Lanthanide Complexes of [α-2-P2W17O61]10-: Solid State and Solution Studies
journal contributionposted on 17.10.2002, 00:00 by Qunhui Luo, Robertha C. Howell, Judit Bartis, Michaela Dankova, William DeW. Horrocks,, Arnold L. Rheingold, Lynn C. Francesconi
We have isolated the 1:1 Ln:[α-2-P2W17O61]10- complexes for a series of lanthanides. The single-crystal X-ray structure of the Eu3+ analogue reveals two identical [Eu(H2O)3(α-2-P2W17O61)]7- moieties connected through two Eu−O−W bonds, one from each polyoxometalate unit. An inversion center relates the two polyoxometalate units. The Eu(III) ion is substituted for a [WO]4+ unit in the “cap” region of the tungsten−oxygen framework of the parent Wells−Dawson ion. The point group of the dimeric molecule is Ci. The extended structure is composed of the [Eu(H2O)3(α-2-P2W17O61)]214- anions linked together by surface-bound potassium cations. The space group is P1̄, a = 12.7214(5) Å, b = 14.7402(7) Å, c = 22.6724(9) Å, α = 71.550(3)°, β = 84.019(3)°, γ = 74.383(3)°, V = 3883.2(3) Å3, Z = 1. The solution studies, including 183W NMR spectroscopy and luminescence lifetime measurements, show that the molecules dissociate in solution to form monomeric [Ln(H2O)4(α-2-P2W17O61)]7- species.