Please use this identifier to cite or link to this item: https://doi.org/10.1016/j.tet.2005.01.027
Title: Conformational behavior of dithia[n.3.3](1,3,5)cyclophanes and dithia[n.3.3](1,2,6)cyclophanes
Authors: Xu, J.-W.
Lin, T.-T.
Lai, Y.-H. 
Keywords: (1,2,6)Cyclophane
(1,3,5)Cyclophane
Conformation
Issue Date: 28-Feb-2005
Citation: Xu, J.-W., Lin, T.-T., Lai, Y.-H. (2005-02-28). Conformational behavior of dithia[n.3.3](1,3,5)cyclophanes and dithia[n.3.3](1,2,6)cyclophanes. Tetrahedron 61 (9) : 2431-2440. ScholarBank@NUS Repository. https://doi.org/10.1016/j.tet.2005.01.027
Abstract: The conformational behavior of a series of crown-fused dithia[n.3.3](1,2,6) cyclophanes (126-CPs) and dithia[n.3.3](1,3,5)cyclophanes (135-CPs) was investigated by variable-temperature 1H and 13C NMR spectroscopy, X-ray crystallography and density functional theory (DFT) calculations. Single crystal X-ray structure analysis showed that two thia-bridges in 126-CPs adopted a pseudochair-pseudochair (cc) conformation and the cyclophane decks underwent a ring-tilting motion in the case of [10.3.3](1,2,6)cyclophane (1a). In contrast, the thia-bridges in 135-CPs took both cc and pseudoboat-pseudochair (bc) conformations, and the ring-tilting process was also found in [10.3.3](1,3,5)cyclophane (2a). Variable temperature 1H NMR study revealed that there was no wobbling-motion for two thia-bridges in 126-CPs while thia-bridges in 135-CPs experienced a wobbling-process with a conformational barrier of 9.21 and 8.80 kcal mol -1, respectively, for 2a and [13.3.3](1,3,5)cyclophane (2b). DFT calculations for the two cyclophanes series revealed that 126-CPs preferred a cc conformation which was consistent with the experimental observation; similarly, 135-CPs took a preferential cc conformation, agreeing with 2a having a predominant cc conformer (cc:bc ratio=70:30), but not 2b having a predominant bc conformer (cc:bc ratio=15:85) in the solid state. © 2005 Elsevier Ltd. All rights reserved.
Source Title: Tetrahedron
URI: http://scholarbank.nus.edu.sg/handle/10635/93357
ISSN: 00404020
DOI: 10.1016/j.tet.2005.01.027
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

SCOPUSTM   
Citations

11
checked on Dec 17, 2018

WEB OF SCIENCETM
Citations

10
checked on Dec 17, 2018

Page view(s)

29
checked on Nov 23, 2018

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.