This article is about the class of compounds having two imine groups. For compound having the molecular formula N2H2 and often called "diimine", see
diazene.
Diimines are
organic compounds containing two
imine (RCH=NR') groups. Common derivatives are 1,2-
diketones and 1,3-diimines. These compounds are used as
ligands and as precursors to
heterocycles. Diimines are prepared by
condensation reactions where a dialdehyde or diketone is treated with amine and water is eliminated. Similar methods are used to prepare
Schiff bases and
oximes.
1,2-Diimines
Sample of alpha-diimine derived from 2,6-diisopropylaniline and glyoxal.
The 1,2-diketimine ligands also called α-diimines and 1,4-diazabutadienes. They are derived from the condensation of 1,2-diketones and glyoxal with amines, often
anilines.[1]
A substituted 1,2-diimine ligand and an idealized metal complex.
For example,
acetylacetone (2,4-pentanedione) and a primary alkyl- or arylamine will react, typically in acidified ethanol, to form a diketimine.
1,3-Diketimines are often referred to as H
NacNac, a modification of the abbreviation Hacac for the conjugate acid of
acetylacetone. These species form bidentate anionic ligands.
^
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^Asay, Matthew; Jones, Cameron; Driess, Matthias (2011-02-09). "N-Heterocyclic Carbene Analogues with Low-Valent Group 13 and Group 14 Elements: Syntheses, Structures, and Reactivities of a New Generation of Multitalented Ligands†". Chemical Reviews. 111 (2): 354–396.
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^Ittel, S. D.; Johnson, L. K.; Brookhart, M. (2000). "Late-Metal Catalysts for Ethylene Homo- and Copolymerization". Chemical Reviews. 100 (4): 1169–1203.
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