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Phosphinoimidate
Phosphinoimidates, also known as phophinimides, are the anions derived from phosphine imides with the structure 3P=Nsup>− (R = alkyl or aryl). Phosphinimide ligands are used to for transition metal complexes that are highly active catalysts in some olefin polymerization reactions.Dehnicke, K.; Krieger, M.; Massa, W. Phosphoraneiminato complexes of transition metals. Coord. Chem. Rev. 1999, vol. 182, pp. 19-65. Synthesis of phosphinoimidate complexes Although phosphinoimidates are formally anions, salts of the anions are typically unavailable owing to their high basicity. Instead the ligand is installed indirectly. Staudinger reaction Preparation of phosphinoimidate complexes are achieved in high yield from the corresponding silyl derivatives R3PNSiMe3 (Me = -CH3). These derivatives are prepared by oxidation of phosphine ligands with trimethylsilyl azide, also known as the Staudinger reaction: :PR3 + Me3SiN3 → Me3SiN=PR3 + N2 Starting from these silyl compounds, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anion
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphine Imide
In chemistry a phosphine imide (sometimes abbreviated to phosphinimide) also known as a iminophosphorane is a functional group with the formula R3P=NR. While structurally related to phosphine oxide its chemistry has more in common with phosphonium ylides. Anions of this group, with the structure R3P=N−, are called phosphinoimidates and are used as ligands to form phosphinimide complexes which are highly active catalysts in some olefin polymerization reactions. Synthesis Phosphine imides can be isolated as intermediates in the Staudinger reaction and have also been prepared by the action of hydroxylamine-O-sulfonic acid on phosphines, proceeding via a p-aminophosphonium salt. Reactions and applications The functional group will readily hydrolyse to give a phosphine oxide and an amine :R3P=NR' + H2O → R3P=O + R'NH2 Phosphinimide ligands of the general formula NPR3− form transition metal phosphinimide complexeses. Some of these complexes are potential catalysts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphinimide Ligands
Phosphinimide ligands, also known as phosphorane iminato ligands, are any of a class of organic compounds of the general formula NPR3−. The R groups represent organic substituents or, in rare cases, halides or NR2 groups. NPR3− is isoelectronic with phosphine oxides (OPR3) and siloxides ( SiR3sup>−), but far more basic. By varying the R groups on P, a variety of ligands with different electronic and steric properties can be produced, and due to the high oxidation state of phosphorus, these ligands have good thermal stability. Many transition metal phosphinimide complexes have been well-developed as have main group phosphinimide complexes. In main group phosphinimide complexes, only terminal and μ2-N-bridging bonding modes are observed. The terminally bound bent ligands are primarily commonly have M-N-P bond angles ranging from 120-150°. Both the M-N and N-P bond lengths are appropriate for double bonds. This bonding can best be described by a covalent single bond wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylsilyl Azide
Trimethylsilyl azide ((CH3)3SiN3) is a chemical compound used as a reagent in organic chemistry. Preparation Trimethylsilyl azide is commercially available. It may be prepared by the reaction of trimethylsilyl chloride and sodium azide: : TMSCl + NaN3 → TMSN3 + NaCl (TMS = (CH3)3Si) Applications It is considered a safer alternative to hydrazoic acid in many reactions; however, over time it will hydrolyze to hydrazoic acid Hydrazoic acid, also known as hydrogen azide or azoimide, This also contains a detailed description of the contemporaneous production process. is a compound with the chemical formula . It is a colorless, volatile, and explosive liquid at room tem ..., and therefore must be stored free of moisture. It has been used in the Oseltamivir total synthesis. Safety Trimethylsilyl azide is incompatible with moisture, strong oxidizing agents, and strong acids. In 2014, a graduate student at the University of Minnesota was injured in an explosion that occurred in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrido Complex
Metal nitrido complexes are coordination compounds and metal clusters that contain an atom of nitrogen bound only to transition metals. These compounds are ''molecular'', i.e. discrete in contrast to the polymeric, dense nitride materials that are useful in materials science. The distinction between the molecular and solid-state polymers is not always very clear as illustrated by the materials Li6MoN4 and more condensed derivatives such as Na3MoN3. Transition metal nitrido complexes have attracted interest in part because it is assumed that nitrogen fixation proceeds via nitrido intermediates. Nitrido complexes have long been known, the first example being salts of sO3Nsup>−, described in the 19th century. Structural trends Mononuclear complexes feature terminal nitride ligands, typically with short M-N distances consistent with metal ligand multiple bonds. For example, in the anion in PPh4 oNCl4 the Mo-N distance is 163.7 pm. The occurrence of terminal nitrido ligands ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
