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Acetylacetonate Complex
Metal acetylacetonates are coordination complexes derived from the acetylacetonate anion () 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 (RCOCHCO−). 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. in some cases also binds to metals through the central carbon atom; this bonding mode is more common for the third-row transition me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Complex
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many metal-containing chemical compound, compounds, especially those that include transition metals (elements like titanium that belong to the periodic table's d-block), are coordination complexes. Nomenclature and terminology Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly. The atom within a ligand that is bonded to the central metal atom or ion is called the donor atom. In a typical complex, a metal ion is bonded to several donor atoms, which can be the same or different. A Ligand#Polydentate and polyhapto ligand motifs and nomenclature, polydentate (multiple bonded) ligand is a molecule or ion that bonds to the central atom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium Bis(acetylacetonate)dichloride
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. The complex is prepared by treatment of titanium tetrachloride with excess acetylacetone: :TiCl4 + 2 Hacac → Ti(acac)2Cl2 + 2 HCl It is an octahedral complex that crystallizes as a racemic mixture In chemistry, a racemic mixture or racemate () is a mixture that has equal amounts (50:50) of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as r ... of the chiral ''cis'' isomers. It is fluxional in solution, as the result of rapid ''cis–trans'' equilibrium. References {{Acetylacetonate complexes Titanium compounds Acetylacetonate complexes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Planar Molecular Geometry
In chemistry, the square planar molecular geometry describes the stereochemistry (spatial arrangement of atoms) that is adopted by certain chemical compounds. As the name suggests, molecules of this geometry have their atoms positioned at the corners. Examples Numerous compounds adopt this geometry, examples being especially numerous for transition metal complexes. The noble gas compound xenon tetrafluoride adopts this structure as predicted by VSEPR theory. The geometry is prevalent for transition metal complexes with d8 configuration, which includes Rh(I), Ir(I), Pd(II), Pt(II), and Au(III). Notable examples include the anticancer drugs cisplatin, tCl2(NH3)2 and carboplatin. Many homogeneous catalysts are square planar in their resting state, such as Wilkinson's catalyst and Crabtree's catalyst. Other examples include Vaska's complex and Zeise's salt. Certain ligands (such as porphyrins) stabilize this geometry. Splitting of d-orbitals A general d-orbital splitti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(II) Acetylacetonate
Chromium(II) acetylacetonate is the coordination compound with the formula Cr(O2C5H7)2. It is the homoleptic acetylacetonate complex of chromium(II). It is an air-sensitive, paramagnetic yellow-brown solid. According to X-ray crystallography, the Cr center is square planar. In contrast to the triplet ground state for this complex, the bis(pyridine) adduct features noninnocent acac2- ligand attached to Cr(III). Chromium(II) acetylacetonate is prepared by treating chromous acetate with acetylacetone Acetylacetone is an organic compound with the chemical formula . It is classified as a 1,3-diketone. It exists in equilibrium with a tautomer . The mixture is a colorless liquid. These tautomers interconvert so rapidly under most conditions that ...: : See also * Chromium(III) acetylacetonate References Acetylacetonate complexes Chromium complexes Chromium–oxygen compounds Chromium(II) compounds {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon-13 NMR
Carbon-13 (C13) nuclear magnetic resonance (most commonly known as carbon-13 NMR spectroscopy or 13C NMR spectroscopy or sometimes simply referred to as carbon NMR) is the application of nuclear magnetic resonance (NMR) spectroscopy to carbon. It is analogous to proton NMR ( NMR) and allows the identification of carbon atoms in an organic molecule just as proton NMR identifies hydrogen atoms. 13C NMR detects only the isotope. The main carbon isotope, does not produce an NMR signal. Although ca. 1 mln. times less sensitive than 1H NMR spectroscopy, 13C NMR spectroscopy is widely used for characterizing organic and organometallic compounds, primarily because 1H-decoupled 13C-NMR spectra are more simple, have a greater sensitivity to differences in the chemical structure, and, thus, are better suited for identifying molecules in complex mixtures. At the same time, such spectra lack quantitative information about the atomic ratios of different types of carbon nuclei, because n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(III) Acetylacetonate
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. Synthesis, structure, bonding The compound is prepared by the reaction of chromium(III) oxide with acetylacetone (Hacac): :Cr2O3 + 6 Hacac → 2 Cr(acac)3 + 3 H2O The complex has idealized D3 symmetry. The Cr-O distances are 1.93 Å. The complex has been resolved into individual enantiomers by separation of its adduct with dibenzoyltartrate. Like many other Cr(III) compounds, it has a quartet ground state, meaning that it has three unpaired electrons. This situation is consistent with the electronic configuration (t2g)3(eg)0. The color of the complex arises from d-d electronic transitions. The complex is relatively inert toward substitution (hence it is susceptible to optical resolution). It rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(III) Acetylacetonate
Vanadium(III) acetylacetonate is the coordination compound with the formula V(C5H7O2)3, sometimes designated as V(acac)3. It is an orange-brown solid that is soluble in organic solvents. Structure and synthesis The complex has idealized D3 symmetry. Like other V(III) compounds, it has a triplet ground state. The compound is prepared by reduction of ammonium vanadate in the presence of acetylacetone. Applications and research V(acac)3 is a common precatalyst for the production of EPDM polymers. It has also been shown to be a precursor to vanadium pentoxide Vanadium(V) oxide (''vanadia'') is the inorganic compound with the formula V2 O5. Commonly known as vanadium pentoxide, it is a dark yellow solid, although when freshly precipitated from aqueous solution, its colour is deep orange. Because of ... nanostructures. References {{Acetylacetonate complexes Acetylacetonate complexes Vanadium(III) compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadyl
The vanadyl or oxovanadium(IV) cation, VO2+, is a functional group that is common in the coordination chemistry of vanadium. Complexes containing this functional group are characteristically blue and paramagnetic. A triple bond is proposed to exist between the V4+ and O2− centers. The description of the bonding in the vanadyl ion was central to the development of modern ligand-field theory. Natural occurrence Minerals Cavansite and pentagonite are vanadyl-containing minerals. Water VO2+, often in an ionic pairing with sodium (NaH2VO4), is the second most abundant transition metal in seawater, with its concentration only being exceeded by molybdenum. In the ocean the average concentration is 30 nM. Some mineral water springs also contain the ion in high concentrations. For example, springs near Mount Fuji often contain as much as 54 μg per liter. Vanadyl containing compounds Oxovanadium(IV) * vanadyl acetylacetonate, VO(acac)2 * vanadyl sulfate, VOSO4 * van ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadyl Acetylacetonate
Vanadyl acetylacetonate is the chemical compound with the chemical formula, formula VO(acac)2, where acac– is the conjugate base of acetylacetone. It is a blue-green solid that dissolves in polar organic solvents. The complex (chemistry), coordination complex consists of the vanadyl ion, vanadyl group, VO2+, bound to two acac– ligands via the two oxygen atoms on each. Like other charge-neutral acetylacetonate complexes, it is not soluble in water. Synthesis The complex is generally prepared from vanadium(IV), e.g. vanadyl sulfate: :VOSO4 + 2 Hacac → VO(acac)2 + H2SO4 It can also be prepared by a redox reaction starting with vanadium pentoxide. In this reaction, some acetylacetone is oxidized to 2,3,4-Pentanetrione. Structure and properties The complex has a square pyramidal structure with a short V=O bond. This d1 compound is paramagnetic. Its optical spectrum exhibits two transitions. It is a weak Lewis acid, forming adducts with pyridine and methylamine. Applications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tris(acetylacetonato)titanium(III)
Tris(acetylacetonato)titanium(III), often abbreviated Ti(acac)3, is a coordination complex of titanium(III) featuring acetylacetonate (acac) ligands, making it one of a family of metal acetylacetonates. It is a blue air-sensitive solid that dissolves in nonpolar organic solvents. The compound is prepared by treating titanium trichloride with acetylacetone in the presence of base. Being paramagnetic, it gives a contact-shifted proton NMR signal at 60 ppm upfield of TMS assigned to the methyl group. Structure It is an octahedral complex. The Ti-O bonds lengths range from 2.023 to 2.013 Å, the large variation being attributed to the Jahn-Teller effect. Ti(acac)3 possesses helical chirality, giving rise to Δ- and Λ-enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...s. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium Acetylacetonate
Zirconium acetylacetonate is the coordination complex with the formula Zr(C5H7O2)4. It is a common acetylacetonate of zirconium. It is a white solid that exhibits high solubility in nonpolar organic solvents, but not simple hydrocarbons. The complex is prepared by treating zirconium oxychloride with acetylacetone: :ZrOCl2 + 4 Hacac → Zr(acac)4 + 2 HCl + H2O The complex has a square antiprismatic geometry with eight nearly equivalent Zr-O bonds of length 2.19 Å. The molecular symmetry is D2, i.e. the complex is chiral. Compounds of high coordination number tend to be stereochemically nonrigid as indicated by the observation of one methyl signal by proton NMR spectroscopy Proton nuclear magnetic resonance (proton NMR, hydrogen-1 NMR, or 1H NMR) is the application of nuclear magnetic resonance in NMR spectroscopy with respect to hydrogen-1 nuclei within the molecules of a substance, in order to determine the struct .... More volatile than Zr(acac)4 is the relate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
