1
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Penki VSS, Chu YT, Chen HY, Sudewi S, Li CH, Huang GG, Hsu SCN. Steric and electronic influence on Cu-Cu short contacts in β-thioketiminato tricopper(I) clusters. Dalton Trans 2024. [PMID: 39045681 DOI: 10.1039/d4dt01549e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
A series of β-thioketiminate copper(I) complex trimers [LCuI]3 were synthesized by modifying the ligand framework with electron-withdrawing groups (F and Cl) or electron-donating groups (iPr and Me) at the N-aryl ring as well as with CF3 groups on the chelating backbone. This ligand modification significantly impacts the enhancement of Cu⋯Cu short contacts, which can be rationalized by using steric and electronic factors of the chelated ligand. We observed that this intramolecular cuprophilicity among [LCuI]3 complexes is primarily governed by the size of N-aryl ortho-substituents. These findings were well supported by X-ray crystallography, Raman spectroscopy, and Mayer bond order analysis. The electronic effects induced by the ligand modification on the LCuI fragment were investigated using CO and 2,4,6-CNC6H2Me3 as probe molecules. Corroborated by the FTIR and CV measurements, our results reveal that the β-thioketiminate SN chelators induce more pronounced changes in the electronic character of the LCuI fragment due to the presence of CF3 groups on the chelating backbone in comparison with the F or Cl substituents on the N-aryl ring.
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Affiliation(s)
| | - Yu-Ting Chu
- International PhD Program for Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Sri Sudewi
- Department of Pharmacy, Faculty of Mathematic and Natural Science, Universitas Sam Ratulangi, Manado 95115, Indonesia
| | - Chien-Hung Li
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Genin Gary Huang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Sodio C N Hsu
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
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2
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Kim D, Rosko MC, Castellano FN, Gray TG, Teets TS. Long Excited-State Lifetimes in Three-Coordinate Copper(I) Complexes via Triplet-Triplet Energy Transfer to Pyrene-Decorated Isocyanides. J Am Chem Soc 2024; 146:19193-19204. [PMID: 38956456 DOI: 10.1021/jacs.4c04288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
There has been much effort to improve excited-state lifetimes in photosensitizers based on earth-abundant first-row transition metals. Copper(I) complexes have gained significant attention in this field, and in most cases, sterically driven approaches are used to optimize their lifetimes. This study presents a series of three-coordinate copper(I) complexes (Cu1-Cu3) where the excited-state lifetime is extended by triplet-triplet energy transfer. The heteroleptic compounds feature a cyclohexyl-substituted β-diketiminate (CyNacNacMe) paired with aryl isocyanide ligands, giving the general formula Cu(CyNacNacMe)(CN-Ar) (CN-dmp = 2,6-dimethylphenyl isocyanide for Cu1; CN-pyr = 1-pyrenyl isocyanide for Cu2; CN-dmp-pyr = 2,6-dimethyl-4-(1-pyrenyl)phenyl isocyanide for Cu3). The nature, energies, and dynamics of the low-energy triplet excited states are assessed with a combination of photoluminescence measurements at room temperature and 77 K, ultrafast transient absorption (UFTA) spectroscopy, and DFT calculations. The complexes with the pyrene-decorated isocyanides (Cu2 and Cu3) exhibit extended excited-state lifetimes resulting from triplet-triplet energy transfer (TTET) between the short-lived charge-transfer excited state (3CT) and the long-lived pyrene-centered triplet state (3pyr). This TTET process is irreversible in Cu3, producing exclusively the 3pyr state, and in Cu2, the 3CT and 3pyr states are nearly isoenergetic, enabling reversible TTET and long-lived 3CT luminescence. The improved photophysical properties in Cu2 and Cu3 result in improvements in activity for both photocatalytic stilbene E/Z isomerization via triplet energy transfer and photoredox transformations involving hydrodebromination and C-O bond activation. These results illustrate that the extended excited-state lifetimes achieved through TTET result in newly conceived photosynthetically relevant earth-abundant transition metal complexes.
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Affiliation(s)
- Dooyoung Kim
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Michael C Rosko
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Thomas G Gray
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Thomas S Teets
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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3
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Kim D, Teets TS. Sterically Encumbered Aryl Isocyanides Extend Excited-State Lifetimes and Improve the Photocatalytic Performance of Three-Coordinate Copper(I) β-Diketiminate Charge-Transfer Chromophores. J Am Chem Soc 2024. [PMID: 38853542 DOI: 10.1021/jacs.4c05180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Copper(I) complexes are prominent candidates to replace noble metal-based photosensitizers. We recently introduced a three-coordinate design for copper(I) charge-transfer chromophores that pair β-diketiminate ligands with aryl isocyanides. The excited-state lifetime in these compounds can be extended using a bichromophoric "triplet reservoir" strategy, which comes at the expense of a decrease in excited-state energy and reducing power. In this work, we introduce a complementary, sterically driven strategy for increasing the excited-state lifetimes of these photosensitizers, which gives a higher-energy, more strongly reducing charge-transfer triplet state than does the bichromophore approach. The compounds presented (Cu1-Cu4) have the general formula Cu(CyNacNacMe)(CN-Ar), where CyNacNacMe is a cyclohexyl-substituted β-diketiminate and CN-Ar is an aryl isocyanide with a variable steric profile. Their structural features and electrochemical and photophysical properties are described. The complexes with sterically encumbered 2,6-diisopropylphenyl or m-terphenyl isocyanide ligands (Cu2-Cu4) exhibit prolonged excited-state lifetimes relative to those of the parent 2,6-dimethylphenyl isocyanide compound Cu1. Specifically, one of the m-terphenyl isocyanide compounds, Cu3, displays an excited-state lifetime of 276 ns, approximately 30 times longer than that of Cu1 (9.3 ns). The photoluminescence quantum yield of Cu3 (0.09) also increases by two orders of magnitude compared to that of Cu1 (0.0008). The strong excited-state reducing power (*Eox = -2.4 V vs Fc+/0) and long lifetime of Cu3 lead to higher yields in photoredox and photocatalytic isomerization reactions, which include dehalogenation and/or hydrodgenation of benzophenone substrates, C-O bond activation of a lignin model substrate, and photocatalytic E/Z isomerization of stilbene.
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Affiliation(s)
- Dooyoung Kim
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Thomas S Teets
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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4
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Kim D, Rosko MC, Dang VQ, Castellano FN, Teets TS. Sterically Encumbered Heteroleptic Copper(I) β-Diketiminate Complexes with Extended Excited-State Lifetimes. Inorg Chem 2023; 62:16759-16769. [PMID: 37782937 DOI: 10.1021/acs.inorgchem.3c02042] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
One of the main challenges in developing effective copper(I) photosensitizers is their short excited-state lifetimes, usually attributed to structural distortion upon light excitation. We have previously introduced copper(I) charge-transfer chromophores of the general formula Cu(N^N)(ArNacNac), where N^N is a conjugated diimine ligand and ArNacNac is a substituted β-diketiminate ligand. These chromophores were promising regarding their tunable redox potentials and intense visible absorption but were ineffective as photosensitizers, presumably due to short excited-state lifetimes. Here, we introduce sterically crowded analogues of these heteroleptic chromophores with bulky alkyl substituents on the N^N and/or ArNacNac ligand. Structural analysis was combined with electrochemical and photophysical characterization, including ultrafast transient absorption (UFTA) spectroscopy to investigate the effects of the alkyl groups on the excited-state lifetimes of the complexes. The molecular structures determined by single-crystal X-ray diffraction display more distortion in the ground state as alkyl substituents are introduced into the phenanthroline or the NacNac ligand, showing smaller τ4 values due to the steric hindrance. UFTA measurements were carried out to determine the excited-state dynamics. Sterically encumbered Cu5 and Cu6 display excited-state lifetimes 15-20 times longer than unsubstituted complex Cu1, likely indicating that the incorporation of bulky alkyl substituents inhibits the pseudo-Jahn-Teller (PJT) flattening distortion in the excited state. This work suggests that the steric properties of these heteroleptic copper(I) charge-transfer chromophores can be readily modified and that the excited-state dynamics are strongly responsive to these modifications.
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Affiliation(s)
- Dooyoung Kim
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Michael C Rosko
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Vinh Q Dang
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Thomas S Teets
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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5
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Chand K, Meitei NJ, Chang YL, Tsai CL, Chen HY, Hsu SCN. Ligand Degradation Study of Unsymmetrical β-Diketiminato Copper Dioxygen Adducts: The Length Chelating Arm Effect. ACS OMEGA 2023; 8:21096-21106. [PMID: 37332796 PMCID: PMC10268616 DOI: 10.1021/acsomega.3c02004] [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: 03/27/2023] [Accepted: 05/12/2023] [Indexed: 06/20/2023]
Abstract
An investigation on the reactivity of O2 binding to unsymmetrical β-diketiminato copper(I) complexes by spectroscopic and titration analysis was performed. The length of chelating pyridyl arms (pyridylmethyl arm vs pyridylethyl arm) leads to the formation of mono- or di-nuclear copper-dioxygen species at -80 °C. The pyridylmethyl arm adduct (L1CuO2) forms mononuclear copper-oxygen species and shows ligand degradation, resulting in the formation of (2E,3Z)-N-(2,6-diisopropylphenyl)-4-(((E)-pyridin-2-ylmethylene)amino)pent-3-en-2-imine, which slowly converts to its cyclization isomer 1-(2,6-diisopropylphenyl)-4,6-dimethyl-2-(pyridin-2-yl)-1,2-dihydropyrimidine after addition of NH4OH at room temperature. On the other hand, the pyridylethyl arm adduct [(L2Cu)2(μ-O)2] forms dinuclear species at -80 °C and does not show any ligand degradation product. Instead, free ligand formation was observed after the addition of NH4OH. These experimental observations and product analysis results indicate that the chelating length of pyridyl arms governs the Cu/O2 binding ratio and the ligand degradation behavior.
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Affiliation(s)
- Kuldeep Chand
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
| | - Naorem Jemes Meitei
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
| | - Yu-Lun Chang
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
- Department
of Chemistry, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Cheng-Long Tsai
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
| | - Hsing-Yin Chen
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
| | - Sodio C. N. Hsu
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
- Department
of Chemistry, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
- Department
of Medical Research, Kaohsiung Medical University
Hospital, Kaohsiung 807, Taiwan
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6
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Huang YC, Chen HY, Chang YL, Vasanthakumar P, Chen SY, Kao CL, Wu CHY, Hsu SC. Synthesis of triisocyanomesitylene β‑diketiminato copper(I) complexes and evaluation of isocyanide π-back bonding. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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8
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Tsurugi H, Ikeda Y, Shinohara K, Shirase S, Toya N, Tanaka S, Mashima K. Synthesis and Characterization of Alkoxide-Bridged Heterometallic Clusters of Cerium and Copper. Inorg Chem 2019; 58:12565-12572. [DOI: 10.1021/acs.inorgchem.9b01213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yuri Ikeda
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Koichi Shinohara
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Satoru Shirase
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Nozomi Toya
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Shinji Tanaka
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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9
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Chand K, Tsai C, Chen H, Ching W, Hsu S, Carey JR, Hsu SCN. Improved Synthesis of Unsymmetrical
N
‐Aryl‐
N′
‐alkylpyridyl ß‐Diketimines Using Molecular Sieves and their Lithium Complexes. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701383] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kuldeep Chand
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University 807 Kaohsiung Taiwan
| | - Cheng‐Long Tsai
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University 807 Kaohsiung Taiwan
| | - Hsuan‐Ying Chen
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University 807 Kaohsiung Taiwan
| | - Wei‐Min Ching
- Instrumentation Center National Taiwan Normal University 11677 Department of Chemistry Taiwan
| | - Sung‐Po Hsu
- Department of Physiology School of Medicine College of Medicine Taipei Medical University 110 Taipei Taiwan
| | - James R. Carey
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University 807 Kaohsiung Taiwan
- Department of Applied Chemistry National University of Kaohsiung 804 Kaohsiung Taiwan
| | - Sodio C. N. Hsu
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University 807 Kaohsiung Taiwan
- Department of Medical Research Kaohsiung Medical University Hospital 807 Kaohsiung Taiwan
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10
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Hicken A, White AJP, Crimmin MR. Reversible Coordination of Boron–, Aluminum–, Zinc–, Magnesium–, and Calcium–Hydrogen Bonds to Bent {CuL2} Fragments: Heavy σ Complexes of the Lightest Coinage Metal. Inorg Chem 2017; 56:8669-8682. [DOI: 10.1021/acs.inorgchem.7b00182] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Alexandra Hicken
- SSCP
DTP, Grantham Institute, and ‡Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, U.K
| | - Andrew J. P. White
- SSCP
DTP, Grantham Institute, and ‡Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, U.K
| | - Mark R. Crimmin
- SSCP
DTP, Grantham Institute, and ‡Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, U.K
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11
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Chuang WJ, Hsu SP, Chand K, Yu FL, Tsai CL, Tseng YH, Lu YH, Kuo JY, Carey JR, Chen HY, Chen HY, Chiang MY, Hsu SCN. Reactivity Study of Unsymmetrical β-Diketiminato Copper(I) Complexes: Effect of the Chelating Ring. Inorg Chem 2017; 56:2722-2735. [PMID: 28225607 DOI: 10.1021/acs.inorgchem.6b02876] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
β-Diketiminato copper(I) complexes play important roles in bioinspired catalytic chemistry and in applications to the materials industry. However, it has been observed that these complexes are very susceptible to disproportionation. Coordinating solvents or Lewis bases are typically used to prevent disproportionation and to block the coordination sites of the copper(I) center from further decomposition. Here, we incorporate this coordination protection directly into the molecule in order to increase the stability and reactivity of these complexes and to discover new copper(I) binding motifs. Here we describe the synthesis, structural characterization, and reactivity of a series of unsymmetrical N-aryl-N'-alkylpyridyl β-diketiminato copper(I) complexes and discuss the structures and reactivity of these complexes with respect to the length of the pyridyl arm. All of the aforementioned unsymmetrical ß-diketiminato copper(I) complexes bind CO reversibly and are stable to disproportionation. The binding ability of CO and the rate of pyridyl ligand decoordination of these copper(I) complexes are directly related to the competition between the degree of puckering of the chelate system and the steric demands of the N-aryl substituent.
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Affiliation(s)
- Wan-Jung Chuang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Sung-Po Hsu
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University , Taipei 110, Taiwan.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University , Taipei 110, Taiwan
| | - Kuldeep Chand
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Fu-Lun Yu
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Cheng-Long Tsai
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Yu-Hsuan Tseng
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Yuh-Hsiu Lu
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Jen-Yu Kuo
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - James R Carey
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan.,Department of Applied Chemistry, National University of Kaohsiung , Kaohsiung 804, Taiwan
| | - Hsuan-Ying Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Michael Y Chiang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan.,Department of Chemistry, National Sun Yat-Sen University , Kaohsiung 804, Taiwan
| | - Sodio C N Hsu
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
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12
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Chen C, Bellows SM, Holland PL. Tuning steric and electronic effects in transition-metal β-diketiminate complexes. Dalton Trans 2015; 44:16654-70. [PMID: 26244489 DOI: 10.1039/c5dt02215k] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
β-Diketiminates are widely used supporting ligands for building a range of metal complexes with different oxidation states, structures, and reactivities. This Perspective summarizes the steric and electronic influences of ligand substituents on these complexes, with an eye toward informing the design of new complexes with optimized properties. The backbone and N-aryl substituents can give significant steric effects on structure, reactivity and selectivity of reactions. The electron density on the metal can be tuned by installation of electron withdrawing or donating groups on the β-diketiminate ligand as well. Examples are shown from throughout the transition metal series to demonstrate different types of effects attributable to systematic variation of β-diketiminate ligands.
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Affiliation(s)
- Chi Chen
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, USA.
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13
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Cu(II) complexes of sterically and electronically divergent β-diketiminate ligands: Structural and electrochemical aspects. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.05.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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15
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Oguadinma PO, Schaper F. Synthesis and structures of isopropyl-β-diketiminato copper(I) complexes. CAN J CHEM 2010. [DOI: 10.1139/v10-013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The reaction of N,N′-diisopropyl-2-amino-4-iminopent-2-ene (nacnaci-PrH, 1) either with CuOt-Bu or with a mixture of mesityl copper and 10% CuOt-Bu afforded, in the presence of PPh3, CN(C6Me2H3), or MeCN, the Lewis base coordinated complexes nacnaci-PrCuPPh3·0.5 C6H14 (2), nacnaci-PrCuCN(C6Me2H3) (3), and nacnaci-PrCu(NCMe) (4). Compounds 2, 3, and 4 were characterized by single-crystal X-ray diffraction studies. Compound 4 afforded two species in deuterated benzene in a 2:1 ratio, which were assigned to {nacnaci-PrCu}2(μ-NCMe) and nacnaci-PrCuNCMe (4). Upon addition of 5 equiv. of MeCN, the two sets collapsed into that of 4. No copper complexes were formed in the presence of styrene, stilbene, or diphenylacetylene.
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Affiliation(s)
- Paul O. Oguadinma
- Département de chimie, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Frank Schaper
- Département de chimie, Université de Montréal, Montréal, QC H3C 3J7, Canada
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16
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Oguadinma PO, Schaper F. π Back-Bonding in Dibenzyl-β-diketiminato Copper Olefin Complexes. Organometallics 2009. [DOI: 10.1021/om900840f] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul O. Oguadinma
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Frank Schaper
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
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17
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Oguadinma PO, Schaper F. Bis(2-phenylethyl)-nacnac: A Chiral Diketiminate Ligand and Its Copper Complexes. Organometallics 2009. [DOI: 10.1021/om9002279] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Paul O. Oguadinma
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Frank Schaper
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
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