Infrared vibrational spectra of tert-butyl halides in low-aluminum H-Y Faujasite: Vibrational excitation exchange and other effects of guest-host interactions

Fourier transform infrared (FTIR) studies at 295 K of low-aluminum H-Y (LAHY, Si/Al = 40) faujasite zeolite supercage-included tert-butyl halides, (CH3)3C-X (X = Cl, Br, I), are presented in comparison with the adsorbate molecular gas-phase and unloaded host solid-state spectra. The FTIR results, aided by computer modeling studies, reveal a propensity toward the exchange of quanta of vibrational excitation between guest modes, and between guest and host modes. The exchange phenomenon and some pseudo-hydrogen bonding effects are related to the siting of the guest molecules in the host supercage, and to the guest-host interactions at the guest site.