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Toyama M, Hasegawa T, Nagao N. Colorimetric fluoride detection in dimethyl sulfoxide using a heteroleptic ruthenium( ii) complex with amino and amide groups: X-ray crystallographic and spectroscopic analyses. RSC Adv 2022; 12:25227-25239. [PMID: 36199333 PMCID: PMC9450000 DOI: 10.1039/d2ra03593f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 08/19/2022] [Indexed: 11/25/2022] Open
Abstract
A bis-heteroleptic ruthenium(ii) complex, [Ru(Hdpa)2(H2pia)]X2 (1·X2; X = Cl, OTf, or F; Hdpa = di-2-pyridylamine; H2pia = 2-pycolinamide; OTf− = CF3SO3−), was synthesized and spectroscopically and crystallographically characterized. The crystal structures of 1·Cl2·2.5H2O and 1·F2·2EtOH revealed essentially identical geometries for the 12+ dication; however, the dihedral angle between the two pyridyl groups in the Hdpa ligands, which represented the degree of bending of the bent conformation, was affected by hydrogen-bonding interactions between the NH group and counterions. In 1·F2·2EtOH, one of the Hdpa ligands had an unusually smaller dihedral angle (15.8°) than the others (29.9°–35.0°). The two NH groups of each Hdpa ligand and the NH2 group of the H2pia ligand in 12+ acted as receptors for F− anion recognition via hydrogen-bonding interactions in a dimethyl sulfoxide (DMSO) solution, and the reaction showed an unambiguous color change in the visible region. Upon the addition of tetra-n-butylammonium fluoride to the red DMSO solution of 1·(OTf)2·H2O, the solution turned dark brown. 1H NMR analysis and absorption spectroscopy of the reaction between 12+ and the added F− anions revealed that the F− anions did not distinguish between the two amino groups of Hdpa and the amide group of H2pia, although they were in different environments in the DMSO solution. A tris-F-adduct with 12+, 1·F3−, was formed when sufficient F− anions were present in the solution, despite the presence of four NH protons in 12+. Time-dependent DFT calculations of 12+ and 1·F3− were consistent with their absorption spectra. A bis-heteroleptic ruthenium(ii) complex; [Ru(Hdpa)2(H2pia)]X2 (1·X2; X = Cl, OTf, or F; Hdpa = di-2-pyridylamine; H2pia = 2-pycolinamide; OTf– = CF3SO3–) was synthesized and spectroscopically and crystallographically characterized.![]()
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Affiliation(s)
- Mari Toyama
- Department of Engineering Science, Faculty of Engineering, Osaka Electro-Communication University, 18-8 Hatsucho, Neyagawa, Osaka, 572-8530, Japan
- Department of Chemistry of Functional Molecules, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe, Hyogo, 658-8501, Japan
- Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama, Kawasaki, Kanagawa, 214-8571, Japan
| | - Tomoki Hasegawa
- Department of Chemistry of Functional Molecules, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe, Hyogo, 658-8501, Japan
| | - Noriharu Nagao
- Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama, Kawasaki, Kanagawa, 214-8571, Japan
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