X-ray structure and conformational study of tris(2-(dimethylamino)phenyl)methanol: Roles of hydrogen bond in conformational conversions of molecules

• Tris(2-(dimethylamino)phenyl)methanol was synthesized and characterized.
• The X-ray crystal structure of the 2-syn/1-anti conformer is reported.
• Variable-temperature 1H NMR studies indicate four conformers in solution.
• Intra-molecular hydrogen bond affects inter-conversions between conformers.
• Mechanisms of intra- and inter-conformational conversions are proposed.

Tris(2-(dimethylamino)phenyl)methanol, (2-(Me)2N-C6H4)3COH, was synthesized and characterized by using NMR, EA and ESI-MS. Single crystal of the 2-syn/1-anti conformer of the tertiary alcohol was obtained and analyzed by X-ray diffraction. The variable-temperature 1H NMR experiments reveal that, in solution, the tertiary alcohol is an equilibrium mixture of four conformers, all-syn, 2-syn/1-anti, 1-syn/2-anti and all-anti. The results show that hydrogen bond plays an important role in both intra- and inter-conformational conversions of molecules. The intra-conformational conversions within specific conformers are just helical changes. The inter-conformational conversions between conformers occurred via one-ring flip process.

Roles of hydrogen bond in conformational conversions of tris(2-(dimethylamino)phenyl)methanol: synthesis, X-ray structure and conformational study by variable-temperature 1H NMR spectroscopy.Figure optionsDownload as PowerPoint slide