Inorganic & Metal Complex Fluorophosphates

Metal complex fluorophosphates are attractive as catalysts in a wide range of applications. Hexafluorophosphate, being a large anion helps to stabilize large cations. Tetrakis(acetonitrile)copper (I) hexafluorophosphate is a coordination compound with the formula [Cu(CH₃CN)₄]PF₆ and is used in the synthesis of copper complexes. This compound may serve as a precursor in the non-aqueous syntheses of other Cu(I) compounds. Water-immiscible organic nitriles have been shown to selectively extract Cu²⁺ from aqueous chloride solutions. Through this method, copper can be separated from a mixture of other metals. Hexafluorophosphate is commonly used as a counter-anion for positively charged anion-receptor molecules, being a poor H-bond acceptor. Electrochemiluminescent moieties are useful in the field of medical diagnostics, environmental analysis, and food safety monitoring. The most efficient electrochemiluminescence reaction to date is based on the tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃2+) hexafluorophosphate complex (Zhou, X.; Zhu, D.; Liao, Y.; Liu, H.; Liu, H.; Ma, Z.; Xing, D. Nature Protocols, 2014, 9, 1146-–1159.

Hexafluorophosphate salts provide an inert and non-coordinating counterion in organometallic synthesis. The cationic Iridium complex, 1,5-cyclooctadiene-bis[methyldiphenylphosphine]Iridium hexafluorophosphate, is a widely used catalyst in carbohydrate chemistry for the isomerization of allyl ethers to 1-propenyl ethers. The compound [Ir(ppy-F₂)₃Me₄phen]PF₆, where ppy-F₂ is 2-(2’,4’-fluorophenyl)pyridine (Me₄phen:3,4,7,8-tetramethyl-1,10-phenanthroline) is used to prepare a solid-state light-emitting electrochemical cell (LEC). A series of oxy-fluorinated open-framework iron phosphates have also been reported. Manganese(III) fluorophosphates have been synthesized hydrothermally in a fluoride-rich medium, through the use of MnF₃, HPF₆, and monovalent metal fluorides as reactants.