Dear Junfeng,
I'm not an expert in organometallics but after reading this publication my best guess is that there might be an equilibrium between monomeric and oligomeric tin methoxides:
Peter J. Smith, R.F.M. White
A 119Sn NMR and Mössbauer study of some di- and tri-alkyltin(IV) alkoxides
Journal of Organometallic Chemistry 1972, 40, 341-353.
Doi: 10.1016/S0022-328X(00)93372-2
It could be interesting to record a NOESY spectrum to see if there is exchange?
Best regards,
Johannes Liermann
---------------------------------------------------------------
Dr. rer. nat. Johannes Liermann
Johannes Gutenberg-Universität Mainz
Institut für Organische Chemie
Duesbergweg 10-14
55128 Mainz
Tel. (06131) 39-25466
Fax (06131) 39-25454
mailto:liermann_at_uni-mainz.de
http://www.nmr.oc.chemie.uni-mainz.de/
Von: jfxiang_at_iccas.ac.cn [mailto:jfxiang_at_iccas.ac.cn]
Gesendet: Mittwoch, 11. November 2015 14:29
An: ammrl <ammrl_at_ammrl.org>
Betreff: AMMRL: the assignment of the proton spectrum of tri-n-butyltin methoxide in CDCl3
Dear Colleage
Recently, one Ph D student had asked me the following question: why he couldn't obtain a single resonance for methyl protons in methoxyl group of tri-n-butyltin methoxide? There were always two additional peaks at 3.479 and 3.465 ppm compared with a large peak at 3.624 ppm. At the first glance, I thought there were some contaminants in the sample. The large peak at 3.624 ppm should be assigned to methyl protons in methoxyl group, the additional two small signals may come from other side products. However, when I checked it in the proton spectra library, they both have the same feature. Anyone have comments?
Many thanks!
Junfeng Xiang
NMR Lab
ICCAS China
The spectrum and the molecular structure are appended in the attached file.
Received on Thu Nov 12 2015 - 01:55:24 MST