Exploring structural and conformational behaviour of cyclophanes incorporating imidazole-2-thiones

Research output: Contribution to journalArticle

Abstract

New cyclophanes containing two imidazole-2-thione moieties linked by two xylylene groups have been synthesized by the reaction of imidazolium-linked cyclophanes with sulfur in the presence of K2CO3. The conformational behaviour of the new cyclophanes was explored by NMR spectroscopy and X-ray diffraction studies. In cyclophanes containing o-xylylene or 2,4,6-trimethyl-m-xylylene linking groups, the imidazole-2-thione groups were mutually syn in both the solid state and in solution, the cyclophanes adopting a conformation reminiscent of the cone conformation of calix[4]arenes. Cyclophanes containing p-xylylene or m-xylylene linking groups exhibited two conformations in solution, one in which the imidazole-2-thione groups are mutually syn, the other in which they are mutually anti, and these conformations did not interconvert on the NMR timescale. Both conformations co-crystallised in the m-xylylene linked cyclophane, while for the p-xylylene-linked cyclophane the anti conformation crystallised separately.

Original languageEnglish
Pages (from-to)2956-2966
Number of pages11
JournalTetrahedron
Volume74
Issue number24
DOIs
Publication statusPublished - 14 Jun 2018

Fingerprint

Thiones
Conformations
Sulfur
X-Ray Diffraction
Magnetic Resonance Spectroscopy
Nuclear magnetic resonance spectroscopy
imidazole
Cones
Nuclear magnetic resonance
X ray diffraction

Cite this

@article{3792ca4c8cb24b8ab8f06b4e3bc020cb,
title = "Exploring structural and conformational behaviour of cyclophanes incorporating imidazole-2-thiones",
abstract = "New cyclophanes containing two imidazole-2-thione moieties linked by two xylylene groups have been synthesized by the reaction of imidazolium-linked cyclophanes with sulfur in the presence of K2CO3. The conformational behaviour of the new cyclophanes was explored by NMR spectroscopy and X-ray diffraction studies. In cyclophanes containing o-xylylene or 2,4,6-trimethyl-m-xylylene linking groups, the imidazole-2-thione groups were mutually syn in both the solid state and in solution, the cyclophanes adopting a conformation reminiscent of the cone conformation of calix[4]arenes. Cyclophanes containing p-xylylene or m-xylylene linking groups exhibited two conformations in solution, one in which the imidazole-2-thione groups are mutually syn, the other in which they are mutually anti, and these conformations did not interconvert on the NMR timescale. Both conformations co-crystallised in the m-xylylene linked cyclophane, while for the p-xylylene-linked cyclophane the anti conformation crystallised separately.",
keywords = "Conformations, Cyclophanes, Imidazole-2-thiones, Imidazolium salts",
author = "Mageed, {Ahmed H.} and Skelton, {Brian W.} and Sobolev, {Alexandre N.} and Baker, {Murray V.}",
year = "2018",
month = "6",
day = "14",
doi = "10.1016/j.tet.2018.04.074",
language = "English",
volume = "74",
pages = "2956--2966",
journal = "Tetrahedron",
issn = "0040-4020",
publisher = "Pergamon",
number = "24",

}

Exploring structural and conformational behaviour of cyclophanes incorporating imidazole-2-thiones. / Mageed, Ahmed H.; Skelton, Brian W.; Sobolev, Alexandre N.; Baker, Murray V.

In: Tetrahedron, Vol. 74, No. 24, 14.06.2018, p. 2956-2966.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Exploring structural and conformational behaviour of cyclophanes incorporating imidazole-2-thiones

AU - Mageed, Ahmed H.

AU - Skelton, Brian W.

AU - Sobolev, Alexandre N.

AU - Baker, Murray V.

PY - 2018/6/14

Y1 - 2018/6/14

N2 - New cyclophanes containing two imidazole-2-thione moieties linked by two xylylene groups have been synthesized by the reaction of imidazolium-linked cyclophanes with sulfur in the presence of K2CO3. The conformational behaviour of the new cyclophanes was explored by NMR spectroscopy and X-ray diffraction studies. In cyclophanes containing o-xylylene or 2,4,6-trimethyl-m-xylylene linking groups, the imidazole-2-thione groups were mutually syn in both the solid state and in solution, the cyclophanes adopting a conformation reminiscent of the cone conformation of calix[4]arenes. Cyclophanes containing p-xylylene or m-xylylene linking groups exhibited two conformations in solution, one in which the imidazole-2-thione groups are mutually syn, the other in which they are mutually anti, and these conformations did not interconvert on the NMR timescale. Both conformations co-crystallised in the m-xylylene linked cyclophane, while for the p-xylylene-linked cyclophane the anti conformation crystallised separately.

AB - New cyclophanes containing two imidazole-2-thione moieties linked by two xylylene groups have been synthesized by the reaction of imidazolium-linked cyclophanes with sulfur in the presence of K2CO3. The conformational behaviour of the new cyclophanes was explored by NMR spectroscopy and X-ray diffraction studies. In cyclophanes containing o-xylylene or 2,4,6-trimethyl-m-xylylene linking groups, the imidazole-2-thione groups were mutually syn in both the solid state and in solution, the cyclophanes adopting a conformation reminiscent of the cone conformation of calix[4]arenes. Cyclophanes containing p-xylylene or m-xylylene linking groups exhibited two conformations in solution, one in which the imidazole-2-thione groups are mutually syn, the other in which they are mutually anti, and these conformations did not interconvert on the NMR timescale. Both conformations co-crystallised in the m-xylylene linked cyclophane, while for the p-xylylene-linked cyclophane the anti conformation crystallised separately.

KW - Conformations

KW - Cyclophanes

KW - Imidazole-2-thiones

KW - Imidazolium salts

UR - http://www.scopus.com/inward/record.url?scp=85046667086&partnerID=8YFLogxK

U2 - 10.1016/j.tet.2018.04.074

DO - 10.1016/j.tet.2018.04.074

M3 - Article

VL - 74

SP - 2956

EP - 2966

JO - Tetrahedron

JF - Tetrahedron

SN - 0040-4020

IS - 24

ER -