Magnus's green salt

Magnus's green salt

Names
IUPAC name Tetraammineplatinum(II) tetrachloroplatinate(II)
Identifiers
CAS Number	13820-46-7
3D model (JSmol)	Interactive image
ChemSpider	141440
ECHA InfoCard	100.034.078
EC Number	237-501-0
PubChem CID	16213091
InChI InChI=1S/4ClH.4H2N.2Pt/h4*1H;4*1H2;;/q;;;;4*-1;2*+2/p-4 Key: VDZZIFNGBFCNGW-UHFFFAOYSA-J
SMILES [NH3+][Pt-2]([NH3+])([NH3+])[NH3+].Cl[Pt-2](Cl)(Cl)Cl
Properties
Chemical formula	[Pt(NH3)4][PtCl4]
Molar mass	600.09 g/mol
Appearance	green solid
Density	3.7 g/cm3
Melting point	320 °C (608 °F; 593 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y  verify  (what is  YN ?) Infobox references

Magnus's green salt is the inorganic compound with the formula [Pt(NH₃)₄][PtCl₄]. This salt is named after Heinrich Gustav Magnus, who, in the early 1830s, first reported the compound. The compound is a linear chain compound, consisting of a chain of platinum atoms. It is dark green, which is unusual for platinum compounds.

Structure

This species has attracted interest in materials chemistry and solid-state physics because of its one-dimensional structure. It contains a chain of alternating [PtCl₄]²⁻ anions and [Pt(NH₃)₄]²⁺ cations, in which the platinum atoms are separated by 3.25 Å. ^[1] It is a semiconductor.

Preparation

The compound may be prepared by combining aqueous solutions of [Pt(NH₃)₄]²⁺ and [PtCl₄]²⁻, which gives a deep green solid precipitate. ^[2] Under some conditions, this reaction affords a pink polymorph of Magnus's green salt. In this so-called "Magnus's pink salt", the square planar Pt complexes are not stacked. ^[3]

Related compounds

Magnus's green salt is one of three compounds with the empirical formula PtCl₂(NH₃)₂, the others being cisplatin (an important anticancer drug) and transplatin. ^[4] These cis and trans compounds are molecules, whereas Magnus's green salt is a polymer. This difference is manifested by the solubility of the molecular complexes in water, whereas Magnus's green salt is insoluble.

Magnus's green salt occurred as an impurity in early routes to cisplatin from potassium tetrachloroplatinate. Modern production avoids contamination by first converting the tetrachloroplatinate to potassium tetraiodoplatinate, as the iodo ligand's stronger trans effect favors the cis molecule over the polymeric salt. ^[5]

Soluble analogues of Magnus's green salt can be prepared by replacing the ammonia with ethylhexylamine. ^{[6] [7]}

The corresponding palladium compound ([Pd(NH₃)₄][PdCl₄]) is known as "Vauquelin’s salt".

History

Magnus's green salt was one of the first examples of a metal ammine complex.

References

1. Atoji, Masao; Richardson, James W.; Rundle, R. E. (June 1957). "Pt(NH₃)₄PtCl₄¹". Journal of the American Chemical Society. 79 (12): 3017–3020. doi:10.1021/ja01569a009.
2. Keller, R. N.; Moeller, Therald; Quagliano, J. V. (2007). "Tetrammineplatinum(II) Chloride: (Tetrammineplatinous Chloride)". Inorganic Syntheses. pp. 250–253. doi:10.1002/9780470132333.ch80. ISBN   978-0-470-13233-3.
3. Lucier, Bryan E. G.; Johnston, Karen E.; Xu, Wenqian; Hanson, Jonathan C.; Senanayake, Sanjaya D.; Yao, Siyu; Bourassa, Megan W.; Srebro, Monika; Autschbach, Jochen; Schurko, Robert W. (29 January 2014). "Unravelling the Structure of Magnus' Pink Salt" (PDF). Journal of the American Chemical Society. 136 (4): 1333–1351. doi:10.1021/ja4076277. PMID   24437378.
4. Wilson, Justin J.; Lippard, Stephen J. (23 April 2014). "Synthetic Methods for the Preparation of Platinum Anticancer Complexes". Chemical Reviews. 114 (8): 4470–4495. doi:10.1021/cr4004314. PMC   3999256 . PMID   24283498.
5. Alderden, Rebecca A.; Hall, Matthew D.; Hambley, Trevor W. (2006). "The Discovery and Development of Cisplatin". Journal of Chemical Education. 83 (5): 728. Bibcode:2006JChEd..83..728A. doi:10.1021/ed083p728.
6. Caseri, Walter (1 July 2004). "Derivatives of Magnus' Green Salt". Platinum Metals Review. 48 (3): 91–100. doi: 10.1595/147106704X1504 .
7. Bremi, Juliane; Caseri, Walter; Smith, Paul (2001). "A new compound derived from Magnus' green salt: solid state structure and evidence for platinum chains in solution". Journal of Materials Chemistry. 11 (10): 2593–2596. doi:10.1039/b104675f. S2CID   95456246. INIST   14086852.