Acetylacetone complex structures

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

The great bulk of studies carried out on the spectra of five-coordinate complexes of oxovanadium(IV) has involved essentially square pyramidal structures. A classic example is the acetylacetonate complex whose structure is shown in Fig. 6 (18). 

In the above structure, if Ph3P is replaced by a bidentate ligand such as bipyridyl, there results a C-rj, -acetylacetonate complex in which palladium is tr-bonded to a terminal CH2 group. These presumably exist as tautomeric keto and enol forms (equation l).53... 

Chromium complexes acetylacetone complex formation, 386 exchange reactions, 380 amidines, 276 bridging ligands, 198 chelating ligands, 203 carbamic add, 450 paddlewheel structure, 451 carboxylic adds, 438 trinuclear, 441 oorroles, 874... 

This structural similarity has been confirmed by X-ray crystallography.1 The metalla-acetylacetone complex possesses idealized C2 v molecular symmetry. The atoms comprising the backbone of the metalla ligand system are essentially coplanar, having a maximum atomic deviation from planarity of 0.08 A. The... 

Crystal structures have been determined for many of the adducts. Eu(acac)3(phen) is antiprismatic, but Nd(ttfa)3(Ph3PO)2, Eu(dpm)3(py)2, and Ho(dpm)3(4-pico-line)2 are dodecahedral. Of the seven-coordinate adducts, Lu(dpm)3(3-picoline) is a side-face capped trigonal prism and Eu(dpm)3(quinuclidine) a capped octahedron. With the tridentate ligand terpyridyl, nine-coordination is possible as in Eu(dpm)3(terpy) Pr(facam)3(DMF)3 is also nine-coordinate. What may be another case of nine-coordination are the acetylacetonate complexes Ln(acac)3(Ph3PO)3 (Ln = Nd, Sm, Eu, Tb, Dy, Ho). 

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. 

These compounds are used as the precursors for MOCVD processes. Compared with halides and hydrides, the metal-organic compounds have much more complex structures because they contain large functional groups (e.g. allyl, butyl, methyl etc) and ligands (such as carbonyl, acetylacetonate, hexafluoroacetyl acetonate and so forth). Some representative examples are listed below [19,22] ... 

In this polyurethane-prepolymerized isocyanate reaction, the fastest catalyst are the acetylacetonate complexes. Looking at the molecular structures involved, an octoate is a 2-ethylhexoate, having the structure... 

A second t q)e of 3-carbon-bonded acetylacetonate complex is illustrated by the trimethyl(acetylacetonato)platinum(IV) dimer. Although the X-ray crystal structure analysis has not been carried out for this specific complex, both X-ray and neutron diffraction studies have been done for the analogous trimethyl(nonane-4,6-dionato)platinum(IV) complex (25, 26). This and other similarities suggest that the acetylacetonate complex has the same structure. The structure of the nonane-4,6-dionate complex is illustrated in Fig. IE along with some selected bond lengths. Compounds of this kind have been referred to as bridgebonding complexes by Gibson (23). 

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