Halogen-acetylacetonate complexes

Also increasingly common, as CVD precursors, are many halogen-acetylacetonate complexes, such as trifluoro-acetylacetonate thorium, Th(C5H4F302)4, used in the deposition of thoriated tungsten for thermionic emitters, the trifluoro-acetylacetonates of hafnium and zirconium and the hexafluoro-acetylacetonates of calcium, copper, magnesium, palladium, strontium, and yttrium. 

Some cyclopentadienyltitanium complexes react with FeClj or iron acetylacetonate with transfer of the cyclopentadienyl ligand from titanium to iron. The yield of ferrocene also depends on the other ligands on titanium. The yield increases with decreasing number of electron-attractive halogen atoms in the molecule (see Table IV). 

Active catalysts for butadiene polymerization are obtained from aluminium alkyl halides and soluble Co and Co salts and complexes. The structure of the organic grouping attached to the cobalt is not important, but compounds most widely employed are acetylacetonates and carboxylic acid salts such as the octoate and naphthenate. The activity of the catalyst and structure of the polymer are affected by the groupings in the complex. Catalysts from aluminium trialkyls and cobalt salts other than halides are relatively unstable and give syndiotactic 1,2-polybutadiene. If halogens are present, e.g., from CoClj or CoBrj,... 

Chloro- and 1-bromobenzotriazoles halogenate metal acetylacetonates in the y-position with the preservation of the chelate structure or with the formation of complexes with the partial substitution of acetylacetone with benzotriazolyl moiety (96TMC457) (Scheme 61). 

Trichloro(tripyridine)chromium(III), synthesis 36 Tris(3-bromoacetylacetonato)chromium(III), synthesis 37 Cyclopentadienyl tricarbonyl hydrides of chromium, molybdenum, and tungsten, synthesis 38 Trichloro(tripyridine)molybdenum(III), synthesis 39 Potassium octacyanotungstate(IV) 2-hydrate, synthesis 40 Chlorine(CP )-labeled thionyl chloride, silicon tetrachloride, boron chloride, germanium (IV) chloride and phosphorus(III) chloride, synthesis 44 Unipositive halogen complexes, synthesis 46 Monopyridineiodine(I) chloride, synthesis 47 Manganese(III) acetylacetonate, synthesis 49 Triiron dodecacarbonyl, synthesis 52... 

The vanadium group element homoleptic compounds with uM —C bonds are relatively thermally unstable and very sensitive to oxidizing agents and water. They also have the tendency to expand the coordination number as a result of R" or Lewis base (amine, phosphine, etc.) addition. Heteroleptic complexes possessing cyclopentadienyl, halogen, 0x0, acetylacetonate, etc., ligands are usually more thermally stable than homoleptic complexes such as MR4. 

Recent examples of kinetic studies of substitution in organic ligands include a qualitative investigation of the halogenation of the copper(n) complex of 8-hydroxyquinoline by the halogens themselves or by iV-halogenosuccinimides, and the establishment of the relative reactivity of the 3-position of acetylacetone co-ordinated to chromium(m) and to cobalt(m) from the relative rates of nitration and of formylation of the complexes Cr(acac)s and Co(acac)3. ... 

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