An NMR Study of Trimethylsilylmethyllithium Aggregates and Mixed Trimethylsilylmethyllithium/Lithium trimethylsilylmethoxide Aggregates

An NMR spectroscopy study of trimethylsilylmethyllilthium, TMSM-Li, indicates that TMSM-Li exists as two different aggregates in cyclopentane solution. Using previously reported colligative properties of TMSM-Li in different solutions in connection with new 13C and 6Li NMR data collected in this study, aggregation states were assigned as octamer and hexamer. Low temperature 13C and 6Li NMR peak intensities indicated an equilibrium exists between the two aggregates that shifts toward the octamer as the temperature decreases. ΔH was calculated to be 5.23 + 0.15 kcal/mol and ΔS was calculated to be 17.9 + 0.6 eu for the hexamer/octamer equilibrium system. Samples of TMSM-Li were mixed with TMSM-OH in attempts to form mixed alkyllithium/lithium alkoxide aggregates. 13C NMR data for these mixtures gave inconclusive results whether or not these compounds formed, which is different from other primary alkyllithium compounds studied in the past. A study of neopentyllithium, NpLi, indicates only one aggregate in solution with the aggregation state unknown using low temperature 13C NMR spectroscopy.

Grantor dc:publisher

University of North Texas

Year dc:date

2004

Author dc:creator

• Medley, Marilyn S.

Contributors dc:contributor

• Thomas, Ruthanne D.
• Omary, Mohammad

• Organolithium compounds.
• Aggregation (Chemistry)
• NMR spectroscopy
• aggregates
• organolithium
• trimethylsilylmethyl

Statement dc:rights

• Use restricted to UNT Community
• Copyright
• Medley, Marilyn S.
• Copyright is held by the author, unless otherwise noted. All rights reserved.

Language dc:language

English

Identifier

oclc: 58796381
https://digital.library.unt.edu/ark:/67531/metadc4657/
ark: ark:/67531/metadc4657

OAI identifier oai:identifier

info:ark/67531/metadc4657