Synthesis, X-ray Powder Structure, and Photophysical Properties of Three New Ce(III) Sulfate- Diaminotetraphosphonate-Based Coordination Polymers

The hydrothermal reactions between Ce(SO(4))(2) and two diamino tetraphosphonic acids (H(8)L(1) = 1.4-N,N,N',N'-diaminobutyl tetraphosphonic acids and H(8)L(2) = 1.4-N,N,N',N'-diaminobutyl tetraphosphonic acid) lead to the formation of three new mixed Ce(111) sulfate-tetraphosphonate polymeric frameworks of general formula [[Ce(2)(H(2)O)(x)-(H(4)L(m))(HSO(4))(2)]center dot yH(2)O](n) with x = 6, 2, 6.y = 4, 2, 0, and m = 1,1,2 for 1, 2, and 3, respectively. Two pseudopolyrnorphic structures, 1 and 2, are obtained by varying the synthetic conditions. The structures have been solved oh info. from laboratory X-ray powder diffraction data and refined using the Rietveld method. 1, 2, and 3 are 3D networks with different topology. In all the structures, the Ce metals are eight-coordinated from the oxygen atoms belonging either to water molecules, phosphonates. or sulphates groups. While the latter acts as bidentate hgands with the CeO(x) polyhedra, the coordination of the phosphonates groups differs in the structures. The ceriumlphosphonate moieties form 1D columnar pillars, parallel to the a axis in 1D and corrugated 2D layers in 2 and 3. The sulfate groups connect the 1D and 2D objects to form the 3D network, The thermal behavior of the three compounds has been studied by coupling thermogravimetric and in situ diffractometric analyses. The three new materials are dual luminescent compounds. emitting in both the UV and visible regions. in two different time scales.