New Dimetallic Palladium and Platinum Complexes Containing the Tetrakis(1-pyrazolyl)borate Ligand − Crystal Structures of [{(C6F5)2Pd}2(μ-pz)2B- (μ-pz)2], [{(C6F5)(tBuNC)Pd}2(μ-pz)2B(μ-pz)2]+ and [(C6F5)2Pd(μ-pz)2B(μ-pz)2Pd(η3-C4H7)]

Ruíz, José; Florenciano, Félix; Rodrı́guez, Venancio; Haro, Concepción de; López, Gregorio; Pérez, José

doi:10.1002/1099-0682(200210)2002:10<2736::aid-ejic2736>3.0.co;2-h

Cited by 12 publications

(3 citation statements)

References 16 publications

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“…We are examining other related complexes as emissive dopants in monochromatic and white OLEDs. The tetrakis(pyrazolyl)borate ligand also offers the possibility of expanded coordination, , since the noncoordinated pyrazoles of ( tpy ) 2 Ir(pz) 2 Bpz 2 can be used to bind a second metal center. Related dinuclear organometallic complexes have been reported for Pd and Ru complexes but not, thus far, for photoactive metal fragments such as the Ir complexes reported here.…”

Section: Discussionmentioning

confidence: 99%

Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

et al. 2005

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The synthesis and photophysical characterization of a series of (N,C 2′ -(2-para-tolylpyridyl)) 2 Ir(LL′) [(tpy) 2 Ir(LL′)] (LL′ ) 2,4-pentanedionato (acac), bis(pyrazolyl)borate ligands and their analogues, diphosphine chelates and tertbutylisocyanide (CN-t-Bu)) are reported. A smaller series of [(dfppy) 2 Ir(LL′)] (dfppy ) N,C 2′ -2-(4′,6′-difluorophenyl)pyridyl) complexes were also examined along with two previously reported compounds, (ppy) 2 Ir(CN) 2and (ppy) 2 Ir(NCS) 2 -(ppy ) N,C 2′ -2-phenylpyridyl). The (tpy) 2 Ir(PPh 2 CH 2 ) 2 BPh 2 and [(tpy) 2 Ir(CN-t-Bu) 2 ](CF 3 SO 3 ) complexes have been structurally characterized by X-ray crystallography. The Ir−C aryl bond lengths in (tpy) 2 Ir(CN-t-Bu) 2 + (2.047-(5) and 2.072(5) Å) and (tpy) 2 Ir(PPh 2 CH 2 ) 2 BPh 2 (2.047(9) and 2.057(9) Å) are longer than their counterparts in (tpy) 2 Ir(acac) (1.982(6) and 1.985(7) Å). Density functional theory calculations carried out on (ppy) 2 Ir(CN-Me) 2 + show that the highest occupied molecular orbital (HOMO) consists of a mixture of phenyl-π and Ir-d orbitals, while the lowest unoccupied molecular orbital is localized primarily on the pyridyl-π orbitals. Electrochemical analysis of the (tpy) 2 Ir(LL′) complexes shows that the reduction potentials are largely unaffected by variation in the ancillary ligand, whereas the oxidation potentials vary over a much wider range (as much as 400 mV between two different LL′ ligands). Spectroscopic analysis of the cyclometalated Ir complexes reveals that the lowest energy excited state (T 1 ) is a triplet ligand-centered state ( 3 LC) on the cyclometalating ligand admixed with 1 MLCT (MLCT ) metal-to-ligand charge-transfer) character. The different ancillary ligands alter the 1 MLCT state energy mainly by changing the HOMO energy. Destabilization of the 1 MLCT state results in less 1 MLCT character mixed into the T 1 state, which in turn leads to an increase in the emission energy. The increase in emission energy leads to a linear decrease in ln(k nr ) (k nr ) nonradiative decay rate). Decreased 1 MLCT character in the T 1 state also increases the Huang−Rhys factors in the emission spectra, decreases the extinction coefficient of the T 1 transition, and consequently decreases the radiative decay rates (k r ). Overall, the luminescence quantum yields decline with increasing emission energies. A linear dependence of the radiative decay rate (k r ) or extinction coefficient ( ) on (1/∆E) 2 has been demonstrated, where ∆E is the energy difference between the 1 MLCT and 3 LC transitions. A value of 200 cm -1 for the spin−orbital coupling matrix element 〈 3 LC|H SO | 1 MLCT〉 of the (tpy) 2 Ir(LL′) complexes can be deduced from this linear relationship. The (fppy) 2 Ir(LL′) complexes with corresponding ancillary ligands display similar trends in excited-state properties.

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Section: Discussionmentioning

confidence: 99%

Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

et al. 2005

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“…For example, the metallophilic interaction can be controlled by the steric hindrance of the bridging ligands. Different classes of bridging ligands can be used to obtain bimetallic platinum(II) complexes; − bispyrazolate complexes in particular have received considerable attention from the scientific community as they are readily available and allow for a change of the intermetallic distance. ,− When the steric demand at the pyrazolate is small, the Pt–Pt distance is long enough to prevent the formation of any Pt–Pt interaction ( 2 in Scheme ). In contrast, when the steric demand is increased, the ligand pushes the platinum(II) centers closer together.…”

Section: Introductionmentioning

confidence: 99%

Photophysical Properties of Phosphorescent Mono- and Bimetallic Platinum(II) Complexes with C^∧C* Cyclometalating NHC Ligands

2021

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Due to their square-planar geometry, platinum(II) complexes demonstrate an extraordinary and unique photophysical behavior. The photophysical properties of monometallic platinum(II) complexes depend on the concentration, while in bimetallic platinum(II) complexes they depend on the distance between the metal centers. In this study we reveal a correlation between the electronic and photophysical properties of monomeric monometallic platinum(II) complexes and their aggregates with the corresponding bimetallic complexes.

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“…However, Strassner and co-workers reported that the Pt(II)–NHC complex has a remarkably strong tendency to aggregate and exhibits an increasing quantum yield. , Apart from the aggregates, arising from the overlap of the 5d z 2 orbitals, the strong metallophilic interactions are exploited to create bimetallic complexes, and the metallophilic interactions can be controlled via steric hindrance of the bridging ligands. Various bridging ligands have been synthesized and applied to achieve bimetallic Pt(II) complexes. − Therefore, constructing a relationship between the triplet potential energy surface and structure of the bimetallic Pt(II) complex is beneficial for designing excellent phosphors and improving the diversity of the Pt(II) complex.…”

Section: Introductionmentioning

confidence: 99%

Controlling the Triplet Potential Energy Surface of Bimetallic Platinum(II) Complex by Constructing Structure–Property Relationship: A Theoretical Exploration

et al. 2023

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For phosphorescent materials, managing the triplet potential energy surface stands for controlling the phosphorescence quantum yield. However, due to the complexity and variability, the triplet potential energy surface can be managed with difficulty. In this work, a series of bimetallic Pt(II) complexes, namely Pt-1, Pt-1-1, Pt-1-2, Pt-2, Pt-3–5, and Pt-6–7, are employed as models to construct a relationship between the structures and triplet potential energy surfaces, aiming to achieve meaningful information to manage the triplet potential energy surface. On the basis of the results, it is observed that the triplet potential energy surface has an intimate connection with the structures of bimetallic Pt(II) complexes. In the case of the primordial Pt(II) complex, the triplet potential energy surface consists of two minimal points, illustrating various properties, which can largely affect the phosphorescence quantum yield. Once the intramolecular steric hindrance, restriction effect, and metallophilic interaction (Pt–Pd/Pd–Pd) are employed by tailoring the structures of primordial Pt(II) complexes, the triplet potential energy surface can be reconstructed via one minimal point-charactered short metal–metal distance, resulting in different photophysical properties. The relationship between the triplet potential energy surface and structure is essentially unveiled from the structural and electronic viewpoints. The conclusions originated from the structural and electronic investigations can be regarded as indicators to accurately and expediently predict the triplet potential energy surfaces of bimetallic Pt(II) complexes. The results presented here are helpful in addressing the designed strategies as they show that the triplet potential energy surfaces of bimetallic Pt(II) complexes can be properly tuned.

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New Dimetallic Palladium and Platinum Complexes Containing the Tetrakis(1-pyrazolyl)borate Ligand − Crystal Structures of [{(C6F5)2Pd}2(μ-pz)2B- (μ-pz)2], [{(C6F5)(tBuNC)Pd}2(μ-pz)2B(μ-pz)2]+ and [(C6F5)2Pd(μ-pz)2B(μ-pz)2Pd(η3-C4H7)]

Cited by 12 publications

References 16 publications

Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

Photophysical Properties of Phosphorescent Mono- and Bimetallic Platinum(II) Complexes with C^∧C* Cyclometalating NHC Ligands

Controlling the Triplet Potential Energy Surface of Bimetallic Platinum(II) Complex by Constructing Structure–Property Relationship: A Theoretical Exploration

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New Dimetallic Palladium and Platinum Complexes Containing the Tetrakis(1-pyrazolyl)borate Ligand − Crystal Structures of [{(C6F5)2Pd}2(μ-pz)2B- (μ-pz)2], [{(C6F5)(tBuNC)Pd}2(μ-pz)2B(μ-pz)2]+ and [(C6F5)2Pd(μ-pz)2B(μ-pz)2Pd(η3-C4H7)]

Cited by 12 publications

References 16 publications

Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

Photophysical Properties of Phosphorescent Mono- and Bimetallic Platinum(II) Complexes with C∧C* Cyclometalating NHC Ligands

Controlling the Triplet Potential Energy Surface of Bimetallic Platinum(II) Complex by Constructing Structure–Property Relationship: A Theoretical Exploration

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Photophysical Properties of Phosphorescent Mono- and Bimetallic Platinum(II) Complexes with C^∧C* Cyclometalating NHC Ligands