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How Changing the Bridgehead Can Affect the Properties of Tripodal Ligands
Author(s) -
Plajer Alex J.,
Colebatch Annie L.,
Rizzuto Felix J.,
Pröhm Patrick,
Bond Andrew D.,
GarcíaRodríguez Raúl,
Wright Dominic S.
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201802350
Subject(s) - chemistry , ligand (biochemistry) , stereochemistry , reactivity (psychology) , coordination complex , tris , tripodal ligand , group (periodic table) , crystallography , crystal structure , metal , organic chemistry , receptor , alternative medicine , medicine , biochemistry , pathology
Although a multitude of studies have explored the coordination chemistry of classical tripodal ligands containing a range of main‐group bridgehead atoms or groups, it is not clear how periodic trends affect ligand character and reactivity within a single ligand family. A case in point is the extensive family of neutral tris‐2‐pyridyl ligands E(2‐py) 3 (E=C−R, N, P), which are closely related to archetypal tris‐pyrazolyl borates. With the 6‐methyl substituted ligands E(6‐Me‐2‐py) 3 (E=As, Sb, Bi) in hand, the effects of bridgehead modification alone on descending a single group in the periodic table were assessed. The primary influence on coordination behaviour is the increasing Lewis acidity (electropositivity) of the bridgehead atom as Group 15 is descended, which not only modulates the electron density on the pyridyl donor groups but also introduces the potential for anion selective coordination behaviour.