2.4- Pentanedionato complexes

Other exchange studies involve bis-(2,4-pentanedionato) complexes of Co(ii) and Ni(ii), (331) oe-dioximates of Ni(ii), (332) thiosemi-carbazide-type complexes, (333) aquomethyl-iV,Al -ethylene-bis-(salicylideniminato)cobalt with metal cations, (334) nickel(ii) acetato complexes, (133) and chromium(ii) formate complexes. (335)... 

The l,l,l,5,5,5-hexafluoro-2,4-pentanedionato complexes ofnickel-(II) and cobalt(II), when isolated as dimethylformamide adducts, are crystalline solids, stable to at least 135° in vacuo. The crystalline nickel complex is unaffected by immersion in water at room temperature for 3 days. 

Extensive studies on the preparative and structural aspects of 2,4-pentane-dionato and other /S-diketonato complexes of transition metals have been made over the last 1(X) years. However, such complexes of molybdenum have not received much attention. The study of the coordination chemistry of molybdenum in general has had an impetus in recent years because of its key role in many biological systems. Two 2,4-pentanedionato complexes of oxomolybdenum(VI, V) are well characterized. Mo02(acac)2 has been prepared starting from either M0O3 or (NH4)6M07O24 4H2O. A method for... 

The editor of Volume XII is particularly indebted to a number of people who have contributed significantly to this volume. Dr. George Parshall, Prof. A. D. Allen, Dr. Frank Bottomley, and their associates made particularly valuable contributions to Chapter One. Professor John Fackler assisted in the accumulation of syntheses on pentanedionato complexes Prof. Aaron Wold assisted with the work on solids, and Prof. John Ruff assisted with the section on fluorine chemistry. The assistance of these men is gratefully acknowledged. Finally, every vol-... 

Tris(2,4-pentanedionato)iron(III) [14024-18-1], Fe(C H202)3 or Fe(acac)3, forms mby red rhombic crystals that melt at 184°C. This high spin complex is obtained by reaction of iron(III) hydroxide and excess ligand. It is only slightly soluble in water, but is soluble in alcohol, acetone, chloroform, or benzene. The stmcture has a near-octahedral arrangement of the six oxygen atoms. Related complexes can be formed with other P-diketones by either direct synthesis or exchange of the diketone into Fe(acac)3. The complex is used as a catalyst in oxidation and polymerization reactions. 

A similar catalytic dimerization system has been investigated [40] in a continuous flow loop reactor in order to study the stability of the ionic liquid solution. The catalyst used is the organometallic nickel(II) complex (Hcod)Ni(hfacac) (Hcod = cyclooct-4-ene-l-yl and hfacac = l,l,l,5,5,5-hexafluoro-2,4-pentanedionato-0,0 ), and the ionic liquid is an acidic chloroaluminate based on the acidic mixture of 1-butyl-4-methylpyridinium chloride and aluminium chloride. No alkylaluminium is added, but an organic Lewis base is added to buffer the acidity of the medium. The ionic catalyst solution is introduced into the reactor loop at the beginning of the reaction and the loop is filled with the reactants (total volume 160 mL). The feed enters continuously into the loop and the products are continuously separated in a settler. The overall activity is 18,000 (TON). The selectivity to dimers is in the 98 % range and the selectivity to linear octenes is 52 %. 

The square planar Ni11 complex (583) was prepared from the template reaction of 3,3 -(ethylene bis(iminomethylidene)bis(2,4-pentanedionato)nickel(II) with l,3-diamino-2-propanol (Equation (18)). The uncoordinated OH group reacted smoothly with acylating agents, resulting in... 

Zinc complex formation with 1,3-diketones in aqueous solution has been investigated with pentane-2,4-dione, l,l,l-trifluoropentane-2,4-dione, and 4,4,4-trifluoro-l-(2-thienyl)butane-l, 3-dione. The buffer dimethylarsinic acid was shown to have a catalytic effect on complex formation with pentane-2,4-dione and the proton transfer reactions were affected.471,472 High-resolution solid state 13C NMR studies of bis(2,4-pentanedionato) zinc complexes have been carried out.473... 

In 1989, a method for the peroxysilylation of alkenes nsing triethylsUane and oxygen was reported by Isayama and Mnkaiyama (eqnation 25). The reaction was catalyzed by several cobalt(II)-diketonato complexes. With the best catalyst Co(modp)2 [bis(l-morpholinocarbamoyl-4,4-dunethyl-l,3-pentanedionato)cobalt(n)] prodnct yields ranged between 75 and 99%. DiaUcyl peroxides can also be obtained starting from tertiary amines 87, amides 89 or lactams via selective oxidation in the a-position of the Af-fnnctional group with tert-butyl hydroperoxide in the presence of a ruthenium catalyst as presented by Murahashi and coworkers in 1988 ° (Scheme 38). With tertiary amines 87 as substrates the yields of the dialkyl peroxide products 88 ranged between 65 and 96%, while the amides 89 depicted in Scheme 38 are converted to the corresponding peroxides 90 in yields of 87% (R = Me) and 77% (R = Ph). 

In this procedure cis- [dihalobis(2,4-pentanedionato)titanium(IV)] complexes (halo = F, Cl, Br) are prepared in high yields through the reaction of a titanium tetrahalide with 2,4-pentanedione in dichloromethane. 

Scheme 5.2-6 Synthesis of a deuterated analogue of the square-planar Ni-complex (t -4-cycloocten-l-yl](l,5-diphenyl-2,4-pentanedionato-0,0 )nickel for H NMR investigations.

C7H704Rh, Rhodium(I), dicarbonyl(2,4-pentanedionato)-, 34 128 C7HgN4, Bis(l-pyrazolyl)methane, bpm, complex with nickel(ll), 34 139 CgH5FeKN20, Ferrate(ll), carbonyldicyano-(cyclopentadienyl)-, potassium, 34 172 CgH23Ns, Tetraethylenepentamine, tetren, complex with nickel(ll), 34 147, 148 CgH24B2N4, Diborane(4), tetrakis(dimethyl-amino)-, 34 1... 

Bis(1,5-dichloro-2,4-pentanedione) copper(ll) complex Copper, bis(1,5-dichloro-2,4-pentanedionato-O.O )- (12) (135943-96-3)... 

The 2,4-pentanedionato or acetylacetonato (acac) complexes are useful synthetic intermediates because they react with protic acids through the reaction (l) 1... 

The Cotton effects in mixed amino acidate/acetylacetonate complexes [Cr(acac)2L] (L = l-alanine, L-valine or L-phenylalanine) have been studied 774 absolute configurations were assigned by reference to the parent tris(acetylacetonate) complexes. Synthesis was achieved by the photolysis of mixtures of the amino acid and [Cr(acac)3]. The partial photoresolution of both cis- and irans-(l,l,l-trifluoro-2,4-pentanedionato)chromium has been accomplished by irradiation with circularly polarized light (5461 A) in chlorobenzene solution.775 The results indicated that both bond rupture and twist mechanisms were important. A number of other jS-diketonates have also been investigated.776... 

The electrophilic substitutions of acetylacetonate complexes have been taken as suggesting aromatic character in the chelate ring. Results with seventeen different 1,3-diketonatochromium(III) complexes were recently held to support this suggestion (176-178 equation 43).784 The bromination of tris(l,l,l-trifluoro-2,4-pentanedionato)chromium(III), previously claimed to be unreactive,785 has been reported.786... 

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