Synthesis, characterization, photophysics and electrochemical study of luminescent iridium(<scp>iii</scp>) complexes with isocyanoborate ligands

Chan, K. S.; Chu, Wing‐Kin; Man, Wai‐Lun; Ko, Chi‐Chiu

doi:10.1039/c5dt00904a

Cited by 26 publications

(52 citation statements)

References 62 publications

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“…After removing the silver chloride precipitate, the cyano ligand was readily incorporated by adding a methanolic solution of potassium cyanide. Complexes 1 – 6 were synthesized on the basis of a Lewis acid/base reaction between the cyano precursor complexes and tris(pentafluorophenyl)borane (Scheme ) in anhydrous dichloromethane solution following our previously reported procedures for the preparation of isocyanoborato complexes . After recrystallization by the slow diffusion of n ‐hexane or n ‐pentane into concentrated chloroform, dichloromethane, or diethyl ether solutions of the complexes, analytically pure compounds were isolated as yellow to greenish‐yellow crystalline solids.…”

Section: Synthesis and Characterizationmentioning

confidence: 69%

“…On the basis of their different emission decay lifetimes, the emission properties of these complexes in an EtOH/MeOH glassy medium at 77 K have been studied by time‐resolved emission spectroscopy. Together with our previous work on luminescent isocyanoborato transition‐metal complexes, this work further demonstrates that the anionic isocyanoborate ligand can be used for converting cationic emitters into charge‐neutral emitters with similar emission properties. Further modification of the ligands to improve the emission properties and a study of the electroluminescent applications of this type of charge‐neutral Cu I complex are now in progress.…”

Section: Discussionmentioning

confidence: 99%

“…The C≡N bonds of the isocyano and isocyanoborato ligands of 1 – 6 are characterized by two IR stretches in the range of 2070–2191 cm –1 . The C≡N stretch at the higher frequency (2180–2191 cm –1 ), similarly to those of related complexes, has been assigned to that of the isocyanotris(pentafluorophenyl)borate. The other stretch at 2098–2147 cm –1 can be ascribed to the C≡N of the isocyanide ligand.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…For the isocyanoborate ligand, the C≡N and N–B distances are in the ranges of 1.14–1.15 and 1.55–1.56 Å, respectively, which are similar to those of other isocyanoborato complexes 17a], [17d] For the 4‐(pentafluorosulfanyl)phenyl isocyanide ligand in 6 , the SF 5 group adopts an octahedral geometry with typical S–F bond lengths of 1.57–1.59 Å, similar to those of other SF 5 ‐substituted organic compounds and metal complexes …”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…We have previously reported the incorporation of the anionic isocyanoborate ligand for the conversion of cationic emitters of rhenium(I), osmium(II), and iridium(III) into charge‐neutral emitterswith enhanced emission properties. Moreover, the feasibility of the application of isocyanoborato complexes in emissive devices has been confirmed.…”

Section: Introductionmentioning

confidence: 99%

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Luminescent Charge‐Neutral Copper(I) Phenanthroline Complexes with Isocyanoborate Ligand

Chan

Cheng

et al. 2018

Eur J Inorg Chem

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Copper(I) complexes with thermal activated delayed fluorescence (TADF) have attracted considerable attention for the development of emissive materials in organic light-emitting devices. However, many emissive Cu I complexes are cationic emitters and cannot be vacuum-sublimed, a process used for device fabrication. This has limited their applications in devices. In this work we have developed a series of emissive charge-There is a growing interest in the development of earth-abundant luminescent transition-metal complexes for a wide range of applications, including dye-sensitized solar cells, [1] oxygen sensors, [2] and organic light-emitting devices (OLEDs). [3] Although many luminescent precious-metal complexes have been demonstrated to show promising applications, [4] the exploration of earth-abundant luminescent transition-metal complexes for related applications would be highly desirable because of their sustainability. The much-less-explored first-row luminescent transition-metal complexes in comparison with second-and third-row complexes can be attributed to the presence of the low-lying nonradiative deactivating ligand-field excited state and nonradiative ligand reorganization deactivation processes, which could quench the emissive excited states.Copper(I) complexes have received considerable attention because of their closed-shell electronic configurations and their relatively small singlet-triplet splitting, which lead to their welldocumented thermal-activated delayed fluorescence (TADF). [5] Emission materials with TADF properties are of particular interest for OLED emissive materials as these materials are capable of harvesting both singlet and triplet excitons, which may improve the overall efficiency of the devices. Luminescent Cu I diimine complexes, such as those with sterically bulky ligands, for example, 2,9-dimethyl-1,10-phenanthroline (Me 2 phen), are an important class of luminescent Cu I complexes. The presence of sterically bulky substituents is essential for maintaining the emissive nature of these complexes as they can significantly [a] ] through the incorporation of a strong π-accepting anionic isocyanoborate ligand. All the complexes have been structurally characterized and their photophysical properties have been studied.

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Section: Synthesis and Characterizationmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Synthesis and Characterizationmentioning

confidence: 99%

Section: Synthesis and Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Luminescent Charge‐Neutral Copper(I) Phenanthroline Complexes with Isocyanoborate Ligand

Chan

Cheng

et al. 2018

Eur J Inorg Chem

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Excited State Dynamics of Isocyano Rhenium(I) Phenanthroline Complexes from Time‐Resolved Spectroscopy

Cheng

Chu

et al. 2019

ChemPhysChem

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The photophysical processes in a series of isocyano Re(I) phenanthroline complexes {[Re(CNR)n(CO)4‐n(phen)](PF6); n=2, 3, 4, R=2,6‐(iPr)2C6H3‐ or tBu‐ (n=2)} in acetonitrile have been studied by resonance Raman spectroscopy, transient resonance Raman spectroscopy, and femtosecond / nanosecond transient spectroscopy to elucidate the nature of their electronic transitions and emissive excited state(s). The kinetics of the intersystem crossing, vibrational relaxation and radiative decay of the metal‐to‐ligand charge transfer {MLCT [dπ(Re)→π*(phen)]} excited state have also been determined.

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Cyclometalated Iridium(III) Complexes Featuring Disubstituted Cyanamides

et al. 2018

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The neutral cyclometalated iridium(III) complexes [Ir(ppy) 2 Cl (NCNR 2 )] [ppy = 2-phenylpyridinato-C 2 ,N, R = Me 3 a, Et 3 b, 1 = 2 C 5 H 10 3 c] were prepared via the reaction of the chlorobridged dimer [Ir 2 (ppy) 4 (μ-Cl) 2 ] (1) with corresponding dialkylcyanamides NCNR 2 (2 a-c) and 3 a-c were isolated in 74-85% yields. The cationic cyclometalated iridium(III) complex [Ir (ppy) 2 (NCNMe 2 ) 2 ](OTf) (4) was obtained by replacement of chloride ligands with NCNMe 2 in 1 in the presence of AgOTf. UV/Vis absorption and emission properties of 3 a À c and 4 were studied; these complexes exhibit luminescence in the solid state upon photoexcitation (340 nm, 77 K). The characteristic feature of the X-ray structures of 3 a-c is a deviation of the fragment Ir-N-C from linearity by 13.8(5)-22.8(3)°. Quantum chemical DFT calculations and topological analysis of the electron density distribution within the formalism of Bader's theory (AIM method) performed for 3 a-c demonstrated that the Ir-N-C fragments in the optimized equilibrium structures of [Ir(ppy) 2 Cl(NCNR 2 )] significantly deviate from the linearity (by 19.8-30.7°) and indicated that the Ir-N contacts between the metal centers and dialkylcyanamide ligands are relatively weak (24-30 kcal/mol) and have a closed-shell dative interactions character. The charge decomposition analysis (CDA) shows existence of {M} ! L donation with almost negligible contribution of the {M}!L back-donation in 3 a-c.

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Synthesis, characterization, photophysics and electrochemical study of luminescent iridium(iii) complexes with isocyanoborate ligands

Cited by 26 publications

References 62 publications

Luminescent Charge‐Neutral Copper(I) Phenanthroline Complexes with Isocyanoborate Ligand

Luminescent Charge‐Neutral Copper(I) Phenanthroline Complexes with Isocyanoborate Ligand

Excited State Dynamics of Isocyano Rhenium(I) Phenanthroline Complexes from Time‐Resolved Spectroscopy

Cyclometalated Iridium(III) Complexes Featuring Disubstituted Cyanamides

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