Unambiguously distinguishing Si[3Si,1Al] and Si[3Si,1OH] stuctural units in zeolite by 1H/29Si/27Al triple resonance solid state NMR spectroscopy

Qing Luo; Jun Yang; Wei Hu; Mingjin Zhang; Yong Yue; Chaohui Ye; Feng Deng

doi:10.1016/j.ssnmr.2005.02.004

Unambiguously distinguishing Si[3Si,1Al] and Si[3Si,1OH] stuctural units in zeolite by 1H/29Si/27Al triple resonance solid state NMR spectroscopy

Solid State Nucl Magn Reson. 2005 Jul;28(1):9-12. doi: 10.1016/j.ssnmr.2005.02.004.

Authors

Qing Luo¹, Jun Yang, Wei Hu, Mingjin Zhang, Yong Yue, Chaohui Ye, Feng Deng

Affiliation

¹ Wuhan Institute of Physics and Mathematics, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, The Chinese Academy of Sciences, Wuhan City, Hubei Province 430071, PR China.

PMID: 16026686
DOI: 10.1016/j.ssnmr.2005.02.004

Abstract

We present an experimentally feasible triple-resonance NMR method that establishes the correlation among three different nuclei, avoiding the difficulty to directly explore the weak coupling between two NMR nuclei, such as (29)Si and (27)Al. Using this method, we are able to give an unambiguous assignment to the various peaks in (29)Si CP NMR spectrum of MCM-22 zeolite and discriminate (29)Si signals from SiOHAl and SiOH groups. In addition, in combination with (1)H/(27)Al double-resonance technique, the (1)H/(27)Al/(29)Si triple-resonance experiment suggests the presence of two different kinds of Brönsted acid sites in H-MCM-22 zeolite.