1
|
Cotic A, Heinemann FW, Slep LD, Cadranel A. Influence of Donor-Acceptor Interactions on MLCT Hole Reconfiguration in {Ru(bpy)} Chromophores. Chemphyschem 2024; 25:e202400246. [PMID: 38656666 DOI: 10.1002/cphc.202400246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 04/26/2024]
Abstract
In MLCT chromophores, internal conversion (IC) in the form of hole reconfiguration pathways (HR) is a major source of dissipation of the absorbed photon energy. Therefore, it is desirable to minimize their impact in energy conversion schemes by slowing them down. According to previous findings on {Ru(bpy)} chromophores, donor-acceptor interactions between the Ru ion and the ligand scaffold might allow to control HR/IC rates. Here, a series of [Ru(tpm)(bpy)(R-py)]2+ chromophores, where tpm is tris(1-pyrazolyl)methane, bpy is 2,2'-bipyridine and R-py is a 4-substituted pyridine, were prepared and fully characterized employing electrochemistry, spectroelectrochemistry, steady-state absorption/emission spectroscopy and electronic structure computations based on DFT/TD-DFT. Their excited-state decay was monitored using nanosecond and femtosecond transient absorption spectroscopy. HR/IC lifetimes as slow as 568 ps were obtained in DMSO at room temperature, twice as slow as in the reference species [Ru(tpm)(bpy)(NCS)]+.
Collapse
Affiliation(s)
- Agustina Cotic
- Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
- CONICET - Universidad de Buenos Aires, Instituto de Química Física de Materiales, Medio Ambiente y Energía (INQUIMAE), Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Frank W Heinemann
- Department Chemie und Pharmazie, Anorganische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany
| | - Leonardo D Slep
- Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
- CONICET - Universidad de Buenos Aires, Instituto de Química Física de Materiales, Medio Ambiente y Energía (INQUIMAE), Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Alejandro Cadranel
- Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
- CONICET - Universidad de Buenos Aires, Instituto de Química Física de Materiales, Medio Ambiente y Energía (INQUIMAE), Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
- Department Chemie und Pharmazie, Physikalische Chemie I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany
- Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany
| |
Collapse
|
2
|
Yin HJ, Yu S, Yang Y, He C, Cheng F. Ru(II)-Ru(II) and Ru(II)-Os(II) Homo-/Heterodinuclear Complexes and Ru 3(II)-Ru(II) Homotetranuclear Complexes Based on Heteroditopic Bridging Ligands: Synthesis, Photophysics, and Effective Energy Transfer. Inorg Chem 2024; 63:621-634. [PMID: 38100652 DOI: 10.1021/acs.inorgchem.3c03501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
In this paper, the synthesis, photophysics, electrochemistry, and intramolecular energy transfer of two series of dinuclear and tetranuclear metallic complexes [(bpy)2M1LxM2(bpy)2]4+ (x = 1, 2; M1 = Ru, M2 = Ru/Os; M1 = Os, M2 = Ru) and {[Ru(bpy)2(Lx)]3Ru}8+ based on new heteroditopic bridging ligands (L1 = 6-phenyl-4-Hpip-2-2'-bipyridine, L2 = 6-Hpip-2-2'-bipyridine, Hpip = 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline) are reported. The dimetallic and tetrametallic complexes exhibit rich redox properties with successive reversible metal-centered oxidation and ligand-centered reduction couples. All complexes display intense absorption in the entire ultraviolet-visible spectral regions. The mononuclear [LxRu(bpy)2]2+ and homodinuclear [(bpy)2RuLxRu(bpy)2]4+ complexes display strong Ru-based characteristic emission at room temperature. Interestingly, the optical studies of heterodinuclear complexes reveal almost complete quenching of the RuII-based emission and efficient photoinduced energy transfer, resulting in an OsII-based emission in the near-infrared region. As a result of the intramolecular energy transfer from the center to the periphery and steric hindrance quenching of the peripheral RuII-centered emissive triplet metal-to-ligand charge transfer states, the tetranuclear complexes exhibit weak RuII-based emission with a short lifetime. Since the light absorbed by several chromophores is efficiently directed to the subunit with the lowest-energy excited state, the present multinuclear complexes can be used as well-visible-light-absorption antennas.
Collapse
Affiliation(s)
- Hong-Ju Yin
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, P. R. China
| | - Shiwen Yu
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, P. R. China
| | - Yuting Yang
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, P. R. China
| | - Chixian He
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, P. R. China
| | - Feixiang Cheng
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, P. R. China
| |
Collapse
|
3
|
Yin CW, Tsai MK, Chen YJ. Low-Temperature Observation of the Excited-State Decay of Ruthenium-(Mono-2,2':6',2″-Terpyridine) Ions with Innocent Ligands: DFT Modeling of an 3MLCT- 3MC Intersystem Crossing Pathway. ACS OMEGA 2023; 8:11623-11633. [PMID: 37008138 PMCID: PMC10061511 DOI: 10.1021/acsomega.3c01006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 02/28/2023] [Indexed: 06/19/2023]
Abstract
The synthesis, electrochemistry, and photophysical characterization of five 2,2':6',2″-terpyridine ruthenium complexes (Ru-tpy complexes) is reported. The electrochemical and photophysical behavior varied depending on the ligands, i.e., amine (NH3), acetonitrile (AN), and bis(pyrazolyl)methane (bpm), for this series of Ru-tpy complexes. The target [Ru(tpy)(AN)3]2+ and [Ru(tpy)(bpm)(AN)]2+ complexes were found to have low-emission quantum yields in low-temperature observations. To better understand this phenomenon, density functional theory (DFT) calculations were performed to simulate the singlet ground state (S0), Te, and metal-centered excited states (3MC) of these complexes. The calculated energy barriers between Te and the low-lying 3MC state for [Ru(tpy)(AN)3]2+ and [Ru(tpy)(bpm)(AN)]2+ provided clear evidence in support of their emitting state decay behavior. Developing a knowledge of the underlying photophysics of these Ru-tpy complexes will allow new complexes to be designed for use in photophysical and photochemical applications in the future.
Collapse
Affiliation(s)
- Chi-Wei Yin
- Department
of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Ming-Kang Tsai
- Department
of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan, ROC
| | - Yuan Jang Chen
- Department
of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| |
Collapse
|
4
|
Dai W, Yu S, Kong C, Zhao D, He C, Liu Z, Dong J, Liu JJ, Cheng F. Effect of electronic structure of energy transfer in bimetallic Ru(II)/Os(II) complexes. Dalton Trans 2023; 52:990-999. [PMID: 36601979 DOI: 10.1039/d2dt03709b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Novel monometallic (μ-LL')Ru, Ru(μ-LL'), homobimetallic Ru(μ-LL')Ru, and heterodimetallic Ru(μ-LL')Os and Os(μ-LL')Ru complexes based on two asymmetrical ligands LL' (where LL' = L1L1', L2L2') have been synthesized and characterized. Spectroscopic analysis indicates that all complexes exhibit intense spin-allowed ligand-centered (LC) transitions at 288 nm and Ru-based moderate spin-allowed MLCT absorption between 440-450 nm. The Ru(μ-LL')Os and Os(μ-LL')Ru dinuclear complexes show Os-based unit absorption in the range of 565-583 nm. The Ru-based units of the complexes present different emission intensities due to differing steric hindrance at the coordination sites of the two bridging ligands. The Os(μ-LL')Ru dinuclear complexes present weaker emission intensity than their parent monometallic complexes (μ-LL')Ru. These results indicate that the emission of Os(μ-LL')Ru dinuclear complexes is quenched by the Os(II)-based units.
Collapse
Affiliation(s)
- Weijun Dai
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Shiwen Yu
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Ci Kong
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Defang Zhao
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Chixian He
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Zining Liu
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Jianwei Dong
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Jian-Jun Liu
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Feixiang Cheng
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| |
Collapse
|
5
|
Chih YR, Lin YT, Yin CW, Chen YJ. High Intrinsic Phosphorescence Efficiency and Density Functional Theory Modeling of Ru(II)-Bipyridine Complexes with π-Aromatic-Rich Cyclometalated Ligands: Attributions of Spin-Orbit Coupling Perturbation and Efficient Configurational Mixing of Singlet Excited States. ACS OMEGA 2022; 7:48583-48599. [PMID: 36591186 PMCID: PMC9798779 DOI: 10.1021/acsomega.2c07276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
A series of π-aromatic-rich cyclometalated ruthenium(II)-(2,2'-bipyridine) complexes ([Ru(bpy)2(πAr-CM)]+) in which πAr-CM is diphenylpyrazine or 1-phenylisoquinoline were prepared. The [Ru(bpy)2(πAr-CM)]+ complexes had remarkably high phosphorescence rate constants, k RAD(p), and the intrinsic phosphorescence efficiencies (ιem(p) = k RAD(p)/(νem(p))3) of these complexes were found to be twice the magnitudes of simply constructed cyclometalated ruthenium(II) complexes ([Ru(bpy)2(sc-CM)]+), where νem(p) is the phosphorescence frequency and sc-CM is 2-phenylpyridine, benzo[h]quinoline, or 2-phenylpyrimidine. Density functional theory (DFT) modeling of the [Ru(bpy)2(CM)]+ complexes indicated numerous singlet metal-to-ligand charge transfers for 1MLCT-(Ru-bpy) and 1MLCT-(Ru-CM), excited states in the low-energy absorption band and 1ππ*-(aromatic ligand) (1ππ*-LAr) excited states in the high-energy band. DFT modeling of these complexes also indicated phosphorescence-emitting state (Te) configurations with primary MLCT-(Ru-bpy) characteristics. The variation in ιem(p) for the spin-forbidden Te (3MLCT-(Ru-bpy)) excited state of the complex system that was examined in this study can be understood through the spin-orbit coupling (SOC)-mediated sum of intensity stealing (∑SOCM-IS) contribution from the primary intensity of the low-energy 1MLCT states and second-order intensity perturbation from the significant configuration between the low-energy 1MLCT and high-energy intense 1ππ*-LAr states. In addition, the observation of unusually high ιem(p) magnitudes for these [Ru(bpy)2(πAr-CM)]+ complexes can be attributed to the values for both intensity factors in the ∑SOCM-IS formalism being individually greater than those for [Ru(bpy)2(sc-CM)]+ ions.
Collapse
Affiliation(s)
| | | | | | - Yuan Jang Chen
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, R.O.C.
| |
Collapse
|
6
|
Toupin N, Steinke SJ, Nadella S, Li A, Rohrabaugh TN, Samuels ER, Turro C, Sevrioukova IF, Kodanko JJ. Photosensitive Ru(II) Complexes as Inhibitors of the Major Human Drug Metabolizing Enzyme CYP3A4. J Am Chem Soc 2021; 143:9191-9205. [PMID: 34110801 DOI: 10.1021/jacs.1c04155] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We report the synthesis and photochemical and biological characterization of the first selective and potent metal-based inhibitors of cytochrome P450 3A4 (CYP3A4), the major human drug metabolizing enzyme. Five Ru(II)-based derivatives were prepared from two analogs of the CYP3A4 inhibitor ritonavir, 4 and 6: [Ru(tpy)(L)(6)]Cl2 (tpy = 2,2':6',2″-terpyridine) with L = 6,6'-dimethyl-2,2'-bipyridine (Me2bpy; 8), dimethylbenzo[i]dipyrido[3,2-a:2',3'-c]phenazine (Me2dppn; 10) and 3,6-dimethyl-10,15-diphenylbenzo[i]dipyrido[3,2-a:2',3'-c]phenazine (Me2Ph2dppn; 11), [Ru(tpy)(Me2bpy)(4)]Cl2 (7) and [Ru(tpy)(Me2dppn)(4)]Cl2 (9). Photochemical release of 4 or 6 from 7-11 was demonstrated, and the spectrophotometric evaluation of 7 showed that it behaves similarly to free 4 (type II heme ligation) after irradiation with visible light but not in the dark. Unexpectedly, the intact Ru(II) complexes 7 and 8 were found to inhibit CYP3A4 potently and specifically through direct binding to the active site without heme ligation. Caged inhibitors 9-11 showed dual action properties by combining photoactivated dissociation of 4 or 6 with efficient 1O2 production. In prostate adenocarcinoma DU-145 cells, compound 9 had the best synergistic effect with vinblastine, the anticancer drug primarily metabolized by CYP3A4 in vivo. Thus, our study establishes a new paradigm in CYP inhibition using metalated complexes and suggests possible utilization of photoactive CYP3A4 inhibitory compounds in clinical applications, such as enhancement of therapeutic efficacy of anticancer drugs.
Collapse
Affiliation(s)
- Nicholas Toupin
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Sean J Steinke
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sandeep Nadella
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Ao Li
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Thomas N Rohrabaugh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | | | - Claudia Turro
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | | | - Jeremy J Kodanko
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States.,Barbara Ann Karmanos Cancer Institute, Detroit, Michigan 48201, United States
| |
Collapse
|
7
|
Lu IC, Tsai CN, Lin YT, Hung SY, Chao VPS, Yin CW, Luo DW, Chen HY, Endicott JF, Chen YJ. Near-IR Charge-Transfer Emission at 77 K and Density Functional Theory Modeling of Ruthenium(II)-Dipyrrinato Chromophores: High Phosphorescence Efficiency of the Emitting State Related to Spin-Orbit Coupling Mediation of Intensity from Numerous Low-Energy Singlet Excited States. J Phys Chem A 2021; 125:903-919. [PMID: 33470828 DOI: 10.1021/acs.jpca.0c05910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Efficient charge-transfer (CT) phosphorescence in the near-IR (NIR) spectral region is reported for four substituted Ru-(R-dipyrrinato) complexes, [Ru(bpy)2(R-dipy)](PF6), where bpy is 2,2'-bipyridine and the substituent R is phenyl (ph), 2,4,6-trimethylphenyl, 4-carboxyphenyl (HOOC-ph), or 4-pyridinyl. The experimentally determined phosphorescence efficiency, ιem(p) = kRAD(p)/(νem(p))3 (where kRAD(p) and νem(p) are the phosphorescence rate constant and the phosphorescence frequency, respectively), of the [Ru(bpy)2(R-dipy)]+ complexes was approximately double that of [Ru(bpy)(Am)4]2+ complexes (Am = ammine ligand) in the NIR region. Density functional theory (DFT) modeling indicated two strikingly different electronic configurations of the triplet emitting state (Te) in the two types of complexes. The Te of [Ru(bpy)2(R-dipy)]+ complexes shows a CT-type corresponding to the metal-to-ligand charge transfer (MLCT)-(Ru-(R-dipy)) and the ππ*-(R-dipy) moiety configurations, and the Te state in the [Ru(bpy)(Am)4]2+ complexes corresponds to an approximately MLCT excited state consisting of mostly MLCT-(Ru-bpy) with a minimal ππ*(bpy) contribution. DFT modeling also indicated that the low-energy singlet excited states in the Te geometry (Sn(T)) of the [Ru(bpy)2(ph-dipy)]+ complex consist of numerous CT-Sn(T)-type states of the Ru-dipy and Ru-bpy moieties, whereas the [Ru(bpy)(Am)4]2+ ions show quite simple MLCT-Sn(T)-type states of the Ru-bpy moiety. Based on experimental observations, DFT modeling, and the plain spin-orbit coupling (SOC) principle, we conclude that the remarkably high ιem(p) amplitudes of the [Ru(bpy)2(R-dipy)]+ complexes relative to those of [Ru(bpy)(Am)4]2+ complexes can be attributed to the relatively substantial contribution of intrinsic SOC-mediated intensity stealing from the numerous low-energy CT-type Sn(T) states.
Collapse
Affiliation(s)
- I-Chen Lu
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Chia Nung Tsai
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Yu-Ting Lin
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Shin-Yi Hung
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Vincent P S Chao
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Chi-Wei Yin
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Dao-Wen Luo
- Instruments Center and Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan, ROC
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC
| | - John F Endicott
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Yuan Jang Chen
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| |
Collapse
|
8
|
Zhang XZ, Cheng CC, Chih YR, Lin YT, Chen HY, Chen YJ, Endicott JF. Low-Temperature Spectra and Density Functional Theory Modeling of Ru(II)-Bipyridine Complexes with Cyclometalated Ancillary Ligands: The Excited State Spin-Orbit Coupling Origin of Variations in Emission Efficiencies. J Phys Chem A 2019; 123:9431-9449. [PMID: 31557033 DOI: 10.1021/acs.jpca.9b05695] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The 77 K emission spectra of cyclometalated ruthenium(II)-2,2'-bipyridine (CM-Ru-bpy) chromophores are very similar to those of related Ru-bpy complexes with am(m)ine or diimmine ancillary ligands, and density functional theory (DFT) modeling confirms that the lowest energy triplet metal to ligand charge transfer (3MLCT) excited states of CM-Ru-bpy and related Ru-bpy complexes have very similar electronic configurations. However, the phosphorescence decay efficiencies of CM-Ru-bpy excited states are about twice those of the conventional Ru-bpy analogues. In contrast to the similar 3MLCT excited state electronic configurations of the two classes of complexes, the CM-Ru-bpy chromophores have much broader visible region MLCT absorptions resulting from several overlapping transitions, even at 87 K. The emitting excited-state emission efficiencies depend on spin-orbit coupling (SOC) mediated intensity stealing from singlet excited states, and this work explores the relationship between the phosphorescence efficiency and visible region absorption spectra of Ru-bpy 3MLCT excited states in the weak SOC limit. The intrinsic 3MLCT emission efficiency, ιem, depends on mixing with singlet excited states whose RuIII-dπ-orbital angular momenta differ from that of the emitting state. DFT modeling of the 1MLCT excited-state electronic configurations that contribute significantly to the lowest energy absorption bands have RuIII-dπ orbitals that differ from those of their emitting 3MLCT excited states. This leads to a very close relationship between ιem and the lowest energy MLCT band absorptivities in Ru-bpy chromophores. Thus, the larger number of 1MLCT transitions that contribute to the lowest energy absorption bands accounts for the enhanced phosphorescence efficiency of Ru-bpy complexes with cyclometalated ancillary ligands.
Collapse
Affiliation(s)
- Xiu Zhu Zhang
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Ching Chia Cheng
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Yu Ru Chih
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Yu-Ting Lin
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry , Kaohsiung Medical University , Kaohsiung 80708 , Taiwan , ROC
| | - Yuan Jang Chen
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - John F Endicott
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| |
Collapse
|
9
|
Liu R, Gao X, Barbatti M, Jiang J, Zhang G. Promoting Intersystem Crossing of a Fluorescent Molecule via Single Functional Group Modification. J Phys Chem Lett 2019; 10:1388-1393. [PMID: 30836747 DOI: 10.1021/acs.jpclett.9b00286] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pure light-atom organic phosphorescent molecules have been under scientific scrutiny because they are inexpensive, flexible, and environment friendly. The development of such materials, however, faces a bottleneck problem of intrinsically small spin-orbit couplings, which can be addressed by seeking a proper balance between intersystem crossing (ISC) and fluorescence rates. Using N-substituted naphthalimides as the prototype molecule, we applied chemical modifications with several electrophilic and nucleophilic functional groups, to approach the goal. The selected electron donating groups actively restrain the fluorescence, enabling an efficient ISC to the triplet manifold. Electron withdrawing groups do not change the luminescent properties of the parent species. The changes in ISC and fluorescence rates are related to the nature of the lowest singlet state, which changes from localized excitation into charge-transfer excitation upon configuration change of excited molecules. This finding opens an alternative strategy for designing pure light-atom organic phosphorescent molecules for emerging luminescent materials applications.
Collapse
Affiliation(s)
- Ran Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), School of Chemistry and Materials Science , University of Science and Technology of China , Hefei , Anhui 230026 , P. R. China
| | - Xing Gao
- Department of Chemistry , 930 N University Ave, University of Michigan , Ann Arbor , Michigan 48109 , United States
| | | | - Jun Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), School of Chemistry and Materials Science , University of Science and Technology of China , Hefei , Anhui 230026 , P. R. China
| | - Guozhen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), School of Chemistry and Materials Science , University of Science and Technology of China , Hefei , Anhui 230026 , P. R. China
| |
Collapse
|
10
|
Synthesis, characterization, and photophysical properties of cyclometalated N-Heterocyclic carbene Platinum(II) complexes. J Organomet Chem 2019. [DOI: 10.1016/j.jorganchem.2018.10.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
11
|
Alnaed MK, Endicott JF. Chemical Scavenging Yields for Short-Lived Products from the Visible Light Photoionization of the Tris(bipyridine)ruthenium(II) Triplet Metal-to-Ligand Charge-Transfer Excited State. J Phys Chem A 2018; 122:9251-9266. [PMID: 30387605 DOI: 10.1021/acs.jpca.8b08471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The rate of visible light photoionization of the tris(bipyridine)ruthenium(II) triplet metal-to-ligand charge-transfer excited state (3MLCT) is very strongly dependent on the acid concentration in aqueous solution, and the pattern of this dependence is similar to that reported for the photoionization of iodide. With 405 nm visible irradiation of 3MLCT, less than 15% of the photoionized products appear as free solvated electrons in bulk solution, while more than 75% of the photoproducts appear to be solvent-separated, (oxidized substrate)-electron ion pairs that efficiently recombine with the photo-oxidized complex in the absence of an electron scavenger. The quantum yield of free solvated electrons generated by these 405 nm irradiations is approximately 0.004, but the net quantum yield of scavengeable electrons is estimated to be about 0.04. A visible-region photoionization threshold energy for the 3MLCT is consistent with thermodynamic expectations, and similar behavior is expected for many redox-active complexes.
Collapse
Affiliation(s)
- Marim K Alnaed
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - John F Endicott
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| |
Collapse
|
12
|
Tsai CN, Mazumder S, Zhang XZ, Schlegel HB, Chen YJ, Endicott JF. Are Very Small Emission Quantum Yields Characteristic of Pure Metal-to-Ligand Charge-Transfer Excited States of Ruthenium(II)-(Acceptor Ligand) Chromophores? Inorg Chem 2016; 55:7341-55. [DOI: 10.1021/acs.inorgchem.6b00374] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Chia Nung Tsai
- Department of Chemistry, Fu-Jen Catholic University, New
Taipei City 24205, Taiwan, Republic of China
| | - Shivnath Mazumder
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Xiu Zhu Zhang
- Department of Chemistry, Fu-Jen Catholic University, New
Taipei City 24205, Taiwan, Republic of China
| | - H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Yuan Jang Chen
- Department of Chemistry, Fu-Jen Catholic University, New
Taipei City 24205, Taiwan, Republic of China
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - John F. Endicott
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| |
Collapse
|
13
|
Spectroscopy and Chemical Bonding in Transition Metal Complexes. STRUCTURE AND BONDING 2016. [DOI: 10.1007/430_2015_195] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
14
|
Bandyopadhyay S, Métivier R, Pallavi P, Preis E, Nakatani K, Landfester K, Patra A, Scherf U. Conjugated Polymer Nanoparticle-Triplet Emitter Hybrids in Aqueous Dispersion: Fabrication and Fluorescence Quenching Behavior. Macromol Rapid Commun 2015; 37:271-7. [PMID: 26663576 DOI: 10.1002/marc.201500618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/16/2015] [Indexed: 01/19/2023]
Abstract
Conjugated polymer nanoparticles based on poly[9,9-bis(2-ethylhexyl)fluorene] and poly[N-(2,4,6-trimethylphenyl)-N,N-diphenylamine)-4,4'-diyl] are fabricated using anionic surfactant sodium dodecylsulphate in water by miniemulsion technique. Average diameters of polyfluorene and polytriarylamine nanoparticles range from 70 to 100 and 100 to 140 nm, respectively. The surface of the nanoparticles is decorated with triplet emitting dye, tris(2,2'-bipyridyl)ruthenium(II) chloride. Intriguing photophysics of aqueous dispersions of these hybrid nanoparticles is investigated. Nearly 50% quenching of fluorescence is observed in the case of dye-coated polyfluorene nanoparticles; excitation energy transfer is found to be the dominant quenching mechanism. On the other hand, nearly complete quenching of emission is noticed in polytriarylamine nanoparticle-dye hybrids. It is proposed that the excited state electron transfer from the electron-rich polytriarylamine donor polymer to Ru complex leads to the complete quenching of emission of polytriarylamine nanoparticles. The current study offers promising avenues for developing aqueous solution processed-electroluminescent devices involving a conjugated polymer nanoparticle host and Ru or Ir-based triplet emitting dye as the guest.
Collapse
Affiliation(s)
- Sujoy Bandyopadhyay
- Department of Chemistry, Indian Institute of Science, Education and Research (IISER) Bhopal, Bhopal, 462066, India
| | - Rémi Métivier
- PPSM, ENS Cachan, CNRS, UniverSud, 61 av President Wilson, 94230, Cachan, France
| | - Pragyan Pallavi
- Department of Chemistry, Indian Institute of Science, Education and Research (IISER) Bhopal, Bhopal, 462066, India
| | - Eduard Preis
- Macromolecular Chemistry, Bergische University Wuppertal, Gauss-Str. 20, D-42119, Wuppertal, Germany
| | - Keitaro Nakatani
- PPSM, ENS Cachan, CNRS, UniverSud, 61 av President Wilson, 94230, Cachan, France
| | - Katharina Landfester
- Max Planck Institute for Polymer Research, Department of Physical Chemistry of Polymers, Ackermannweg 10, D-55128, Mainz, Germany
| | - Abhijit Patra
- Department of Chemistry, Indian Institute of Science, Education and Research (IISER) Bhopal, Bhopal, 462066, India
| | - Ullrich Scherf
- Macromolecular Chemistry, Bergische University Wuppertal, Gauss-Str. 20, D-42119, Wuppertal, Germany
| |
Collapse
|
15
|
Tsai CN, Mazumder S, Zhang XZ, Schlegel HB, Chen YJ, Endicott JF. Metal-to-Ligand Charge-Transfer Emissions of Ruthenium(II) Pentaammine Complexes with Monodentate Aromatic Acceptor Ligands and Distortion Patterns of their Lowest Energy Triplet Excited States. Inorg Chem 2015; 54:8495-508. [PMID: 26302226 DOI: 10.1021/acs.inorgchem.5b01193] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This is the first report of the 77 K triplet metal-to-ligand charge-transfer ((3)MLCT) emission spectra of pentaammine-MDA-ruthenium(II) ([Ru(NH3)5(MDA)](2+)) complexes, where MDA is a monodentate aromatic ligand. The emission spectra of these complexes and of the related trans-[Ru(NH3)4(MDA) (MDA')](2+) complexes are closely related, and their emission intensities are very weak. Density functional theory (DFT) calculations indicate that the energies of the lowest (3)MLCT excited states of Ru-MDA complexes are either similar to or lower than those of the lowest energy metal-centered excited states ((3)MC(X(Y))), that the barrier to internal conversion at 77 K is large compared to kBT, and that the (3)MC(X(Y)) excited states are weakly bound. The [Ru(NH3)5py](2+) complex is an exception to the general pattern: emission has been observed for the [Ru(ND3)5(d5-py)](2+) complex, but its lifetime is apparently very short. DFT modeling indicates that the excited state distortions of the different (3)MC excited states are very large and are in both Ru-ligand bonds along a single Cartesian axis for each different (3)MC excited state, nominally resulting in (3)MC(X(Y)), (3)MC((X)Y), and (3)MC(Z) lowest energy metal-centered states. The (3)MC(X(Y)) and (3)MC((X)Y) states appear to be the pseudo-Jahn-Teller distorted components of a (3)MC((XY)) state. The (3)MC(X(Y)) states are distorted up to 0.5 Å in each H3N-Ru-NH3 bond along a single Cartesian axis in the pentaammine and trans-tetraammine complexes, whereas the (3)MC(Z) states are found to be dissociative. DFT modeling of the (3)MLCT excited state of [Ru(NH3)5(py)](2+) indicates that the Ru center has a spin density of 1.24 at the (3)MLCT energy minimum and that the (3)MLCT → (3)MC(Z) crossing is smooth with a very small barrier (<0.5 kcal/mol) along the D3N-Ru-py distortion coordinate, implying strong (3)MLCT/(3)MC excited state configurational mixing. Furthermore, the DFT modeling indicates that the long-lived intermediate observed in earlier flash photolysis studies of [Ru(NH3)5py](2+) is a Ru(II)-(η(2)(C═C)-py) species.
Collapse
Affiliation(s)
- Chia Nung Tsai
- Department of Chemistry, Fu-Jen Catholic University , New Taipei City 24205, Taiwan, R.O.C
| | - Shivnath Mazumder
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - Xiu Zhu Zhang
- Department of Chemistry, Fu-Jen Catholic University , New Taipei City 24205, Taiwan, R.O.C
| | - H Bernhard Schlegel
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - Yuan Jang Chen
- Department of Chemistry, Fu-Jen Catholic University , New Taipei City 24205, Taiwan, R.O.C
| | - John F Endicott
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| |
Collapse
|