In chemistry and materials science, linear chain compounds are materials composed of one-dimensional arrays of metal-metal bonded molecules or ions. Such materials exhibit anisotropic electrical conductivity. [1] [2]
In chemistry and materials science, linear chain compounds are materials composed of one-dimensional arrays of metal-metal bonded molecules or ions. Such materials exhibit anisotropic electrical conductivity. [1] [2]
Most examples are composed of square planar complexes. Thus, upon crystallization, molecules of Rh(acac)(CO)2 stack with Rh···Rh distances of about 326 pm. [3] Classic examples include Krogmann's salt and Magnus's green salt. Another example is the partially oxidized derivatives of [Pt(oxalate)2]2−. The otherwise ordinary complex IrBr(CO)3 gives an electrically conductive derivative upon oxidation, e.g., with bromine to give IrBr1+x(CO)3-x, where x ~0.05. [2] [4] Related chlorides have the formulae IrCl1+x(CO)3 and K0.6Ir(CO)2Cl2·½H2O. [5]
In contrast to linear chain compounds, extended metal atom chains (EMACs) are molecules or ions that consist of a finite, often short, linear strings of metal atoms, surrounded by organic ligands. [6]
One group of platinum chains is based on alternating cations and anions of [Pt(CNR)4]2+ (R = iPr, c-C12H23, p-(C2H5)C6H4) and [Pt(CN)4]2−. [1] These may be able to be used as vapochromic sensor materials, or materials which change color when exposed to different vapors. [8] [9] [10]
Linear chains of Pd-Pd bonds protected by a "π-electron sheath" are known. [1] [11]
Not only do these olefin-stabilized metal chains constitute a significant contribution to the field of organometallic chemistry, both the complex's metal atom structures and the olefin ligands themselves can conduct a current. [1] [12]
Some linear chain compounds are produced or fabricated by electrocrystallization. The technique is used to obtain single crystals of low-dimensional electrical conductors. [13]
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation of an atom in a chemical compound. Conceptually, the oxidation state may be positive, negative or zero. While fully ionic bonds are not found in nature, many bonds exhibit strong ionicity, making oxidation state a useful predictor of charge.
Cyanate is an anion with the structural formula [O=C=N]−, usually written OCN−. It also refers to any salt containing it, such as ammonium cyanate.
Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. Metal carbonyls are useful in organic synthesis and as catalysts or catalyst precursors in homogeneous catalysis, such as hydroformylation and Reppe chemistry. In the Mond process, nickel tetracarbonyl is used to produce pure nickel. In organometallic chemistry, metal carbonyls serve as precursors for the preparation of other organometallic complexes.
Palladium(II) dicyanide is the inorganic compound with the formula Pd(CN)2. A grey solid, it is a coordination polymer. It was the first palladium compound isolated in pure form. In his attempts to produce pure platinum metal in 1804, W.H. Wollaston added mercuric cyanide to a solution prepared by dissolving impure platinum in aqua regia. This precipitated palladium cyanide which was then ignited to recover palladium metal—a new element.
Diiron nonacarbonyl is an organometallic compound with the formula Fe2(CO)9. This metal carbonyl is an important reagent in organometallic chemistry and of occasional use in organic synthesis. It is a more reactive source of Fe(0) than Fe(CO)5. This micaceous orange solid is virtually insoluble in all common solvents.
In organic chemistry, carbon–hydrogen bond functionalization is a type of organic reaction in which a carbon–hydrogen bond is cleaved and replaced with a C−X bond. The term usually implies that a transition metal is involved in the C−H cleavage process. Reactions classified by the term typically involve the hydrocarbon first to react with a metal catalyst to create an organometallic complex in which the hydrocarbon is coordinated to the inner-sphere of a metal, either via an intermediate "alkane or arene complex" or as a transition state leading to a "M−C" intermediate. The intermediate of this first step can then undergo subsequent reactions to produce the functionalized product. Important to this definition is the requirement that during the C−H cleavage event, the hydrocarbyl species remains associated in the inner-sphere and under the influence of "M".
Metal nitrosyl complexes are complexes that contain nitric oxide, NO, bonded to a transition metal. Many kinds of nitrosyl complexes are known, which vary both in structure and coligand.
Krogmann's salt is a linear chain compound consisting of stacks of tetracyanoplatinate. Sometimes described as molecular wires, Krogmann's salt exhibits highly anisotropic electrical conductivity. For this reason, Krogmann's salt and related materials are of some interest in nanotechnology.
Transition metal hydrides are chemical compounds containing a transition metal bonded to hydrogen. Most transition metals form hydride complexes and some are significant in various catalytic and synthetic reactions. The term "hydride" is used loosely: some of them are acidic (e.g., H2Fe(CO)4), whereas some others are hydridic, having H−-like character (e.g., ZnH2).
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).
Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.
A transition metal fullerene complex is a coordination complex wherein fullerene serves as a ligand. Fullerenes are typically spheroidal carbon compounds, the most prevalent being buckminsterfullerene, C60.
A metal carbido complex is a coordination complex that contains a carbon atom as a ligand. Carbido complexes are a molecular subclass of carbides, which are prevalent. Carbido complexes represent models for intermediates in Fischer–Tropsch synthesis and related catalytic processes. They are also used as precursors for the synthesis of more complicated carbides. They are analogous to metal nitrido complexes.
In chemistry, a metal carbonyl cluster is a compound that contains two or more metals linked in part by metal-metal bonds and containing carbon monoxide (CO) as the exclusive or predominant ligand. The area is a subfield of metal carbonyl chemistry, and many metal carbonyl clusters are in fact prepared from simple metal carbonyls. Simple examples include Fe2(CO)9, Fe3(CO)12, Mn2(CO)10. High nuclearity clusters include [Rh13(CO)24H3]2− and the stacked Pt3 triangules [Pt3n(CO)6n]2− (n = 2–6).
Transition metal nitrile complexes are coordination compounds containing nitrile ligands. Because nitriles are weakly basic, the nitrile ligands in these complexes are often labile.
Transition metal pyridine complexes encompass many coordination complexes that contain pyridine as a ligand. Most examples are mixed-ligand complexes. Many variants of pyridine are also known to coordinate to metal ions, such as the methylpyridines, quinolines, and more complex rings.
Transition metal isocyanide complexes are coordination compounds containing isocyanide ligands. Because isocyanides are relatively basic, but also good pi-acceptors, a wide range of complexes are known. Some isocyanide complexes are used in medical imaging.
In chemistry, a transition metal chloride complex is a coordination complex that consists of a transition metal coordinated to one or more chloride ligand. The class of complexes is extensive.
Transition metal oxalate complexes are coordination complexes with oxalate (C2O42−) ligands. Some are useful commercially, but the topic has attracted regular scholarly scrutiny. Oxalate (C2O42-) is a kind of dicarboxylate ligand. As a small, symmetrical dinegative ion, oxalate commonly forms five-membered MO2C2 chelate rings. Mixed ligand complexes are known, e.g., [Co(C2O4)(NH3)4]κ+.
Transition metal azide complexes are coordination complexes containing one or more azide (N3−) ligands.