Background:
The preparation and use of pyridinyl alcohols as ligands showed incredible increment
in the past three decades. Important property of pyridinyl alcoholato ligands is their strong basicity, which is
mainly due to the lack of resonance stabilization of the corresponding anion. This strongly basic anionic nature
gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a
terminal fashion. They are needed as ligands due to their ability to interact with transition metals both
covalently (with oxygen) and hemilabile coordination (through nitrogen).
Objective:
The review focuses on the wide application of α-pyridinyl alcohols, α,α’-pyridine diols, α-
bipyridinyl alcohols, and α,α’-bipyridine diols as structure motifs in the preparation of important organic
molecules which is due to their strongly basic anionic nature.
Conclusion:
It is clear from the review that in addition to their synthetic utility in the homogeneous and
asymmetric catalytic reactions, the preparation of the crown ethers, cyclic and acyclic ethers, coordinated
borates (boronic esters), pyridinyl-phosphine ligands, pyridinyl-phosphite ligands, and pyridinyl-phosphinite
ligands is the other broad area of application of pyridinyl alcohols. In addition to the aforementioned
applications they are used for modeling mode of action of enzymes and some therapeutic agents. Their strongly
basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only
one metal center in a terminal fashion in the synthesis of transition metal cluster complexes. Not least numbers
of single molecule magnets that can be used as storage of high density information were the result of transition
metal complexes of pyridinyl alcoholato ligands.
A unified picture of the covalent bond within quantum-accurate force fields: From organic molecules to metallic complexes’ reactivity