Chloropentamminecobalt chloride
{{Short description|Cobalt compound}}
{{Chembox
| Name = Pentaamminechlorocobalt(III) chloride
| ImageFileL1 = CoA5Cl3.svg
| ImageSizeL1 = 120px
| ImageFileR1 = CoA5ClCl2.jpg
| ImageSizeL2 = 280px
| IUPACName = Pentaamminechloridocobalt(III) chloride
| OtherNames = Pentaamminechlorocobalt(III) chloride
|Section1={{Chembox Identifiers
| CASNo = 13859-51-3
| PubChem =15771825
| ChemSpiderID = 140421
| EINECS = 237-594-8
| SMILES = [Cl-].Cl[Co-3]([NH3+])([NH3+])([NH3+])([NH3+])[NH3+].[Cl-] }}
|Section2={{Chembox Properties
| Formula = [Co(NH3)5Cl]Cl2
| MolarMass = 250.4 g/mol
| Appearance = red-violet rhomb-shaped crystal
| Density = 1.783 g/mL
| MeltingPt =
| BoilingPt = N/A
| VaporPressure = 5990 mm Hg
| Solubility = 0.4 g/100 mL }}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
|Section4={{Chembox Thermochemistry
| DeltaHf = -1037.6 kJ/mol
| DeltaGf = −606.48 kJ/mol
| DeltaHc =
| Entropy =
| HeatCapacity =
}}
}}
Chloropentamminecobalt chloride is the dichloride salt of the coordination complex [Co(NH3)5Cl]2+. It is a red-violet, diamagnetic, water-soluble salt. The compound has been of academic and historical interest.
Synthesis and reactions
The salt is prepared with a two-step process starting with oxidizing a solution of cobalt chloride and ammonia.{{cite book |author=Gert G. Schlessinger|title=Inorganic Syntheses |chapter=Chloropentaamminecobalt(III) Chloride |series=Inorganic Syntheses |volume=9 |page=160 |year=1967 |doi=10.1002/9780470132401.ch43|isbn=9780470132401 }}{{cite journal | title = Coordination complexes of cobalt: inorganic synthesis in the general chemistry laboratory | journal = Journal of Chemical Education | year = 1989 | author1 = Williams, Gregory M| author2 = Olmsted, John, III| author3 = Preksa, Andrew P., III | doi = 10.1021/ed066p1043| volume = 66 | issue = 12 | pages = 1043–5| bibcode = 1989JChEd..66.1043W }}
:2 CoCl2·6H2O + 10 NH3 + 2 HCl + H2O2 → 2 [Co(NH3)5(OH2)]Cl3 + 12 H2O
This intermediate is then heated to induce coordination of one of the outer sphere chloride ligands:
:[Co(NH3)5(OH2)]Cl3 → [Co(NH3)5Cl]Cl2 + H2O
The dication [Co(NH3)5Cl]2+ has idealized C4v symmetry.{{cite journal |author=G. G. Messmer|author2= E. L. Amma|title= Redetermination of the crystal structure of chloropentaamminecobalt(III) dichloride |journal= Acta Crystallogr. B |volume=24 |pages= 417–422 |year=1968 |issue= 3|doi=10.1107/S0567740868002475}}{{cite journal | title = Comparisons of π-bonding and hydrogen bonding in isomorphous compounds: [M(NH3)5Cl]Cl2 (M = Cr, Co, Rh, Ir, Ru, Os) | journal = Inorganic Chemistry | year = 1986 | author1 = Hambley, Trevor W.| author2 = Lay, Peter A. | doi = 10.1021/ic00245a020| volume = 25 | issue = 25 | pages = 4553–8}}
In an aqueous solution, chloropentaamminecobalt(III) chloride reforms aquopentammine complex. With concentrated sulfuric acid, chloropentaamminecobalt(III) chloride forms the hydrogen sulfate complex [Co(NH3)5OSO3H]2+.
History
Cobalt complexes have been of long-standing interest in inorganic chemistry because they are numerous, easily prepared, and colorful. It was partly on the basis of his study of cobalt coordination chemistry that Alfred Werner was awarded the Nobel Prize in Chemistry. Prior to Werner, the models of amine complexes postulated chains of pentavalent nitrogen centers. This Jørgensen–Bloomstrand model was overthrown by Werner who introduced the idea that coordination complexes feature metal atoms of octahedral and tetrahedral shapes, with ammonia and other ligands attached individually to the metal. Werner's model accounted for the inner sphere ligands being less reactive.{{cite journal|last1=Schwab|first1=E.|title=Cobalt|journal=Chemical & Engineering News|date=8 September 2003|volume=81|issue=36|pages=80|doi=10.1021/cen-v081n036.p080}} In [Co(NH3)5Cl]Cl2, two chloride ions are outer sphere (counter ions) and one is bound to the Co(III) center: reaction with excess silver nitrate would immediately precipitate the two chloride counter ions, but the bound chloride ion would not be precipitated.
Health
Also known as CPACC the molecule is investigated in relation with limiting the magnesium available for mitochondria and subsequent metabolic health benefits.{{Cite web |last=Antonio |first=University of Texas Health Science Center at San |date=2023-04-09 |title=Magnesium Magic: New Drug Delivers Weight Loss Even on Sugary, Fatty Diet |url=https://scitechdaily.com/magnesium-magic-new-drug-delivers-weight-loss-even-on-sugary-fatty-diet/ |access-date=2023-04-10 |website=SciTechDaily |language=en-us}}{{Cite journal |last=Madaris |first=Travis R. |last2=Venkatesan |first2=Manigandan |last3=Maity |first3=Soumya |last4=Stein |first4=Miriam C. |last5=Vishnu |first5=Neelanjan |last6=Venkateswaran |first6=Mridula K. |last7=Davis |first7=James G. |last8=Ramachandran |first8=Karthik |last9=Uthayabalan |first9=Sukanthathulse |last10=Allen |first10=Cristel |last11=Osidele |first11=Ayodeji |last12=Stanley |first12=Kristen |last13=Bigham |first13=Nicholas P. |last14=Bakewell |first14=Terry M. |last15=Narkunan |first15=Melanie |date=2023-03-28 |title=Limiting Mrs2-dependent mitochondrial Mg2+ uptake induces metabolic programming in prolonged dietary stress |url=https://pubmed.ncbi.nlm.nih.gov/36857182/ |journal=Cell Reports |volume=42 |issue=3 |pages=112155 |doi=10.1016/j.celrep.2023.112155 |issn=2211-1247 |pmid=36857182|pmc=10134742 }}{{Cite web |last=Sansom |first=Will |date=2023-03-21 |title=Novel drug makes mice slim even on sugary, fatty diet |url=https://news.uthscsa.edu/novel-drug-makes-mice-slim-even-on-sugary-fatty-diet/ |access-date=2023-04-10 |website=UT Health San Antonio |language=en-US}}