High-resolution laser-induced fluorescence spectra of 7-azaindole-water complexes and 7-azaindole dimer

The geometric structures of 7-azaindole-water complexes, (7-AzI)-(H2O)(n) (n = 1-3), and 7-AzI dimer were investigated by laser-induced fluorescence (LIF) spectroscopy with high resolution (similar to 0.01 cm(-1)). For the 7-AzI-(H2O), complexes (n = 1-3), the LIF spectra show partially resolved rotational structure, which has been analyzed in combination with theoretical calculations. This analysis yields the rotational constants and characterizes the structures. In 7-AzI-(H2O)(1), the H2O molecule is located in the molecular plane, forming a six-membered ring with two hydrogen bonds. Analyses for 7-AzI-(H2O)(2) and -(H2O)(3) show, furthermore, that both the second and the third H2O are located in the molecular plane of 7-AzI, forming a network ring of hydrogen bonds. For the 7-AzI dimer, the LIF spectrum shows an unresolved rotational envelope. The rotational contour has been analyzed, and we discuss the dimer's likely structure.