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A Strategy for Controlling the Central Torsion Angle in Biphenyl‐Based Molecular‐Scale Bridges
Author(s) -
Benniston Andrew C.,
Harriman Anthony,
Patel Pritesh V.,
Sams Craig A.
Publication year - 2005
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200500550
Subject(s) - chemistry , dihedral angle , biphenyl , crown ether , acetonitrile , alkali metal , ether , titration , ligand (biochemistry) , torsion (gastropod) , crystallography , molecule , inorganic chemistry , hydrogen bond , organic chemistry , ion , medicine , biochemistry , receptor , surgery
The synthesis of a series of crown ether ligands ( C4 – C6 ) based upon the 2,2′‐biphenyl unit is described. In the series, the length of the polyether chain connecting the two oxygen atoms increases progressively. These polyethers are moderately fluorescent in acetonitrile solution, but this emission is partially quenched upon the addition of various alkali metal cations. Spectrofluorimetric titrations performed with MClO 4 (M = Li + , Na + ) or KPF 6 show that binding to crown ethers C4 – C6 involves the formation of a 1:1 cation/ligand complex. The geometry of the resultant complex depends on the nature of the bound cation and also on ionic strength. In particular, the photophysical properties of the polyether are sensitive to the torsion angle around the central connector in the biphenyl group. This approach, therefore, could be used to systematically vary the dihedral angle for biphenyl‐based molecular‐scale bridges. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)