Structure, Physical, and Photophysical Properties of Platinum(II) Complexes Containing Bidentate Aromatic and Bis(diphenylphosphino)methane as Ligands

DePriest, Jeffrey C.; Gy, Zheng; Goswami, Niranjan; Eichhorn, David M.; Woods, Clifton; Dp, Rillema

doi:10.1021/ic991306d

Cited by 115 publications

(106 citation statements)

References 55 publications

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“…It seems reasonable to assign this broad absorption feature to the multiple components of the d p !p* (or MLCT) transition on the basis of their positions and relative intensities. [15] It is notable that all complexes have another weak, but distinct absorption band that extends into the lower-energy region of 550-560 nm. Such a peak could be attributed to the strong coupling of spin-allowed 1 MLCT and the spin-forbidden 3 MLCT (or even 3 pp) absorption bands.…”

Section: Resultsmentioning

confidence: 98%

Iridium(I) Pyridyl Azolate Complexes with Saturated Red Metal‐to‐Ligand Charge Transfer Phosphorescence; Fundamental and Potential Applications in Organic Light‐Emitting Diodes

Fang

Chen

Yang

et al. 2007

Chemistry A European J

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Preparation of a new series of neutral metal complexes [(cod)Ir(fppz)] (1), [(cod)Ir(bppz)] (2), [(cod)Ir(fptz)] (3) and [(cod)Ir(bptz)] (4), bearing one cod ligand and a pyridyl azolate chelate are reported. A single-crystal X-ray diffraction study of 3 reveals the expected distorted square-planar geometry. The lowest absorption band consists of IrI atom increased triplet dpi-->pi* transitions (3MLCT), the assignment of which is firmly supported by the theoretical approaches. Complexes 1-4 exhibit weak phosphorescence in degassed solution at room temperature, whereas much more intense, solid-state phosphorescence appears in the range 622-649 nm. The pure MLCT emission was used as a prototypical model to address its remarkable spectral differences from the IrIII isoquinoline pyrrolide complex (5), which has mainly 3pipi phosphorescence. Complex 3 was used as a dopant to fabricate red-emitting phosphorescent organic light-emitting diodes (OLEDs). For the 7 % doped device, a maximum brightness of 3010 cd m-2 was achieved at an applied voltage of 15 V and with CIE coordinates of (0.56, 0.33), demonstrating for the first time the potential of neutral IrI complexes in OLED applications.

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Section: Resultsmentioning

confidence: 98%

Iridium(I) Pyridyl Azolate Complexes with Saturated Red Metal‐to‐Ligand Charge Transfer Phosphorescence; Fundamental and Potential Applications in Organic Light‐Emitting Diodes

Fang

Chen

Yang

et al. 2007

Chemistry A European J

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“…A s I r ) was used to calculate the quantum yields, where F s is the quantum yield of the sample, F r is the quantum yield of the reference, h is the refractive index of the solvent, A s and A r are the absorbance of the sample and the reference at the wavelength of excitation, and I s and I r are the integrated areas of emission bands [9]. The radiative decay rate (k r )was obtained using the formula of k r = F t .…”

Section: Methodsmentioning

confidence: 99%

Efficient Blue‐ and White‐Emitting Electrophosphorescent Devices Based on Platinum(II) [1,3‐Difluoro‐4,6‐di(2‐pyridinyl)benzene] Chloride

et al. 2008

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Electrophosphorescence based on cyclometalated Ir and Pt complexes has attracted broad attentions from academia and industries, owing to the potential of these complexes for harvesting both electrogenerated singlet and triplet excitons to achieve 100% internal quantum efficiency.[1] Efficient blue, green, and red phosphorescent organic light-emitting devices (OLEDs) have been fabricated with the judicious ligand design of these Ir and Pt complexes. [2][3][4] Compared with reported efficient green-and red-phosphorescent OLEDs, [2] few choices of materials are provided for the fabrication of blue-phosphorescent OLEDs, which is considered to be important to the applications of OLEDs for displays and solid-state lighting. So far, the approaches to achieve efficient blue-phosphorescent OLEDs are focused on Ir-based complexes, by either adopting high-tripletenergy ligands such as 4,6-difluorophenylpyridine [3a-e] and 1-phenyl-3-methylimidazolium [3f] or by using electronwithdrawing ancillary ligands such as picolinate (FIrPic), [3a] tetrakis(1-pyrazolyl)borate (FIr6), [3b,c] triazolate (FIrtaz), and tetrazolate (FIrN4).[3d] Although some Pt complexes have been reported to show blue phosphorescent emission at room temperature, the quality of light emission and the efficiency of devices that use current Pt complexes are not comparable to those using Ir alternatives.[4a-c] For example, devices based on (Fig. 1) Therefore, designing and studying Pt(N^C^N)X materials for application in blue-and white-phosphorescent OLEDs is a worthwhile undertaking. In this Communication we report the photophysics, electrochemistry, and electroluminescent properties of a novel platinum [1,3-difluoro-4,6-di(2-pyridinyl)benzene] chloride , shown in Figure 1. Blueemitting devices based on this complex showed a peak EQE of 16% ph/el and CIE coordinates of (0.15, 0.26). Single-dopant white-emitting devices based on this complex showed a peak EQE of ca. 9.3% ph/el and CIE coordinates of (0.33, 0.36). The electrochemistry of FPt and Pt-4 was examined using cyclic voltammetry. Pt-4 showed a reversible reduction at À2.06 V (versus Fc þ /Fc) and an irreversible oxidation at 0.5 V in N,N-dimethyl formamide (DMF) solution, whereas FPt has a reversible reduction at À2.29 V and an irreversible oxidation at 0.5 V, comparable to the literature data.[4a]The lower reduction potential of Pt-4 suggests that Pt-4 has a deeper lowest unoccupied molecular orbital (LUMO) energy level than FPt. The room-temperature absorption and emission spectra of FPt and Pt-4 are shown in Figure 2. Both of them display very intense absorption bands (e > 1.5 Â 10 4 M À1 cm À1 ) at wavelength between 250-300 nm, assigned to 1 p-p* transitions of the cyclometalating ligands.Weaker bands at longer wavelength (300-400 nm, e ¼ 5000-9000 M À1 cm À1) were assigned to metal-to-ligand charge-transfer (MLCT) transitions. The lowest-energy absorption bands (460-470 nm, e ¼ 40-150 M À1 cm À1

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“…the now popular 2-phenylpyridine complexes mentioned in the Introduction [3,4]. Rillema and co-workers have extensively studied the absorption and emission properties of a number of Pt(2,2 -bph) complexes with the mono-and bidentate ligands, pyridine, acetonitrile, ethylenediamine, CO (27) [23,42], dppm [44,45], and the bridging ligand SEt 2 [41]. Absorption spectra of mono-metallic [Pt(2,2 -bph)(py) 2 ] (52), [Pt(2,2 -bph)(NCMe) 2 ] bonyl complex 27 have been carried out to examine singlet and triplet excited states, and to compare calculated geometries with those from the X-ray crystallographic data previously obtained [42,43].…”

Section: Luminescent Transition Metal 22 -Biphenyl Complexesmentioning

confidence: 99%

Dibenzometallacyclopentadienes, boroles and selected transition metal and main group heterocyclopentadienes: Synthesis, catalytic and optical properties

Steffen

Ward

Jones

et al. 2010

Coordination Chemistry Reviews

113

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Structure, Physical, and Photophysical Properties of Platinum(II) Complexes Containing Bidentate Aromatic and Bis(diphenylphosphino)methane as Ligands

Cited by 115 publications

References 55 publications

Iridium(I) Pyridyl Azolate Complexes with Saturated Red Metal‐to‐Ligand Charge Transfer Phosphorescence; Fundamental and Potential Applications in Organic Light‐Emitting Diodes

Iridium(I) Pyridyl Azolate Complexes with Saturated Red Metal‐to‐Ligand Charge Transfer Phosphorescence; Fundamental and Potential Applications in Organic Light‐Emitting Diodes

Efficient Blue‐ and White‐Emitting Electrophosphorescent Devices Based on Platinum(II) [1,3‐Difluoro‐4,6‐di(2‐pyridinyl)benzene] Chloride

Dibenzometallacyclopentadienes, boroles and selected transition metal and main group heterocyclopentadienes: Synthesis, catalytic and optical properties

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