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 other 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.
The cyanate ion is an anion with the chemical formula OCN−. It is a resonance of three forms: [O−−C≡N] (61%) ↔ [O=C=N−] (30%) ↔ [O+≡C−N2−] (4%).
Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)n, where n varies from 0 to 3. These are diamagnetic solids featuring octahedral Rh(III) centres. Depending on the value of n, the material is either a dense brown solid or a soluble reddish salt. The soluble trihydrated (n = 3) salt is widely used to prepare compounds used in homogeneous catalysis, notably for the industrial production of acetic acid and hydroformylation.
Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula C8H12, specifically [−(CH2)2−CH=CH−]2.
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.
In organic chemistry and organometallic chemistry, carbon–hydrogen bond activation is a type of organic reaction in which a carbon–hydrogen bond is cleaved and replaced with a C−X bond. Some authors further restrict the term C–H activation to reactions in which a C–H bond, one that is typically considered to be "unreactive", interacts with a transition metal center M, resulting in its cleavage and the generation of an organometallic species with an M–C bond. The intermediate of this step could then undergo subsequent reactions with other reagents, either in situ or in a separate step, to produce the functionalized product.
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.
In coordination chemistry, the bite angle is the angle on a central atom between two bonds to a bidentate ligand. This ligand–metal–ligand geometric parameter is used to classify chelating ligands, including those in organometallic complexes. It is most often discussed in terms of catalysis, as changes in bite angle can affect not just the activity and selectivity of a catalytic reaction but even allow alternative reaction pathways to become accessible.
In organometallic chemistry, a metallacycle is a derivative of a carbocyclic compound wherein a metal has replaced at least one carbon center; this is to some extent similar to heterocycles. Metallacycles appear frequently as reactive intermediates in catalysis, e.g. olefin metathesis and alkyne trimerization. In organic synthesis, directed ortho metalation is widely used for the functionalization of arene rings via C-H activation. One main effect that metallic atom substitution on a cyclic carbon compound is distorting the geometry due to the large size of typical metals.
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).
In organometallic chemistry, a transition metal indenyl complex is a coordination compound that contains one or more indenyl ligands. The indenyl ligand is formally the anion derived from deprotonation of indene. The η5-indenyl ligand is related to the η5cyclopentadienyl anion (Cp), thus indenyl analogues of many cyclopentadienyl complexes are known. Indenyl ligands lack the 5-fold symmetry of Cp, so they exhibit more complicated geometries. Furthermore, some indenyl complexes also exist with only η3-bonding mode. The η5- and η3-bonding modes sometimes interconvert.
In organometallic chemistry, extended metal atom chains (EMACs) are molecules that consist of a linear chain of directly bonded metal atoms, surrounded by organic ligands. These compounds represent the smallest molecular wires. Such species are researched for the bottom-up approach to nanoelectronics, although no applications are near term.
Molybdenum(II) acetate is a coordination compound with the formula Mo2(O2CCH3)4. It is a yellow, diamagnetic, air-stable solid that is slightly soluble in organic solvents. Molybdenum(II) acetate is an iconic example of a compound with a metal-metal quadruple bond.
Iron tetracarbonyl dihydride is the organometallic compound with the formula H2Fe(CO)4. This compound was the first transition metal hydride discovered. The complex is stable at low temperatures but decomposes rapidly at temperatures above –20 °C.
In organometallic chemistry, A-frame complexes are coordination compounds that contain two bridging bidentate ligands and a single atom bridge. They have the formula M2(μ-X)(bd)2L2, where bd is a bidentate ligand like dppm, and X and L are a wide variety of ligands. The term was coined to describe products arising from the oxidative addition to Rh(I)Rh(I) complexes.
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).
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.
The Weak-Link Approach (WLA) is a supramolecular coordination-based assembly methodology, first introduced in 1998 by the Mirkin Group at Northwestern University. This method takes advantage of hemilabile ligands -ligands that contain both strong and weak binding moieties- that can coordinate to metal centers and quantitatively assemble into a single condensed ‘closed’ structure. Unlike other supramolecular assembly methods, the WLA allows for the synthesis of supramolecular complexes that can be modulated from rigid ‘closed’ structures to flexible ‘open’ structures through reversible binding of allosteric effectors at the structural metal centers. The approach is general and has been applied to a variety of metal centers and ligand designs including those with utility in catalysis and allosteric regulation.
Brookhart's acid is the salt of the diethyl ether oxonium ion and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BAr′4). It is a colorless solid, used as a strong acid. The compound was first reported by Volpe, Grant, and Brookhart in 1992.
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.
{{cite journal}}: CS1 maint: multiple names: authors list (link)