1
|
Hatanaka M, Kato H, Sakai M, Kariya K, Nakatani S, Yoshimura T, Inagaki T. Insights into the Luminescence Quantum Yields of Cyclometalated Iridium(III) Complexes: A Density Functional Theory and Machine Learning Approach. J Phys Chem A 2023; 127:7630-7637. [PMID: 37651718 DOI: 10.1021/acs.jpca.3c02179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Cyclometalated iridium(III) complexes have been used in various optical materials, including organic light-emitting diodes (OLEDs) and photocatalysts, and a deeper understanding and prediction of their luminescence quantum yields (LQYs) greatly aid in accelerating material design. In this study, we integrated density functional theory (DFT) calculations with machine learning (ML) techniques to extract factors controlling LQY. Although a substantial data set of Ir(III) complexes and their LQYs is indispensable for constructing accurate ML models to predict LQYs, generating this type of data set is challenging due to the complexities associated with ab initio calculations of LQYs. To address this issue, we investigated the nonradiative decay process of nine Ir(III) complexes emitting blue to green, each exhibiting varying experimental LQYs, by using DFT calculations. For all nine complexes, the quenching process was induced by the rotation of the single bond in one of the ligands, which converted the six-coordinate structure to the five-coordinate structure. Since the decay mechanism was common for the nine Ir(III) complexes, parameters correlated with LQYs could be used as objective variables instead of LQYs. Based on this idea, we collected a data set featuring Ir(III) complexes and the energy differences between their six- and five-coordinate triplet structures, which correlated with LQYs. We also constructed ML models using the calculated LQYs as the objective variables with the parameters from the ground-state calculations as explanatory variables. The analyses of the constructed model revealed that the LUMO energy of the ligand made the most significant negative contribution to LQY. This suggests that the potential energy surface of the metal-to-ligand charge transfer (MLCT) excited state, which stabilizes the six-coordinate structure, is reduced by decreasing the energy of the unoccupied orbitals.
Collapse
Affiliation(s)
- Miho Hatanaka
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Hiromoto Kato
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Minami Sakai
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikokma, Nara 630-0192, Japan
| | - Kosuke Kariya
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Shunsuke Nakatani
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Takayoshi Yoshimura
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Taichi Inagaki
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| |
Collapse
|
2
|
Rosko MC, Espinoza EM, Arteta S, Kromer S, Wheeler JP, Castellano FN. Employing Long-Range Inductive Effects to Modulate Metal-to-Ligand Charge Transfer Photoluminescence in Homoleptic Cu(I) Complexes. Inorg Chem 2023; 62:3248-3259. [PMID: 36749829 DOI: 10.1021/acs.inorgchem.2c04315] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Four Cu(I) bis(phenanthroline) photosensitizers formulated from a new ligand structural motif (Cu1-Cu4) coded according to their 2,9-substituents were synthesized, structurally characterized, and fully evaluated using steady-state and time-resolved absorption and photoluminescence (PL) measurements as well as electrochemistry. The 2,9-disubstituted-3,4,7,8-tetramethyl-1,10-phenanthroline ligands feature the following six-membered ring systems prepared through photochemical synthesis: 4,4-dimethylcyclohexyl (1), tetrahydro-2H-pyran-4-yl (2), tetrahydro-2H-thiopyran-4-yl (3), and 4,4-difluorocyclohexyl (4). Universally, these Cu(I) metal-to-ligand charge transfer (MLCT) chromophores display excited-state lifetimes on the microsecond time scale at room temperature, including the three longest-lived homoleptic cuprous phenanthroline excited states measured to date in de-aerated CH2Cl2, τ = 2.5-4.3 μs. This series of molecules also feature high PL quantum efficiencies (ΦPL = 5.3-12% in CH2Cl2). Temperature-dependent PL lifetime experiments confirmed that all these molecules exhibit reverse intersystem crossing and display thermally activated delayed PL from a 1MLCT excited state lying slightly above the 3MLCT state, 1050-1490 cm-1. Ultrafast and conventional transient absorption measurements confirmed that the PL originates from the MLCT excited state, which remains sterically arrested, preventing an excessive flattening distortion even when dissolved in Lewis basic CH3CN. Combined PL and electrochemical data provided evidence that Cu1-Cu4 are highly potent photoreductants (Eox* = -1.73 to -1.62 V vs Fc+/0 in CH3CN), whose potentials are altered solely based on which heteroatoms or substituents are resident on the 2,9-appended ring derivatives. It is proposed that long-range electronic inductive effects are responsible for the systematic modulation observed in the PL spectra, excited-state lifetimes, and the ground state absorption spectra and redox potentials. Cu1-Cu4 quantitatively follow the energy gap law, correlating well with structurally related cuprous phenanthrolines and are also shown to triplet photosensitize the excited states of 9,10-diphenylanthracene with bimolecular rate constants ranging from 1.61 to 2.82 × 108 M-1 s-1. The ability to tailor both photophysical and electrochemical properties using long-range inductive effects imposed by the 2,9-ring platforms advocates new directions for future MLCT chromophore discovery.
Collapse
Affiliation(s)
- Michael C Rosko
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Eli M Espinoza
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Sarah Arteta
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Sarah Kromer
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jonathan P Wheeler
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| |
Collapse
|
3
|
|
4
|
Yiu SC, Ho PY, Kwok YY, He X, Wang Y, Yu WH, Ho CL, Huang S. Development of Strong Visible-Light-Absorbing Cyclometalated Iridium(III) Complexes for Robust and Efficient Light-Driven Hydrogen Production. Chemistry 2022; 28:e202104575. [PMID: 35170133 DOI: 10.1002/chem.202104575] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Indexed: 12/12/2022]
Abstract
Weak light absorption of common Ir(III) complexes (e. g., using phenylpyridine as the ligand) has hindered their applications in photocatalytic hydrogen generation from water as an efficient photosensitizer. To address this issue, a series of cyclometalated Ir(III) complexes (Ir1-Ir5), featuring different electron-donating substituents to enhance the absorptivity, have been synthesized and studied as photosensitizers (PSs) for light-driven hydrogen production from water. Ir6-Ir7 were prepared as fundamental systems for comparisons. Electron donors, including 9-phenylcarbazole, triphenylamine, 4,4'-dimethoxytriphenylamine, 4,4'-di(N-hexylcarbazole)triphenylamine moieties were introduced on 6-(thiophen-2-yl)phenanthridine-based cyclometalating (C^N) ligands to explore the donor effect on the hydrogen evolution performance of these cationic Ir(III) complexes. Remarkably, Ir4 with 4,4'-dimethoxytriphenylamine achieved the highest turn-over number (TON) of 12 300 and initial turnover frequency (TOFi ) of 394 h-1 , with initial activity (activityi ) of 547 000 μmol g-1 h-1 and initial apparent quantum yield (AQYi ) of 9.59 %, under the illumination of blue light-emitting diodes (LEDs) for 105 hours, which demonstrated a stable three-component photocatalytic system with high efficiency. The TON (based on n(H2 )/n(PSr)) in this study is the highest value reported to date among the similar photocatalytic systems using Ir(III) complexes with Pt nanoparticles as catalyst. The great potential of using triphenylamine-based Ir(III) PSs in boosting photocatalytic performance has also been shown.
Collapse
Affiliation(s)
- Sze-Chun Yiu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University Hung Hom, Hong Kong, P. R. China.,PolyU Shenzhen Research Institute, Shenzhen, P. R. China.,Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China
| | - Po-Yu Ho
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University Hung Hom, Hong Kong, P. R. China.,PolyU Shenzhen Research Institute, Shenzhen, P. R. China.,Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China.,Biological Inorganic Chemistry Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, United Kingdom.,Department of Chemistry, King's College London Britannia House, 7 Trinity Street, London, SE1 1DB, United Kingdom
| | - Yan-Yi Kwok
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University Hung Hom, Hong Kong, P. R. China.,PolyU Shenzhen Research Institute, Shenzhen, P. R. China
| | - Xiaojie He
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Yi Wang
- Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China
| | - Wai-Hong Yu
- Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China
| | - Cheuk-Lam Ho
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University Hung Hom, Hong Kong, P. R. China.,PolyU Shenzhen Research Institute, Shenzhen, P. R. China.,Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P. R. China
| | - Shuping Huang
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| |
Collapse
|
5
|
Pirzada BM, Dar AH, Shaikh MN, Qurashi A. Reticular-Chemistry-Inspired Supramolecule Design as a Tool to Achieve Efficient Photocatalysts for CO 2 Reduction. ACS OMEGA 2021; 6:29291-29324. [PMID: 34778605 PMCID: PMC8581999 DOI: 10.1021/acsomega.1c04018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/30/2021] [Indexed: 05/03/2023]
Abstract
Photocatalytic CO2 reduction into C1 products is one of the most trending research subjects of current times as sustainable energy generation is the utmost need of the hour. In this review, we have tried to comprehensively summarize the potential of supramolecule-based photocatalysts for CO2 reduction into C1 compounds. At the outset, we have thrown light on the inert nature of gaseous CO2 and the various challenges researchers are facing in its reduction. The evolution of photocatalysts used for CO2 reduction, from heterogeneous catalysis to supramolecule-based molecular catalysis, and subsequent semiconductor-supramolecule hybrid catalysis has been thoroughly discussed. Since CO2 is thermodynamically a very stable molecule, a huge reduction potential is required to undergo its one- or multielectron reduction. For this reason, various supramolecule photocatalysts were designed involving a photosensitizer unit and a catalyst unit connected by a linker. Later on, solid semiconductor support was also introduced in this supramolecule system to achieve enhanced durability, structural compactness, enhanced charge mobility, and extra overpotential for CO2 reduction. Reticular chemistry is seen to play a pivotal role as it allows bringing all of the positive features together from various components of this hybrid semiconductor-supramolecule photocatalyst system. Thus, here in this review, we have discussed the selection and role of various components, viz. the photosensitizer component, the catalyst component, the linker, the semiconductor support, the anchoring ligands, and the peripheral ligands for the design of highly performing CO2 reduction photocatalysts. The selection and role of various sacrificial electron donors have also been highlighted. This review is aimed to help researchers reach an understanding that may translate into the development of excellent CO2 reduction photocatalysts that are operational under visible light and possess superior activity, efficiency, and selectivity.
Collapse
Affiliation(s)
- Bilal Masood Pirzada
- Department
of Chemistry, Khalifa University of Science
and Technology (KU), Abu Dhabi 127788, United Arab Emiratus
- ,
| | - Arif Hassan Dar
- Institute
of NanoScience and Technology (INST), Mohali 160062, India
| | - M. Nasiruzzaman Shaikh
- Interdisciplinary
Research Center for Hydrogen and Energy Storage (IRC-HES), King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Ahsanulhaq Qurashi
- Department
of Chemistry, Khalifa University of Science
and Technology (KU), Abu Dhabi 127788, United Arab Emiratus
| |
Collapse
|
6
|
Bevernaegie R, Wehlin SAM, Elias B, Troian‐Gautier L. A Roadmap Towards Visible Light Mediated Electron Transfer Chemistry with Iridium(III) Complexes. CHEMPHOTOCHEM 2021. [DOI: 10.1002/cptc.202000255] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Robin Bevernaegie
- Laboratoire de Chimie Organique CP160/06 Université libre de Bruxelles 50 avenue F. R. Roosevelt 1050 Brussels Belgium
- Institut de la Matière Condensée et des Nanosciences (IMCN) Molecular Chemistry, Materials and Catalysis (MOST) Université catholique de Louvain (UCLouvain) Place Louis Pasteur 1 box L4.01.02 1348 Louvain-la-Neuve Belgium
| | - Sara A. M. Wehlin
- Laboratoire de Chimie Organique CP160/06 Université libre de Bruxelles 50 avenue F. R. Roosevelt 1050 Brussels Belgium
| | - Benjamin Elias
- Institut de la Matière Condensée et des Nanosciences (IMCN) Molecular Chemistry, Materials and Catalysis (MOST) Université catholique de Louvain (UCLouvain) Place Louis Pasteur 1 box L4.01.02 1348 Louvain-la-Neuve Belgium
| | - Ludovic Troian‐Gautier
- Laboratoire de Chimie Organique CP160/06 Université libre de Bruxelles 50 avenue F. R. Roosevelt 1050 Brussels Belgium
| |
Collapse
|
7
|
Choi J, Ahn M, Lee JH, Ahn DS, Ki H, Oh I, Ahn CW, Choi EH, Lee Y, Lee S, Kim J, Cho DW, Wee KR, Ihee H. Ultrafast excited state relaxation dynamics in a heteroleptic Ir( iii) complex, fac-Ir(ppy) 2(ppz), revealed by femtosecond X-ray transient absorption spectroscopy. Inorg Chem Front 2021. [DOI: 10.1039/d0qi01510e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The experimental and calculation results demonstrate that the 3MLppzCT state generated by the spin-forbidden transition rapidly relaxes to 3MLppyCT through internal conversion process with a time constant of ∼450 fs.
Collapse
|
8
|
Kuramochi Y, Satake A. Photocatalytic CO 2 Reductions Catalyzed by meso-(1,10-Phenanthrolin-2-yl)-Porphyrins Having a Rhenium(I) Tricarbonyl Complex. Chemistry 2020; 26:16365-16373. [PMID: 32726503 PMCID: PMC7756820 DOI: 10.1002/chem.202002558] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/12/2020] [Indexed: 11/17/2022]
Abstract
We have prepared Zn and free-base porphyrins appended with a fac-Re(phen)(CO)3 Br (where phen is 1,10-phenanthroline) at the meso position of the porphyrin, and performed photocatalytic CO2 reduction using porphyrin-Re dyads in the presence of either triethylamine (TEA) or 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as an electron donor. The Zn porphyrin dyad showed a high turnover number for CO production compared with the free-base porphyrin dyad, suggesting that the central Zn ion of porphyrin plays an important role in suppressing electron accumulation on the porphyrin part and achieving high durability of the photocatalytic CO2 reduction using both TEA and BIH. The effect of acids on the CO2 reduction was investigated using the Zn porphyrin-Re dyad and BIH. Acetic acid, a relatively strong Brønsted acid, rapidly causes the porphyrin's color to fade upon irradiation and dramatically decreases CO production, whereas proper weak Brønsted acids such as 2,2,2-trifluoroethanol and phenol enhance the CO2 reduction.
Collapse
Affiliation(s)
- Yusuke Kuramochi
- Graduate School of ScienceTokyo University of Science1–3 KagurazakaShinjuku-kuTokyo162-8601Japan
- Department of Chemistry, Faculty of Science Division IITokyo University of Science1–3 KagurazakaShinjuku-kuTokyo162-8601Japan
| | - Akiharu Satake
- Graduate School of ScienceTokyo University of Science1–3 KagurazakaShinjuku-kuTokyo162-8601Japan
- Department of Chemistry, Faculty of Science Division IITokyo University of Science1–3 KagurazakaShinjuku-kuTokyo162-8601Japan
| |
Collapse
|
9
|
You SQ, Zhou J, Chen MM, Sun CY, Qi XJ, Yousaf A, Wang XL, Su ZM. A hydrazone-based covalent organic framework/iridium (III) complex for photochemical CO2 reduction with enhanced efficiency and durability. J Catal 2020. [DOI: 10.1016/j.jcat.2020.09.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|