Facile Approaches to Phosphorescent Bis(cyclometalated) Pentafluorophenyl PtIV Complexes: Photophysics and Computational Studies. Issue 24 (11th April 2017)

• Record Type: Journal Article
• Authors: Giménez, Nora; Lara, Rebeca; Moreno, M. Teresa; Lalinde, Elena
• Is Part Of: Chemistry. Volume 23:Issue 24(2017)
• Page Start: 5758
• Page End: 5771
• Publication Date: 2017-04-11
• Subjects: cyclometalating ligands -- density functional calculations -- luminescence -- photochemistry -- platinum; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201605809
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A convenient and general strategy for the synthesis of stable bis(cyclometalated) pentafluorophenyl Pt IV complexes fac ‐[Pt(C^N)2 (C6 F5 )Cl] (3 a –f ) and mer ‐[Pt(C^N)2 (C6 F5 )(CN)] (4 c, d ) has been developed. Complexes3 were selectively generated by low‐temperature oxidation of the cyclometalated Pt II complexes [Pt(C^N)(HC^N)(C6 F5 )]2 [prepared from cis ‐[Pt(C6 F5 )2 (HC^N)2 ] (1 ) intermediates] with PhICl2 and subsequent metalation of the pendant HC^N ligand. Complexes3 a, b were also alternatively generated by irradiation (Hg lamp, 400 W) of complexes2 a, b, respectively, in CH2 Cl2 . This latter reaction proceeds via the hydride Pt IV species cis ‐[Pt(C^N)2 (C6 F5 )H], detected as the only intermediate species. The molecular structures of1 a, d, 2 a, and3 a, b, d, e were confirmed by X‐ray diffraction. The substitution of Cl − by CN − in fac ‐[Pt(C^N)2 (C6 F5 )Cl] [C^N=2‐phenylbenzothiazole (3 c ), 2‐(4‐bromophenyl)benzothiazole (3 d )] evolved with isomerization to give rise to the isomers ( OC‐ 6–42)‐[Pt(C^N)2 (C6 F5 )(CN)] (4 c, 4 d ) having a mer disposition of the cyclometalated and C6 F5 groups (X‐ray, 4 c ). All the complexes are luminescent and their electronic spectra have been compared and interpreted with the aid of time‐dependent DFT calculations. Abstract : Light‐emitting Pt IV complexes : Very stable fac ‐bis(cyclometalated) pentafluorophenyl Pt IV complexes3 have been prepared from mono(cyclometalated) Pt II precursors2 containing an additional N‐donor HC^N ligand. Under photochemical conditions3 a, b were generated through a relatively stable Pt IV pentafluorophenyl hydride intermediate. These Pt IV derivatives exhibit extremely long‐lived ligand‐centered emissions ( 3 LC) that can be tuned from blue to yellow by changing the cyclometalating ligands (see figure).