A PROTON MAGNETIC RESONANCE LIGAND PREFERENCE STUDY OF COMPLEXES OF ACETONE DIETHYL ETHER N,N-DIMETHYLFORMAMIDE DIMETHYL SULFOXIDE TETRAHYDROFURAN TETRAMETHYLENE SULFONE TETRAMETHYLENE SULFOXIDE AND TETRAMETHYLUREA WITH BORON TRIFLUORIDE

A proton magnetic resonance ligand preference study of complexes of acetone (A), diethyl ether (EE), N,N-dimethylformamide (DMF), dimethyl sulfoxide(DMSO), tetrahydrofuran (THF), tetramethylene sulfone (TMSO2), tetramethylene sulfoxide (TMSO), and tetramethylurea (TMU) with boron trifluoride has been completed. By addingboron trifluoride to pure, excess ligand and cooling to temperatures suitable to slow solvent exchange, proton magnetic resonance signals were observed for bulk and complexed ligand molecules. By studying samples containing two organic bases and integrating all signal areas, a direct, quantitative measure was made of the amount of boron trifluoride complexed by each component. In this way complexing ability was estimated to decrease in the order TMSO > DMF, DMSO > TMU;≫ THF ≫ EE > A > TMSO2. This order reflects the relative basic strengths of these molecules toward BF3. © 1969, American Chemical Society. All rights reserved.