperature H-1 NMR of the morpholine, cyclohexylamine, iso quinoline and benzylamine adducts of PTB and MXB indicate that a ligan d dissociation-recombination process is occurring with Delta G(double dagger) of ca 43-49 kJ mol(-1).