Molecular cyclo -P 3 complexes of the rare-earth elements via a one-pot reaction and selective reduction.

Synthesis of new organo-lanthanide polyphosphides with an aromatic cyclo -[P 4 ] 2- moiety and a cyclo -[P 3 ] 3- moiety is presented. For this purpose, the divalent Ln II -complexes [(NON)Ln II (thf) 2 ] (Ln = Sm, Yb) ((NON) 2- = 4,5-bis(2,6-diisopropylphenyl-amino)-2,7-di- tert -butyl-9,9-dimethylxanthene) and trivalent Ln III -complexes [(NON)Ln III BH 4 (thf) 2 ] (Ln = Y, Sm, Dy) were used as precursors in the reduction process of white phosphorus. While using [(NON)Ln II (thf) 2 ] as a one-electron reducing agent the formation of organo-lanthanide polyphosphides with a cyclo -[P 4 ] 2- Zintl anion was observed. For comparison, we investigated a multi-electron reduction of P 4 by a one-pot reaction of [(NON)Ln III BH 4 (thf) 2 ] with elemental potassium. As products molecular polyphosphides with a cyclo -[P 3 ] 3- moiety were isolated. The same compound could also be obtained by reducing the cyclo -[P 4 ] 2- Zintl anion within the coordination sphere of Sm III in [{(NON)Sm III (thf) 2 } 2 (μ-η 4 :η 4 -P 4 )]. Reduction of a polyphosphide within the coordination sphere of a lanthanide complex is unprecedented. Additionally, the magnetic properties of the dinuclear Dy III -compound bearing a bridging cyclo -[P 3 ] 3- moiety were investigated.