Phosphorescent d6 and d8 metal complexes containing ?-conjugated ligands with N and/or C donor atoms have attracted widespread research interest due to their excellent emission properties and potential applications in fields such as optoelectronic devices, chemo-/biosensors, bioimaging and medicinal chemistry. Hydroxyarylimine bidentate ligands are versatile and tunable structures, easy to prepare, and have been widely applied in the development of metal catalysts. On the contrary, their transition-metal complexes are less studied and developed in optoelectronics. In this communication we present the synthesis of two novel neutral square planar Pt(II) complexes, Pt-1 and Pt-2, characterized by the presence of an ancillary C^N (ppy or ppz) cyclometalated ligand and a O^N hydroxyarylimine one. These complexes are synthesized as depicted in scheme 1 reacting the platinum chloro intermediate 1a,b with the O^N ligand. Reacting the intermediate 1a with NpOPh, we obtained a single compound whose structure is indicated as Pt 1 (Scheme 1).1 On the contrary, the reaction of 1b, carrying C^N = ppz ligand, with NpOPh ligand provided a mixture of two compounds which were easily isolated by chromatography and structurally characterized by HPLC-MS, NMR analysis and X-Ray diffraction. The two compounds proved to be the geometrical isomers cis-Pt 2 and trans-Pt 2 reported in scheme 1. To the best of our knowledge this is the first example of cis/trans isomer formation in neutral Pt(II) complexes carrying two different chelating ligands. Pt 1 and cis/trans-Pt 2 isomers were thoroughly investigated by means of UV-Vis spectroscopy, photoluminescence emission, cyclovoltammetry, FTIR and DFT calculations. The physical and electronic data are correlated to the structural parameters.
Cyclometalated Pt(II) Hydroxyarylimine Complexes: Structure-Property correlations in cis/trans isomers
A Forni;C Baldoli;A Bossi
2014
Abstract
Phosphorescent d6 and d8 metal complexes containing ?-conjugated ligands with N and/or C donor atoms have attracted widespread research interest due to their excellent emission properties and potential applications in fields such as optoelectronic devices, chemo-/biosensors, bioimaging and medicinal chemistry. Hydroxyarylimine bidentate ligands are versatile and tunable structures, easy to prepare, and have been widely applied in the development of metal catalysts. On the contrary, their transition-metal complexes are less studied and developed in optoelectronics. In this communication we present the synthesis of two novel neutral square planar Pt(II) complexes, Pt-1 and Pt-2, characterized by the presence of an ancillary C^N (ppy or ppz) cyclometalated ligand and a O^N hydroxyarylimine one. These complexes are synthesized as depicted in scheme 1 reacting the platinum chloro intermediate 1a,b with the O^N ligand. Reacting the intermediate 1a with NpOPh, we obtained a single compound whose structure is indicated as Pt 1 (Scheme 1).1 On the contrary, the reaction of 1b, carrying C^N = ppz ligand, with NpOPh ligand provided a mixture of two compounds which were easily isolated by chromatography and structurally characterized by HPLC-MS, NMR analysis and X-Ray diffraction. The two compounds proved to be the geometrical isomers cis-Pt 2 and trans-Pt 2 reported in scheme 1. To the best of our knowledge this is the first example of cis/trans isomer formation in neutral Pt(II) complexes carrying two different chelating ligands. Pt 1 and cis/trans-Pt 2 isomers were thoroughly investigated by means of UV-Vis spectroscopy, photoluminescence emission, cyclovoltammetry, FTIR and DFT calculations. The physical and electronic data are correlated to the structural parameters.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
