Potassium diplatinum(II) tetrakispyrophosphite

Potassium diplatinum(II) tetrakispyrophosphite
Names
	Other names platinum pop
Identifiers
CAS Number	80011-26-3;
3D model (JSmol)	Interactive image;
	InChI InChI=1S/4K.4O5P2.2H2O.2Pt/c;;;;41-6(2)5-7(3)4;;;;/h;;;;;;;;21H2;;/q4+1;;;;;;;2-6/p+8 Key: KEWZHLOBJOYCDC-UHFFFAOYSA-V;
	SMILES [K+].[K+].[K+].[K+].[Pt+2]1234[Pt+2]([P-](=O)(O)O[P-](=O)(O)1)([P-](=O)(O)O[P-](=O)(O)2)([P-](=O)(O)O[P-](=O)(O)3)[P-](=O)(O)O[P-](=O)(O)4.O.O;
Properties
Chemical formula	H8K4O20P8Pt2
Molar mass	1122.395 g·mol−1
Appearance	yellow solid
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Potassium diplatinum(II) tetrakispyrophosphite (abbreviated as [Pt₂(pop)₄]⁴⁻) is the inorganic compound with the formula K₄[Pt₂(HO₂POPO₂H)₄]. It is a water-soluble yellow salt. The compound has a long-lived, strongly luminescent excited state, with an emission maximum at ~510 nm and a lifetime near 10 μs.^[1]

Synthesis and reactions

The complex is prepared by heating a mixture of potassium tetrachloroplatinate and phosphorous acid:^[2]

2 K₂PtCl₄ + 8 H₃PO₃ → K₄[Pt₂(HO₂POPO₂H)₄] + 8 HCl + 4 H₂O

Several quat salt derivatives are known.^[3]^[4]

The anion reacts with boron trifluoride to give the BF₂-capped complex [Pt₂(P₂PO₅)₄(BF₂)₈]^4-.^[5]

The compound reacts with halogens to give Pt(III) dimers:

K₄[Pt₂(HO₂POPO₂H)₄ + Cl₂ → K₄[Pt₂(HO₂POPO₂H)₄Cl₂]

With substoichiometric halogen, linear chain compounds result.

Structure

The pair of square-planar platinum(II) centers are bridged by four pyrophosphito (HO(O)POP(O)OH^2-) ligands. The ligands interact via hydrogen bonds between the POH and P=O group. The Pt---Pt separation is 293 pm for the dihydrate. In the Pt(III) dichloride, the Pt-Pt distance is 270 pm, indicating Pt-Pt bonding.^[1]

References

^ ^a ^b Roundhill, D. Max; Gray, Harry B.; Che, Chi Ming (1989). "Pyrophosphito-Bridged Diplatinum Chemistry". Accounts of Chemical Research. 22 (2): 55–61. doi:10.1021/ar00158a002.
^ Alexander, K. A.; Bryan, S. A.; Dickson, M. K.; Hedden, D.; Roundhill, D. Max (1986). "Potassium Tetrakis[Dihydrogen Diphosphito(2-)]Diplatinate(II)". Inorganic Syntheses: 211–213. doi:10.1002/9780470132555.ch61.
^ Yasuda, Nobuhiro; Uekusa, Hidehiro; Ohashi, Yuji (2004). "X-ray Analysis of Excited-State Structures of the Diplatinum Complex Anions in Five Crystals with Different Cations". Bulletin of the Chemical Society of Japan. 77 (5): 933–944. doi:10.1246/bcsj.77.933.
^ Iguchi, Hiroaki; Takaishi, Shinya; Breedlove, Brian K.; Yamashita, Masahiro; Matsuzaki, Hiroyuki; Okamoto, Hiroshi (2012). "Controlling the Electronic States and Physical Properties of MMX-Type Diplatinum-Iodide Chain Complexes via Binary Countercations". Inorganic Chemistry. 51 (18): 9967–9977. doi:10.1021/ic301469u. PMID 22946488.
^ Záliš, Stanislav; Lam, Yan-Choi; Gray, Harry B.; Vlček, Antonín (2015). "Spin–Orbit TDDFT Electronic Structure of Diplatinum(II,II) Complexes". Inorganic Chemistry. 54 (7): 3491–3500. doi:10.1021/acs.inorgchem.5b00063. PMID 25775368.

[Max-1] Roundhill, D. Max; Gray, Harry B.; Che, Chi Ming (1989). "Pyrophosphito-Bridged Diplatinum Chemistry". Accounts of Chemical Research. 22 (2): 55–61. doi:10.1021/ar00158a002.

[2] Alexander, K. A.; Bryan, S. A.; Dickson, M. K.; Hedden, D.; Roundhill, D. Max (1986). "Potassium Tetrakis[Dihydrogen Diphosphito(2-)]Diplatinate(II)". Inorganic Syntheses: 211–213. doi:10.1002/9780470132555.ch61.

[3] Yasuda, Nobuhiro; Uekusa, Hidehiro; Ohashi, Yuji (2004). "X-ray Analysis of Excited-State Structures of the Diplatinum Complex Anions in Five Crystals with Different Cations". Bulletin of the Chemical Society of Japan. 77 (5): 933–944. doi:10.1246/bcsj.77.933.

[4] Iguchi, Hiroaki; Takaishi, Shinya; Breedlove, Brian K.; Yamashita, Masahiro; Matsuzaki, Hiroyuki; Okamoto, Hiroshi (2012). "Controlling the Electronic States and Physical Properties of MMX-Type Diplatinum-Iodide Chain Complexes via Binary Countercations". Inorganic Chemistry. 51 (18): 9967–9977. doi:10.1021/ic301469u. PMID 22946488.

[5] Záliš, Stanislav; Lam, Yan-Choi; Gray, Harry B.; Vlček, Antonín (2015). "Spin–Orbit TDDFT Electronic Structure of Diplatinum(II,II) Complexes". Inorganic Chemistry. 54 (7): 3491–3500. doi:10.1021/acs.inorgchem.5b00063. PMID 25775368.

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