DIRECT EVIDENCE FOR MN SUBSTITUTION IN A FRAMEWORK SITE IN MNAPO-11 MOLECULAR-SIEVE FROM THE ADSORBED WATER COORDINATION CONFIGURATION DEDUCED BY ELECTRON-SPIN ECHO MODULATION ANALYSIS

Electron spin echo modulation analysis of 0.1 mol % Mn (relative to P) in MnAPO-11 with adsorbed D2O shows two deuteriums at 0.24 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO4 configuration with a D-O bond orientation for the waters as expected for a negatively charged site. When Mn substitutes for Al in the AlPO4-11 framework it forms a negatively charged site, whereas Mn would form a positively charged site in an extraframework position. Thus the spin echo analysis indicates that Mn at low concentration substitutes in a framework position of MnAPO-11 during synthesis.