Electrogenerated chemiluminescence from newly synthesized α-diimine-ligated heteroleptic iridium(III) complexes

Tae Kyeong Kang, Chang Hoon Kang, Jihoon Lee, Shin Han Kim, Byeong Hyo Kim, Wonyong Lee

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A series of α-diimine ligands including alkyl-, bromo-, silyl- or silylethynyl-substituted 2,2′-bipyridines (bpy) for auxiliary neutral ligands on iridium(III) complexes were prepared. Using those ligands, α-diimine-ligated heteroleptic iridium(III) complexes with 2,4-difluorophenylpyridine as the primary cyclometalating ligand were synthesized by a conventional two-step synthesis followed by the anion exchange reaction using NH4PF6. The physical features such as spectroscopic, electrochemical and electrogenerated chemiluminescence (ECL) properties for the newly prepared complexes were characterized and compared to that of well-known tris(2,2′-bipyridine)rutheniun(II), [Ru(bpy)3](PF6)2, and previously reported (2,2′-bipyridine)bis[2-(2,4-difluorophenyl)pyridine]iridium(III), [Ir(dfppy)2(bpy)](PF6) (2), complex as the reference. All the iridium(III) complexes synthesized showed strong green emission and higher ECL intensities compared to the well-known Ru(bpy)32 +. The iridium(III) complexes containing α-diimine ligands with electron donating dimethyl, trimethylsilyl, and triphenylsilyl groups on bpy showed the increased ECL intensities compared to that of the reference (2). Among those iridium(III) complexes, the complex ligated with 5-(trimethylsilyl)-2,2′-bipyridine and 2,4-difluorophenylpyridine showed the most intense ECL responses and exhibited ECL intensities as high as 7.6 times greater than that of the reference (2). However, the iridium(III) complexes containing α-diimine ligands containing more conjugated carbon-carbon triple bond showed the decreased ECL intensities compared to that of the complexes with no triple bond conjugation.

Original languageEnglish
Pages (from-to)83-90
Number of pages8
JournalJournal of Electroanalytical Chemistry
Volume775
DOIs
Publication statusPublished - 2016 Aug 15

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Iridium
Chemiluminescence
Ligands
Carbon
Pyridine
Anions
Ion exchange
Negative ions
Electrons

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

Cite this

Kang, Tae Kyeong ; Kang, Chang Hoon ; Lee, Jihoon ; Kim, Shin Han ; Kim, Byeong Hyo ; Lee, Wonyong. / Electrogenerated chemiluminescence from newly synthesized α-diimine-ligated heteroleptic iridium(III) complexes. In: Journal of Electroanalytical Chemistry. 2016 ; Vol. 775. pp. 83-90.
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title = "Electrogenerated chemiluminescence from newly synthesized α-diimine-ligated heteroleptic iridium(III) complexes",
abstract = "A series of α-diimine ligands including alkyl-, bromo-, silyl- or silylethynyl-substituted 2,2′-bipyridines (bpy) for auxiliary neutral ligands on iridium(III) complexes were prepared. Using those ligands, α-diimine-ligated heteroleptic iridium(III) complexes with 2,4-difluorophenylpyridine as the primary cyclometalating ligand were synthesized by a conventional two-step synthesis followed by the anion exchange reaction using NH4PF6. The physical features such as spectroscopic, electrochemical and electrogenerated chemiluminescence (ECL) properties for the newly prepared complexes were characterized and compared to that of well-known tris(2,2′-bipyridine)rutheniun(II), [Ru(bpy)3](PF6)2, and previously reported (2,2′-bipyridine)bis[2-(2,4-difluorophenyl)pyridine]iridium(III), [Ir(dfppy)2(bpy)](PF6) (2), complex as the reference. All the iridium(III) complexes synthesized showed strong green emission and higher ECL intensities compared to the well-known Ru(bpy)32 +. The iridium(III) complexes containing α-diimine ligands with electron donating dimethyl, trimethylsilyl, and triphenylsilyl groups on bpy showed the increased ECL intensities compared to that of the reference (2). Among those iridium(III) complexes, the complex ligated with 5-(trimethylsilyl)-2,2′-bipyridine and 2,4-difluorophenylpyridine showed the most intense ECL responses and exhibited ECL intensities as high as 7.6 times greater than that of the reference (2). However, the iridium(III) complexes containing α-diimine ligands containing more conjugated carbon-carbon triple bond showed the decreased ECL intensities compared to that of the complexes with no triple bond conjugation.",
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Electrogenerated chemiluminescence from newly synthesized α-diimine-ligated heteroleptic iridium(III) complexes. / Kang, Tae Kyeong; Kang, Chang Hoon; Lee, Jihoon; Kim, Shin Han; Kim, Byeong Hyo; Lee, Wonyong.

In: Journal of Electroanalytical Chemistry, Vol. 775, 15.08.2016, p. 83-90.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Electrogenerated chemiluminescence from newly synthesized α-diimine-ligated heteroleptic iridium(III) complexes

AU - Kang, Tae Kyeong

AU - Kang, Chang Hoon

AU - Lee, Jihoon

AU - Kim, Shin Han

AU - Kim, Byeong Hyo

AU - Lee, Wonyong

PY - 2016/8/15

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N2 - A series of α-diimine ligands including alkyl-, bromo-, silyl- or silylethynyl-substituted 2,2′-bipyridines (bpy) for auxiliary neutral ligands on iridium(III) complexes were prepared. Using those ligands, α-diimine-ligated heteroleptic iridium(III) complexes with 2,4-difluorophenylpyridine as the primary cyclometalating ligand were synthesized by a conventional two-step synthesis followed by the anion exchange reaction using NH4PF6. The physical features such as spectroscopic, electrochemical and electrogenerated chemiluminescence (ECL) properties for the newly prepared complexes were characterized and compared to that of well-known tris(2,2′-bipyridine)rutheniun(II), [Ru(bpy)3](PF6)2, and previously reported (2,2′-bipyridine)bis[2-(2,4-difluorophenyl)pyridine]iridium(III), [Ir(dfppy)2(bpy)](PF6) (2), complex as the reference. All the iridium(III) complexes synthesized showed strong green emission and higher ECL intensities compared to the well-known Ru(bpy)32 +. The iridium(III) complexes containing α-diimine ligands with electron donating dimethyl, trimethylsilyl, and triphenylsilyl groups on bpy showed the increased ECL intensities compared to that of the reference (2). Among those iridium(III) complexes, the complex ligated with 5-(trimethylsilyl)-2,2′-bipyridine and 2,4-difluorophenylpyridine showed the most intense ECL responses and exhibited ECL intensities as high as 7.6 times greater than that of the reference (2). However, the iridium(III) complexes containing α-diimine ligands containing more conjugated carbon-carbon triple bond showed the decreased ECL intensities compared to that of the complexes with no triple bond conjugation.

AB - A series of α-diimine ligands including alkyl-, bromo-, silyl- or silylethynyl-substituted 2,2′-bipyridines (bpy) for auxiliary neutral ligands on iridium(III) complexes were prepared. Using those ligands, α-diimine-ligated heteroleptic iridium(III) complexes with 2,4-difluorophenylpyridine as the primary cyclometalating ligand were synthesized by a conventional two-step synthesis followed by the anion exchange reaction using NH4PF6. The physical features such as spectroscopic, electrochemical and electrogenerated chemiluminescence (ECL) properties for the newly prepared complexes were characterized and compared to that of well-known tris(2,2′-bipyridine)rutheniun(II), [Ru(bpy)3](PF6)2, and previously reported (2,2′-bipyridine)bis[2-(2,4-difluorophenyl)pyridine]iridium(III), [Ir(dfppy)2(bpy)](PF6) (2), complex as the reference. All the iridium(III) complexes synthesized showed strong green emission and higher ECL intensities compared to the well-known Ru(bpy)32 +. The iridium(III) complexes containing α-diimine ligands with electron donating dimethyl, trimethylsilyl, and triphenylsilyl groups on bpy showed the increased ECL intensities compared to that of the reference (2). Among those iridium(III) complexes, the complex ligated with 5-(trimethylsilyl)-2,2′-bipyridine and 2,4-difluorophenylpyridine showed the most intense ECL responses and exhibited ECL intensities as high as 7.6 times greater than that of the reference (2). However, the iridium(III) complexes containing α-diimine ligands containing more conjugated carbon-carbon triple bond showed the decreased ECL intensities compared to that of the complexes with no triple bond conjugation.

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