Exploring photophysical properties of new boron and palladium(ii) complexes with β-diketone pyridine type ligands: From liquid crystals to metal fluorescence probes

María José Mayoral, Paloma Ovejero, José Antonio Campo, José Vicente Heras, Elisabete Oliveira, Bruno Pedras, Carlos Lodeiro, Mercedes Cano

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30 Citations (Scopus)


Pyridine-functionalized β-diketone ligands of the type 1-(2-pyridyl)-3-(4-n-alkyloxyphenyl)propane-1,3-dione [HLR(n)py] (R = C6H4OCnH2n + 1, n = 12 (1), 14 (2)) were carried to react with the BF2 fragment giving rise to the corresponding adducts [BF2(LR(n)py)] (n = 12 (5), 14 (6)) which were characterized and their luminescent and thermal behaviour studied. All the ligands and boron derivatives are photoluminescent both in the solid state and in solution. The related compounds 2-[3-(4-n-alkyloxyphenyl)propane-1, 3-dion-1-yl]pyridinium chloride [HLR(n)pyH]Cl (n = 12 (3), 14 (4)) were also proved to have luminescent properties. On the other hand the organometallic compounds [Pd(η3-C3H 5)(HLR(14)py)][PF6] (7) and [Pd(η3-C3H5)(LR(14)pyH)][PF 6] (8), based on the coordination of the [Pd(η3-C 3H5)]+ fragment to the above neutral 2 or ionic 4 β-diketone derivatives, respectively, were also established to be luminescent materials, compound 8 exhibiting liquid crystalline properties. The luminescent behaviour of all compounds was also investigated as a function of the metal addition of Zn2+ and Cu2+ ions. As a result it is proven that the free β-diketone pyridine ligands [HLR(n)py], the related chloride salts [HLR(n)pyH]Cl and their palladium(ii) complexes behave as fluorescence chemosensors for Zn2+ and Cu 2+. The luminescent behaviour of the allyl-palladium complex 8, which exhibits enantiotropic liquid crystalline properties, was also studied as a function of the temperature. As a consequence it is established that the liquid crystal state does not quench the fluorescence emission.

Original languageEnglish
Pages (from-to)1255-1263
Number of pages9
JournalJournal Of Materials Chemistry
Issue number4
Publication statusPublished - 28 Jan 2011


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