In:
Dalton Transactions, Royal Society of Chemistry (RSC), Vol. 50, No. 38 ( 2021), p. 13294-13305
Abstract:
The synthesis of bis-cyclometalated halido(aryl) Pt( iv ) complexes [PtX(Ar)(C^N) 2 ], with C^N = cyclometalated 4-( tert -butyl)-2-phenylpyridine (bppy), 2-( p -tolyl)pyridine (tpy), 2-(2-thienyl)pyridine (thpy), or 1-phenylisoquinoline (piq), X = I, Cl, or F, and Ar = Ph (for all C^N ligands) or t -BuPh (for C^N = tpy), and the photophysical properties of the chlorido and fluorido series is reported. The oxidative addition of iodobenzene to cis -[Pt(C^N) 2 ] precursors is demonstrated to occur in MeCN under irradiation with visible light to give complexes [PtI(Ph)(C^N) 2 ], presumably involving radical species that also produce the activation of the solvent to give cyanomethyl complexes [PtI(CH 2 CN)(C^N) 2 ]. The introduction of an aryl ligand can also be achieved by reacting cis -[Pt(C^N) 2 ] with (Ar 2 I)PF 6 (Ar = Ph, t -BuPh), which affords cationic intermediates of the type [Pt(Ar)(C^N) 2 (NCMe)] + . The subsequent addition of an iodide or chloride salt gives the corresponding iodido- or chlorido(aryl) complexes. The fluorido(aryl) derivatives can be obtained from the iodido complexes by halide exchange using AgF. The chlorido- and fluorido(aryl) complexes display intense phosphorescence in deaerated CH 2 Cl 2 solution and poly(methyl methacrylate) (PMMA) films at 298 K from triplet excited states primarily localized on the cyclometalated ligands ( 3 LC) with a small MLCT admixture. Compared with the chlorido complexes, the fluorido derivatives consistently present significantly shorter emission lifetimes and higher radiative and nonradiative rate constants due to a greater MLCT contribution to the emissive state. In contrast, the introduction of the t -BuPh group did not induce significant changes in radiative rates with respect to the phenyl complexes.
Type of Medium:
Online Resource
ISSN:
1477-9226
,
1477-9234
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2021
detail.hit.zdb_id:
1472887-4
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