Luminescence of five-coordinated nickel(II) complexes with substituted-8-hydroxyquinolines and macrocyclic ligands
- Santana, M.D. 1
- García-Bueno, Rocío. 1
- García, Gabriel. 1
- Pérez, J. 2
- García, L. 2
- Monge, M. 3
- Laguna, A. 4
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1
Universidad de Murcia
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2
Universidad Politécnica de Cartagena
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3
Universidad de La Rioja
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4
Universidad de Zaragoza
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ISSN: 1477-9226
Año de publicación: 2010
Volumen: 39
Número: 7
Páginas: 1797-1806
Tipo: Artículo
Otras publicaciones en: Dalton Transactions
Resumen
A series of heteroleptic quinolinolate pentacoordinated nickel(ii) complexes, [Ni(mcN 3)(R 1,R 2,R 3-8-hq)](PF 6), were synthesized and characterized by spectroscopic methods. Single-crystal X-ray diffraction studies for [(Me 3-mcN 3)Ni(N,O-2-CN-8-hq)][PF 6] (6a), [(Me 4-mcN 3)Ni(N,O-8-hq)][PF 6] (2b) and [(Me 4-mcN 3)Ni(N,O-5,7-I 2-8-hq)][PF 6] (5b) indicate that these complexes consist of a square-pyramidal ligand arrangement containing one chelating quinolinolate and one macrocyclic ligand (mcN 3). Variation of the substituents on quinolinolate ligands imposes obvious electronic or structural effects on the nickel atom. These chromophores absorb moderately in the visible region and emit in the yellowish-green spectral region from a quinolinolate-centered intraligand charge-transfer excited state. The emission maxima are in the range 520-548 nm, with quantum yields between 0.11 and 1.63%, in deoxygenated organic solvents at room temperature. TD-DFT calculations allow exploration of the photophysical properties of complex [(Me 4-mcN 3)Ni(N,O-8-hq)][PF 6] 2b and reveal the influence of the quinolinolate ligand on the HOMO/LUMO energies and oscillator strengths. © The Royal Society of Chemistry 2010.