Potassium diplatinum(II) tetrakispyrophosphite


Potassium diplatinum tetrakispyrophosphite is the inorganic compound with the formula K4. 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.

Synthesis and reactions

The complex is prepared by heating a mixture of potassium tetrachloroplatinate and phosphorous acid:
Several quat salt derivatives are known.
The anion reacts with boron trifluoride to give the BF2-capped complex 4-.
The compound reacts with halogens to give Pt dimers:
With substoichiometric halogen, linear chain compounds result.

Structure

The pair of square-planar platinum centers are bridged by four pyrophosphito POP 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 dichloride, the Pt-Pt distance is 270 pm, indicating Pt-Pt bonding.