Synthesis and Structure of ITQ-3, the First Pure Silica Polymorph with a Two-Dimensional System of Straight Eight-Ring Channels

✍ Scribed by Dr. Miguel A. Camblor; Prof. Dr. Avelino Corma; Dr. Philip Lightfoot; Luis A. Villaescusa; Dr. Paul A. Wright

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 389 KB
• Volume: 36
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.199726591

✦ Synopsis

For example. the 'H NMR spectrum of 3 in [DJbenzene contains sharp signals and, in particular, a downfield NH-singlet at 6=8.83 that is independent of concentration; the corresponding NH-singlet in model (nondimeric) glycolurils is at 6 -5.0 in [DJbenzene. The FTIR spectrum of 3 (benzene, 2 x I @ -1 x 10.'~) showed only the NH stretching absorption at 3229cm..!, which is about 180cm-' lower than that observed for nonassembled glycolurils. From 'H NMR dilution experiments (5 x lo-'-1.5 x 10 ?M). a lower limit for the dimerization constant KD O f IO'M-' was estimated. Solutions of 3 in benzene were analyzed by electrospray mass spectrometry (ESI-MS) and showed, in addition to the signal for monomer 3 at 1268 Da, a fairly strong (ca. 20%) signal for dimer 6 at 2535 Da.

[9] See. for example.