Browse
Submit Data
Databases
API
Help

Dataset Information

21 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Azo-triazolide bis-cyclometalated Ir(iii) complexes via cyclization of 3-cyanodiarylformazanate ligands.

ABSTRACT: In this work we describe the synthesis of sterically encumbered 1,5-diaryl-3-cyanoformazanate bis-cyclometalated iridium(iii) complexes, two of which undergo redox-neutral cyclization during the reaction to produce carbon-bound 2-aryl-4-arylazo-2H-1,2,3-triazolide ligands. This transformation offers a method for accessing 2-aryl-4-arylazo-2H-1,2,3-triazolide ligands, a heretofore unreported class of chelating ligands. One formazanate complex and both triazolide complexes are structurally characterized by single-crystal X-ray diffraction, with infrared spectroscopy being the primary bulk technique to distinguish the formazanate and triazolide structures. All complexes are further characterized by UV-Vis absorption spectroscopy and cyclic voltammetry, with the triazolide compounds having similar frontier orbital energies to the formazanate complexes but much less visible absorption.

SUBMITTER: Mu G

PROVIDER: S-EPMC7328346 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Azo-triazolide bis-cyclometalated Ir(iii) complexes via cyclization of 3-cyanodiarylformazanate ligands.

Mu Ge G Wen Zhili Z Wu Judy I-Chia JI Teets Thomas S TS

Dalton transactions (Cambridge, England : 2003) 20191127 12

In this work we describe the synthesis of sterically encumbered 1,5-diaryl-3-cyanoformazanate bis-cyclometalated iridium(iii) complexes, two of which undergo redox-neutral cyclization during the reaction to produce carbon-bound 2-aryl-4-arylazo-2H-1,2,3-triazolide ligands. This transformation offers a method for accessing 2-aryl-4-arylazo-2H-1,2,3-triazolide ligands, a heretofore unreported class of chelating ligands. One formazanate complex and both triazolide complexes are structurally charact ...[more]

PMID: 31774084

Similar Datasets

Cyclometalated Ir(III) Complexes as Lysosome-Targeted Photodynamic Anticancer Agents.

Project description:We have designed and synthesized two Ir(III) complexes (Ir1 and Ir2) coordinated with an 8-sulfonamidoquinoline derivative ligand as photosensitizers, which exhibit strong red phosphorescence emission and a long phosphorescence lifetime. The Ir(III) complexes exhibit a high population of triplet states, which enable red phosphorescence and efficient singlet oxygen generation. Ir1 and Ir2 rapidly enter the cancer cells and accumulate in lysosomes, producing large amounts of intracellular singlet oxygen when exposed to light irradiation, eventually leading to cancer cell death, and the phototoxic indexes of complexes Ir1 and Ir2 against cancer cells are in the range of 76-228. Overall, our studies indicate that the synthesized Ir(III) complexes with quinoline ligands exhibit photosensitizing properties, effectively inducing cancer cell death when exposed to light. These promising results suggest their potential application in photodynamic therapy.

| S-EPMC10536871 | biostudies-literature

Cyclometalated Iridium(III) Complexes Incorporating Aromatic Phosphonate Ligands: Syntheses, Structures, and Tunable Optical Properties.

Project description:The incorporation of phosphonate ligands into the cyclometalated iridium(III) complexes can not only tune their electronic and optical properties but also provide the possibility of anchoring these molecules on the semiconductor surfaces for further applications. Herein, we report the first examples of mononuclear cyclometallated iridium(III) complexes incorporating phosphonate ligands, namely, [Ir(ppy)2(HL1)]·0.5H2O (1), [Ir(ppy)2(HL2)]·0.5H2O (2), [Ir(dfppy)2(HL1)] (3), and [Ir(dfppy)2(HL2)]·3.5H2O (4) (ppy = 2-phenylpyridine, dfppy = 2-(2,4-difluorophenyl)pyridine, H2L1 = 2-pyridylphosphonic acid, H2L2 = 2-quinolinephosphonic acid). Luminescent spectra are studied both in solution and in the solid state, and significantly red-shifted broad emission bands are observed in complexes 2 and 4. The experimental and density functional theory (DFT) time-dependent-DFT calculation results indicate that the expansion of the aromatic conjugation length in the ancillary phosphonate ligands decreases the lowest unoccupied molecular orbital energy levels of the systems, originating from the triplet state associated with the ancillary ligand such as 3MLCT, 3LC, and 3LLCT charge-transfer transitions.

| S-EPMC6788060 | biostudies-literature

Cationic heteroleptic cyclometalated iridium(III) complexes containing phenyl-triazole and triazole-pyridine clicked ligands.

Project description:Novel heteroleptic iridium complexes containing the 1-substituted-4-phenyl-1H-1,2,3-triazole (phtl) cyclometalating ligand have been synthesized. The 3+2 Huisgen dipolar cycloaddition method ('click' chemistry) was utilized to prepare a class of bidentate ligands (phtl) bearing different substituents on the triazole moiety. By using various ligands (phtl-R1 and pytl-R2) (R1 = adamantane, methyl and R2 = adamantane, methyl, beta-cyclodextrin, ursodeoxycholic acid), we prepared a small library of new luminescent ionic iridium complexes [Ir(phtr-R1)2(pytl-R2)]Cl and report on their photophysical properties. The flexibility of the clicking approach allows a straightforward control on the chemical-physical properties of the complexes by varying the nature of the substituent on the ligand.

| S-EPMC6257372 | biostudies-literature

On the Importance of Ligand-Centered Excited States in the Emission of Cyclometalated Ir(III) Complexes.

Project description:The photophysical behavior of the cyclometalating Ir(III) complexes [Ir(ppy)2(bpy)]+, where Hppy is 2-phenylpyridine and bpy is 2,2'-bipyridine (complex 1), and [Ir(diFppy)2(dtb-bpy)]+, where diFppy is 2-(2,4-difluorophenyl)pyridine and dtb-bpy is 4,4'-di-tert-butyl-2,2'-bipyridine (complex 2), has been theoretically investigated by performing density functional theory calculations. The two complexes share the same molecular skeleton, complex 2 being derived from complex 1 through the addition of fluoro and tert-butyl substituents, but present notable differences in their photophysical properties. The remarkable difference in their emission quantum yields (0.196 for complex 1 in dichloromethane and 0.71 for complex 2 in acetonitrile) has been evaluated by characterizing both radiative and nonradiative decay paths. It has emerged that the probability of decaying through the nonradiative triplet metal-centered state, normally associated with the loss of the emission quantum yield, does not appear to be the reason behind the reported substantially different emission efficiency. A more critical factor appears to be the ability of complex 2 to emit from both the usual metal-to-ligand charge-transfer state and from two additional ligand-centered states, as supported by the fact that the respective minima belong to the potential energy surface of the lowest triplet T1 state and that their phosphorescence lifetimes are in the same order of magnitude. In contrast, the emission of complex 1 can be originated only from the metal-to-ligand charge-transfer state, being the only emissive T1 minimum. The results constitute a significant case in which the emission from ligand-centered states is the key for determining the high emission quantum yield of a complex.

| S-EPMC8424641 | biostudies-literature

Oncosis-inducing cyclometalated iridium(iii) complexes.

Project description:Oncosis is a non-apoptotic form of programmed cell death (PCD), which differs from apoptosis in both morphological changes and inner pathways, and might hold the key to defeating a major obstacle in cancer therapy - drug-resistance, which is often a result of the intrinsic apoptosis resistance of tumours. However, despite the fact that the term "oncosis" was coined and used much earlier than apoptosis, little effort has been made to discover new drugs which can initiate this form of cell death, in comparison to drugs inducing apoptosis or any other type of PCD. So herein, we present the synthesis of a series of mitochondria-targeting cyclometalated Ir(iii) complexes, which activated the oncosis-specific protein porimin and calpain in cisplatin-resistant cell line A549R, and determined their cytotoxicity against a wide range of drug-resistant cancer types. To the best of our knowledge, these complexes are the very first metallo-components to induce oncosis in drug-resistant cancer cells.

| S-EPMC6000986 | biostudies-literature

Bis-cyclometalated iridium(iii) complexes with terpyridine analogues: syntheses, structures, spectroscopy and computational studies.

Project description:Two ligands based upon a 2,6-disubstituted pyridine bridge introduce bis-quinoxalinyl units in a fashion that yields analogues to the archetypal terdentate ligand, 2,2':6',2''-terpyridine. The ligands were synthesised from the key intermediate 2,6-bis(bromoacetyl)pyridine: a new, high-yielding route is described for this reagent. Two ligand variants (differentiated by H/Me substituents on the quinoxaline ring) were explored as coordinating moieties for iridium(iii) in the development of luminescent complexes. Computational studies (DFT approaches employing B3LYP, B3LYP/LANL2DZ, and M062X/LANL2DZ levels) were used to investigate the geometric and coordination mode preferences of the new ligands and two possibilities arose from theoretical investigations: [Ir(N^N^N)2]3+ and [Ir(N^N^C)2]+, with the former predicted to be more energetically favourable. Upon synthesis and isolation of the Ir(iii) complexes, X-ray crystallographic studies revealed coordination spheres that were cyclometalated, the structures both showing a [Ir(N^N^C)2]PF6 arrangement. Further spectroscopic characterization via NMR confirmed the ligand arrangements in the complexes, and photophysical studies, supported by DFT, showed that a mixture of metal-to-ligand charge transfer (MLCT) and intra-ligand charge transfer (ILCT) character is likely to contribute to the emission features of the complexes, which phosphoresce orange-red (λ em = 580-618 nm). The emission wavelength was influenced by the substituents on the quinoxaline ring (H vs. Me), thereby implying further tuneability is possible with future ligand iterations.

| S-EPMC9044569 | biostudies-literature

Cyclometalated gold(iii) complexes: noticeable differences between (N,C) and (P,C) ligands in migratory insertion.

Project description:Gold(iii) complexes are garnering increasing interest for opto-electronic, therapeutic and catalytic applications. But so far, very little is known about the factors controlling their reactivity and the very influence of the ancillary ligand. This article reports the first comprehensive study on this topic. The reactivity of a cationic (N,C) gold(iii) complex, namely 1A, towards ethylene has been thoroughly studied and compared with that of the related (P,C) complex 1C. A cationic gold(iii) complex 5A resulting from double insertion of ethylene was selectively obtained. Complex 5A was found to be remarkably stable. It was trapped with chloride and fully characterized. In marked contrast to that observed with 1C, no β-H elimination or linear-to-branched rearrangement of the alkyl chain occurred with 1A. The energy profile for the reactions of 1A with ethylene has been comprehensively investigated computationally, and the influence of the ancillary ligand has been precisely delineated. Because nitrogen is a weaker donor than carbon (and phosphorus), the (N,C) ligand is very electronically dissymmetric, much more than the (P,C) ligand. This makes the two reactive sites at gold quite different, which noticeably influences the competition between migratory insertion and β-H elimination, and actually changes the outcome of the olefin insertion at gold. This study provides valuable insight into the influence of ancillary ligands on gold(iii) reactivity, something critical to further develop Au(iii) and Au(i)/Au(iii) catalysis.

| S-EPMC5941201 | biostudies-literature

Exploration of the Structural and Photophysical Characteristics of Mono- and Binuclear Ir(III) Cyclometalated Complexes for Optoelectronic Applications.

Project description:Intrinsic characteristics possessed and exhibited by Ir(III) cyclometalated complexes need to be further examined, understood, and explored for greater value enhancement and potentiation. This work focuses primarily on the comparative studies of the ligand structures, types, and their substituent influence on the photophysical and optoelectronic properties of typical cyclometalated mono- and binuclear iridium(III) complexes in solution or solid states.

| S-EPMC6747829 | biostudies-literature

Probing Electron Excitation Characters of Carboline-Based Bis-Tridentate Ir(III) Complexes.

Project description:In this work, we report a series of bis-tridentate Ir(III) metal complexes, comprising a dianionic pyrazole-pyridine-phenyl tridentate chelate and a monoanionic chelate bearing a peripheral carbene and carboline coordination fragment that is linked to the central phenyl group. All these Ir(III) complexes were synthesized with an efficient one-pot and two-step method, and their emission hue was fine-tuned by variation of the substituent at the central coordination entity (i.e., pyridinyl and phenyl group) of each of the tridentate chelates. Their photophysical and electrochemical properties, thermal stabilities and electroluminescence performances are examined and discussed comprehensively. The doped devices based on [Ir(cbF)(phyz1)] (Cb1) and [Ir(cbB)(phyz1)] (Cb4) give a maximum external quantum efficiency (current efficiency) of 16.6% (55.2 cd/A) and 13.9% (43.8 cd/A), respectively. The relatively high electroluminescence efficiencies indicate that bis-tridentate Ir(III) complexes are promising candidates for OLED applications.

| S-EPMC8512491 | biostudies-literature

Unveiling the anti-cancer mechanism for half-sandwich and cyclometalated Ir(iii)-based complexes with functionalized α-lipoic acid.

Project description:Alpha lipoic acid (LA) is a natural compound and coenzyme with sufficient safety information for serving as a promising anticancer agent. To further clarify the mechanism of action (MoA), two Ir(iii) complexes with the functionalized α-lipoic acid (N∧N-LA, N∧N, 2,2-bipyridine derivative), namely Ir1 and Ir2, were synthesized, where Ir1 possessed a half-sandwich structure with the formula [Ir(Cp*)(N∧N-LA)Cl]PF6 (Cp* = 1,2,3,4,5-pentamethyl-cyclopentadiene) and Ir2 possessed the cyclometalated structure with the formula [Ir(C∧N)2(N∧N-LA)]PF6 (C∧N = 2-phenylpyridine). Even though both complexes were constructed based on the same N∧N-LA ligand, Ir1 showed no cytotoxicity (IC50 > 200 μM), which was due to its low lipophilicity for hard penetration into the cancer cells, easy hydrolysis, and reaction with GSH. Ir2 exhibited excellent cytotoxicity (IC50 = 3.43-6.74 μM) toward diverse cancer cell lines in vitro and a promising ability to overcome the cisplatin-resistance in A549R cells. The anticancer mechanism of Ir2 in A549 cells was investigated in detail, and it was found it could localize and accumulate in the lysosomes of A549 cells, induce ROS, arrest the cycle at G0/G1, and lead to cell death by autophagy. Comparison with Ir-NH2 ([Ir(C∧N)2(N∧N-NH2)]PF6) demonstrated that introduction of the LA ligand to Ir2 could highly enhance the cytotoxicity and help to overcome the cisplatin-resistance. This study of the half-sandwich and cyclometalated Ir(iii)-based anticancer agents highlighted the different MoAs toward cancer cells and provided new insights for understanding their structure-property relationships.

| S-EPMC9049077 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data