91165-41-2Relevant academic research and scientific papers
Structure and Dynamics of Crowns containing the Phenyldinaphthylmethane Subunit (a Three-bladed Propeller): Observations of Correlated Rotation of The Propeller Blades and Certain Ether Segments
Lockhart, Joyce C.,McDonnell, Martin B.,Clegg, William,Hill, M. N. Stuart
, p. 639 - 650 (2007/10/02)
We describe some crowns (dinaphthopolyoxacycloalkanins) containing the phenyldinaphthylmethane subunit, regarded as a propeller, the aryl rings (blades) of which are fluxional, twisting about the aryl-methine bonds.This torsional propeller movement is flu
Comparison of the Steric Barriers in Three- and Two-Bladed Propeller Crowns
Clegg, William,Lockhart, Joyce C.,McDonnell, Martin B.
, p. 1019 - 1024 (2007/10/02)
The propeller crowns (2) and (4) (dinaphthopolyoxacycloalkanins) have been characterised by single crystal X-ray structure determinations.Only one enantiomeric pair of isomers is present in each crystal structure.The presence of the trimethoxyphenyl substituent in (4) has remarkably little effect on the conformation of the ether ring.The propeller skeleton of (4) is different from that observed previously in the o-methoxyphenyl propeller; these two skeletal isomers are related by a two-ring flip of one naphthyl and the phenyl ring.Room-temperature 1H n.m.r. spectra of (4) and of the 6-t-butyldinaphthylpolycycloalkanin correspond to one 'averaged' species with a rapid averaging of naphthyl rings via a two-ring flip, slowed at 220 K.The relative steric demands of the propeller and the ether moieties are discussed.
Propeller Substituents imposing Steric Restraint on Crown Ethers
Lockhart, Joyce C.,McDonnell, Martin B.,Clegg, William
, p. 365 - 367 (2007/10/02)
Crown ethers with steric restraint imposed by a three-bladed propeller substituent have been synthesised and the X-ray crystal structures of one example and its NaNCS complex indicate approximately the same conformation of the propeller but quite different conformations of the ether ring in the two; n.m.r. solution spectra indicate that the flipping of the propeller and of the crown moieties are mutually restricted in these crown ethers.
