In chemistry, the middle dot is used to separate the parts of formulas of addition compounds, mixture salts or solvates (mostly hydrates), such as of copper(II) sulphate pentahydrate, .
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Cocrystals are "solids that are crystalline single phase materials composed of two or more different molecular or ionic compounds generally in a stoichiometric ratio which are neither solvates nor simple salts." A broader definition is that cocrystals "consist of two or more components that form a unique crystalline structure having unique properties." Several subclassifications of cocrystals exist. Cocrystals can encompass many types of compounds, including hydrates, solvates and clathrates, which represent the basic principle of host–guest chemistry.
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Like other polycyclic aromatic compounds, perylene is reduced by alkali metals to give a deeply colored radical anion and a dianion. The diglyme solvates of these salts have been characterized by X-ray crystallography.
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There are four molecules per unit cell. It reacts with petrolatum, nitromethane, acetonitrile, dimethylformamide, and over 25° with carbon tetrachloride. Titanyl perchlorate also exists in solvates with water, dimethyl sulfoxide, dioxane, pyridine-N-oxide and quinoline-N-oxide.
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Yasuda, M; Haga, M; Nagaoka, Y; Baba, A. Eur. J. Org. Chem. 2010, 5359–5363. :File:Two_intermediates_formed_during_IMA.svg A variety of organoindium(III) species such as InRX3− and solvates of RXIn+, R2In+, and X2In+ are thought to rapidly interconvert at room temperature.
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In other substitution reactions, it undergoes halogenation. Polychlorinated biphenyls were once popular pesticides. Lithium biphenyl contains the radical anion, which is highly reducing (-3.1 V vs Fc+/0). Several solvates of alkali metal salts of biphenyl anion have been characterized by X-ray crystallography.
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Most commonly, APIs have hydrogen-bonding capability at their exterior which makes them more susceptible to polymorphism, especially in the case of cocrystal solvates which can be known to have different polymorphic forms. Such a case is in the drug sulfathiazole, a common oral and topical antimicrobial, which has over a hundred different solvates. It is thus important in the field of pharmaceuticals to screen for every polymorphic form of a cocrystal before it is considered as a realistic improvement to the existing API. Pharmaceutical cocrystal formation can also be driven by multiple functional groups on the API, which introduces the possibility of binary, ternary, and higher ordered cocrystal forms.
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At temperatures above solubility maximum the solvate is not stable even when immersed in saturated solution and melts with formation of fcc . Crystallization at temperatures above the solubility maximum results in formation of pure fcc . Millimeter-sized crystals of and can be grown from solution both for solvates and for pure fullerenes.
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Sulfoaildenafil (thioaildenafil) is a synthetic chemical compound that is a structural analog of sildenafil (Viagra). It was first reported in 2005,Li, Shuxin; Ren, Jianping; Zhao, Yanjin; Lv, Qiujun; Guo, Jinhua. Pyrazolopyrimidinethione Derivatives, Salts and Solvates thereof, Preparation Methods and Use thereof. and it is not approved by any health regulation agency.
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Solid chloroauric acid is a hydrophilic (ionic) protic solute. It is soluble in water and other oxygen-containing solvents, such as alcohols, esters, ethers, and ketones. For example, in dry dibutyl ether or diethylene glycol, the solubility exceeds 1 mol/L. Saturated solutions in the organic solvents often are the liquid solvates of specific stoichiometry.
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HMPA is a specialty solvent for polymers, gases, and organometallic compounds. It improves the selectivity of lithiation reactions by breaking up the oligomers of lithium bases such as butyllithium. Because HMPA selectively solvates cations, it accelerates otherwise slow SN2 reactions by generating more bare anions. The basic nitrogen centers in HMPA coordinate strongly to Li+.
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U.S. Patent No. 8871759 was published in 2014 for the specified compounds useful for hepatitis C virus NS5A inhibitors. The patent protects Merck's formulation for the drug and its other associated salt forms, hydrates, solvates, prodrugs and isomers. U.S. Patent No. 7973040 was published in 2011. The patent protects the invention by Merck of the macrocyclic compound within the formula as an inhibitor for NS3 protease.
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Of the solvents with dielectric constant of 10 or less, tetrahydrofuran (THF) is particularly relevant in this context, as it solvates cations strongly with the result that simple electrolytes have sufficient solubility to make the study of ion association possible. In this solvent ion association is the rule rather than the exception. Indeed, higher associates such as tetramers are often formed. Triple cations and triple anions have also been characterized in THF solutions.
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The compound has been characterized by X-ray crystallography as the solvent-free form as well as the mono- and diammonia solvates. In KNH2(NH3)2, the potassium centers are each bonded to two amido ligands and four ammonia ligands, all six of which bridge to adjacent potassium centers. The result is a chain of hexacoordinate potassium ions. The K-NH2 distances are 2.7652(11) whereas the K-NH3 distances are respectively 2.9234(11) and 3.0698(11) Å.
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A more inclusive definition is that cocrystals "consist of two or more components that form a unique crystalline structure having unique properties." Due to variation in the use of the term, structures such as solvates and clathrates may or may not be considered cocrystals in a given situation. The difference between a crystalline salt and a cocrystal lies merely in the transfer of a proton. The transfer of protons from one component to another in a crystal is dependent on the environment.
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When one substance is dissolved into another, a solution is formed. This is opposed to the situation when the compounds are insoluble like sand in water. In a solution, all of the ingredients are uniformly distributed at a molecular level and no residue remains. A solvent- solute mixture consists of a single phase with all solute molecules occurring as solvates (solvent-solute complexes), as opposed to separate continuous phases as in suspensions, emulsions and other types of non-solution mixtures.
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The determination of enantiomeric purity and absolute configuration is frequently necessary in organic synthesis. Pirkle's alcohol is applied to obtain this information by NMR spectroscopy. When Pirkle's alcohol is in solution with an ensemble of chiral molecules, short- lived diastereomeric solvates may be formed from Pirkle's alcohol and the enantiomers of the analyte. Enantiomorphic protons of the analyte enantiomers, which without Pirkle's alcohol are indistinguishable by NMR, become diastereomorphic when the analyte interacts with Pirkle's alcohol, and appear as different signals in an NMR spectrum.
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Photographer: Armin Kübelbeck, CC-BY-SA, Wikimedia Commons Solvent polarity is the most important factor in determining how well it solvates a particular solute. Polar solvents have molecular dipoles, meaning that part of the solvent molecule has more electron density than another part of the molecule. The part with more electron density will experience a partial negative charge while the part with less electron density will experience a partial positive charge. Polar solvent molecules can solvate polar solutes and ions because they can orient the appropriate partially charged portion of the molecule towards the solute through electrostatic attraction.
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Pure HBF4 has been described as a "nonexistent compound", as a sufficiently 'naked' proton is expected to abstract a fluoride from the tetrafluoroborate ion to give hydrogen fluoride and boron trifluoride: [H+][BF4–] → HF + BF3. (The same holds true for the superacids that are known by the simple formulas HPF6 and HSbF6.) However, a solution of BF3 in HF is highly acidic, having an approximate speciation of [H2F+][BF4–] and a Hammett acidity function of –16.6 at 7 mol % BF3, easily qualifying as a superacid. Although the solvent-free HBF4 has not been isolated, its solvates are well characterized. These salts consist of protonated solvent as a cation, e.g., H3O+ and , and the tetrahedral anion.
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Triethyl orthoformate is an organic compound with the formula HC(OC2H5)3. This colorless volatile liquid, the orthoester of formic acid, is commercially available. The industrial synthesis is from hydrogen cyanide and ethanol.Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, page 9288 It may also be prepared from the reaction of sodium ethoxide and chloroform: : CHCl3 \+ 3 Na+ \+ 3 EtO− -> HC(OEt)3 \+ H2 \+ 3 NaCl Triethyl orthoformate is used in the Bodroux-Chichibabin aldehyde synthesis, for example: : RMgBr + HC(OC2H5)3 → RC(H)(OC2H5)2 \+ MgBr(OC2H5) : RC(H)(OC2H5)2 \+ H2O → RCHO + 2 C2H5OH In coordination chemistry, it is used to convert metal aquo complexes to the corresponding ethanol complexes:Willem L. Driessen, Jan Reedijk "Solid Solvates: The Use of Weak Ligands in Coordination Chemistry" Inorg. Synth., 1992, Vol. 29,111–118. :[Ni(H2O)6](BF4)2 \+ 6 HC(OC2H5)3 → [Ni(C2H5OH)6](BF4)2 \+ 6 HC(O)(OC2H5) + 6 HOC2H5 Triethyl orthoformate (TEOF) is an excellent reagent for converting compatible carboxylic acids to ethyl esters.
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