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Sumner E, Pižl M, McQuaid KT, Hartl F. Nitrile Substituents at the Conjugated Dipyridophenazine Moiety as Infrared Redox Markers in Electrochemically Reduced Heteroleptic Ru(II) Polypyridyl Complexes. Inorg Chem 2024; 63:2460-2469. [PMID: 38262043 PMCID: PMC10848246 DOI: 10.1021/acs.inorgchem.3c03484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/25/2024]
Abstract
Ruthenium(II) complexes [Ru(tap)2(NN)]2+ (tap = 1,4,5,8-tetraazaphenanthrene, NN = 11-cyano-dipyrido[3,2-a:2',3'-c]phenazine (11-CN-dppz) and 11,12-dicyano-dipyrido[3,2-a:2',3'-c]phenazine (11,12-CN-dppz)) feature the C≡N groups as infrared (IR)-active redox markers. They were studied by cyclic voltammetry, UV-vis, and IR spectroelectrochemistry (SEC), and density functional theory calculations to assign the four 1e- reduction waves R1-R4 observed in dichloromethane. Generally, the NN ligands are reduced first (R1). For [Ru(tap)2(11,12-CN-dppz)]2+, R1 is sufficiently separated from R2 and delocalized over both tap ligands. Accordingly, IR SEC conducted at R1 shows a large red shift of the νs,as(C≡N) modes by -18/-28 cm-1, accompanied by a 4-fold enhancement of the νs(C≡N) intensity, comparably with reference data for free 11,12-CN-dppz. The first tap-based reduction of spin-doublet [Ru(tap)2(11,12-CN-dppz)]+ to spin-triplet [Ru(tap)2(11,12-CN-dppz)] at R2 decreased ν(C≡N) by merely -2 cm-1, while the intensity enhancement reached an overall factor of 8. Comparably, a red shift of ν(C≡N) by -27 cm-1 resulted from the 1e- reduction of [Ru(tap)2(11-CN-dppz)]2+ at R1 (poorly resolved from R2), and the intensity enhancement was roughly 3-fold. Concomitant 1e- reductions of the tap ligands (R2 and R3) caused only minor ν(C≡N) shifts of -3 cm-1 and increased the absorbance by overall factors of 6.5 and 8, respectively.
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Affiliation(s)
- Elizabeth Sumner
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6DX, U.K.
| | - Martin Pižl
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6DX, U.K.
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Kane T. McQuaid
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6DX, U.K.
| | - František Hartl
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6DX, U.K.
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Zhou L, Feng RR, Zhang W, Gai F. Triple-Bond Vibrations: Emerging Applications in Energy and Biological Sciences. J Phys Chem Lett 2024; 15:187-200. [PMID: 38156972 DOI: 10.1021/acs.jpclett.3c02619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Triple bonds, such as that formed between two carbon atoms (i.e., C≡C) or that formed between one carbon atom and one nitrogen atom (i.e., C≡N), afford unique chemical bonding and hence vibrational characteristics. As such, they are not only frequently used to construct molecules with tailored chemical and/or physical properties but also employed as vibrational probes to provide site-specific chemical and/or physical information at the molecular level. Herein, we offer our perspective on the emerging applications of various triple-bond vibrations in energy and biological sciences with a focus on C≡C and C≡N triple bonds.
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Affiliation(s)
- Liang Zhou
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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Liu Y, Shao X, Gao Z, Xie Q, Ying Y, Zhu X, Pan Z, Yang J, Lin H, Tang X, Chen W, Pei W, Tu Y. In situ and General Multidentate Ligand Passivation Achieves Efficient and Ultra-Stable CsPbX 3 Perovskite Quantum Dots for White Light-Emitting Diodes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305664. [PMID: 37691085 DOI: 10.1002/smll.202305664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/13/2023] [Indexed: 09/12/2023]
Abstract
Inorganic CsPbX3 perovskite quantum dots (PeQDs) show great potential in white light-emitting diodes (WLEDs) due to excellent optoelectronic properties, but their practical application is hampered by low photoluminescence quantum yield (PLQY) and especially poor stability. Herein, we developed an in-situ and general multidentate ligand passivation strategy that allows for CsPbX3 PeQDs not only near-unit PLQY, but significantly improved stability against storage, heat, and polar solvent. The enhanced optical property arises from high effectiveness of the multidentate ligand, diethylenetriaminepentaacetic acid (DTPA) with five carboxyl groups, in passivating uncoordinated Pb2+ defects and suppressing nonradiative recombination. First-principles calculations reveal that the excellent stability is attributed to tridentate binding mode of DTPA that remarkably boosts the adsorption capacity to PeQD core. Finally, combining the green and red PeQDs with blue chip, we demonstrated highly luminous WLEDs with distinctly enhanced operation stability, a wide color gamut of 121.3% of national television system committee, standard white light of (0.33,0.33) in CIE 1931, and tunable color temperatures from warm to cold white light readily by emitters' ratio. This study provides an operando yet general approach to achieve efficient and stable PeQDs for WLEDs and accelerates their progress to commercialization.
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Affiliation(s)
- Yongfeng Liu
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Xiuwen Shao
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Zhaoju Gao
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Qingyu Xie
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Yupeng Ying
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Xiaolin Zhu
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Zhangcheng Pan
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Jinpeng Yang
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Hao Lin
- College of Optoelectronic Engineering, Chongqing University, Chongqing, 400044, P. R. China
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR, 999078, P. R. China
| | - Xiaosheng Tang
- College of Optoelectronic Engineering, Chongqing University, Chongqing, 400044, P. R. China
- College of Optoelectronic Engineering, Chongqing University of Post and Telecommunications, Chongqing, 400065, People's Republic of China
| | - Weiwei Chen
- College of Optoelectronic Engineering, Chongqing University of Post and Telecommunications, Chongqing, 400065, People's Republic of China
| | - Wei Pei
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
| | - Yusong Tu
- College of Physical Science and Technology & Microelectronics Industry Research Institute, Yangzhou University, Yangzhou, 225002, P. R. China
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Yang Y, Liu J, Feng RR, Zhang W, Gai F. C≡N Stretching Frequency as a Convenient Reporter of Charge Separation in Molecular Systems. J Phys Chem B 2023; 127:6999-7003. [PMID: 37525395 DOI: 10.1021/acs.jpcb.3c02707] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Previously, several studies have shown that, for a set of structurally related nitrile compounds, there could be a linear relationship between the total charge on the nitrile group (qCN) and its stretching frequency (νCN). However, it is unclear whether the corresponding frequency and charge properties of structurally different nitrile compounds can be described by a single linear νCN-qCN relationship. Herein, we compute the qCN magnitudes of a large number of nitrile-containing molecules whose νCN values cover a spectral range of ca. 200 cm-1 and are measured under different experimental conditions. Our results reveal that νCN indeed exhibits a linear dependence on qCN, with a slope of 637 ± 30 cm-1/charge. Because the nitrile moiety is a commonly used building block in electronic donor-acceptor (D-A) molecular systems, we believe that this linear relationship will find utility in a wide range of applications where such D-A constructs are used, such as in organic photovoltaic assemblies. In addition, we apply this linear relationship to characterize the degree of charge transfer upon photoexcitation of two indole derivatives, 5-cyanoindole and 6-cyanoindole, and are able to show that in both cases, the fluorescence emission arises from a charge-transfer or La state.
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Affiliation(s)
- Yuyao Yang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jingsong Liu
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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Liu J, Feng RR, Zhou L, Gai F, Zhang W. Photoenhancement of the C≡N Stretching Vibration Intensity of Aromatic Nitriles. J Phys Chem Lett 2022; 13:9745-9751. [PMID: 36222647 DOI: 10.1021/acs.jpclett.2c02418] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The C≡N stretching vibration is a versatile infrared (IR) reporter that is useful for a wide range of applications. Aiming to further expand its spectroscopic utility, herein, we show that, using 4-cyanoindole and 4-cyano-7-azaindole as examples, photoexcitation can significantly shift the frequency (νCN) and enhance the molar extinction coefficient (εCN) of this vibrational mode of aromatic nitriles and that, for these indole derivatives, the enhancement factor can reach 13. Moreover, we find that while solvent relaxation at the excited electronic state(s) always leads to an increase in εCN, its effect on νCN depends on the solute and the solvent. Taken together, these results demonstrate that solvent relaxation can differently affect the local environment of the nitrile group and its conjugation with the indole ring and, more importantly, that the C≡N stretching vibration can serve as a sensitive IR probe of charge and electron transfer processes in which an aromatic nitrile is involved.
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Affiliation(s)
- Jingsong Liu
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Liang Zhou
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
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Grills DC, Layne BH, Wishart JF. Coupling Pulse Radiolysis with Nanosecond Time-Resolved Step-Scan Fourier Transform Infrared Spectroscopy: Broadband Mid-Infrared Detection of Radiolytically Generated Transients. APPLIED SPECTROSCOPY 2022; 76:1142-1153. [PMID: 35414202 DOI: 10.1177/00037028221097429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We describe the first implementation of broadband, nanosecond time-resolved step-scan Fourier transform infrared (S2-FT-IR) spectroscopy at a pulse radiolysis facility. This new technique allows the rapid acquisition of nano- to microsecond time-resolved infrared (TRIR) spectra of transient species generated by pulse radiolysis of liquid samples at a pulsed electron accelerator. Wide regions of the mid-infrared can be probed in a single experiment, which often takes < 20-30 min to complete. It is therefore a powerful method for rapidly locating the IR absorptions of short-lived, radiation-induced species in solution, and for directly monitoring their subsequent reactions. Time-resolved step-scan FT-IR detection for pulse radiolysis thus complements our existing narrowband quantum cascade laser-based pulse radiolysis-TRIR detection system, which is more suitable for acquiring single-shot kinetics and narrowband TRIR spectra on small-volume samples and in strongly absorbing solvents, such as water. We have demonstrated the application of time-resolved step-scan FT-IR spectroscopy to pulse radiolysis by probing the metal carbonyl and organic carbonyl vibrations of the one-electron-reduced forms of two Re-based CO2 reduction catalysts in acetonitrile solution. Transient IR absorption bands with amplitudes on the order of 1 × 10-3 are easily detected on the sub-microsecond timescale using electron pulses as short as 250 ns.
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Affiliation(s)
- David C Grills
- Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA
| | - Bobby H Layne
- Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA
| | - James F Wishart
- Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA
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Weaver JB, Kozuch J, Kirsh JM, Boxer SG. Nitrile Infrared Intensities Characterize Electric Fields and Hydrogen Bonding in Protic, Aprotic, and Protein Environments. J Am Chem Soc 2022; 144:7562-7567. [PMID: 35467853 PMCID: PMC10082610 DOI: 10.1021/jacs.2c00675] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitriles are widely used vibrational probes; however, the interpretation of their IR frequencies is complicated by hydrogen bonding (H-bonding) in protic environments. We report a new vibrational Stark effect (VSE) that correlates the electric field projected on the -C≡N bond to the transition dipole moment and, by extension, the nitrile peak area or integrated intensity. This linear VSE applies to both H-bonding and non-H-bonding interactions. It can therefore be generally applied to determine electric fields in all environments. Additionally, it allows for semiempirical extraction of the H-bonding contribution to the blueshift of the nitrile frequency. Nitriles were incorporated at H-bonding and non-H-bonding protein sites using amber suppression, and each nitrile variant was structurally characterized at high resolution. We exploited the combined information available from variations in frequency and integrated intensity and demonstrate that nitriles are a generally useful probe for electric fields.
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Affiliation(s)
- Jared Bryce Weaver
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States
| | - Jacek Kozuch
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jacob M Kirsh
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States
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