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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.
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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
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Dai W, Yu S, Xu W, Kong C, Liu Z, Yin H, He C, Liu JJ, Cheng F. Energy transfer in metal-exchange binuclear complexes covalently linked by asymmetric ligands. Dalton Trans 2023; 52:16993-17004. [PMID: 37933477 DOI: 10.1039/d3dt03307d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Nitrogen complexation with π-conjugated ligands is an effective strategy for synthesizing luminescent molecules. The asymmetric bridging ligands L (L1 and L2) have been designed. The terminal chelating sites of the L1 and L2 bridging ligands consisted of 2,2'-bipyridine (bpy) and 1,10-phenanthroline moieties (where L = L1 and L2; L1 = 2-(3-((4-([2,2'-bipyridin]-6-yl)benzyl)oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and L2 = 2-(3-((4-(6-phenyl-[2,2'-bipyridin]-4-yl)benzyl)oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline). The full use of the synthetic strategy of the "complexes as ligands and complexes as metals" was expected to successfully design and synthesize a series of conjugated metal-exchange complexes linked by the asymmetric bridging ligands L1 and L2. These compounds included monometallic complexes Ru(L) and (L)Ru (C1, C2, C7, and C8), homometallic complexes Ru(L)Ru (C3 and C4), and heterometallic complexes Os(L)Ru and Ru(L)Os (C5, C6, C9, and C10) with Ru- or Os-based units. C3-C10 complexes exhibited various degrees of octahedral distortion around the Ru(II) or Os(II) center, which was consistent with the optimized geometry of the coordination complexes based on density functional theory calculation. These complexes exhibited intense spin-allowed ligand-centered transitions with high absorbance at around 288 nm upon absorbing visible light. Notably, all complexes exhibited spin-allowed metal-to-ligand charge transfer absorption of the Ru-based units in the 440-450 nm range. In addition, the heterometallic C5, C6, C9, and C10 complexes showed absorption of the Os-based units in the range of 565-583 nm. The intramolecular energy transfer of C3 and C5 was briefly discussed by comparing the emission intensity of monometallic C1 and C2 to that of binuclear complexes C3 and C5, respectively. The results indicated that the intramolecular energy transfer of the Ru(II)/Os(II) polypyridine complexes proceeded from the Ru(II)- to the Os(II)-based units in the heterometallic C5 and C6 complexes.
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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.
| | - Wen Xu
- 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.
| | - Zining Liu
- College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China.
| | - Hongju Yin
- 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.
| | - 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.
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Amunugama S, Asempa E, Jakubikova E, Verani CN. Probing the effect of nitro-substituents in the modulation of LUMO energies for directional electron transport through 4d 6 ruthenium(II)-based metallosurfactants. Dalton Trans 2023; 52:12423-12435. [PMID: 37594397 DOI: 10.1039/d3dt01797d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Electron-withdrawing nitro-substituents were installed onto terpyridine- and phenanthroline-based metallosurfactants with 4d6 ruthenium(II), which were deposited as Langmuir-Blodgett monolayers aiming to study the feasibility of charge transport in Au|LB|Au junctions. The nitro groups are intended to modulate the energy of the frontier molecular orbitals to near to, or match that of Fermi levels in the gold electrodes. A series of heteroleptic metallosurfactants [RuII(C18OPh-terpy)(X-terpy)](PF6)2 and [RuII(C18OPh-terpy)(X-phen)Cl]PF6 were synthesized, where C18OPh-terpy is the 4'-[4-(octadecyloxy)phenyl]-2,2':6',2''-terpyridine amphiphile common to all species, X-terpy is a terpyridine with-H (1) or-phenyl-NO2 (2) and X-phen is a phenanthroline with-H (3) or-NO2 (4) groups. These metallosurfactants were characterized by experimental and computational methods, and the presence of nitro groups affect more affordable reductions at less negative potentials, as well as slightly more positive oxidations, these changes are less pronounced in species 2 than in 4. Species 1 and 2 showed limited Pockels-Langmuir and Langmuir-Blodgett film formation with lower collapse pressure of 27 mN m-1. In contrast, metallosurfactants 3 and 4 showed enhanced hydrophilicity indicated by higher collapse pressures of ca. 36 mN m-1. The LB monolayers of 3 and 4 were deposited on gold electrodes to form Au|LB|Au junctions and electron transport was measured as I/V curves. The NO2-bearing species 4 showed asymmetric curves associated with directional electron transport with amplitudes up to -2.0 nA and rectification ratios from 5 to 26 between -1 to +1 V and from 3 to 14 between -3 to +3 V.
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Affiliation(s)
- Samudra Amunugama
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
| | - Eyram Asempa
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
| | - Cláudio N Verani
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
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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.
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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.
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Rupp MT, Shevchenko N, Hanan GS, Kurth DG. Enhancing the photophysical properties of Ru(II) complexes by specific design of tridentate ligands. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214127] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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