Holmium is a chemical element; it has symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish oxide coating when exposed to air. When isolated, holmium is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily, and also burns in air when heated.
Chromium(III) acetylacetonate is the coordination compound with the formula Cr(C5H7O2)3, sometimes designated as Cr(acac)3. This purplish coordination complex is used in NMR spectroscopy as a relaxation agent because of its solubility in nonpolar organic solvents and its paramagnetism.
Nickel(II) bis(acetylacetonate) is a coordination complex with the formula [Ni(acac)2]3, where acac is the anion C5H7O2− derived from deprotonation of acetylacetone. It is a dark green paramagnetic solid that is soluble in organic solvents such as toluene. It reacts with water to give the blue-green diaquo complex Ni(acac)2(H2O)2.
Metal acetylacetonates are coordination complexes derived from the acetylacetonate anion (CH
3COCHCOCH−
3) and metal ions, usually transition metals. The bidentate ligand acetylacetonate is often abbreviated acac. Typically both oxygen atoms bind to the metal to form a six-membered chelate ring. The simplest complexes have the formula M(acac)3 and M(acac)2. Mixed-ligand complexes, e.g. VO(acac)2, are also numerous. Variations of acetylacetonate have also been developed with myriad substituents in place of methyl (RCOCHCOR′−). Many such complexes are soluble in organic solvents, in contrast to the related metal halides. Because of these properties, acac complexes are sometimes used as catalyst precursors and reagents. Applications include their use as NMR "shift reagents" and as catalysts for organic synthesis, and precursors to industrial hydroformylation catalysts. C
5H
7O−
2 in some cases also binds to metals through the central carbon atom; this bonding mode is more common for the third-row transition metals such as platinum(II) and iridium(III).
Dysprosium acetylacetonate is a chemical compound of dysprosium with formula Dy(C5H7O2)3(H2O)n.
Europium acetylacetonate is a coordination complex with formula Eu(C5H7O2)3. Although this anhydrous acetylacetonate complex is widel discussed, some sources suggest that it is really the dihydrate Eu(C5H7O2)3(H2O)2.
Gadolinium acetylacetonate is a coordination compound with the formula Gd(C5H7O2)3. This anhydrous acetylacetonate complex is widely discussed but unlikely to exist per se. The 8-coordinated dihydrate Gd(C5H7O2)3(H2O)2 is a more plausible formula based on the behavior of other lathanide complexes. It has also been characterized twice by X-ray crystallography.
Iridium acetylacetonate is the iridium coordination complex with the formula Ir(O2C5H7)3, which is sometimes known as Ir(acac)3. The molecule has D3-symmetry. It is a yellow-orange solid that is soluble in organic solvents.
Rhodium acetylacetonate is the coordination complex with the formula Rh(C5H7O2)3, which is sometimes known as Rh(acac)3. The molecule has D3-symmetry. It is a yellow-orange solid that is soluble in organic solvents.
Titanium bis(acetylacetonate)dichloride is the coordination complex with the formula Ti(C5H7O2)2Cl2. It is a common acetylacetonate complex of titanium. It is a red-orange solid that hydrolyzes slowly in air.
Platinum(II) bis(acetylacetonate) is the coordination compound with the formula Pt(O2C5H7)2, abbreviated Pt(acac)2. The homoleptic acetylacetonate complex of platinum(II), it is a yellow, benzene-soluble solid. According to X-ray crystallography, the Pt center is square planar. The compound is a widely used precursor to platinum-based catalysts.
Neodymium(III) acetylacetonate is a coordination compound with the chemical formula Nd(O2C5H7)3. Although many sources discuss this anhydrous acetylacetonate complex, it is the dihydrate Nd(O2C5H7)3(H2O)2 that has been characterized by X-ray crystallography. It commonly occurs as a white powder. Upon heating under vacuum, other dihydrated lanthanide trisacetylacetonates convert to oxo-clusters M4O(C5H7O2)10. This result suggests that Nd(O2C5H7)3 may not exist.
Praseodymium acetylacetonate is a coordination complex with the formula Pr(C3H7O2)3. This purported anhydrous acetylacetonate complex is widely discussed but only the dihydrate Pr(C3H7O2)3(H2O)2 has been characterized by X-ray crystallography.
Erbium acetylacetonate is a coordination compound with the formula Er(C5H7O2)3. This anhydrous acetylacetonate complex is often discussed but unlikely to exist per se. The 8-coordinated dihydrate Er(C5H7O2)3(H2O)2 is a more plausible formula based on the behavior of other lanthanide acetylacetonates. The dihydrate has been characterized by X-ray crystallography.
Thulium acetylacetonate is a coordination compound with the formula Tm(C5H7O2)3. This anhydrous acetylacetonate complex is often discussed but unlikely to exist per se. The 8-coordinated dihydrate Tm(C5H7O2)3(H2O)2 is a more plausible formula based on the behavior of other lanthanide acetylacetonates. The dihydrate has been characterized by X-ray crystallography. Upon attempted dehydration by heating under vacuum, other hydrated lanthanide tris(acetylacetonate) complexes decompose to give oxo-clusters.
Lanthanum acetylacetonate refers to the coordination complex with the formula La(C5H7O2)3. This anhydrous acetylacetonate complex has not been characterized well, but the dihydrate La(C5H7O2)3(H2O)2 has been characterized by X-ray crystallography.
Samarium acetylacetonate is a coordination compound with the formula Sm(C5H7O2)3. This anhydrous acetylacetonate complex is widely discussed but unlikely to exist per se. The 8-coordinated dihydrate Sm(C5H7O2)3(H2O)2 is a more plausible formula based on the behavior of other lanthanide acetylacetonates. The dihydrate has been characterized by X-ray crystallography. Upon attempted dehydration by heating under vacuum, other hydrated lanthanide tris(acetylacetonate) complexes decompose to give oxo-clusters.
Lutetium acetylacetonate is a coordination compound with the chemical formula Lu(C5H7O2)3, or Lu(acac)3 for short. The complex per se is unlikely to exist, but the dihydrate would be expected based on the behavior of other lanthanide tris(acetylacetonate)s. Consistent with this scenario, It forms adducts Lu(acac)3(phen) and Lu(acac)3(dipy) where phen and bipy are 1,10-phenanthroline and 2,2'-bipyridine, respectively.
Terbium acetylacetonate is a coordination compound with the formula Tb(C5H7O2)3. This anhydrous acetylacetonate complex is often discussed but unlikely to exist per se. The 8-coordinated dihydrate Tb(C5H7O2)3(H2O)2 is a more plausible formula based on the behavior of other lanthanide acetylacetonates. The dihydrate has been characterized by X-ray crystallography. Upon attempted dehydration by heating under vacuum, other hydrated lanthanide tris(acetylacetonate) complexes decompose to give oxo-clusters. The complex can be prepared from terbium salts, acetylacetone, and a base such as ammonia.
Ytterbium(III) acetylacetonate is a coordination compound with the chemical formula Yb(C5H7O2)3(H2O)2. Its structure is different from the acetylacetone complexes of neodymium, europium and holmium. The adjacent Yb-Yb The distance is 8.3 Å. Yb(acac)3(bpy) can be obtained by reacting its trihydrate with 2,2'-bipyridine in ethanol.
