Al-27 MAS NMR and XAS cross-study of the aluminophosphonate Al(OH)(O3PC6H5)

An aluminium phenylphosphonate, has Al(OH)(O3PC6H5), been studied. Its poor long-range crystallographic organisation required the use of local probe techniques such as P-31 and Al-27 MAS NMR and XAS. An unexpectedly narrow and symmetric Al-27 MAS NMR signal was obtained, with an isotropic chemical shift that has not been observed earlier in aluminium phosphonates. XANES and EXAFS studies showed unambiguously that this signal had to be attributed to a five-fold coordination site, the first observed for a phosphonato-aluminum atom.