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Tris(2-phenylpyridine)iridium
Tris(2-phenylpyridine)iridium, abbreviated r(ppy)3is the organoiridium complex with the formula Ir(C6H4-C5H4N)3. The complex, a yellow-green solid, is a derivative of Ir3+ bound to three monoanionic 2-pyridinylphenyl ligands. It is electroluminescent, emitting green light. The complex is observed with the facial stereochemistry, which is chiral. The complex is prepared by cyclometalation reactions of 2-phenylpyridine and iridium trichloride Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is useful for preparing other iridium compounds. The anhydrous salt is a dark green crystalline solid. Mo ..., as represented by this idealized equation: :IrCl3 + 3C6H5-C5H4N → Ir(C6H4-C5H4N)3 + 3 HCl The complex and many analogues have been investigated for application in photoredox catalysis. Its excited state has a reduction potential of −2.14 V, nearly 1 V more negative than the reducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoiridium Complex
Organoiridium chemistry is the chemistry of organometallic compounds containing an iridium-carbon chemical bond. Organoiridium compounds are relevant to many important processes including olefin hydrogenation and the industrial synthesis of acetic acid. They are also of great academic interest because of the diversity of the reactions and their relevance to the synthesis of fine chemicals. Classification based on principal oxidation states Organoiridium compounds share many characteristics with those of rhodium, but less so with cobalt. Iridium can exist in oxidation states of -III to +V, but iridium(I) and iridium(III) are the more common. iridium(I) compounds (d8 configuration) usually occur with square planar or trigonal bipyramidal geometries, whereas iridium(III) compounds (d6 configuration) typically have an octahedral geometry. Iridium(0) Iridium(0) complexes are binary carbonyls, the principal member being tetrairidium dodecacarbonyl, Ir4(CO)12. Unlike the related ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroluminescent
Electroluminescence (EL) is an optical and electrical phenomenon, in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission resulting from heat (incandescence), a chemical reaction (chemiluminescence), sound (sonoluminescence), or other mechanical action (mechanoluminescence). Mechanism Electroluminescence is the result of radiative recombination of electrons & holes in a material, usually a semiconductor. The excited electrons release their energy as photons - light. Prior to recombination, electrons and holes may be separated either by doping the material to form a p-n junction (in semiconductor electroluminescent devices such as light-emitting diodes) or through excitation by impact of high-energy electrons accelerated by a strong electric field (as with the phosphors in electroluminescent displays). It has been recently shown that as a solar cell improves its light-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Phenylpyridine
2-Phenylpyridine is an organic compound with the formula C6H5C5H4N (or C11H9N). It is a colourless viscous liquid. The compound and related derivatives have attracted interest as precursors to highly fluorescent metal complexes of possible value as organic light emitting diodes (OLEDs). The compound is prepared by the reaction of phenyl lithium with pyridine: :C6H5Li + C5H5N → C6H5-C5H4N + LiH The reaction of iridium trichloride Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is useful for preparing other iridium compounds. The anhydrous salt is a dark green crystalline solid. Mo ... with 2-phenylpyridine proceeds via cyclometallation to give the chloride-bridged complex: :4 C6H5-C5H4N + 2 IrCl3(H2O)3 → Ir2Cl2(C6H4-C5H4N)4 + 4 HCl This complex can be converted to the pictured tris(cyclometallated) derivative tris(2-phenylpyridine)iridium. References Further reading * {{DEF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium Trichloride
Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is useful for preparing other iridium compounds. The anhydrous salt is a dark green crystalline solid. More commonly encountered is the trihydrate IrCl3(H2O)3. Preparation Iridium is separated from the other platinum group metals as crystalline ammonium hexachloroiridate, (NH4)2 rCl6 which can be reduced to iridium metal in a stream of hydrogen. The spongy Ir thus produced reacts with chlorine at 300–400 °C to give iridium(III) chloride. Hydrated iridium trichloride is obtained by heating hydrated iridium(III) oxide with hydrochloric acid. Structure Like the related rhodium compound, IrCl3 adopts the structure seen for aluminium chloride. This is the monoclinic α polymorph. A rhombohedral β polymorph also exists. Both polymorphs have effectively the same anion lattice but differ in the octahedral interstices the iridium ions oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoredox Catalysis
Photoredox catalysis is a branch of photochemistry that uses single-electron transfer. Photoredox catalysts are generally drawn from three classes of materials: transition-metal complexes, organic dyes, and semiconductors. While organic photoredox catalysts were dominant throughout the 1990s and early 2000s, soluble transition-metal complexes are more commonly used today. Photochemistry of transition metal sensitizers Sensitizers absorb light to give redox-active excited states. For many metal-based sensitizers, excitation is realized as a metal-to-ligand charge transfer, whereby an electron moves from the metal (e.g., a d orbital) to an orbital localized on the ligands (e.g. the π* orbital of an aromatic ligand). The initial excited electronic state relaxes to the lowest energy singlet excited state through internal conversion, a process where energy is dissipated as vibrational energy rather than as electromagnetic radiation. This singlet excited state can relax further by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruthenium Tris(bipyridine)
Tris(bipyridine)ruthenium(II) chloride is the chloride salt coordination complex with the formula u(bpy)3sup>2+ 2Cl−. This polypyridine complex is a red crystalline salt obtained as the hexahydrate, although all of the properties of interest are in the cation u(bpy)3sup>2+, which has received much attention because of its distinctive optical properties. The chlorides can be replaced with other anions, such as PF6−. Synthesis and structure left, 144px, Cis-Dichlorobis(bipyridine)ruthenium(II), ''cis''-Dichlorobis(bipyridine)ruthenium(II) is an intermediate in the synthesis of tris(bipyridine)ruthenium(II) chloride. This salt is prepared by treating an aqueous solution of ruthenium trichloride with 2,2'-bipyridine. In this conversion, Ru(III) is reduced to Ru(II), and hypophosphorous acid is typically added as a reducing agent. u(bpy)3sup>2+ is octahedral, containing a central low spin d6 Ru(II) ion and three bidentate bpy ligands. The Ru-N distances are 2.053(2), shorte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photochemistry
Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible light (400–750 nm) or infrared radiation (750–2500 nm). In nature, photochemistry is of immense importance as it is the basis of photosynthesis, vision, and the formation of vitamin D with sunlight. Photochemical reactions proceed differently than temperature-driven reactions. Photochemical paths access high energy intermediates that cannot be generated thermally, thereby overcoming large activation barriers in a short period of time, and allowing reactions otherwise inaccessible by thermal processes. Photochemistry can also be destructive, as illustrated by the photodegradation of plastics. Concept Grotthuss–Draper law and Stark-Einstein law Photoexcitation is the first step in a photochemical process where the reactant is elevat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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