Platinum(II) complexes with spatially encumbered chelates; syntheses, structure and photophysics

Hsieh, Hsi-Ying; Lin, Chen-Huey; Tu, Guan-Min; Chi, Yun; Lee, Gene‐Hsiang

doi:10.1016/j.ica.2009.06.041

Cited by 23 publications

(7 citation statements)

References 54 publications

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“…We next conducted the reaction of 2 with pyrazoles under basic conditions, with an anticipation that the pyrazolate is capable of replacing the chloride anion, giving dinuclear complexes connected with two bridging pyrazolates. − To our surprise, when the mixture of 2 , mpz/dmpz (8 equiv), and K 2 CO 3 (5 equiv) was refluxed in DGME for 12 h, these reactions went in a different direction and afforded the diiridium metal complexes [Ir 2 (κ 5 -N3C)(mpz) 2 (CO)(H) 2 ] ( 7 ) and [Ir 2 (κ 5 -N3C)(dmpz) 2 (CO)(H) 2 ] ( 8 ) as shown in Chart , for which their 1 H NMR spectra exhibited two hydride signals at δ −16.70 and δ −19.73 and δ −16.66 and δ −19.75 and IR spectra displayed a characteristic ν(CO) stretching band at 2011 and 2007 cm –1 , respectively. For the hydride signals in 1 H NMR spectra, one appears as a doublet with 2 J HH of ∼8.3 Hz, which is caused by the mutual coupling of cis -oriented hydrides, while the second multiplet, with an additional, smaller coupling constant of 5 J HF = ∼3.8 Hz, is attributed to the long-range (or through space) coupling to an adjacent CF 3 substituent.…”

Section: Resultsmentioning

confidence: 99%

Iridium(III) Complexes Bearing a Formal Tetradentate Coordination Chelate: Structural Properties and Phosphorescence Fine-Tuned by Ancillaries

et al. 2019

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Synthesis of the multidentate coordinated chelate N3C–H2, composed of a linked functional pyridyl pyrazole fragment plus a peripheral phenyl and pyridyl unit, was obtained using a multistep protocol. Preparation of Ir(III) metal complexes bearing a N3C chelate in the tridentate (κ3), tetradentate (κ4), and pentadentate (κ5) modes was executed en route from two nonemissive dimer intermediates [Ir(κ3-N3CH)Cl2]2 (1) and [Ir(κ4-N3C)Cl]2 (2). Next, a series of mononuclear Ir(III) complexes with the formulas [Ir(κ4-N3C)Cl(py)] (3), [Ir(κ4-N3C)Cl(dmap)] (4), [Ir(κ4-N3C)Cl(mpzH)] (5), and [Ir(κ4-N3C)Cl(dmpzH)] (6), as well as diiridium complexes [Ir2(κ5-N3C)(mpz)2(CO)(H)2] (7) and [Ir2(κ5-N3C)(dmpz)2(CO)(H)2] (8), were obtained upon treatment of dimer 2 with pyridine (py), 4-dimethylaminopyridine (dmap), 4-methylpyrazole (mpzH), and 3,5-dimethylpyrazole (dmpzH), respectively. These Ir(III) metal complexes were identified using spectroscopic methods and by X-ray crystallographic analysis of representative derivatives 3, 5, and 7. Their photophysical and electrochemical properties were investigated and confirmed by the theoretical simulations. Notably, green-emitting organic light-emitting diode (OLED) on the basis of Ir(III) complex 7 gives a maximum external quantum efficiency up to 25.1%. This result sheds light on the enormous potential of this tetradentate coordinated chelate in the development of highly efficient iridium complexes for OLED applications.

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Section: Resultsmentioning

confidence: 99%

Iridium(III) Complexes Bearing a Formal Tetradentate Coordination Chelate: Structural Properties and Phosphorescence Fine-Tuned by Ancillaries

et al. 2019

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“…MepmMepy was newly synthesized by a condensation of a reported amidine , with acetylacetoaldehyde dimethylacetal, according to the modified procedure described in the literature . A new compound, [Cu(MepmMepy)(L mes )] + BF 4 – ( 1 + BF 4 – ), was synthesized by a reaction of tetrakis(acetonitrile)copper(I) tetrafluoroborate ([Cu(MeCN) 4 ] + BF 4 – ) with MepmMepy and L mes , in dichloromethane at room temperature, according to the slightly modified procedures described in our previous literature (Scheme ) .…”

Section: Resultsmentioning

confidence: 99%

Reversible Copper(II)/(I) Electrochemical Potential Switching Driven by Visible Light-Induced Coordinated Ring Rotation

et al. 2012

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We here describe the first metal complex system in which electronic signals can be repeatedly extracted by converting bistable states related to an intramolecular ligand rotational motion, which is fueled by visible light. The molecular structure for relating an electron transfer and a motion consists of a copper center and a coordinated unsymmetrically substituted pyrimidine derivative, whose rotational isomerization causes an electrochemical potential shift. To harness light energy effectively through metal-to-ligand charge transfer (MLCT) excitation, we prepared a simple copper(I) complex coordinated by a 4-methyl-2-(6'-methyl-2'-pyridyl)pyrimidine and a bulky diimine. The thermodynamic and kinetic parameters of redox and rotational reactions were analyzed by cyclic voltammograms at variable temperatures, by considering four stable isomers related to copper(II)/(I) states and rotational isomeric states. The key feature of this compound is that the rotation is frozen in the copper(I) state (rate constant for the rotation, k(Ii→o) = 10(-4) s(-1)) but is active in the copper(II) state (k(IIi→o) = 10(-1) s(-1)) at 203 K. The compound makes a bypass route to the isomeric metastable copper(I) state, via a tentative copper(II) state formed by photoelectron transfer (PET) in the presence of a redox mediator, decamethylferrocenium ion (DMFc(+)), or upon a partial oxidation of the complex. Light- and heat-driven rotation in the copper(I) state with a potential shift (ΔE°' = 0.14 V) was analyzed by electrochemical measurements of the complex in the solution state. The rotor could be reset to the initial state by heating, thereby completing the cycle and enabling repeated operation fueled by light energy. A significant redox potential shift associated with the copper(II)/(I) transition accompanied the rotation, thereby providing a new type of molecular signaling system.

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“…All these crystallographic ndings are in agreement with the already reported structures of Pt(II) complexes containing 1,2,4triazolate ligands with a kN 1 coordination mode. [48][49][50] Noteworthy, in the crystal packing the complex molecules are organized in a parallel head-to-head staggered fashion, but no closed-shell Pt/Pt interaction (Pt/Pt distance ¼ 4.845 Å) has been observed, resulting in a negligible interaction between neighbour molecules. Such absence of interaction could most likely be due to the presence of the DMSO molecules within the crystal structure engaged in hydrogen bond interaction with the OH moiety of the ancillary pyridine…”

Section: Synthesis and Single-crystal X-ray Determinationmentioning

confidence: 99%

Bio-imaging with neutral luminescent Pt(ii) complexes showing metal⋯metal interactions

et al. 2014

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Platinum(II) complexes with spatially encumbered chelates; syntheses, structure and photophysics

Cited by 23 publications

References 54 publications

Iridium(III) Complexes Bearing a Formal Tetradentate Coordination Chelate: Structural Properties and Phosphorescence Fine-Tuned by Ancillaries

Iridium(III) Complexes Bearing a Formal Tetradentate Coordination Chelate: Structural Properties and Phosphorescence Fine-Tuned by Ancillaries

Reversible Copper(II)/(I) Electrochemical Potential Switching Driven by Visible Light-Induced Coordinated Ring Rotation

Bio-imaging with neutral luminescent Pt(ii) complexes showing metal⋯metal interactions

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