Copper II acetylacetonate

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 ... 

Copper (II) -acetylacetonate complex (Resonating ring compound)... 

Nasibulin AG, Richard 0, Kauppinen El, Brown DP, Jokiniemi JK, Altman IS (2002) Nanoparticle synthesis by copper (II) acetylacetonate vapor decomposition in the presence of oxygen. Aerosol Sci Technol 36 899-911... 

Cobalt (III) acetylacetonate [Co(acac)3] (14), manganese (III) acetylacetonate [Mn(acac)3] (15), iron(III) acetylacetonate [Fe(acac)3] (30), chromium(III) acetylacetonate [Cr(acac)3] (13), nickel(II) acetylacetonate [Ni(acac)2] (8), and copper (II) acetylacetonate [Cu(acac)2] (18) were prepared and purified. Cobalt, manganese, iron, chromium, nickel, and copper naphthenates were all commercially available. 

It has been noted that for the ammonium ylide generation copper catalysts such as copper(ii) acetylacetonate [Cu(acac)2] and Cu(hfacac)2 are superior over Rh(ii) catalysts. Sweeney and co-workers have recently reported copper-catalyzed [2,3]-sigmatropic rearrangement of ammonium ylide generated from tetrahydropyridines 150 and diazo ester 129 (Equation (22)). A detailed study on the reaction conditions has revealed that Cu(acac)2 is the best catalyst for this reaction. 

Values of y are not given because there is some uncertainty as to the value of AE(Eg). In the case of copper(II) acetylacetonate, which is one of the few systems where the signs of A and B as well as the magnitudes have been determined, there are three bands observed in the visible spectrum at 14,900 cm-1, 18,200 cm-1 and 25,800 cm-1. It seems likely that AE(Blg) = 14,900 cm 1 and this value was used in computing values in Table IV. 

The electrophilic substitution of P-diketonate complexes appears to occur as for arenes, and a process involving initial coordination of the electrophile, followed by an intramolecular group transfer, has not been observed, although it has been postulated for the reaction of copper(II) acetylacetonate with thioacetals (equation 14).31... 

Other reagents that have been used to reduce support-bound aromatic nitro compounds include phenylhydrazine at high temperatures (Entry 5, Table 10.12), sodium borohydride in the presence of copper(II) acetylacetonate [100], chromium(II) chloride [196], Mn(0)/TMSCl/CrCl2 [197], lithium aluminum hydride (Entry 3, Table... 

A few examples are available in which regiocontrol in the cyclopropanation of non-conjugated diene is catalyst-dependent. An early example is showed in equation 118. Copper(II) triflate catalysed cyclopropanation of diene 132 with diazomethane occurs preferentially at the less substituted double bond, whereas copper(II) acetylacetonate in contrast promotes cyclopropanation at the more substituted double bond (equation 118)13. Regiocontrol in the cyclopropanation of norbornene derivative 133 is strongly catalyst-dependent (equation 119). When diphenyldiazomethane is used as carbenoid precursor, the regioselectivity of this cyclopropanation is significantly enhanced165. 

Under optimized conditions, e.g. 20 mol% 219 and pure copper(II) acetylacetonate (5 mol%), benzaldehyde was converted into the product (R,R)-trans-202a in 73% yield and with 94% ee (Scheme 6.97) [219]. The diastereoselectivity of this reaction is excellent - d.r. (trans/cis) > 98 2. The selectivity is high because of irreversible formation of the anti-betaine whereas formation of the syn-betaine is reversible [219]. 

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]. 

Anhydro-4-hydroxyoxazolium hydroxides were first obtained in 1974 by the decomposition of the a-diazoimides (295) induced by copper(II) acetylacetonate. The reaction proceeds by way of a carbene or a carbenoid species (equation 147). The triphenyl derivative is formed when the imide shown in equation (148) is treated with triethyl phosphite (82JOC723). 

A similar intramolecular cyclopropanation of methyl 2-diazo-3-oxo-4-(2-cyclopentyl) butyrate was performed using copper (II) acetylacetonate as a method for preparing 2-ethoxycarbonyltricyclo-[3.3.1.0 ]octan-3-one and is discussed (4). 

A solution of copper(II)acetylacetonate (5 mg), 4-chloro-benxaldehyde and tosyl hydrazone lithium salt (2.5 eq) were mixed and heated to 45 °C 3 hours, cooled, and 1ml EtOAc/water, 1 1, added. The epoxide was isolated as a white solid in 54% yield with a trans/cis ratio of 2.8 1, respectively. 

Absorption of metallic acetylacetonates was carried out by immersing test papers in nonaqueous solutions of the iron (III) or copper (II) compound. In both cases, the solution concentration was 5 X 10-3 M. Iron(III) acetylacetonate was dissolved in acetone, and a mixture of acetone and chloroform (1 1) was used to dissolve copper(II) acetylacetonate. Test samples were immersed in metallic acetylacetonate solutions for 30 min and then were air dried. 

Rates of degradation observed in the presence of ionic iron and copper systems have been compared with those obtained for the respective acetylacetonate chelate systems in Tables X and XI. Lower relative lifetime and relative stability values are observed for the copper(II) acetylacetonate catalyzed system than those obtained in the presence of higher concentrations of the ionic copper species. A similar increase in the catalytic efficiency of copper upon coordination has been reported by Ericsson et al. (10). However, iron(III) acetylacetonate shows no catalytic effect at all. This observation of contrary effects on the stability of paper with the same chelates of two highly active transition metal catalysts is most interesting. Unlike the relatively stable octahedral iron(III) acetylacetonate molecule, the tetrahedral, tetracoordinate copper(II) chelate could accept two more ligands if it were to assume an... 

Copper(II) acetylacetonate was used as catalyst in the diastereoselective aziridination of the homochiral protected cts-diol 5. The JV-tosyl aziridine 6 obtained was converted to ( + )-pan-crastatin121. 

Activated copper powder or copper(II) acetylacetonate were effective catalysts in the pyrolytic cyclization of 2-azido-3-(2,4-pentadienyl)-l,4-quinones to benzopyrolizines 17 by the presumed intermediacy of a copper(II)-nitrene species which adds to the diene by a radical pathway. Although the yields were generally low, complete regioselectivity and diastereoselectivity (simple and substrate induced) were observed152. 

Carbenic fragmentation is formally the reverse of addition of carbenes to the sulfur atom of the thiophene ring, and has been observed only with 2,5-dichlorothiophenium bis(alkoxycarbonyl)methylides (30). When 30 (R = CHj) is heated at 110°C in refluxing toluene in the presence of rhodium(II) acetate or copper(II) acetylacetonate, fragmentation of the ylid to 2,5-dichlorothiophene and the carbenoid occurs. The bis(methoxycarbonyl)-carbene has been trapped with alkenes to produce high yields of the cyclopropanated products (78CC641). Since the ylid is a stable crystalline solid with a long shelf life, it represents a convenient source of bis-(methoxycarbonyl)carbene. 

Apart from these findings, the limited application of ZnCl (cyclopropanation of some cyclic 1,3-dienes, isoprene and ethyl vinyl ether and copper(II) acetylacetonate (cyclopropanation of enamines ) still stand alone. 

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