Synthesis and Characterization of Luminescent Bis-Cyclometalated Platinum<sup>IV</sup> Complexes

Jenkins, Dustin M.; Bernhard, Stefan

doi:10.1021/ic100761f

Cited by 55 publications

(75 citation statements)

References 63 publications

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“…Unless otherwise noted, preparations were carried out under atmospheric conditions. The compounds PhICl 2 ,25 1 a–d ,26 and 2 a and 2 b ,13c were prepared following published procedures. Complexes 2 c , 2 d , and 4 d were not previously reported and their synthesis and spectroscopic and analytical data are given in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations

Juliá¹,

Aullón²,

Bautista³

et al. 2014

Chemistry A European J

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The synthesis, structure, electrochemistry, and photophysical properties of a series of heteroleptic tris- cyclometalated Pt(IV) complexes are reported. The complexes mer-[Pt(C^N)2 (C'^N')]OTf, with C^N=C-deprotonated 2-(2,4-difluorophenyl)pyridine (dfppy) or 2-phenylpyridine (ppy), and C'^N'=C-deprotonated 2-(2-thienyl)pyridine (thpy) or 1-phenylisoquinoline (piq), were obtained by reacting bis- cyclometalated precursors [Pt(C^N)2 Cl2] with AgOTf (2 equiv) and an excess of the N'^C'H pro-ligand. The complex mer-[Pt(dfppy)2 (ppy)]OTf was obtained analogously and photoisomerized to its fac counterpart. The new complexes display long-lived luminescence at room temperature in the blue to orange color range. The emitting states involve electronic transitions almost exclusively localized on the ligand with the lowest π-π* energy gap and have very little metal character. DFT and time-dependent DFT (TD-DFT) calculations on mer-[Pt(ppy)2 (C'^N')](+) (C'^N'=thpy, piq) and mer/fac-[Pt(ppy)3](+) support this assignment and provide a basis for the understanding of the luminescence of tris-cyclometalated Pt(IV) complexes. Excited states of LMCT character may become thermally accessible from the emitting state in the mer isomers containing dfppy or ppy as chromophoric ligands, leading to strong nonradiative deactivation. This effect does not operate in the fac isomers or the mer complexes containing thpy or piq, for which nonradiative deactivation originates mainly from vibrational coupling to the ground state.

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Section: Methodsmentioning

confidence: 99%

Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations

Juliá¹,

Aullón²,

Bautista³

et al. 2014

Chemistry A European J

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“…The complexes contained bis-cyclometalating (C^N) ligands of the general formula Pt(C^N) 2 (CH 2 Cl)Cl and were prepared by a photooxidative addition of CH 2 Cl 2 onto the corresponding bis-cyclometalated Pt(II) parental complexes. Although Pt(IV) complexes have attracted great attention in cancer therapy [104–106], only in the very recent past they are receiving increasing interest as luminescent compounds [107–108]. Such derivatives are characterized by long-lived triplet-manifold π–π* excited states with either 3 LC or 3 ILCT nature.…”

Section: Reviewmentioning

confidence: 99%

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

Cebrián

Mauro

2018

Beilstein J. Org. Chem.

145

114

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Phosphorescent organometallic compounds based on heavy transition metal complexes (TMCs) are an appealing research topic of enormous current interest. Amongst all different fields in which they found valuable application, development of emitting materials based on TMCs have become crucial for electroluminescent devices such as phosphorescent organic light-emitting diodes (PhOLEDs) and light-emitting electrochemical cells (LEECs). This interest is driven by the fact that luminescent TMCs with long-lived excited state lifetimes are able to efficiently harvest both singlet and triplet electro-generated excitons, thus opening the possibility to achieve theoretically 100% internal quantum efficiency in such devices. In the recent past, various classes of compounds have been reported, possessing a beautiful structural variety that allowed to nicely obtain efficient photo- and electroluminescence with high colour purity in the red, green and blue (RGB) portions of the visible spectrum. In addition, achievement of efficient emission beyond such range towards ultraviolet (UV) and near infrared (NIR) regions was also challenged. By employing TMCs as triplet emitters in OLEDs, remarkably high device performances were demonstrated, with square planar platinum(II) complexes bearing π-conjugated chromophoric ligands playing a key role in such respect. In this contribution, the most recent and promising trends in the field of phosphorescent platinum complexes will be reviewed and discussed. In particular, the importance of proper molecular design that underpins the successful achievement of improved photophysical features and enhanced device performances will be highlighted. Special emphasis will be devoted to those recent systems that have been employed as triplet emitters in efficient PhOLEDs.

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“…Since then, families of platinum(IV) complexes based on functionalised cyclometallating ligands have been published. Jenkins and Bernhard reported a library of cationic platinum(IV) complexes based on the [Pt(C^N) 2 (N^N)] + structure, where C^N are functionalised 2‐phenylpyridine ligands and N^N are functionalised 2,2′‐bipyridines (Figure b) . More recently, Juliá et al.…”

Section: Introductionmentioning

confidence: 99%

“… Model structures from a) Chassot et al . who reported a platinum(IV) system with 2‐(2‐thienyl)pyridine) ligands after the oxidative addition of CH 2 Cl 2 ; b) Jenkins and Bernhard showing the [Pt(C^N) 2 (N^N)] + base unit, with reported functionalisation of both the C^N and N^N rings with fluorine and methoxy groups; c) the mer and fac isomers of the base unit of tris(cyclometallated)platinum(IV) complexes reported by Juliá et al., with reported functionalisation of the C^N rings with fluorine and methyl groups, as well as systems where the pyridyl ring is replaced with pyrazole; Juliá et al . showing d) symmetric and e) asymmetric bis‐cyclometallated 2‐phenylpyridine systems, where X=F, Cl, Br, I, OTf, OAc, TFA.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Mesomorphism, and Photophysics of 2,5‐Bis(dodecyloxyphenyl)pyridine Complexes of Platinum(IV)

Parker

Sarju

Whitwood

et al. 2018

Chemistry A European J

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It has been shown for the first time that the Pt complex cis-[Pt(N^C-tolpy) Cl ] (tolpy=2-(4-tolyl)pyridinyl) can be prepared in a one-pot reaction from K [PtCl ], although analogous complexes containing 2,5-bis(4-dodecyloxyphenyl)pyridine (=HL) could be prepared using existing routes. The resulting complexes cis-[Pt(N^C-L) Cl ] are liquid crystals and small-angle X-ray scattering suggests formation of a lamellar mesophase. Surprisingly, heating [Pt(κ -N^C-L) Cl(κ -N^C-LH)] also leads to a mesomorphic compound, which results from thermally induced oxidation to cis-[Pt(N^C-L) Cl ] and what is presumed to be another geometric isomer of the same formula. The Pt complexes are quite strongly luminescent in deoxygenated solution, with φ≈10 % and show vibrationally structured emission spectra, λ (0,0)=532 nm, strongly displaced to the red compared to cis-[Pt(N^C-tolpy)Cl ]. Long luminescence lifetimes of 230 μs are attributed to a lower degree of metal character in the excited state accompanying the extension of conjugation in the ligand. There is no significant difference between the emission properties of the bromo- and chloro-complexes, in contrast with the known complexes cis-[Pt(N^C-ppy)X ], where the quantum yield for X=Br is some 30 times lower than for X=Cl (ppyH=2-phenylpyridine). The lower energy of the excited state in the new complexes probably ensures that deactivating LLCT/LMCT states remain thermally inaccessible, even when X=Br.

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Synthesis and Characterization of Luminescent Bis-Cyclometalated Platinum^IV Complexes

Cited by 55 publications

References 63 publications

Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations

Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

Synthesis, Mesomorphism, and Photophysics of 2,5‐Bis(dodecyloxyphenyl)pyridine Complexes of Platinum(IV)

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Synthesis and Characterization of Luminescent Bis-Cyclometalated PlatinumIV Complexes

Cited by 55 publications

References 63 publications

Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations

Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

Synthesis, Mesomorphism, and Photophysics of 2,5‐Bis(dodecyloxyphenyl)pyridine Complexes of Platinum(IV)

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Synthesis and Characterization of Luminescent Bis-Cyclometalated Platinum^IV Complexes