Acetylacetone coordination compounds with

To synthesize coordination compounds with weak ligands, methods have been developed whereby water is either absent from the start or is removed through a chemical reaction/ In this contribution the preparation of coordination compounds of some divalent metals with nitromethane, ethanol, acetone, diphenyl sulfoxide, and acetonitrile are described. These descriptions are merely examples of simple general methods for the preparation of coordination compounds of Mg, Mn, Fe, Co, Ni, Cu, Zn, and Cd with weak ligands, such as those mentioned above and acetic acid, nitrobenzene, hydrogen cyanide, tetrahydrofurane, dioxane, diglyme (l,l-oxybis[2-methoxyethane]), 1,4,7,10,13,16-hexa-oxacyclooctadecane (18-trown-6), ethyl acetate, and 2,4-pentanedione (acetylacetone in the neutral ketonic form). ... 

The methine proton in the keto form and the hydroxyl proton in the enol form of jS-diketones are acidic and their removal generates 1,3-diketonate anions (2), which are the source of an extremely broad class of coordination compounds referred to generically as diketonates or acetylacetonates. The synthesis, structure and properties of these compounds form the focus of this chapter. Di-ketonate anions are powerful chelating species and form complexes with virtually every transition and main group element. The scope of this chemistry is very large and it has been assessed earlier in several excellent reviews.9-14... 

A large class of coordination compounds, metal chelates, is represented in relation to microwave treatment by a relatively small number of reported data, mainly p-diketonates. Thus, volatile copper) II) acetylacetonate was used for the preparation of copper thin films in Ar — H2 atmosphere at ambient temperature by microwave plasma-enhanced chemical vapor deposition (CVD) [735a]. The formed pure copper films with a resistance of 2 3 pS2 cm were deposited on Si substrates. It is noted that oxygen atoms were never detected in the deposited material since Cu — O intramolecular bonds are totally broken by microwave plasma-assisted decomposition of the copper complex. Another acetylacetonate, Zr(acac)4, was prepared from its hydrate Zr(acac)4 10H2O by microwave dehydration of the latter [726]. It is shown [704] that microwave treatment is an effective dehydration technique for various compounds and materials. Use of microwave irradiation in the synthesis of some transition metal phthalocyanines is reported in Sec. 5.1.1. Their relatives - porphyrins - were also obtained in this way [735b]. 

While reports in the literature (13, 14, 15, 16, 23) invariably stress the connection between coordination and enhanced stability, Block (3) cites some interesting examples in which coordination does not improve the thermal stability of the ligand. He discusses the work on acetylace-tone (5), which when heated for several hours at 265°C. in a sealed, evacuated glass tube, degrades very little as judged by the amount of volatile products generated. On the other hand, the coordination compounds of Cu(II), Ni(II), Co(II), and Mn(III) decompose appreciably at this temperature. This is in line with the results of Berg and Truemper (2), who found that the acetylacetonate complexes of Ni(II) and Cu(II) decompose in air at 230°C. 

Fig. 7. Vanadium X edge absorption spectra for compounds with vanadium in various oxygen coordinations OO, acetylacetonate. From Doniach et al. (80).

The interaction of beryllium acetylacetonate with bis(acetoacetyl) compounds leads to coordination polymers. With bis(acetoacetyl)phenyl ether in dimethylformamide the reaction was found to be reversible [214], viz. 

Very many coordination compounds are known between metal atoms and bifunctional organic molecules, where the binding is partly normal covalent links and partly coordinate links for example, copper acetate solution mixed with acetylacetone gives a blue compound that is non-ionized and can be vaporized unchanged. It can be formulated ... 

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. 

Cis-molybdenum(VI) dioxide forms biscatecholate coordination compounds. The third position is already blocked by the two cis-oriented oxo ligands. The reaction of bis(acetylacetonate) cis-dioxomolybdenum with carbonyl-substituted catecholates in the presence of lithium carbonate results in the formation of bis catecholate cis-dioxomolybdenum(VI) complexes that are in equilibrium with their dimers. 

The polymerization o oxetanes with cationic catalysts has been studied by many investigators. (1.H2) RoseC. ), in particular, first reported the homopolymerization of the parent compound, tri-methylene oxide (TMO), with a Lewis acid catalyst, boron trifluoride. The use of coordination catalysts to polymerize oxetanes has been reported in the patent literature by Vandenberg.W In this work, Vandenberg polymerized oxetanes with the aluminum trialkyl -water-acetylacetone coordination catalyst (referred to as chelate catalyst) that he discovered for epoxide polymerization . This paper describes the homo- and co-polymerization of TMO with these coordination catalysts. Specific TMO copolymers, particularly with unsaturated epoxides such as allyl glycidyl ether (AGE), are shown to provide the basis for a new family o polyether elastomers. These new elastomers are compared with the related propylene oxide-allyl glycidyl ether (PO-AGE) copolymer elastomers. The historical development and general characteristics of polyether elastomers and, in particular, the propylene oxide elastomers, are reviewed below. 

Monodisperse CoFe204 nanocrystals are synthesized by using a combination of a nonhydrolytic process and seed-mediated growth [227]. The general strategy is using coordination compounds of iron(III) and cobalt(II) acetylacetonate, Fe(acac)3 and Co(acac)2, as precursors in a nonhydrolytic process to synthesize CoFe204 spherical nanocrystals with a mean diameter of ca. 5 nm. Such nanocrystals then serve as seeds... 

In chelation complexes (sometimes called inner complexes when uncharged) the central metal ion coordinates with a polyfunctional organic base to form a stable ring compound, e.g. copper(II) acetylacetonate or iron(III) cupferrate ... 

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