The coordination chemistry of fluorescent pyridinyl- and quinolinyl-phthalimide ligands with the {Au-I-PPh3} cationic unit

Mullice, Lucy A. and Thorp-Greenwood, Flora L. and Laye, Rebecca H. and Coogan, Michael and Kariuki, BM and Pope, Simon J. A. (2009) The coordination chemistry of fluorescent pyridinyl- and quinolinyl-phthalimide ligands with the {Au-I-PPh3} cationic unit. Dalton Transactions, 38 (34). pp. 6836-6842. ISSN 1477-9234

Abstract

The new mono-dentate ligands, 2-(2-aminoethyl)-N-phthalimido-pyridine (L4) and 8-amino-N-phthalimido-quinoline (L6), were synthesised using a solvent-free melt method. These ligands together with L1–3,5 (3-amino-N-phthalimido-pyridine; 3-aminomethyl-N-phthalimido-pyridine; 4-aminomethyl-N-phthalimido-pyridine; 3-amino-N-phthalimido-quinoline) were then used to access six luminescent AuI complexes of the generic type {Ph3P–Au–Ln}(OTf). X-Ray crystallography has been used to structurally characterise three of the complexes showing that in the cases of L1 and L3 the complexes adopt an approximately linear P–Au–N coordination geometry. However, in the case of the sterically demanding L6 the structure shows distortions within the ligand and deviations from a linear coordination geometry. Solution state 1H and 31P{1H} NMR confirmed that the proposed formulations and coordination modes exist in solution. At room temperature the photophysical studies showed that the emission from each of the six complexes was in the visible region (395–475 nm) and assigned to a ligand-centred fluorescence (τ < 10 ns) in each case.