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Kanbe A, Yokoi K, Yamada Y, Tsurui M, Kitagawa Y, Hasegawa Y, Ogata D, Yuasa J, Aoki S. Optical Resolution of Carboxylic Acid Derivatives of Homoleptic Cyclometalated Iridium(III) Complexes via Diastereomers Formed with Chiral Auxiliaries. Inorg Chem 2023; 62:11325-11341. [PMID: 37432912 PMCID: PMC10369494 DOI: 10.1021/acs.inorgchem.3c00685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Indexed: 07/13/2023]
Abstract
We report on a facile method for the optical resolution of cyclometalated iridium(III) (Ir(III)) complexes via diastereomers formed with chiral auxiliaries. The racemic carboxylic acids of Ir(III) complexes (fac-4 (fac-Ir(ppyCO2H)3 (ppy: 2-phenylpyridine)), fac-6 (fac-Ir(tpyCO2H)3 (tpy: 2-(4'-tolyl)pyridine)), and fac-13 (fac-Ir(mpiqCO2H)3 (mpiq: 1-(4'-methylphenyl)isoquinoline))) were converted into the diastereomers, Δ- and Λ-forms of fac-9 (from fac-6), fac-10 (from fac-4), fac-11 (from fac-6), and fac-14 (from fac-13), respectively, by the condensation with (1R,2R)-1,2-diaminocyclohexane or (1R,2R)-2-aminocyclohexanol. The resulting diastereomers were separated by HPLC (with a nonchiral column) or silica gel column chromatography, and their absolute stereochemistry was determined by X-ray single-crystal structure analysis and CD (circular dichroism) spectra. Spectra of all diastereomers of the Ir(III) complexes are reported. Hydrolysis of the ester moieties of Δ- and Λ-forms of fac-10, fac-11, and fac-14 gave both enantiomers of the corresponding carboxylic acid derivatives in the optically pure forms, Δ-fac and Λ-fac-4, -6, and -13, respectively.
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Affiliation(s)
- Azusa Kanbe
- Faculty
of Pharmaceutical Science, Tokyo University
of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kenta Yokoi
- Faculty
of Pharmaceutical Science, Tokyo University
of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Yasuyuki Yamada
- Department
of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
- Research
Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
- JST,
PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Makoto Tsurui
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Yuichi Kitagawa
- Faculty of
Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-Ku, Sapporo, Hokkaido 060-8628, Japan
- Institute
for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita-21, Nishi-10, Kita-Ku, Sapporo, Hokkaido 001-0021, Japan
| | - Yasuchika Hasegawa
- Faculty of
Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-Ku, Sapporo, Hokkaido 060-8628, Japan
- Institute
for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita-21, Nishi-10, Kita-Ku, Sapporo, Hokkaido 001-0021, Japan
| | - Daiji Ogata
- Faculty
of Science, Tokyo University of Science, 1-3 Kagurazaka,
Shinjuku-ku, Tokyo 162-8601, Japan
| | - Junpei Yuasa
- Faculty
of Science, Tokyo University of Science, 1-3 Kagurazaka,
Shinjuku-ku, Tokyo 162-8601, Japan
| | - Shin Aoki
- Faculty
of Pharmaceutical Science, Tokyo University
of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
- Research
Institute for Science and Technology (RIST), Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
- Research
Institute for Biomedical Science (RIBS), Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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