Iridium(III) Complexes with Sulfonyl and Fluorine Substituents: Synthesis, Stereochemistry and Effect of Functionalisation on their Photophysical Properties

Authors

  • Roberta Ragni,

    1. Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy), Fax: (+39) 0805442076
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  • Enrico Orselli,

    1. Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Mendelstrasse 7, 48149 Münster (Germany), Fax: (+49) 2519802834
    2. Center for Nanotechnology (CeNTech), Heisenbergstrasse 11, 48149 Münster (Germany)
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  • Gregg S. Kottas,

    1. Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Mendelstrasse 7, 48149 Münster (Germany), Fax: (+49) 2519802834
    2. Center for Nanotechnology (CeNTech), Heisenbergstrasse 11, 48149 Münster (Germany)
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  • Omar Hassan Omar,

    1. CNR-ICCOM, Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy)
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  • Francesco Babudri,

    1. Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy), Fax: (+39) 0805442076
    2. CNR-ICCOM, Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy)
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  • Adriana Pedone,

    1. Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy), Fax: (+39) 0805442076
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  • Francesco Naso,

    1. Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy), Fax: (+39) 0805442076
    2. CNR-ICCOM, Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy)
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  • Gianluca M. Farinola Prof. Dr.,

    1. Dipartimento di Chimica, Università degli Studi di Bari via Orabona 4, 70126 Bari (Italy), Fax: (+39) 0805442076
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  • Luisa De Cola Prof. Dr.

    1. Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Mendelstrasse 7, 48149 Münster (Germany), Fax: (+49) 2519802834
    2. Center for Nanotechnology (CeNTech), Heisenbergstrasse 11, 48149 Münster (Germany)
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Abstract

The synthesis and photophysical and electrochemical characterisation of new heteroleptic iridium complexes with electron-withdrawing sulfonyl groups and fluorine atoms bound to phenylpyridine ligands are reported. The emission energy of these materials strongly depends on the position of the sulfonyl groups and on the number of fluorine substituents. A 90 nm wide tuning range of photoluminescence from the blue-green (λem=468 nm) of iridium(III)bis[2-(4′-benzylsulfonyl)phenylpyridinato-N,C2′][3-(pentafluorophenyl)-pyridin-2-yl-1,2,4-triazolate] to the orange (λem=558 nm) of iridium(III)bis[2-(3′-benzylsulfonyl)phenylpyridinato-N,C2′](2,4-decanedionate) has been achieved. Emission quantum yields ranging from 47 to 71 % have also been found for degassed solutions of the complexes, and a surprisingly high value of 16 % was recorded for iridium(III)bis[2-(5′-benzylsulfonyl-3′,6′-difluoro)phenylpyridinato-N,C2′](2,4-decanedionate) in air-equilibrated dichloromethane. A unusual stereochemistry of the benzylsulfonyl-substituted dimer and heteroleptic complexes has been detected by 1H NMR spectroscopy, and is characterised by the mutual cis disposition of the pyridyl nitrogen atoms of the phenylpyridine ligands, which differs from the most common trans arrangement reported in the literature.

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