POLYDENTATE AMINE AND ETHER SOLVATES OF LITHIUM HEXAMETHYLDISILAZIDE (LIHMDS) - RELATIONSHIP OF LIGAND STRUCTURE, RELATIVE SOLVATION ENERGY, AND AGGREGATION STATE

Li-6, N-15, and C-13 NMR spectroscopic investigations of [Li-6, N-15]l ithium hexamethyldisilazide ([Li-6, N-15]LiHMDS) coordinated by 29 pol yamines, polyethers, and aminoethers reveal a range of structural type s including eta(1)-coordinated mono- and disolvated dimers, eta(2)-coo rdinated (3-coordinate) monomers, eta(1),eta(2)-coordinated (4-coordin ate) monomers, eta(2),eta(2)-coordinated (5-coordinate) monomers, poly mers (linked dimers), triple ions, and solvent-separated ion pairs. Li gand binding constants on the LiHMDS monomers shed light on chelate ri ng size and steric effects, aza- and oxaphilicity, mechanisms and rate s of ligand substitution, and the ''macrocyclic effect.''