IR and Raman Investigation of One-Dimensional and Three-Dimensional Aluminophosphite

IR and Raman spectroscopy have been used to investigate the relationship between vibrational spectra and the structure of one-dimentional (1-D) and three-dimentional (3-D) aluminophosphite materials. The vibrational features of structural units, guest molecules inside the pores including organic amine, ammonium cations, and water molecules, have been studied as well as the host−guest interaction of the species in the pores and the framework. The vibration mode of the 1-D and 3-D aluminophosphite framework in the region of 200−1250 cm-1 shows different features. The band in the range of 1200−1250 cm-1 is supposed to be related to the 3-D aluminophosphite framework P−O vibration. The OH stretch vibration of water molecules shift to low frequency when bonding to framework aluminum or H-bonding (···O−H···O) with framework oxygen. IR (Raman) spectra of templates with strong host−guest interaction with the framework show many complex vibration bands compared with the free ones. The characteristic vibrations of ammonium cations and protonated organic amines H-bonded to framework oxygen atoms are in the 1350−1650 and 2700−3200 cm-1 regions.