²⁹Si NMR Relaxation of Silicated Nanoparticles in Tetraethoxysilane−Tetrapropylammonium Hydroxide−Water System (TEOS−TPAOH−H₂O)

Abstract

Silicon-29 longitudinal ( T 1 ) and transverse ( T 2 ) NMR relaxation times have been measured in the clear solution precursor of silicalite-1 of composition 25 TEOS−5 TPAOH−400 H 2 O. The nanoparticles as well as the silicate oligomers are giving rise to observable resonances. An unusually long T 1 relaxation time of 126 s is observed for Q 4 in nanoparticles. Proper care for acquisition is therefore required for quantifying the distribution of Q n of the nanoparticles, an essential measurement to follow the nanoparticles connectivity evolution.