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Pilar Del Río M, Villarroya BE, López JA, Geer AM, Lahoz FJ, Ciriano MA, Tejel C. Mixed-Valence Tetrametallic Iridium Chains. Chemistry 2023; 29:e202301438. [PMID: 37402228 DOI: 10.1002/chem.202301438] [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: 05/05/2023] [Revised: 07/04/2023] [Accepted: 07/04/2023] [Indexed: 07/06/2023]
Abstract
Neutral [X-{Ir2 }-{Ir2 }-X] (X=Cl, Br, SCN, I) and dicationic [L-{Ir2 }-{Ir2 }-L]2+ (L=MeCN, Me2 CO) tetrametallic iridium chains made by connecting two dinuclear {Ir2 } units ({Ir2 }=[Ir2 (μ-OPy)2 (CO)4 ], OPy=2-pyridonate) by an iridium-iridium bond are described. The complexes exhibit fractional averaged oxidation states of +1.5 and electronic delocalization along the metallic chain. While the axial ligands do not significantly affect the metal-metal bond lengths, the metallic chain has a significant impact on the iridium-L/X bond distances. The complexes show free rotation around the unsupported iridium-iridium bond in solution, with a low-energy transition state for the chloride chain. The absorption spectra of these complexes show characteristic bands at 438-504 nm, which can be fine-tuned by varying the terminal capping ligands.
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Affiliation(s)
- M Pilar Del Río
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - B Eva Villarroya
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - José A López
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Ana M Geer
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Fernando J Lahoz
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Miguel A Ciriano
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Cristina Tejel
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
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Braunstein P, Danopoulos AA. Transition Metal Chain Complexes Supported by Soft Donor Assembling Ligands. Chem Rev 2021; 121:7346-7397. [PMID: 34080835 DOI: 10.1021/acs.chemrev.0c01197] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chemistry of discrete molecular chains constituted by metals in low oxidation states, displaying metal-metal proximity and stabilized by suitable metal-bridging, assembling ligands comprising at least one soft donor atom is comprehensively reviewed; complexes with a single (hard or soft) bridging atom (e.g., μ-halide, μ-sulfide, or μ-PR2 etc.) as well as "closed" metal arrays (that fall in the realm of cluster chemistry) are excluded. The focus is on transition metal-based systems, with few excursions to cases combining transition and post-transition elements. Most relevant supporting ligands have neutral C, P, O, or S donor (mainly, N-heterocyclic carbene, phosphine, ether, thioether) or anionic donor (mainly phenyl, ylide, silyl, phosphide, thiolate) groups. A supporting-ligand-based classification of the metal chains is introduced, using as the classifying parameter the number of "bites" (i.e., ligand bridges) subtending each intermetallic separation. The ligands are further grouped according to the number of donor atoms interacting with the metal chain (called denticity in the following) and the column of the Periodic Table to which the set of donor atoms belongs (in ascending order). A complementary metal-based compilation of the complexes discussed is also provided in a concise tabular form.
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Affiliation(s)
- Pierre Braunstein
- CNRS, Chimie UMR 7177, Laboratoire de Chimie de Coordination, Université de Strasbourg, 4 rue Blaise Pascal, 67081 Strasbourg Cedex, France
| | - Andreas A Danopoulos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
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Uemura K, Ito D, Pirillo J, Hijikata Y, Saeki A. Modulation of Band Gaps toward Varying Conductivities in Heterometallic One-Dimensional Chains by Ligand Alteration and Third Metal Insertion. ACS OMEGA 2020; 5:30502-30518. [PMID: 33283099 PMCID: PMC7711699 DOI: 10.1021/acsomega.0c04317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/02/2020] [Indexed: 06/12/2023]
Abstract
A heterometallic one-dimensional (1-D) chain consisting of multiple kinds of metals, Rh, Pt, and Pd, with direct metal-metal bonds was successfully obtained by mixing a Rh dinuclear complex and Pt-Pd-Pt trinuclear complex. The Pt-Pd-Pt trinuclear complex can be reversibly one-electron-oxidized or -reduced, where the electron paramagnetic resonance spectrum of the one-electron-oxidized one shows an axially symmetric signal with hyperfine splitting by two Pt and Pd, indicating that an unpaired electron is delocalized to the d z 2 orbital of Pt-Pd-Pt. Utilized with the highest occupied molecular orbital and lowest unoccupied molecular orbital interaction at the d z 2 orbital, simple mixing of the Pt-Pd-Pt trinuclear complex and Rh dinuclear complex in adequate solvents afforded heterometallic 1-D chains, which are aligned as -Rh-Rh-Pt-Pd-Pt-. Several physical measurements revealed that the metal oxidation state is +2. Diffuse reflectance spectra and theoretical calculations show that heterometallic 1-D chains have σ-type conduction and valence bands where π*(Rh2) are lying between them, whose gaps become narrower than the prototype chains aligned as -Rh-Rh-Pt-Pt-Pt-Pt-. The narrower band gaps are induced by destabilization of the σ-type valence bands and accompanied by insertion of Pd ions because the d-orbital energy level of Pd is closer in value to Rh compared with Pt. Flash-photolysis time-resolved microwave conductivity measurements exhibited an increase in the product of charge carrier mobility and its generation efficiency (8.1 × 10-5 to 4.6 × 10-4 cm2 V-1 s-1) with narrowing the band gaps, suggesting that the better conductivity is attributed to shorter metal-metal distances in 1-D chains. These results imply the possibilities of controlling band gap with ligand modification and third metal insertion in heterometallic 1-D chains to show various conductivities.
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Affiliation(s)
- Kazuhiro Uemura
- Department
of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Daiki Ito
- Department
of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Jenny Pirillo
- Institute
for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Yuh Hijikata
- Institute
for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Akinori Saeki
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Chiu CC, Cheng MC, Lin SH, Yan CW, Lee GH, Chang MC, Lin TS, Peng SM. Structure and magnetic properties of a novel heteroheptanuclear metal string complex [Ni 3Ru 2Ni 2(μ 7-teptra) 4(NCS) 2](PF 6). Dalton Trans 2020; 49:6635-6643. [PMID: 32367097 DOI: 10.1039/d0dt00156b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the synthesis of a novel heteroheptanuclear metal string complex (HMSC) [Ni3Ru2Ni2(μ7-teptra)4(NCS)2](PF6) 1 supported by tetra-pyridyl-tri-amine (H3teptra) ligands. We employed X-ray diffraction and other spectroscopic techniques to characterize the complex. The observed remarkably short Ru-Ru distance of 2.2499(3) Å for 1 is indicative of a unique metal-metal interaction in the mixed-valence [Ru2]5+ (S = 3/2) unit. The complex exhibits a relatively high magnetic moment value of 4.55 B.M. at 4 K, which increases rapidly to 6.00 B.M. at 30 K and remains at 6.11 B.M. from 50 to 300 K as shown by SQUID measurements, indicating a high spin (S≥ 3/2) system which is further supported by the analyses of EPR spectra at low temperatures. These magnetic behaviors can be ascribed to the result of spin-exchange interactions among multi-spin centers.
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Affiliation(s)
- Cheng-Chang Chiu
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., 10617 Taipei, Taiwan, Republic of China.
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Abstract
Significant progress has been made in the past 10-15 years on the design, synthesis, and properties of multimetallic coordination complexes with heterometallic metal-metal bonds that are paramagnetic. Several general classes have been explored including heterobimetallic compounds, heterotrimetallic compounds of either linear or triangular geometry, discrete molecular compounds containing a linear array of more than three metal atoms, and coordination polymers with a heterometallic metal-metal bonded backbone. We focus in this Review on the synthetic methods employed to access these compounds, their structural features, magnetic properties, and electronic structure. Regarding the metal-metal bond distances, we make use of the formal shortness ratio (FSR) for comparison of bond distances between a broad range of metal atoms of different sizes. The magnetic properties of these compounds can be described using an extension of the Goodenough-Kanamori rules to cases where two magnetic ions interact via a third metal atom. In describing the electronic structure, we focus on the ability (or not) of electrons to be delocalized across heterometallic bonds, allowing for rationalizations and predictions of single-molecule conductance measurements in paramagnetic heterometallic molecular wires.
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Affiliation(s)
- Jill A Chipman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison Wisconsin 53706, United States
| | - John F Berry
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison Wisconsin 53706, United States
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