Ligands amidinate

The coordination chemistry of ancillary amidinate ligands with a pyridine functionality has been described. Magnesium, aluminum, zirconium, and lanthanum complexes have been prepared in which the amidinate anions act as tridentate, six-electron-donor ligands Amidinate ligands containing quinolyl substituents were constructed in the coordination sphere of lanthanide... 

Methylenecyclopropanes have been carboxylated with gaseous carbon dioxide in the presence of a stoichiometric amount of nickel(O) complexes [150]. Depending on the polarity of the reaction solvent and the nature of amine ligand (amidine or guanidine base), several reactions pathways have been observed, which may involve either oxidative coupling of CO2 with the C-C double bond of the substrate (see Sect. 5.3) or opening of the three-membered ring and further reaction with the heterocumulene. 

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

Advances in the Coordination Chemistry of Amidinate and Guanidinate Ligands ... 

In addition to the substituents listed in Scheme 1, chiral groups may be introduced and unsymmetrically substituted amidinate anions are also possible. The amidinate anions may also contain additional functional groups, or two such anions can be linked with or without a suitable spacer unit. Yet another variety comprises the amidinate ligands being part of an organic ring system. All these aspects will be covered in the present review. 

The general coordination modes of amidinate and guanidinate (R = NR 2) ligands are shown in Scheme 4. Both ligands display a rich coordination chemistry in which both chelating and bridging coordination modes can be achieved. By far the most common coordination mode is the chelating type A. 

In the presence of N,N,N, N",N"-pentamethyldiethylenetriamine ( = PMDETA), monomeric lithium complexes of bulky formamidinate ligands can be isolated. The compounds (Scheme 12) comprise a Li(PMDETA) center coordinated by a bulky formamidinate in either the E-syn- or E-anti-isomeric form. Two of the structures display coordination of the pendant amidinate imine, and can therefore be considered the first examples of if. r -C = N,N metal amidinate coordination. ... 

A monomeric aluminum amidinate containing asymmetrically substituted ligands has been synthesized as shown in Scheme 26 and isolated in 60% yield as colorless crystals. 

This metathetical route was recently extended to the synthesis of amidinato complexes of Al, Ga, and In containing very bulky amidinate ligands with 2,6-Pr CgHs, adamantyl, m-terphenyl or 9-tiiptycenyl substituents at the central carbon atom. ... 

In a related study, sterically bulky amidinate ligands containing terphenyl substituents on the backbone carbon atoms have been utilized in organoalumi-num chemistry. Mono(amidinate) dialkyl complexes were generated as shown in... 

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