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Conjugated, trans ‐Spanning Ligands as Models for Multivalent p ‐Phenyleneethynylenes
Author(s) -
Vang Herh G.,
Driscoll Zakarias L.,
Robinson Emily R.,
Green Casey E.,
Bosch Eric,
Bowling Nathan P.
Publication year - 2016
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.201501528
Subject(s) - chemistry , titration , ligand (biochemistry) , crystallography , conjugated system , benzene , proton nmr , ring (chemistry) , metal , pyridine , stereochemistry , inorganic chemistry , medicinal chemistry , organic chemistry , biochemistry , receptor , polymer
A conjugated, pyridine‐containing, phenylethynyl ligand that forms complexes with Ag I and Pd II has been developed. NMR titration studies with Pd II reveal a stoichiometric binding of the ligand to the metal atom, while similar studies with Ag I reveal a binding that is dynamic on the NMR timescale. Analysis of the NMR spectroscopic data by Job's plot analysis and non‐linear curve fitting of a titration curve reveals a 1:1 binding ratio of ligand/silver cation and an association constant of K a = 53 M –1 . X‐ray crystal structures of the ligand–metal complexes suggest ample room for the nearly barrierless rotation of the unsubstituted central benzene ring of the para ‐phenylethynyl chain. Subtle electronic differences in substituted systems provide some evidence of impaired rotation.