| 词条 | Hexol |
| 释义 |
| Watchedfields = changed | verifiedrevid = 445350005 | ImageFile = Hexol-2D-wedged.png | ImageSize = 250px | ImageFile1 = Hexol-cation-from-xtal-2000-3D-balls.png | IUPACName = Tris[tetrammine-μ-dihydroxocobalt(III)]cobalt (III) ion | OtherNames = |Section1={{Chembox Identifiers | CASNo_Ref = {{cascite|correct|??}} | CASNo = | PubChem = | SMILES = o=s(=o)([o-])[o-].[NH3+][Co-3]0([NH3+])([NH3+])([NH3+])[OH+][Co-3]12([OH+]0)([OH+][Co-3]([NH3+])([NH3+])([NH3+])([NH3+])[OH+]1)[OH+][Co-3]([NH3+])([NH3+])([NH3+])([NH3+])[OH+]2.o=s(=o)([o-])[o-].o=s(=o)([o-])[o-]}} |Section2={{Chembox Properties | Co=4 | H=42 | N=12 | O=18 | S=3 | MolarMass = | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = Sparingly soluble in water [1] }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }} Hexol is the name for various salts of a coordination complex that has historical significance. The salts were the first synthetic non-carbon-containing chiral compounds.[1] The sulfate salt has the formula {[Co(NH3)4(OH)2]3Co}(SO4)3. Preparation and optical resolutionSalts of hexol were first described by Jørgensen.[2] The salt is prepared by heating [Co(NH3)4(H2O)2]3+ with dilute base such as ammonia followed by precipitation of the sulfate salt: 4 [Co(NH3)4(H2O)2]3+ → {[Co(NH3)4(OH)2]3Co}6+ + 4 NH4+ + 2 H+ + 2 H2O Depending on the conditions one obtains the 9-hydrate, the 6-hydrate, and the 4-hydrate. These salts exists as dark brownish-violet or black tabular crystals. The salts have low solubility in water. The cation can be quantitatively precipitated from its yellow-gray chromate and hexachloroplatinate salts. When treated with concentrated hydrochloric acid, hexol converts to cis-diaquotetramminecobalt(III) sulfate. In boiling dilute sulfuric acid, hexol degrades with evolution of oxygen and nitrogen.[3] Optical resolutionIn a historic set of experiments, Alfred Werner obtained chiral resolution by fractional crystallisation of the diastereomeric D-(+)-bromocamphorsulfonate salt. This ion has a high specific rotation of 2640°.[4]{{verification failed|reason=claimed specific optical rotation not found in the article|date=October 2018}} More efficient methods involve the bis(tartrato)diantimonate(III) salt.[5] The "second hexol"Werner also described a second achiral hexol (a minor byproduct from the production of Fremy's salt) that he incorrectly identified as a linear tetramer. The second hexol is hexanuclear (contains six cobalt centres in each ion), not tetranuclear.[6] References1. ^Miessler, G. L. and Tarr, D. A. Inorganic Chemistry, 3rd ed., Pearson/Prentice Hall publisher, {{ISBN|0-13-035471-6}}. 2. ^{{cite journal|author=Jørgensen, S. M. |title=Zur Konstitution der Kobalt-, Chrom- und Rhodiumbasen|journal= Zeitschrift für anorganische Chemie |year=1898|volume =16| pages =184–197|doi=10.1002/zaac.18980160116}} 3. ^1 {{cite journal|author1=Kauffman, George B. |author2=Pinnell, Robert P. |title=Tris[Tetrammine-μ-Dihydroxo-Cobalt(III)] Cobalt(III) Sulfate 4-Hydrate|journal= Inorganic Syntheses|year= 1960 |volume =6|pages=176–179|doi=10.1002/9780470132371.ch56|isbn=9780470132371}} 4. ^{{cite journal | title=Über mehrkernige Metallammoniake | language=de |trans-title=Poly-nucleated Metal-amines | author=Werner, A. | journal=Ber. Dtsch. Chem. Ges. | year=1907 | volume=40 | issue=2 | pages=2103–2125 | doi=10.1002/cber.190704002126}} 5. ^{{cite journal|author1=Yasui, Takaji |author2=Ama, Tomoharu |author3=Kauffman, George B. |title=Resolution of the Dodecaamminehexa-μ-Hydroxo-Tetracobalt(III) Ion|journal= Inorganic Syntheses |year=1992|volume=29|pages=169–174|doi=10.1002/9780470132609.ch41|isbn=9780470132609}} 6. ^{{cite journal|title=The rediscovery of Alfred Werner's second hexol|journal=Chemical Communications|issue=20|year= 2004|pages=2322–2323|doi=10.1039/B408277J|last1=Jackson|first1=W. Gregory|last2=McKeon|first2=Josephine A.|last3=Zehnder|first3=Margareta|last4=Neuberger|first4=Markus|last5=Fallab|first5=Silvio}} External links
3 : Cobalt compounds|Stereochemistry|Coordination compounds |
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