Metalated Ir(III) Complexes Based on the Luminescent Diimine Ligands: Synthesis and Photophysical Study

Julia R. Shakirova, Olesya A. Tomashenko, Ekaterina E. Galenko, Alexander F. Khlebnikov, Pipsa Hirva, Galina L. Starova, Shih Hao Su, Pi Tai Chou, Sergey P. Tunik

Research output

2 Citations (Scopus)

Abstract

A series of novel diimine (NN) ligands containing developed aromatic [2,1-a]pyrrolo[3,2-c]isoquinoline system have been prepared and used in the synthesis of Ir(III) luminescent complexes. In organic solvents, the ligands display fluorescence which depends strongly on the nature of solvents to give moderate to strong orange emission in aprotic solvents and shows a considerable blue shift and substantial increase in emission intensity in methanol. Insertion of electron-withdrawing and -donating substituents into peripheral phenyl fragment has nearly no effect onto emission parameters. The ligands were successfully used to prepare the metalated [Ir(NC)2(NN)]+ complexes (where NC = phenylpyridine (NC-1), p-tolylpyridine (NC-2), 2-(benzo[b]thiophen-2-yl)pyridine (NC-3), 2-benzo[b]thiophen-3-yl)pyridine (NC-4), and methyl 2-phenylquinoline-4-carboxylate (NC-5)) using standard synthetic procedures. The complexes obtained display moderate to strong phosphorescence in organic solvents; the emission characteristics is determined by the nature of emissive triplet state, which varies substantially with the variations in the structure and donor properties of the C- and N-coordinating functions in metalating ligands. TD-DFT calculations show that for complexes 1, 2, and 4 the emission originates from the mixed 3MLCT/3LLCT excited states with the major contribution from the aromatic moiety of the diimine ligand, whereas in 3 the emissive triplet manifold is mainly located at the NC ligand to give structured emission band typical for the ligand centered (LC) excited state. In the case of 5, the phosphorescence may be also assigned to the mixed 3MLCT/3LLCT excited state; however, the major contribution is attributed to the aromatic moiety of the metalating NC ligand.

Original languageEnglish
Pages (from-to)6853-6864
Number of pages12
JournalInorganic Chemistry
Volume57
Issue number12
DOIs
Publication statusPublished - 18 Jun 2018

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Ligands
ligands
synthesis
Excited states
Phosphorescence
phosphorescence
Organic solvents
pyridines
Display devices
excitation
blue shift
Discrete Fourier transforms
carboxylates
atomic energy levels
Methanol
insertion
methyl alcohol
Fluorescence
fragments
fluorescence

Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

@article{dd3d7fb2805a4a628edcc49bc6658379,
title = "Metalated Ir(III) Complexes Based on the Luminescent Diimine Ligands: Synthesis and Photophysical Study",
abstract = "A series of novel diimine (N∞N) ligands containing developed aromatic [2,1-a]pyrrolo[3,2-c]isoquinoline system have been prepared and used in the synthesis of Ir(III) luminescent complexes. In organic solvents, the ligands display fluorescence which depends strongly on the nature of solvents to give moderate to strong orange emission in aprotic solvents and shows a considerable blue shift and substantial increase in emission intensity in methanol. Insertion of electron-withdrawing and -donating substituents into peripheral phenyl fragment has nearly no effect onto emission parameters. The ligands were successfully used to prepare the metalated [Ir(N∞C)2(N∞N)]+ complexes (where N∞C = phenylpyridine (N∞C-1), p-tolylpyridine (N∞C-2), 2-(benzo[b]thiophen-2-yl)pyridine (N∞C-3), 2-benzo[b]thiophen-3-yl)pyridine (N∞C-4), and methyl 2-phenylquinoline-4-carboxylate (N∞C-5)) using standard synthetic procedures. The complexes obtained display moderate to strong phosphorescence in organic solvents; the emission characteristics is determined by the nature of emissive triplet state, which varies substantially with the variations in the structure and donor properties of the C- and N-coordinating functions in metalating ligands. TD-DFT calculations show that for complexes 1, 2, and 4 the emission originates from the mixed 3MLCT/3LLCT excited states with the major contribution from the aromatic moiety of the diimine ligand, whereas in 3 the emissive triplet manifold is mainly located at the N∞C ligand to give structured emission band typical for the ligand centered (LC) excited state. In the case of 5, the phosphorescence may be also assigned to the mixed 3MLCT/3LLCT excited state; however, the major contribution is attributed to the aromatic moiety of the metalating N∞C ligand.",
author = "Shakirova, {Julia R.} and Tomashenko, {Olesya A.} and Galenko, {Ekaterina E.} and Khlebnikov, {Alexander F.} and Pipsa Hirva and Starova, {Galina L.} and Su, {Shih Hao} and Chou, {Pi Tai} and Tunik, {Sergey P.}",
year = "2018",
month = "6",
day = "18",
doi = "10.1021/acs.inorgchem.8b00390",
language = "English",
volume = "57",
pages = "6853--6864",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "12",

}

TY - JOUR

T1 - Metalated Ir(III) Complexes Based on the Luminescent Diimine Ligands

T2 - Synthesis and Photophysical Study

AU - Shakirova, Julia R.

AU - Tomashenko, Olesya A.

AU - Galenko, Ekaterina E.

AU - Khlebnikov, Alexander F.

AU - Hirva, Pipsa

AU - Starova, Galina L.

AU - Su, Shih Hao

AU - Chou, Pi Tai

AU - Tunik, Sergey P.

PY - 2018/6/18

Y1 - 2018/6/18

N2 - A series of novel diimine (N∞N) ligands containing developed aromatic [2,1-a]pyrrolo[3,2-c]isoquinoline system have been prepared and used in the synthesis of Ir(III) luminescent complexes. In organic solvents, the ligands display fluorescence which depends strongly on the nature of solvents to give moderate to strong orange emission in aprotic solvents and shows a considerable blue shift and substantial increase in emission intensity in methanol. Insertion of electron-withdrawing and -donating substituents into peripheral phenyl fragment has nearly no effect onto emission parameters. The ligands were successfully used to prepare the metalated [Ir(N∞C)2(N∞N)]+ complexes (where N∞C = phenylpyridine (N∞C-1), p-tolylpyridine (N∞C-2), 2-(benzo[b]thiophen-2-yl)pyridine (N∞C-3), 2-benzo[b]thiophen-3-yl)pyridine (N∞C-4), and methyl 2-phenylquinoline-4-carboxylate (N∞C-5)) using standard synthetic procedures. The complexes obtained display moderate to strong phosphorescence in organic solvents; the emission characteristics is determined by the nature of emissive triplet state, which varies substantially with the variations in the structure and donor properties of the C- and N-coordinating functions in metalating ligands. TD-DFT calculations show that for complexes 1, 2, and 4 the emission originates from the mixed 3MLCT/3LLCT excited states with the major contribution from the aromatic moiety of the diimine ligand, whereas in 3 the emissive triplet manifold is mainly located at the N∞C ligand to give structured emission band typical for the ligand centered (LC) excited state. In the case of 5, the phosphorescence may be also assigned to the mixed 3MLCT/3LLCT excited state; however, the major contribution is attributed to the aromatic moiety of the metalating N∞C ligand.

AB - A series of novel diimine (N∞N) ligands containing developed aromatic [2,1-a]pyrrolo[3,2-c]isoquinoline system have been prepared and used in the synthesis of Ir(III) luminescent complexes. In organic solvents, the ligands display fluorescence which depends strongly on the nature of solvents to give moderate to strong orange emission in aprotic solvents and shows a considerable blue shift and substantial increase in emission intensity in methanol. Insertion of electron-withdrawing and -donating substituents into peripheral phenyl fragment has nearly no effect onto emission parameters. The ligands were successfully used to prepare the metalated [Ir(N∞C)2(N∞N)]+ complexes (where N∞C = phenylpyridine (N∞C-1), p-tolylpyridine (N∞C-2), 2-(benzo[b]thiophen-2-yl)pyridine (N∞C-3), 2-benzo[b]thiophen-3-yl)pyridine (N∞C-4), and methyl 2-phenylquinoline-4-carboxylate (N∞C-5)) using standard synthetic procedures. The complexes obtained display moderate to strong phosphorescence in organic solvents; the emission characteristics is determined by the nature of emissive triplet state, which varies substantially with the variations in the structure and donor properties of the C- and N-coordinating functions in metalating ligands. TD-DFT calculations show that for complexes 1, 2, and 4 the emission originates from the mixed 3MLCT/3LLCT excited states with the major contribution from the aromatic moiety of the diimine ligand, whereas in 3 the emissive triplet manifold is mainly located at the N∞C ligand to give structured emission band typical for the ligand centered (LC) excited state. In the case of 5, the phosphorescence may be also assigned to the mixed 3MLCT/3LLCT excited state; however, the major contribution is attributed to the aromatic moiety of the metalating N∞C ligand.

UR - http://www.scopus.com/inward/record.url?scp=85048732680&partnerID=8YFLogxK

U2 - 10.1021/acs.inorgchem.8b00390

DO - 10.1021/acs.inorgchem.8b00390

M3 - Article

AN - SCOPUS:85048732680

VL - 57

SP - 6853

EP - 6864

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 12

ER -