scholarly journals Improved Deep-Red Phosphorescence in Cyclometalated Iridium Complexes via Ancillary Ligand Modification

2019 ◽  
Author(s):  
Evanta Kabir ◽  
Steven Sittel ◽  
Boi-Lien Nguyen ◽  
Thomas Teets
Keyword(s):  
Rate Constant ◽  
Quantum Yields ◽  
Iridium Complexes ◽  
Ancillary Ligand ◽  
Ancillary Ligands ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ligand Modification ◽  
Radiative Rate ◽  
Red Luminescence

In this work, we describe bis-cyclometalated iridium complexes with efficient deep-red luminescence. Two different cyclometalating (C^N) ligands‒1-phenylisoquinoline (piq) and 2-(2- pyridyl)benzothiophene (btp)‒are used with six strong π-donating ancillary ligands (L^X) to furnish a suite of 10 new complexes with the general formula Ir(C^N)2(L^X). Improvements in deep-red photoluminescence quantum yields were accomplished by the incorporation of sterically encumbering substituents onto the ancillary ligand, which can enhance the radiative rate constant (kr) and/or reduce the non-radiative rate constant (knr). Five of the complexes were characterized by X-ray crystallography, and all of them were investigated by in-depth spectroscopic and electrochemical measurements.<br>

scholarly journals Improved Deep-Red Phosphorescence in Cyclometalated Iridium Complexes via Ancillary Ligand Modification

2019 ◽  
Author(s):  
Evanta Kabir ◽  
Steven Sittel ◽  
Boi-Lien Nguyen ◽  
Thomas Teets
Keyword(s):  
Rate Constant ◽  
Quantum Yields ◽  
Iridium Complexes ◽  
Ancillary Ligand ◽  
Ancillary Ligands ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ligand Modification ◽  
Radiative Rate ◽  
Red Luminescence

In this work, we describe bis-cyclometalated iridium complexes with efficient deep-red luminescence. Two different cyclometalating (C^N) ligands‒1-phenylisoquinoline (piq) and 2-(2- pyridyl)benzothiophene (btp)‒are used with six strong π-donating ancillary ligands (L^X) to furnish a suite of 10 new complexes with the general formula Ir(C^N)2(L^X). Improvements in deep-red photoluminescence quantum yields were accomplished by the incorporation of sterically encumbering substituents onto the ancillary ligand, which can enhance the radiative rate constant (kr) and/or reduce the non-radiative rate constant (knr). Five of the complexes were characterized by X-ray crystallography, and all of them were investigated by in-depth spectroscopic and electrochemical measurements.<br>

Improved deep-red phosphorescence in cyclometalated iridium complexes via ancillary ligand modification

2020 ◽  
Vol 7 (6) ◽  
pp. 1362-1373 ◽  
Author(s):  
Evanta Kabir ◽  
Yanyu Wu ◽  
Steven Sittel ◽  
Boi-Lien Nguyen ◽  
Thomas S. Teets
Keyword(s):  
Quantum Yields ◽  
Iridium Complexes ◽  
Ancillary Ligand ◽  
Ancillary Ligands ◽  
Ligand Modification

Bis-cyclometalated iridium complexes with electron-rich ancillary ligands exhibit high phosphorescence quantum yields in the deep red region.

Synthesis, structural characterization and catalytic activity of chlororuthenium(II) complexes with substituted Schiff base/phosphine ancillary ligands

2020 ◽  
Vol 75 (9-10) ◽  
pp. 851-857
Author(s):  
Chong Chen ◽  
Fule Wu ◽  
Jiao Ji ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Schiff Base ◽  
Catalytic Activity ◽  
Structural Characterization ◽  
Room Temperature ◽  
Molecular Structures ◽  
Cationic Complex ◽  
Neutral Complex ◽  
Ancillary Ligands ◽  
X Ray ◽  
X Ray Crystallography

AbstractTreatment of [(η6-p-cymene)RuCl2]2 with one equivalent of chlorodiphenylphosphine in tetrahydrofuran at reflux afforded a neutral complex [(η6-p-cymene)RuCl2(κ1-P-PPh2OH)] (1). Similarly, the reaction of [Ru(bpy)2Cl2·2H2O] (bpy = 2,2′-bipyridine) and chlorodiphenylphosphine in methanol gave a cationic complex [Ru(bpy)2Cl(κ1-P-PPh2OCH3)](PF6) (2), while treatment of [RuCl2(PPh3)3] with [2-(C5H4N)CH=N(CH2)2N(CH3)2] (L1) in tetrahydrofuran at room temperature afforded a ruthenium(II) complex [Ru(PPh3)Cl2(κ3-N,N,N-L1)] (3). Interaction of the chloro-bridged complex [Ru(CO)2Cl2]n with one equivalent of [Ph2P(o-C6H4)CH=N(CH2)2N(CH3)2] (L2) led to the isolation of [Ru(CO)Cl2(κ3-P,N,N-L2)] (4). The molecular structures of the ruthenium(II) complexes 1–4 have been determined by single-crystal X-ray crystallography. The properties of the ruthenium(II) complex 4 as a hydrogenation catalyst for acetophenone were also tested.

Effect of β-Ketoiminato Ancillary Ligand Modification on Emissive Properties of New Iridium Complexes

2019 ◽  
Vol 58 (22) ◽  
pp. 15671-15686 ◽  
Author(s):  
Ewelina Witkowska ◽  
Bartosz Orwat ◽  
Myong Joon Oh ◽  
Gabriela Wiosna-Salyga ◽  
Ireneusz Glowacki ◽  
...  
Keyword(s):  
Iridium Complexes ◽  
Ancillary Ligand ◽  
Ligand Modification

scholarly journals Theoretical investigation on the effect of ancillary ligand modification for highly efficient phosphorescent platinum(ii) complex design

RSC Advances ◽  
2017 ◽  
Vol 7 (28) ◽  
pp. 17368-17376 ◽  
Author(s):  
Hong-Wei Fan ◽  
Fu-Quan Bai ◽  
Zhi-Xiang Zhang ◽  
Yu Wang ◽  
Ze-Xing Qu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Theoretical Investigation ◽  
Organic Light Emitting Diodes ◽  
Luminescent Materials ◽  
Ancillary Ligand ◽  
Ancillary Ligands ◽  
Light Emitting ◽  
Ligand Modification ◽  
Organic Light ◽  
Complex Design

Reasonable modification of ancillary ligands for Pt(ii) complexes can effectively improve the quantum efficiency and strengthen the rigidity of luminescent materials in organic light-emitting diodes.

Structure and spectroscopy of uranyl salicylaldiminate complexes

2013 ◽  
Vol 101 (10) ◽  
pp. 631-636 ◽  
Author(s):  
A. L. Tamasi ◽  
C. L. Barnes ◽  
J. R. Walensky
Keyword(s):  
Schiff Base ◽  
Nmr Spectroscopy ◽  
Coordination Sphere ◽  
Ancillary Ligand ◽  
Schiff Base Ligands ◽  
Uranyl Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Chloride Ligand ◽  
C Nmr

Summary The synthesis of uranyl complexes coordinated to tridentate, monoanionic salicylaldiminate (Schiff base) ligands was achieved by the reaction of UO2Cl2(THF)3, 1, with one equivalent of the corresponding sodium salicylaldiminate salts affording [(C9H6N)N=C(H)C6H2t Bu2O]UO2Cl(THF), 2, [(NC5H4)N=C(H)C6H2 t Bu2O]UO2Cl(THF), 3, and [(C6H4SCH3)N=C(H)C6H2tBu2O]UO2Cl(THF), 4. These are uncommon examples of uranyl complexes with a monoanionic ancillary ligand to stabilize the coordination sphere and one chloride ligand. Compounds 2-4 have been characterized by 1H and 13C NMR spectroscopy as well as IR and UVVis spectroscopy and their structures determined by X-ray crystallography.

scholarly journals Ligand influence on intramolecular cyclometalation in bis(phosphinimine) rare earth alkyl complexes

2016 ◽  
Vol 94 (4) ◽  
pp. 330-341 ◽  
Author(s):  
Kevin R.D. Johnson ◽  
Breanne L. Kamenz ◽  
Paul G. Hayes
Keyword(s):  
Rare Earth ◽  
Kinetic Analysis ◽  
Ancillary Ligand ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alkyl Complexes ◽  
Ortho Metalation ◽  
Elimination Reactions ◽  
Alkane Elimination

The synthesis and reactivity of two new bis(phosphinimine)carbazole ligands (PippN=PMe2)2DMC (HLA, 3) and (PippN=P(C4H8))2DMC (HLB, 10), where Pipp = para-isopropylphenyl and DMC = 3,6-dimethylcarbazole, are reported. Dialkyl lutetium complexes of 3 and 10 were prepared in the presence of DMAP and THF by reaction of the proteo ligands with the new trialkyl reagent, Lu(CH2SiMe3)3(DMAP)2 (4) as well as Lu(CH2SiMe3)3(THF)2. For both ligands 3 and 10, the resulting lutetium complexes were prone to intramolecular cyclometalative alkane elimination reactions whereby the location of cyclometalation was influenced by the identity of the ancillary ligand coordinated to the metal. For ligand 3, cyclometalation of two PMe2 groups generated the complex (LA-κ3N,κ2C)Lu(DMAP)2 (5), whereas ligand 10 resulted in the single ortho-metalation of a para-isopropylphenyl ring to afford (LB-κ3N,κC)Lu(CH2SiMe3) (12). When complexed with scandium, ligand 10 behaved differently; double cyclometalation of two phospholane moieties resulted in the species (LB-κ3N,κ2C)Sc (15). The nature of the cyclometalation reactivity of ligands 3 and 10 is supported by X-ray crystallography and kinetic analysis, respectively.

scholarly journals Conjugated, rigidified bibenzimidazole ancillary ligands for enhanced photoluminescence quantum yields of orange/red-emitting iridium(iii) complexes

2019 ◽  
Vol 48 (26) ◽  
pp. 9639-9653 ◽  
Author(s):  
Adam F. Henwood ◽  
Daniel Antón-García ◽  
Mégane Morin ◽  
Diego Rota Martir ◽  
David B. Cordes ◽  
...  
Keyword(s):  
Optoelectronic Properties ◽  
Quantum Yields ◽  
Iridium Complexes ◽  
Ancillary Ligands ◽  
Enhanced Photoluminescence

A family of six orange/red-emitting cationic iridium complexes were synthesized and their optoelectronic properties comprehensively characterized.

Aza boron-pyridyl-isoindoline isomers: synthesis and photophysical properties

2014 ◽  
Vol 18 (08n09) ◽  
pp. 679-685 ◽  
Author(s):  
Hui Liu ◽  
Yanping Wu ◽  
Zhifang Li ◽  
Hua Lu
Keyword(s):  
Photophysical Properties ◽  
Emission Spectra ◽  
Quantum Yields ◽  
Structure Property ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fluorescence Quantum Yields ◽  
Structure Property Relationships ◽  
New Type ◽  
Vibrational Bands

By changing benzo-fused position on pyridyl unit, three aza boron-pyridyl-isoindoline isomers, a new type of BODIPY analog, are synthesized through a facile two step reaction. These isomers show broad envelopes of intense vibrational bands in the absorption and emission spectra with moderate fluorescence quantum yields. In comparison to those of classical BODIPYs, significant fluorescence intensity are observed for these isomers in film and powder. An analysis of the structure-property relationships has been carried out based on X-ray crystallography, optical spectroscopy, and theoretical calculation.

scholarly journals Isonitrile Ruthenium and Iron PNP Complexes: Synthesis, Characterization and Catalytic Assessment for Base-Free Dehydrogenative Coupling of Alcohols

2020 ◽  
Author(s):  
Duc Hanh Nguyen ◽  
Delphine Merel ◽  
Nicolas Merle ◽  
Xavier Trivelli ◽  
Frederic Capet ◽  
...  
Keyword(s):  
Ruthenium Complexes ◽  
Outer Sphere ◽  
Pincer Complexes ◽  
Initial Activity ◽  
Ancillary Ligands ◽  
X Ray ◽  
Bromide Anion ◽  
X Ray Crystallography ◽  
Dehydrogenative Coupling

Neutral and ionic ruthenium and iron aliphatic PNPH-type pincer complexes (PNPH= NH(CH2CH2PiPr2)2) bearing benzyl, n-butyl or tert-butyl isocyanide ancillary ligands have been prepared and characterized. Reaction of [RuCl2(PNPH)]2 with one equivalent CN-R per ruthe-nium center affords complexes [Ru(PNPH)Cl2(CNR)] (R= benzyl, 1a, R= n-butyl, 1b, R= t-butyl, 1c), with cationic [Ru(PNPH)(Cl)(CNR)2]Cl 2a-c as side-products. Complexes 2a-c are selectively prepared upon reaction of [RuCl2(PNPH)]2 with 2 equiva-lents of isonitrile per ruthenium center. Dichloride species 1a-c react with excess NaBH4 to afford [Ru(PNPH)(H)(BH4)(CN-R)] 3a-c, analogues to benchmark Takasago catalyst [Ru(PNP)(H)(BH4)(CO)]. Reaction of 1a-c with a single equivalent of NaBH4 under protic conditions results in formation of hydrido chloride derivatives [Ru(PNPH)(H)(Cl)(CN-R)] (4a-c), from which 3a-c can be prepared upon reaction with excess NaBH4. Use of one equivalent of NaHBEt3 with 4a and 4c affords bishydrides [Ru(PNPH)(H)2(CN-R)] 5a and 5c. In the case of bulkier t-butylisonitrile, two isomers were observed by NMR, with the PNP framework in either meridional or facial confor-mation. Deprotonation of 4c by KOtBu generates amido derivative [Ru(PNP’)(H)(CN-t-Bu)] (6, PNP’= -N(CH2CH2PiPr2)2), unstable in solution. Addition of excess benzylisonitrile to 4a provides cationic hydride [Ru(PNPH)(H)(CN-CH2Ph)2]Cl (7). Concerning iron chemis-try, [Fe(PNPH)Br2] reacts one equivalent benzylisonitrile to afford [Fe(PNPH)(Br)(CNCH2Ph)2]Br (8). The outer-sphere bromide anion can be exchanged by salt metathesis with NaBPh4 to generate [Fe(PNPH)(Br)(CNCH2Ph)2](BPh4) (9). Cationic hydride species [Fe(PNPH)(H)(CN-t-Bu)2](BH4) (10) is prepared from consecutive addition of excess CN-t-Bu and NaBH4 on [Fe(PNPH)Br2]. Ruthenium complexes 3a-c are active in acceptorless alcohol dehydrogenative coupling into ester under base-free conditions. From kinetic follow-up, the trend in initial activity is 3a ≈ 3b > [Ru(PNPH)(H)(BH4)(CO)] >> 3c; for robustness, [Ru(H)(BH4)(CO)(PNPH)] > 3a > 3b >> 3c. Hy-potheses are given to account for the observed deactivation. Complexes 3b, 3c, 4a, 4c, 5c, 7, cis-8 and 9 were characterized by X-ray crystallography.

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