Probing solvation-shell hydrogen binding in glassy and sol-gel matrixes through vibronic sideband luminescence spectroscopy

The luminescence spectrum from Gd(III) contains vibronic sidebands that provide the vibrational frequencies of molecules that comprise the solvation shell surrounding this cation. The vibronic sidebands obtained from Gd(III) in porous sol-gel matrixes as a function of added glycerol and in trehalose-derived glassy matrixes are used to probe matrix- and solvent-induced changes in the hydrogen bonding between first- and second-shell solvent molecules. The results provide direct insight into the origin of the damped dynamics observed for guest proteins within these types of matrixes. The results are also consistents with the retention of water within the first solvation shell for both the glassy matrixes and the glycerol-bathed sol-gel.