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Phosphorescent Thiazol-2-ylidene Platinum(II) Complexes with β‑Ketoiminates: Single Isomer Formation by Ligand Architecture

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journal contribution
posted on 2016-12-05, 13:33 authored by Hendrik Leopold, Thomas Strassner
We present the synthesis and photophysical properties of six novel N-phenyl-1,3-thiazol-2-ylidene platinum­(II) complexes with sterically demanding N-aryl-β-ketoiminate ligands. Diverse aryl substituents at the coordinating nitrogen atom (phenyl, mesityl, 2,6-diisopropylphenyl, 4-cyanophenyl, 1-naphthyl, and 2,4-difluorophenyl) of the N-aryl-(3Z)-4-amino-3-penten-2-ones exclusively yielded the SP-4-3 coordinated CC* cyclometalated platinum­(II) complexes as single isomers as a consequence of the low steric demand of the CC* cyclometalating thiazole ligand and the bulkiness of the β-ketoiminate ligands. The formation of this isomer was confirmed by 195Pt NMR and extensive 2D NMR experiments, two solid-state structures, and the results of DFT calculations. As a proof of principle, two complexes with the sterically less demanding β-ketoiminate ligands (3Z)-4-amino-3-penten-2-onato and (2Z)-3-amino-1-phenyl-2-buten-1-onato were synthesized and isolated as an isomeric mixture.

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