The Hydrates of TEMPO: Water Vibrations Reveal Radical Microsolvation

An organic radical monohydrate complex is detected in vacuum isolation at low temperature by FTIR supersonic jet spectroscopy for the first time. It shown to exhibit a rich conformational and vibrational coupling dynamics, which can be drastically reduced appropriate isotope substitution. Its detection with new gas recycling infrared spectrometer demonstrates thermal metastability of gaseous TEMPO even under humid conditions. Compared its almost isoelectronic isostructural, closed shell ketone analogue, hydrogen bond solvating water found less directional, but stronger more strongly downshifting bonded OH stretch vibration. A second solvent directs one into metastable position solvate nitrogen center same