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Sensitized Near‐Infrared Emission from Complexes of Yb III , Nd III and Er III by Energy‐Transfer from Covalently Attached Pt II ‐Based Antenna Units

2003; Wiley; Volume: 9; Issue: 21 Linguagem: Inglês

10.1002/chem.200305132

1521-3765

N.M. Shavaleev, L.P. Moorcraft, Simon J. A. Pope, Zöe R. Bell, Stephen Faulkner, Michael D. Ward,

Magnetism in coordination complexes

A series of dinuclear platinum(II)-lanthanide(iii) complexes has been prepared in which a square-planar Pt(II) unit, either [(PPh(3))(2)Pt(pdo)] (H(2)pdo=5,6-dihydroxyphenanthroline) or [Cl(2)Pt(dppz)] [dppz=2,3-bis(2-pyridyl)pyrazine], is connected to a Ln(dik)(3) unit ("dik"=a 1,3-diketonate ligand). The mononuclear complexes [(PPh(3))(2)Pt(pdo)] and [Cl(2)Pt(dppz)] both have external, vacant N,N-donor diimine-type binding sites that react with various [Ln(dik)(3)(H(2)O)(2)] units to give complexes [(PPh(3))(2)Pt(micro-pdo)Ln(tta)(3)] (series A; Htta=thenoyltrifluoroacetone), [Cl(2)Pt(micro-dppz)Ln(tta)(3)] (series B); and [Cl(2)Pt(micro-dppz)Ln(btfa)(3)] (series C; Hbtfa=benzoyltrifluoroacetone); in all of these the lanthanide centres are eight-coordinate. The lanthanides used exhibit near-infrared luminescence (Nd, Yb, Er). Crystal structures of members of each series are described. In all complexes, excitation into the Pt-centred absorption band (at 520 nm for series A complexes; 440 nm for series B and C complexes) results in characteristic near-IR luminescence from the Nd, Yb or Er centres in both the solid state and in CH(2)Cl(2), following energy-transfer from the Pt antenna chromophore. This work demonstrates how d-block-derived chromophores, with their intense and tunable electronic transitions, can be used as sensitisers to achieve near-infrared luminescence from lanthanides in suitably designed heterodinuclear complexes based on simple bridging ligands.