In chemistry, an arsaalkyne is chemical compound with a triple bond between carbon and arsenic. These organoarsenic compounds are rare, especially in comparison with the phosphaalkynes. The parent HCAs has been characterized spectroscopically, otherwise the only arsaalkynes have bulky organic substituents. [1]
Arsaalkynes are produced by dehydrohalogenation or related base-induced elimination reactions. The case of HCAs is illustrative:
Owing to the principles of the double bond rule, arsaalkynes tend to oligomerize more readily than the phosphorus analogues. Thus attempts to prepare AsCCMe3 produce the tetramer, which has a cubane structure. [2] The very bulky substituent C6H2-2,4,6-(t-Bu)3 does however allow the crystallization of the monomeric arsaalkyne. Its As-C bond length is 1.657(7) Å. [3]
Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is generally a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape (conformation) and reactivity of ions and molecules. Steric effects complement electronic effects, which dictate the shape and reactivity of molecules. Steric repulsive forces between overlapping electron clouds result in structured groupings of molecules stabilized by the way that opposites attract and like charges repel.
Organotin chemistry is the scientific study of the synthesis and properties of organotin compounds or stannanes, which are organometallic compounds containing tin carbon bonds. The first organotin compound was diethyltin diiodide, discovered by Edward Frankland in 1849. The area grew rapidly in the 1900s, especially after the discovery of the Grignard reagents, which are useful for producing Sn–C bonds. The area remains rich with many applications in industry and continuing activity in the research laboratory.
Diphosphene is a type of organophosphorus compound that has a phosphorus–phosphorus double bond, denoted by R-P=P-R'. These compounds are not common but are of theoretical interest. Normally, compounds with the empirical formula RP exist as rings. However, like other multiple bonds between heavy main-group elements, P=P double bonds can be stabilized by a large steric hindrance from the substitutions. The first isolated diphosphene bis(2,4,6-tri-tert-butylphenyl)diphosphene was exemplified by Masaaki Yoshifuji and his coworkers in 1981, in which diphosphene is stabilized by two bulky phenyl group.
In chemistry, a phosphaalkyne is an organophosphorus compound containing a triple bond between phosphorus and carbon with the general formula R-C≡P. Phosphaalkynes are the heavier congeners of nitriles, though, due to the similar electronegativities of phosphorus and carbon, possess reactivity patterns reminiscent of alkynes. Due to their high reactivity, phosphaalkynes are not found naturally on earth, but the simplest phosphaalkyne, phosphaethyne (H-C≡P) has been observed in the interstellar medium.
Organogermanium chemistry is the science of chemical species containing one or more C–Ge bonds. Germanium shares group 14 in the periodic table with carbon, silicon, tin and lead. Historically, organogermanes are considered as nucleophiles and the reactivity of them is between that of organosilicon and organotin compounds. Some organogermanes have enhanced reactivity compared with their organosilicon and organoboron analogues in some cross-coupling reactions.
Organoscandium chemistry is an area with organometallic compounds focused on compounds with at least one carbon to scandium chemical bond. The interest in organoscandium compounds is mostly academic but motivated by potential practical applications in catalysis, especially in polymerization. A common precursor is scandium chloride, especially its THF complex.
Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity.
Cyclodiphosphazanes are saturated four membered P2N2 ring systems and one of the major classes of cyclic phosphazene compounds. Bis(chloro)cyclodiphosphazanes, (cis-[ClP(μ-NR)]2) are important starting compounds for synthesizing a variety of cyclodiphosphazane derivatives by nucleophilic substitution reactions; are prepared by reaction of phosphorus trichloride (PCl3) with a primary amine (RNH2) or amine hydrochlorides (RNH3Cl).
Phosphinidenes are low-valent phosphorus compounds analogous to carbenes and nitrenes, having the general structure RP. The "free" form of these compounds is conventionally described as having a singly-coordinated phosphorus atom containing only 6 electrons in its valence level. Most phosphinidenes are highly reactive and short-lived, thereby complicating empirical studies on their chemical properties. In the last few decades, several strategies have been employed to stabilize phosphinidenes, and researchers have developed a number of reagents and systems that can generate and transfer phosphinidenes as reactive intermediates in the synthesis of various organophosphorus compounds.
tert-Butylphosphaacetylene is an organophosphorus compound. Abbreviated t-BuCP, it was the first example of an isolable phosphaalkyne. Prior to its synthesis, the double bond rule had suggested that elements of Period 3 and higher were unable to form double or triple bonds with lighter main group elements because of weak orbital overlap. The synthesis of t-BuCP discredited much of the double bond rule and opened new studies into the formation of unsaturated phosphorus compounds.
Metal bis(trimethylsilyl)amides are coordination complexes composed of a cationic metal with anionic bis(trimethylsilyl)amide ligands and are part of a broader category of metal amides.
Titanium ethoxide is a chemical compound with the formula Ti4(OCH2CH3)16. It is a commercially available colorless liquid that is soluble in organic solvents but hydrolyzes readily. Alkoxides of titanium(IV) and zirconium(IV) are used in organic synthesis and materials science. They adopt more complex structures than suggested by their empirical formulas.
In chemistry, a transition metal boryl complex is a molecular species with a formally anionic boron center coordinated to a transition metal. They have the formula LnM-BR2 or LnM-(BR2LB) (L = ligand, R = H, organic substituent, LB = Lewis base). One example is (C5Me5)Mn(CO)2(BH2PMe3) (Me = methyl). Such compounds, especially those derived from catecholborane and the related pinacolborane, are intermediates in transition metal-catalyzed borylation reactions.
Iminoboranes comprise a group of organoboron compounds with the formula RB=NR'. They are electronically related to acetylenes but are usually more reactive due to the polarity.
An N-Heterocyclic silylene (NHSi) is an uncharged heterocyclic chemical compound consisting of a divalent silicon atom bonded to two nitrogen atoms. The isolation of the first stable NHSi, also the first stable dicoordinate silicon compound, was reported in 1994 by Michael Denk and Robert West three years after Anthony Arduengo first isolated an N-heterocyclic carbene, the lighter congener of NHSis. Since their first isolation, NHSis have been synthesized and studied with both saturated and unsaturated central rings ranging in size from 4 to 6 atoms. The stability of NHSis, especially 6π aromatic unsaturated five-membered examples, make them useful systems to study the structure and reactivity of silylenes and low-valent main group elements in general. Though not used outside of academic settings, complexes containing NHSis are known to be competent catalysts for industrially important reactions. This article focuses on the properties and reactivity of five-membered NHSis.
(Pentamethylcyclopentadienyl)aluminium(I) is an organometallic compound with the formula Al(C5Me5) ("Me" is a methyl group; CH3). The compound is often abbreviated to AlCp* or Cp*Al, where Cp* is the pentamethylcyclopentadienide anion (C5Me5−). Discovered in 1991 by Dhmeier et al., AlCp* serves as the first ever documented example of a room temperature stable monovalent aluminium compound. In its isolated form, Cp*Al exists as the tetramer [Cp*Al]4, and is a yellow crystal that decomposes at temperatures above 100 °C but also sublimes at temperatures above 140 °C.
Plumbylenes (or plumbylidenes) are divalent organolead(II) analogues of carbenes, with the general chemical formula, R2Pb, where R denotes a substituent. Plumbylenes possess 6 electrons in their valence shell, and are considered open shell species.
(Trimethylsilyl)methyllithium is classified both as an organolithium compound and an organosilicon compound. It has the empirical formula LiCH2Si(CH3)3, often abbreviated LiCH2tms. It crystallizes as the hexagonal prismatic hexamer [LiCH2tms]6, akin to some polymorphs of methyllithium. Many adducts have been characterized including the diethyl ether complexed cubane [Li4(μ3-CH2tms)4(Et2O)2] and [Li2(μ-CH2tms)2(tmeda)2].
1-Phosphaallenes is are allenes in which the first carbon atom is replaced by phosphorus, resulting in the structure: -P=C=C<.
A magnesium(I) dimer is a molecular compound containing a magnesium to magnesium bond (Mg-Mg), giving the metal an apparent +1 oxidation state. Alkaline earth metals are commonly found in the +2-oxidation state, such as magnesium. The M2+ are considered as redox-inert, meaning that the +2 state is significant. However, recent advancements in main group chemistry have yielded low-valent magnesium (I) dimers, also given as Mg (I), with the first compound being reported in 2007. They can be generally represented as LMg-MgL, with L being a monoanionic ligand. For example, β-diketiminate, commonly referred to as Nacnac, is a useful chelate regarding these complexes. By tuning the ligand, the thermodynamics of the complex change. For instance, the ability to add substituents onto Nacnac can contribute to the steric bulk, which can affect reactivity and stability. As their discovery has grown, so has their usefulness. They are employed in organic and inorganic reduction reactions. It is soluble in a hydrocarbon solvent, like toluene, stoichiometric, selective, and safe.