High field {sup 31}P ENDOR of MnAlPO{sub 4}-20: Direct evidence for framework substitution

Journal Article · Wed Jun 30 04:00:00 EDT 1999 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja990365n· OSTI ID:20000111

Arieli, D; Vaughan, D E.W.; Strohmaier, K G; Goldfarb, D

The incorporation of Mn(II) into framework sites in the aluminophosphate zeotype AlPO{sub 4}-20, an analog of sodalite, has been investigated using pulsed electron nuclear double resonance (ENDOR) spectroscopy at 95 GHz. The field sweep echo-detected EPR spectrum showed the presence of a single Mn(II) site with a {sup 55}Mn hyperfine coupling of 8.7 mT. ENDOR spectra, recorded using the Mims and Davies sequences, consist of an {sup 27}Al signal at the Larmor frequency and a {sup 31}P Larmor frequency indicates that it originates from the M{sub s} = {+-}1/2 manifolds and that the interaction is primarily isotropic. The relatively large {sup 31}P hyperfine interaction and the weak interaction with {sup 27}Al provide unique and direct evidence for Mn(II) substitution of framework Al. X-band electron spin echo envelope modulation (ESEEM) measurements showed only signals at the {sup 1}H, {sup 14}N, {sup 27}Al, and {sup 31}P Larmor frequencies. The first two are due to weak dipolar interaction with the template molecules, while the others reflect interactions with the framework.

• Research Organization: Weizmann Inst. of Science, Rehovot, (IL)
• OSTI ID: 20000111
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 25 Vol. 121; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM PHOSPHATES
CRYSTAL STRUCTURE
MANGANESE
MOLECULAR SIEVES
NUCLEAR MAGNETIC RESONANCE
PHOSPHORUS 31