Herrera, Juan-Manuel, Pope, Simon J. A. ![]() |
Abstract
Reaction of the cyanoruthenate anions [Ru(bpym)(CN)4]2- and [{Ru(CN)4}2(μ-bpym)]4- (bpym = 2,2‘-bipyrimidine) with lanthanide(III) salts resulted in the crystallization of coordination networks based on Ru−CN−Ln bridges. Four types of structure were obtained: [Ru(bpym)(CN)4][Ln(NO3)(H2O)5] (Ru−Ln; Ln = Sm, Nd, and Gd) are one-dimensional helical chains; [Ru(bpym)(CN)4]2[Ln(NO3)(H2O)2][Ln(NO3)0.5(H2O)5.5](NO3)0.5·5.5H2O (Ru−Ln; Ln = Er and Yb) are two-dimensional sheets containing cross-linked chains based on Ru2Ln2(μ-CN)4 diamond units, which are linked into one-dimensional chains via shared Ru atoms; [{Ru(CN)4}2(μ-bpym)][Ln(NO3)(H2O)5]2·3H2O (Ru2−Ln; Ln = Nd and Sm) are one-dimensional ladders with parallel Ln−NC−Ru−CN−Ln−NC strands connected by the bipyrimidine “cross pieces” acting as rungs on the ladder; and [{Ru(CN)4}2(μ-bpym)][Ln(H2O)6]0.5[Ln(H2O)4](NO3)0.5·nH2O (Ru2−Ln; Ln = Eu, Gd, and Yb; n = 8.5, 8.5, and 8, respectively) are three-dimensional networks in which two-dimensional sheets of Ru2Ln2(μ-CN)4 diamonds are connected via cyanide bridges to Ln(III) ions between the layers. Whereas Ru−Gd shows weak triplet metal-to-ligand charge-transfer (3MLCT) luminescence in the solid state from the Ru-bipyrimidine chromophore, in Ru−Nd, Ru−Er, and Ru−Yb, the Ru-based emission is quenched, and all of these show, instead, sensitized lanthanide-based near-IR luminescence following a Ru → Ln energy transfer. Similarly, Ru2−Nd and Ru2−Yb show lanthanide-based near-IR emission following excitation of the Ru-bipyrimidine chromophore. Time-resolved luminescence measurements suggest that the Ru → Ln energy-transfer rate is faster (when Ln = Yb and Er) than in related complexes based on the [Ru(bipy)(CN)4]2- chromophore, because the lower energy of the Ru-bpym 3MLCT provides better spectroscopic overlap with the low-energy f−f states of Yb(III) and Er(III). In every case, the lanthanide-based luminescence is relatively short-lived as a result of the CN oscillations in the lattice.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Chemistry |
Subjects: | Q Science > QD Chemistry |
Publisher: | American Chemical Society |
ISSN: | 0020-1669 |
Last Modified: | 21 Oct 2022 10:53 |
URI: | https://orca.cardiff.ac.uk/id/eprint/41629 |
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