Nickel acetylacetonate Ni

The reaction of 3-amino-4-cyanofurazan with (3-dicarbonyl compounds in the presence of catalytic amounts of nickel acetylacetonate (Ni(acac)2) gave labile enamines that on treatment with acetic acid afforded fused pyridines of type 100 in 80-95% total yields (Scheme 51) (94MC57). Eurther syntheses of furazano-pyridines can be found in the review by Sheremetev (99RCR137, 99UK154). 

The liquid-phase reduction method was applied to the preparation of the supported catalyst [27]. Virtually, Muramatsu et al. reported the controlled formation of ultrafine Ni particles on hematite particles with different shapes. The Ni particles were selectively deposited on these hematite particles by the liquid-phase reduction with NaBFl4. For the concrete manner, see the following process. Nickel acetylacetonate (Ni(AA)2) and zinc acetylacetonate (Zn(AA)2) were codissolved in 40 ml of 2-propanol with a Zn/Ni ratio of 0-1.0, where the concentration of Ni was 5.0 X lO mol/dm. 0.125 g of Ti02... 

Nickel acetylacetonate, Ni(acac)2, in the presence of a styrene derivative promotes coupling of primary alkyl iodides with organozinc reagents. The added styrene serves to stabilize the active catalytic species, and of the derivatives examined, m-trifluoromethylstyrene was the best.274... 

A full account has appeared of the study of absolute configurations of vicinal diols and amino-alcohols by c.d. measurements in solutions containing nickel acetylacetonate [Ni(acac)2] or the n.m.r. shift reagent [Pr(dpm)3]. Examples of steroidal derivatives examined include 2,3-, 3,4-, 5,6-, 16,17-, 17a,20j8-, and side-chain diols. 

Inexpensive and easily available nickel acetylacetonate (Ni(acac)2) is employed as the catalyst precursor. The procedure can be easily scaled-up to prepare up to 50 g of the vinyl sulfides with high regioselectivity. Moreover, solvent-free conditions without chromatographical purification attain eco-friendly synthetic method of vinyl sulfides. The mechanistic study indicates that the catalytic hydrothiolation takes place under heterogeneous conditions with alkyne insertion into the Ni-S bond of nanosized nickel sulfide species. 

The reaction of a mixture of 1,5,9-cyclododecatriene (CDT), nickel acetylacetonate [3264-82-2], and diethylethoxyalurninum in ether gives red, air-sensitive, needle crystals of (CDT)Ni [12126-69-1] (66). Crystallographic studies indicate that the nickel atom is located in the center of the 12-membered ring of (CDT)Ni (104). The latter reacts readily with 1,5-cyclooctadiene (COD) to yield bis(COD) nickel [1295-35-8] which has yellow crystals and is fairly air stable, mp 142°C (dec) (20). Bis(COD)nickel also can be prepared by the reaction of 1,5-COD, triethylaluminum, and nickel acetylacetonate. 

Oxidative addition of the silyl species to nickel is followed by insertion of unsaturated substrates. Zero-valent nickel complexes, and complexes prepared by reducing nickel acetylacetonate with aluminum trialkyls or ethoxydialkyls, and in general Ziegler-Natta-type systems, are effective as catalysts (244, 260-262). Ni(CO)4 is specific for terminal attack of SiHCl3 on styrene (261). 

LDHs with Ni/Al molar ratio of 2.5 have been synthesized by a sol-gel method using nickel acetylacetonate and aluminium isopropylate as precursors. The sol-gel synthesized samples exhibited lower crystalhte dimensions and greater BET surface areas compared with coprecipitated samples prepared from an aqueous solution of nickel and aluminium nitrates [19,172]. 

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. 

Functionalization of Ni(MeCOCHCOMe)2 occurs in reactions with isocyanates, diethyl azodi-carboxylate and dimethyl acetylenedicarboxylate, which proceed by formal insertion of the methine C—H unit into the substrate multiple bonds to form respectively amides and ester-substituted hydrazines and alkenes. Similar additions of acetylacetone to these electrophiles is catalyzed by nickel acetylacetonate.217,218... 

The 1,7-dicarbollide ion and nickel-acetylacetonate reacted in tetrahy-drofuran to yield a red complex which was air oxidized to (1,7-B9C2H, [)2Ni (18). Further oxidation of the Ni(III) species with ferric ion produced the sublimable (1,7-B9C2H,, )2Ni. The 1,2-dicarbollide complexes appear to be more stable than their 1,7-analogs. 

Monodisperse 4nm Ni particles are formed if nickel acetylacetonate is reduced by Et2AlH in diethyl ether in the presence of PPhs. As protecting shell on the particles surface, PPh is observed, not the original PPhs. The PPh units are formed by hydrogen generated from the alane during the reduction process. 

Vinyl sulfides have been prepared by the catalytic addition of the S—H bond of thiols (85) to terminal alkynes (86) under solvent-free conditions using the nickel complex Ni(acac)2 (47). High alkyne conversions (up to 99%) were achieved after 30 min at 40 °C in favor of the corresponding Markovnikov products (87) (equation 23). Other metal acetylacetonate complexes were examined for this reaction, but none showed any improvement over the nickel catalyst. Mechanistic details suggest that alkyne insertion into the Ni—S bond is important to the catalytic cycle and that nanosized structural units comprised of [Ni(SAr)2] represent the active form of the catalyst. Isothiocyanates and vinyl sulfides have been produced in related Rh(acac)(H2C=CH2)2 (6) and VO(acac)2 (35) catalyzed sulfenylation reactions of aryl cyanides and aryl acetylenes, respectively. 

Preparatiou. The reagent is best prepared by a modification of the original procedure of Wilke. The preparation involves reduction of nickel acetylacetonate (Alfa Inorganics) with triethylaluminum (Texas Alkyls) in the presence of 1, S-cyclooctadicne. Because of the sensitivity of Ni(COD)> to oxygen, special inert-atmosphere techniques mu.st be used. The yield is 81 %. 

Such condensation had been effected previously, but in lower yields, by a system comprising nickel(II) acetylacetonate, Ni(C5H702)2, diisopropoxyphenylphosphine, and sodium borohydridc. The borohydride in this case is essential to effect good conversions. I be order of reactivity of nickel salts in the butadiene-amine-dialkoxyphenyl-phosphine system is... 

The nickel complex, Ni ( 5115)2, has been made by the action of the Grignard reagent on nickel (II) acetylacetonate (217) or from potassium cyclopentadienyl and the ammine [Ni(NHs)el (S N)2 in liquid ammonia (58). It forms dark emerald-green crystals which sublime at 80-90° and which, when heated in nitrogen, melt, with decomposition and the formation of a nickel mirror, at 173-174°. It is only slowly oxidized in air, and cold water neither attacks nor dissolves it it is, however, readily soluble in organic liquids. Oxidation of the compound yields an orange-yellow solution containing the ion [Ni( 5H5)2]+, which is stable for a short period in weakly acidic media, and which may be precipitated as the reineckate or tetraphenylborate. 

What compounds are the active catalysts in this process By this method of catalyst preparation we do not obtain a mixture of indefinite composition, but TT-complexes which can be isolated and are mostly crystalline. If, for instance, nickel acetylacetonate is reduced in the presence of P(CeH5)3 we obtain a new compound, Ni-(0)-[P(CeH5)3]4. This compound is itself an active catalyst for the cyclo-oligomerization of butadiene, producing about 65 to 70% cyclo-octadiene, 20% vinylcyclohexene, and 10% cyclododecatriene. Instead of P(CeH5)3 we can introduce As(CeH5)3 and isolate Ni-(0)-[As(CeH5)3]4 as an active cata-... 

By reaction of nickel acetylacetonate with organometallic compounds in ether in the presence of all-fran -cyclodecatriene, we obtained an intensely red solution from which dark red crystals could be isolated. These are volatile under high vacuum and have the composition NiCi2Hi8- The mass spectrum shows the molecule to have peaks at 220 and 222. This is in agreement with NiCi2Hi8, if we consider that nickel consists of the isotopes Ni and Ni . The infrared spectrum shows that all double bonds are shared with nickel, because there is no absorption corresponding to normal trans double bonds. 

The reaction was initially tested by the use of PdCliCPPhs) . Although 6 equiv of iodide 80 was required to complete the reaction, the desired product 65 was obtained in 80% yield (Table 11, Entry 1) [97]. The catalyst is, however, inadequate especially in terms of cost. Studies were undertaken to search for a better protocol. Nickel system was resorted in this connection. The use of inexpensive nickel(IT) acetylacetonate [Ni(acac)2] was tested to reduce the cost of raw material, which led to a moderate yield of 65 (78%, Table 11, Entry 2) [98]. Easily recoverable heterogeneous palladium on activated carbon (Pd/C) catalyst was then examined. While the use of the standard conditions using THF and toluene as the solvent resulted in a moderate yield (50%, Table 11, Entry 3), addition of DMF to the reaction mixture considerably improved the yield, providing 65 in 94% yield (Table 11, Entry 4) [99]. Much less pyrophoric Pearlman s catalyst [Pd(OH)2/C] was found to give 65 in an excellent yield with such a tiny catalyst loading as 0.65 mol% (Table 11, Entry 5) [100]. 

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