1
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Middya P, Ghosh S, Chattopadhyay S. Synthesis and characterization of cobalt and iron complexes with di-azine ligands based on salicylaldehyde or its derivatives: A review. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.116036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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2
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Dey S, Hazari AS, Mobin SM, Lahiri GK. Diruthenium and triruthenium compounds of the potential redox active non-chelated η 1-N,η 1-N-benzothiadiazole bridge. Dalton Trans 2022; 51:8657-8670. [PMID: 35583102 DOI: 10.1039/d2dt00533f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In the present study, a series of non-chelated BTD (2,1,3-benzothiadiazole)-bridged diruthenium(II) ([{(CH3CN)(acac)2RuII}2(μ-BTD)] 1, [{CH3CN(acac)2RuII}(μ-BTD){RuII(acac)2(η1-N-BTD)}] 2, [{(η1-N-BTD)(acac)2RuII}2(μ-BTD)] 3), and triruthenium ([{(acac)2RuII}3(μ-BTD)2(η1-N-BTD)2] 4) complexes with varying ratios of η1-N and μ-bis-η1-N,η1-N modes of BTD were studied. Complexes 1-4 (S = 0) were obtained via the one-pot reaction of electron-rich Ru(acac)2(CH3CN)2 and electron-deficient BTD in refluxing acetone. The relatively low Ru(II)/Ru(III) potential of 1-4 (0.08-0.44 V versus SCE) further facilitated the isolation of the corresponding mixed valent RuIIRuIII (S = 1/2) and RuIIRuIIRuIII (S = 1/2)/RuIIRuIIIRuIII (S = 1) forms [1]ClO4-[3]ClO4 and [4]ClO4/[4](ClO4)2, respectively. The single-crystal X-ray structures of the representative mixed valent [1]ClO4 and [3]ClO4 established (i) Ru⋯Ru distances of 6.227 Å and 6.256 Å (molecule A)/6.184 Å (molecule B), respectively, (ii) a significant variation of the N-S distance of BTD in [3]ClO4 as a function of its binding mode μ versus η1 and (iii) similar Ru-N (μ-BTD) distances in each case corresponding to a valence delocalised situation. The mixed valent diruthenium (1+-3+) and triruthenium (4+/42+) complexes exhibited metal-based anisotropic electron paramagnetic resonance (EPR) and moderately intense low-energy intervalence charge-transfer (IVCT) transitions in the near-infrared region of 1730-1890 nm. Analysis of the IVCT band using the Hush treatment revealed a valence delocalised class III mixed valent state with the electronic coupling Vab of ≈2640-2890 cm-1, as also corroborated by the Kc values of 105-108, solvent independency of the IVCT band and uniform spin distribution between the metal ions in the singly occupied state(s). Furthermore, the involvement of the BTD (η1 and μ)-based orbitals in the reduction processes was evident by its free radical EPR feature.
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Affiliation(s)
- Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Arijit Singha Hazari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Shaikh M Mobin
- Discipline of Chemistry, Indian Institute of Technology Indore, Simrol, Khandwa Road, Indore-453552, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
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3
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Dhara S, Panda S, Lahiri GK. Redox induced S-S bond cleavage of 2,2'-dithiobisbenzothiazole - leading to a [2Ru-2S] core analogous to [2Fe-2S] cluster. Dalton Trans 2021; 50:12408-12412. [PMID: 34378605 DOI: 10.1039/d1dt02211c] [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
Facile reduction of 2,2'-dithiobisbenzothiazole by the mediation of metal-to-ligand charge transfer or by internal reducing equivalent is demonstrated. It leads to various binding modes of thiolates (κ1, κ2, μ) in a series of mononuclear and dinuclear ruthenium complexes. The dinuclear complex exhibited electron transfer processes similar to a [2Fe-2S] cluster.
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Affiliation(s)
- Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
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4
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Arya Y, Bera SK, Panda S, Lahiri GK. Osmium(II)-Coordination Induced C-C Bond Functionalization of Bis-lawsone. Inorg Chem 2021; 60:11883-11887. [PMID: 34310111 DOI: 10.1021/acs.inorgchem.1c01680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metal-coordination-driven C-C bond functionalization without involvement of the traditional route of oxidative addition, insertion, and reductive elimination has gained immense importance. In this context, the present Communication highlights the facile ring contraction process of the deprotonated bis-lawsone (L2-) to functionalized L12- upon coordination to {Os(bpy)2} or isomeric {Os(pap)2} (bpy = 2,2'-bipyridine and pap = 2-phenylazopyridine) in 1-3. Further, recognition of fractional redox noninnocence of L1 in 1+-3+ via experimental and theoretical events facilitated its inclusion in the redox noninnocent family.
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Affiliation(s)
- Yogita Arya
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India
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5
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Kumari M, Bera SK, Lahiri GK. Noninnocence of the deprotonated 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine bridge in diruthenium frameworks - a function of co-ligands. Dalton Trans 2021; 50:9891-9903. [PMID: 34196336 DOI: 10.1039/d1dt01488a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The article deals with the sensitive electronic forms in accessible redox states of structurally and spectroscopically authenticated deprotonated 1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = H) or 1,2-bis((3,5-dimethyl-1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = Me), a BODIPY analogue bridged diruthenium complex as a function of varying ancillary ligands. It involved rac-(acac)2RuIII(μ-LR 2-)RuIII(acac)21a, R = H; 1b, R = Me (S = 1, acac = acetylacetonate), rac-[(bpy)2RuII(μ-L2-)RuII(bpy)2](ClO4)2 [2](ClO4)2 (S = 0, bpy = 2,2'-bipyridine) and diastereomeric [(pap)2RuII(μ-L2-)RuII(pap)2](ClO4)2meso-[3a](ClO4)2/rac-[3b](ClO4)2 (S = 0, pap = phenylazopyridine). The crystal structure established the linkage of the conjugated -C5[double bond, length as m-dash]N2-N3[double bond, length as m-dash]C6- central unit with the two terminal deprotonated pyrrole units of coordinated L2-. The bridging L2- in 1a, 1b, [2](ClO4)2, [3b](ClO4)2 and [3a](ClO4)2 was slightly twisted and planar with torsional angles of 41.54°, 42.91°, 37.38°, 35.33° and 0°, respectively, with regard to the central N2-N3 bond. The extent of twisting of the bridge followed an inverse relationship with the RuRu separation: 4.935/4.934 Å 1a/1b < 5.141 Å [2](ClO4)2 < 5.201 Å [3b](ClO4)2 < 5.351 Å [3a](ClO4)2. This is also attributed to the intermolecular ππ/CHπ interactions between the nearby aromatic rings of L and bpy or pap in [2](ClO4)2 or [3](ClO4)2, respectively. The multiple redox steps of the complexes varied appreciably based on the σ-donating (acac) and π-acidic (bpy, pap) characteristics of the ancillary ligands. Experimental (structure, EPR) and theoretical (DFT) evaluation pertaining to the electronic forms of 1n, 2n and 3n demonstrated the preferential involvement of L based frontier orbitals in electron transfer processes even in combination with the redox facile ruthenium ion. This in turn highlighted its redox non-innocent feature as in the case of well-documented metal coordinated quinonoid, formazanate, diimine (bpy), azo (pap) and β-diketiminate functions.
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Affiliation(s)
- Maya Kumari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
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6
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Panda S, Goel P, Lahiri GK. Non-Spectator Feature of α-Diimine Mimicked Di/tetrahydro-bisisoquinoline and Biimidazopyridine on {Ru(acac)2
} Platform. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000230] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Sanjib Panda
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai Powai India
| | - Puneet Goel
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai Powai India
| | - Goutam Kumar Lahiri
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai Powai India
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7
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Dutta D, Kundu S, Ghosh P. A Diruthenium Complex of an N-Pyridyl-o-aminophenol Derivative: A Route to Mixed Valency. Chemistry 2019; 25:14901-14911. [PMID: 31411776 DOI: 10.1002/chem.201903028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Indexed: 11/06/2022]
Abstract
An N-pyridyl-o-aminophenol derivative that stabilises mixed-valence states of ruthenium ions is disclosed. A diruthenium complex, [(LIQ 0 )Ru2 Cl5 ]⋅MeOH (1⋅MeOH) is successfully isolated, in which LIQ 0 is the o-iminobenzoquinone form of 2-[(3-nitropyridin-2-yl)amino]phenol (LAP H2 ). In 1, LIQ 0 oriented towards one ruthenium centre is a non-innocent NO-donor redox ligand, whereas another oriented towards another ruthenium centre is an innocent pyridine-donor redox ligand. Complex 1 is a diruthenium(II,III) mixed-valence complex, [RuII (LIQ 0 )(μ-Cl)2 RuIII ], with a minor contribution from the diruthenium(III,III) state. [RuIII (LISQ .- )(μ-Cl)2 RuIII ] contains LISQ .- , which is the o-iminobenzosemiquinonate anion radical form of the ligand. Complexes 1- and 1+ are diruthenium(II,II), [RuII (LIQ 0 )(μ-Cl)2 RuII ], and diruthenium(III,III), [RuIII (LIQ 0 )(μ-Cl)2 RuIII ], complexes, respectively, of LIQ 0 . Complex 12- is a diruthenium(II,II) complex of the o-iminobenzosemiquinonate anion radical (LISQ .- ), [RuII (LISQ .- )(μ-Cl)2 RuII ], with a minor contribution from the diruthenium(III,II) form, [RuIII (LAP 2- )(μ-Cl)2 RuII ]. Complex 12+ is a diruthenium(III,IV) mixed-valence complex of LIQ 0 , [RuIII (LIQ 0 )(μ-Cl)2 RuIV ]. Complexes 1 and 12+ exhibit inter-valence charge-transfer transitions at λ=1300 and 1370 nm, respectively.
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Affiliation(s)
- Debarpan Dutta
- Department of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata, 700103, West Bengal, India
| | - Suman Kundu
- Department of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata, 700103, West Bengal, India
| | - Prasanta Ghosh
- Department of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata, 700103, West Bengal, India
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8
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Bera SK, Panda S, Dey Baksi S, Lahiri GK. Diverse modes of functionalisation of ruthenium coordinated β-ketoiminate analogues. Dalton Trans 2018; 47:15897-15906. [DOI: 10.1039/c8dt02940g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Varying chelation assisted as well as solvent dependent reactivity profiles of isostructural β-ketoiminate analogues explicate their non-spectator behaviour and fractional redox non-innocence.
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Affiliation(s)
- Sudip Kumar Bera
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
| | - Sanjib Panda
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
| | - Sourajit Dey Baksi
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
| | - Goutam Kumar Lahiri
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
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9
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Haiduc I. Inverse coordination – An emerging new chemical concept. Oxygen and other chalcogens as coordination centers. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.02.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Ansari MA, Mandal A, Beyer K, Paretzki A, Schwederski B, Kaim W, Lahiri GK. Non-innocence and mixed valency in tri- and tetranuclear ruthenium complexes of a heteroquinone bridging ligand. Dalton Trans 2017; 46:15589-15598. [DOI: 10.1039/c7dt03509h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The potential of a heteroquinone to bridge up to four metal fragments has been structurally elucidated and multiple redox processes have been ascertained.
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Affiliation(s)
- Mohd. Asif Ansari
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
| | - Abhishek Mandal
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
| | - Katharina Beyer
- Institut für Anorganische Chemie
- Universität Stuttgart
- D-70550 Stuttgart
- Germany
| | - Alexa Paretzki
- Institut für Anorganische Chemie
- Universität Stuttgart
- D-70550 Stuttgart
- Germany
| | | | - Wolfgang Kaim
- Institut für Anorganische Chemie
- Universität Stuttgart
- D-70550 Stuttgart
- Germany
| | - Goutam Kumar Lahiri
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
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11
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Das A, Ghosh P, Priego JL, Jiménez-Aparicio R, Lahiri GK. Unsymmetric (μ-oxido)/(μ-pyrazolato) and Symmetric (μ-pyrazolato)2 Bridged Diosmium Frameworks: Electronic Structure and Magnetic Properties. Inorg Chem 2016; 55:8396-406. [DOI: 10.1021/acs.inorgchem.6b00898] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ankita Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prabir Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - José Luis Priego
- Departamento de Química Inorgánica, Facultad
de Ciencias Químicas, Universidad Complutense, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Reyes Jiménez-Aparicio
- Departamento de Química Inorgánica, Facultad
de Ciencias Químicas, Universidad Complutense, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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12
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Lee Y, Abboud KA, García-Serres R, Murray LJ. A three-coordinate Fe(ii) center within a [3Fe-(μ3-S)] cluster that provides an accessible coordination site. Chem Commun (Camb) 2016; 52:9295-8. [PMID: 27363672 DOI: 10.1039/c6cc04671a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A μ3-sulfide bridged triiron cluster(ii,ii,iii) supported by a cyclophane ligand undergoes metal-based reduction to yield an all-ferrous species. The latter complex incorporates a three-coordinate iron center that provides an accessible coordination site to a solvent molecule.
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Affiliation(s)
- Yousoon Lee
- University of Florida, Department of Chemistry, Center for Catalysis, Gainesville, FL 32611-7200, USA.
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13
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Mandal A, Agarwala H, Ray R, Plebst S, Mobin SM, Priego JL, Jiménez-Aparicio R, Kaim W, Lahiri GK. Sensitivity of the valence structure in diruthenium complexes as a function of terminal and bridging ligands. Inorg Chem 2014; 53:6082-93. [PMID: 24896222 DOI: 10.1021/ic500452h] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The compounds [(acac)2Ru(III)(μ-H2L(2-))Ru(III)(acac)2] (rac, 1, and meso, 1') and [(bpy)2Ru(II)(μ-H2L(•-))Ru(II)(bpy)2](ClO4)3 (meso, [2](ClO4)3) have been structurally, magnetically, spectroelectrochemically, and computationally characterized (acac(-) = acetylacetonate, bpy = 2,2'-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N',O'-coordinated μ-H2L(n-) forms two β-ketiminato-type chelate rings, and 1 or 1' are connected via NH···O hydrogen bridges in the crystals. 1 exhibits a complex magnetic behavior, while [2](ClO4)3 is a radical species with mixed ligand/metal-based spin. The combination of redox noninnocent bridge (H2L(0) → → → →H2L(4-)) and {(acac)2Ru(II)} → →{(acac)2Ru(IV)} or {(bpy)2Ru(II)} → {(bpy)2Ru(III)} in 1/1' or 2 generates alternatives regarding the oxidation state formulations for the accessible redox states (1(n) and 2(n)), which have been assessed by UV-vis-NIR, EPR, and DFT/TD-DFT calculations. The experimental and theoretical studies suggest variable mixing of the frontier orbitals of the metals and the bridge, leading to the following most appropriate oxidation state combinations: [(acac)2Ru(III)(μ-H2L(•-))Ru(III)(acac)2](+) (1(+)) → [(acac)2Ru(III)(μ-H2L(2-))Ru(III)(acac)2] (1) → [(acac)2Ru(III)(μ-H2L(•3-))Ru(III)(acac)2](-)/[(acac)2Ru(III)(μ-H2L(2-))Ru(II)(acac)2](-) (1(-)) → [(acac)2Ru(III)(μ-H2L(4-))Ru(III)(acac)2](2-)/[(acac)2Ru(II)(μ-H2L(2-))Ru(II)(acac)2](2-) (1(2-)) and [(bpy)2Ru(III)(μ-H2L(•-))Ru(II)(bpy)2](4+) (2(4+)) → [(bpy)2Ru(II)(μ-H2L(•-))Ru(II)(bpy)2](3+)/[(bpy)2Ru(II)(μ-H2L(2-))Ru(III)(bpy)2](3+) (2(3+)) → [(bpy)2Ru(II)(μ-H2L(2-))Ru(II)(bpy)2](2+) (2(2+)). The favoring of Ru(III) by σ-donating acac(-) and of Ru(II) by the π-accepting bpy coligands shifts the conceivable valence alternatives accordingly. Similarly, the introduction of the NH donor function in H2L(n) as compared to O causes a cathodic shift of redox potentials with corresponding consequences for the valence structure.
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Affiliation(s)
- Abhishek Mandal
- Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
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14
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Ghosh P, Mondal P, Ray R, Das A, Bag S, Mobin SM, Lahiri GK. Significant Influence of Coligands Toward Varying Coordination Modes of 2,2′-Bipyridine-3,3′-diol in Ruthenium Complexes. Inorg Chem 2014; 53:6094-106. [DOI: 10.1021/ic5004676] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Prabir Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prasenjit Mondal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Ritwika Ray
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Ankita Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sukdev Bag
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Shaikh M. Mobin
- Discipline of Chemistry, School of Basic Sciences, Indian Institute of Technology Indore, Indore 452017, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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15
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Prabhakaran R, Kalaivani P, Renukadevi SV, Huang R, Senthilkumar K, Karvembu R, Natarajan K. Copper Ion Mediated Selective Cleavage of C–S Bond in Ferrocenylthiosemicarbazone Forming Mixed Geometrical [(PPh3)Cu(μ-S)2Cu(PPh3)2] Having Cu2S2 Core: Toward a New Avenue in Copper–Sulfur Chemistry. Inorg Chem 2012; 51:3525-32. [DOI: 10.1021/ic2022616] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Rui Huang
- Department of Chemistry, Michigan
State University, East Lansing, Michigan 48824, United States
| | | | - Ramasamy Karvembu
- Department of Chemistry, National
Institute of Technology, Tiruchirappalli 620 015, India
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16
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Novel mixed-ligand palladium complexes [Pd2(acac)3NO3] and [Pd(acac)NO3]n involving O,O- and γ-C-bonded acetylacetonate linkers. Polyhedron 2012. [DOI: 10.1016/j.poly.2011.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Carlucci L, Ciani G, Maggini S, Proserpio DM, Visconti M. Heterometallic Modular Metal–Organic 3D Frameworks Assembled via New Tris‐β‐Diketonate Metalloligands: Nanoporous Materials for Anion Exchange and Scaffolding of Selected Anionic Guests. Chemistry 2010; 16:12328-41. [DOI: 10.1002/chem.201001256] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lucia Carlucci
- Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, Via Venezian 21, 20133 Milano (Italy), Fax: (+39) 0250314454
| | - Gianfranco Ciani
- Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, Via Venezian 21, 20133 Milano (Italy), Fax: (+39) 0250314454
| | - Simona Maggini
- Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, Via Venezian 21, 20133 Milano (Italy), Fax: (+39) 0250314454
| | - Davide M. Proserpio
- Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, Via Venezian 21, 20133 Milano (Italy), Fax: (+39) 0250314454
| | - Marco Visconti
- Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, Via Venezian 21, 20133 Milano (Italy), Fax: (+39) 0250314454
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18
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García-Deibe AM, Fondo M, Ocampo N, Sanmartín J, Gómez-Fórneas E. Design of chiral homodinuclear complexes based on the coordinating behaviour of some symmetric ligands. NEW J CHEM 2010. [DOI: 10.1039/c0nj00071j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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19
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Koshevoy IO, Gutierrez-Puebla E, Lahuerta P, Monge A, Ubeda M, Sanaú M. Isolation of enantiomerically pure organometallic palladium compounds: synthesis of the triangles prepared from enantiopure [cis-Pd2(C6H4PPh2)2(NCCH3)4]2+. Dalton Trans 2009:2993-8. [DOI: 10.1039/b816803b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zhu BX, Zhang QL, Zhang YQ, Tao Z, Clegg JK, Reimers JR, Lindoy LF, Wei G. Polymeric di- and discrete trinuclear silver(I) assemblies incorporating γ-carbon bonded, neutral acetylacetone-imine motifs assembled from racemic and diastereopure N,N′-bis(acetylacetone)cyclohexanediimine units. Dalton Trans 2009:4896-900. [DOI: 10.1039/b903467f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ghumaan S, Sarkar B, Maji S, Puranik V, Fiedler J, Urbanos F, Jimenez-Aparicio R, Kaim W, Lahiri G. Valence-State Analysis through Spectroelectrochemistry in a Series of Quinonoid-Bridged Diruthenium Complexes [(acac)2Ru(μ-L)Ru(acac)2]n (n=+2, +1, 0, −1, −2). Chemistry 2008; 14:10816-28. [DOI: 10.1002/chem.200800976] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Maji S, Sarkar B, Mobin SM, Fiedler J, Urbanos FA, Jimenez-Aparicio R, Kaim W, Lahiri GK. Valence-State Alternatives in Diastereoisomeric Complexes [(acac)2Ru(μ-QL)Ru(acac)2]n (QL2− = 1,4-Dioxido-9,10-anthraquinone,n = +2, +1, 0, −1, −2). Inorg Chem 2008; 47:5204-11. [DOI: 10.1021/ic800115q] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Somnath Maji
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Biprajit Sarkar
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Shaikh M. Mobin
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Jan Fiedler
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Francisco A. Urbanos
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Reyes Jimenez-Aparicio
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Wolfgang Kaim
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India,
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany,
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague, Czech Republic,
- Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutenses, Ciudad Universitaria, E-28040 Madrid, Spain
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Kaim W, Lahiri GK. Unconventional mixed-valent complexes of ruthenium and osmium. Angew Chem Int Ed Engl 2007; 46:1778-96. [PMID: 17323423 DOI: 10.1002/anie.200602737] [Citation(s) in RCA: 307] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent developments have helped to extend the repertoire of mixed-valent ruthenium and osmium complexes beyond conventional systems. This extension has been achieved by using sophisticated ligands and by creating more variegated coordination patterns. The strategies employed include the use of multidentate ligands (which give rise to multinuclear and chelate complexes) and the use several redox active components (non-innocent ligands and oxidation-state ambivalence). The results offer enhanced chemical insight into metal-ligand electron-transfer situations and suggest that mixed-valent materials may eventually be exploited in molecular electronics and molecular computing.
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Affiliation(s)
- Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550 Stuttgart, Germany.
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Kaim W, Lahiri G. Unkonventionelle gemischtvalente Komplexe des Rutheniums und Osmiums. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200602737] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ghumaan S, Mukherjee S, Kar S, Roy D, Mobin SM, Sunoj RB, Lahiri GK. An Experimental and Density Functional Theory Approach Towards the Establishment of Preferential Metal- or Ligand-Based Electron-Transfer Processes in Large Quinonoid-Bridged Diruthenium Complexes [{(aap)2Ru}2(μ-BL2–)]n+ (aap = 2-Arylazopyridine). Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600638] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ghumaan S, Lahiri GK. Tuning intermetallic electronic coupling in polyruthenium systems via molecular architecture. J CHEM SCI 2006. [DOI: 10.1007/bf02703951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wilton-Ely JDET, Wang M, Benoit DM, Tocher DA. Spectroscopic, Structural and Theoretical Investigation of Alkenyl Ruthenium Complexes Supported by Sulfur–Nitrogen Mixed-Donor Ligands. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600241] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dhara PK, Drew MG, Chattopadhyay P. Ruthenium (III) complexes of tetradentate NSNO pyridylthioazophenolates: Synthesis, spectral studies, crystal structure and redox properties. Polyhedron 2006. [DOI: 10.1016/j.poly.2005.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Ghumaan S, Kar S, Mobin SM, Harish B, Puranik VG, Lahiri GK. 2,4,6-Tris(2-pyridyl)-1,3,5-triazine (tptz)-Derived [RuII(tptz)(acac)(CH3CN)]+ and Mixed-Valent [(acac)2RuIII{(μ-tptz-H+)-}RuII(acac)(CH3CN)]+. Inorg Chem 2006; 45:2413-23. [PMID: 16529460 DOI: 10.1021/ic0514288] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mononuclear [Ru(II)(tptz)(acac)(CH3CN)]ClO4 ([1]ClO4) and mixed-valent dinuclear [(acac)2Ru(III){(mu-tptz-Eta+)-}Ru(II)(acac)(CH3CN)]ClO4 ([5]ClO4; acac = acetylacetonate) complexes have been synthesized via the reactions of Ru(II)(acac)2(CH3CN)2 and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), in 1:1 and 2:1 molar ratios, respectively. In [1]ClO4, tptz binds with the Ru(II) ion in a tridentate N,N,N mode (motif A), whereas in [5]ClO4, tptz bridges the metal ions unsymmetrically via the tridentate neutral N,N,N mode with the Ru(II) center and cyclometalated N,C- state with the Ru(III) site (motif F). The activation of the coordinated nitrile function in [1]ClO4 and [5]ClO4 in the presence of ethanol and alkylamine leads to the formation of iminoester ([2]ClO4 and [7]ClO4) and amidine ([4]ClO4) derivatives, respectively. Crystal structure analysis of [2]ClO4 reveals the formation of a beautiful eight-membered water cluster having a chair conformation. The cluster is H-bonded to the pendant pyridyl ring N of tptz and also with the O atom of the perchlorate ion, which, in turn, makes short (C-H- - - - -O) contacts with the neighboring molecule, leading to a H-bonding network. The redox potentials corresponding to the Ru(II) state in both the mononuclear {[(acac)(tptz)Ru(II)-NC-CH3]ClO4 ([1]ClO4) >> [(acac)(tptz)Ru(II)-NH=C(CH3)-OC2H5]ClO4 ([2]ClO4) > [(acac)(tptz)Ru(II)-NH2-C6H4(CH3)]ClO4 ([3]ClO4) > [(acac)(tptz)Ru(II)-NH=C(CH3)-NHC2H5]ClO4 ([4]ClO4)} and dinuclear {[(acac)2Ru(III){(mu-tptz-H+)-}Ru(II)(acac)(NC-CH3)]ClO4 ([5]ClO4), [(acac)2Ru(III){(mu-tptz-H+(N+-O-)2)-}Ru(II)(acac)(NC-CH3)]ClO4 ([6]ClO4), [(acac)2Ru(III){(mu-tptz-H+)-}Ru(II)(acac)(NH=C(CH3)-OC2H5)]ClO4 ([7]ClO4), and [(acac)2Ru(III){(mu-tptz-Eta+)-}Ru(II)(acac)(NC4H4N)]ClO4 ([8]ClO(4))} complexes vary systematically depending on the electronic nature of the coordinated sixth ligands. However, potentials involving the Ru(III) center in the dinuclear complexes remain more or less invariant. The mixed-valent Ru(II)Ru(III) species ([5]ClO4-[8]ClO4) exhibits high comproportionation constant (Kc) values of 1.1 x 10(12)-2 x 10(9), with substantial contribution from the donor center asymmetry at the two metal sites. Complexes display Ru(II)- and Ru(III)-based metal-to-ligand and ligand-to-metal charge-transfer transitions, respectively, in the visible region and ligand-based transitions in the UV region. In spite of reasonably high K(c) values for [5]ClO4-[8]ClO4, the expected intervalence charge-transfer transitions did not resolve in the typical near-IR region up to 2000 nm. The paramagnetic Ru(II)Ru(III) species ([5]ClO4-[8]ClO4) displays rhombic electron paramagnetic resonance (EPR) spectra at 77 K (g approximately 2.15 and Deltag approximately 0.5), typical of a low-spin Ru(III) ion in a distorted octahedral environment. The one-electron-reduced tptz complexes [Ru(II)(tptz.-)(acac)(CEta3CN)] (1) and [(acac)2Ru(III){(mu-tptz-Eta+).2-}Ru(II)(acac)(CH3CN)] (5), however, show a free-radical-type EPR signal near g = 2.0 with partial metal contribution.
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Affiliation(s)
- Sandeep Ghumaan
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India
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Kar S, Sarkar B, Ghumaan S, Roy D, Urbanos FA, Fiedler J, Sunoj RB, Jimenez-Aparicio R, Kaim W, Lahiri GK. A New Coordination Mode of the Photometric Reagent Glyoxalbis(2-hydroxyanil) (H2gbha): Bis-Bidentate Bridging by gbha2- in the Redox Series {(μ-gbha)[Ru(acac)2]2}n (n = −2, −1, 0, +1, +2), Including a Radical-Bridged Diruthenium(III) and a RuIII/RuIV Intermediate. Inorg Chem 2005; 44:8715-22. [PMID: 16296825 DOI: 10.1021/ic050950r] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bis-bidentate bridging function of gbha2- with N,O-/N,O- coordination was observed for the first time in the complex (mu-gbha)[Ru(III)(acac)2]2 (1). Density functional theory calculations of 1 yield a triplet ground state with a large (deltaE > 6000 cm(-1)) singlet-triplet gap. Intermolecular antiferromagnetic coupling was observed (J approximately -5.3 cm(-1)) for the solid. Complex 1 undergoes two one-electron reduction and two one-electron oxidation steps; the five redox forms [(mu-gbha)[Ru(acac)2]2]n (n = -2, -1, 0, +1, +2) were characterized by UV-vis-NIR spectroelectrochemistry (NIR = near infrared). The paramagnetic intermediates were also investigated by electron paramagnetic resonance (EPR) spectroscopy. The monoanion with a comproportionation constant K(c) of 2.7 x 10(8) does not exhibit an NIR band for a Ru(III)/Ru(II) mixed-valent situation; it is best described as a 1,4-diazabutadiene radical anion containing ligand gbha*3-, which binds two ruthenium(III) centers. A Ru(III)-type EPR spectrum with g1 = 2.27, g2 = 2.21, and g3 = 1.73 is observed as a result of antiferromagnetic coupling between one Ru(III) and the ligand radical. The EPR-active monocation (K(c) = 1.7 x 10(6)) exhibits a broad (deltanu(1/2) = 2600 cm(-1)) intervalence charge-transfer band at 1800 nm, indicating a valence-averaged (Ru3.5)2 formulation (class III) with a tendency toward class II (borderline situation).
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Affiliation(s)
- Sanjib Kar
- Department of Chemistry, Indian Institute of Technology--Bombay, Powai, Mumbai 400076, India
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Kar S, Sarkar B, Ghumaan S, Janardanan D, van Slageren J, Fiedler J, Puranik VG, Sunoj RB, Kaim W, Lahiri GK. 2,5-Dioxido-1,4-benzoquinonediimine (H2L2−), A Hydrogen-Bonding Noninnocent Bridging Ligand Related to Aminated Topaquinone: Different Oxidation State Distributions in Complexes [{(bpy)2Ru}2(μ-H2L)]n (n=0,+,2+,3+,4+) and [{(acac)2Ru}2(μ-H2L)]m (m=2−,−,0,+,2+). Chemistry 2005; 11:4901-11. [PMID: 15954152 DOI: 10.1002/chem.200500202] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The symmetrically dinuclear title compounds were isolated as diamagnetic [(bpy)2Ru(mu-H2L)Ru(bpy)2](ClO4)2 (1-(ClO4)2) and as paramagnetic [(acac)2Ru(mu-H2L)Ru(acac)2] (2) complexes (bpy=2,2'-bipyridine; acac- = acetylacetonate = 2,4-pentanedionato; H2L = 2,5-dioxido-1,4-benzoquinonediimine). The crystal structure of 22 H2O reveals an intricate hydrogen-bonding network: Two symmetry-related molecules 2 are closely connected through two NH(H2L2-)O(acac-) interactions, while the oxygen atoms of H2L2- of two such pairs are bridged by an (H2O)8 cluster at half-occupancy. The cluster consists of cyclic (H2O)6 arrangements with the remaining two exo-H2O molecules connecting two opposite sides of the cyclo-(H2O)6 cluster, and oxido oxygen atoms forming hydrogen bonds with the molecules of 2. Weak antiferromagnetic coupling of the two ruthenium(III) centers in 2 was established by using SQUID magnetometry and EPR spectroscopy. Geometry optimization by means of DFT calculations was carried out for 1(2+) and 2 in their singlet and triplet ground states, respectively. The nature of low-energy electronic transitions was explored by using time-dependent DFT methods. Five redox states were reversibly accessible for each of the complexes; all odd-electron intermediates exhibit comproportionation constants K(c)>10(8). UV-visible-NIR spectroelectrochemistry and EPR spectroscopy of the electrogenerated paramagnetic intermediates were used to ascertain the oxidation-state distribution. In general, the complexes 1n+ prefer the ruthenium(II) configuration with electron transfer occurring largely at the bridging ligand (mu-H2Ln-), as evident from radical-type EPR spectra for 13+ and (+. Higher metal oxidation states (iii, iv) appear to be favored by the complexes 2m; intense long-wavelength absorption bands and RuIII-type EPR signals suggest mixed-valent dimetal configurations of the paramagnetic intermediates 2+ and 2-.
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Affiliation(s)
- Sanjib Kar
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
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Kar S, Chanda N, Mobin SM, Urbanos FA, Niemeyer M, Puranik VG, Jimenez-Aparicio R, Lahiri GK. Unusual Monodentate Binding Mode of 2,2‘-Dipyridylamine (L) in Isomeric trans-(acac)2RuII(L)2, trans-[(acac)2RuIII(L)2]ClO4, and cis-(acac)2RuII(L)2 (acac = Acetylacetonate). Synthesis, Structures, and Spectroscopic, Electrochemical, and Magnetic Aspects. Inorg Chem 2005; 44:1571-9. [PMID: 15733000 DOI: 10.1021/ic049219v] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of cis-Ru(acac)2(CH3CN)2 (acac = acetylacetonate) with 2,2'-dipyridylamine (L) in ethanolic medium resulted in facile one-pot synthesis of stable [(acac)2RuIII(L)]ClO4 ([1]ClO4), trans-[(acac)2RuII(L)2] (2), trans-[(acac)2RuIII)L)2]ClO4 ([2]ClO4), and cis-[(acac)2RuII(L)2] (3). The bivalent congener 1 was generated via electrochemical reduction of [1]ClO4. Although in [1]+ the dipyridylamine ligand (L) is bonded to the metal ion in usual bidentate fashion, in 2/[2]+ and 3, the unusual monodentate binding mode of L has been preferentially stabilized. Moreover, in 2/[2]+ and 3, two such monodentate L's have been oriented in the trans- and cis-configurations, respectively. The binding mode of L and the isomeric geometries of the complexes were established by their single-crystal X-ray structures. The redox stability of the Ru(II) state follows the order 1 < 2 << 3. In contrast to the magnetic moment obtained for [1]ClO4, mu = 1.84 muB at 298 K, typical for low-spin Ru(III) species, the compound [2]ClO4 exhibited an anomalous magnetic moment of 2.71 muB at 300 K in the solid state. The variable-temperature magnetic measurements showed a pronounced decrease of the magnetic moment with the temperature, and that dropped to 1.59 muB at 3 K. The experimental data can be fitted satisfactorily using eq 2 that considered nonquenched spin-orbit coupling and Weiss constant in addition to the temperature-independent paramagnetism. [1]ClO4 and [2]ClO4 displayed rhombic and axial EPR spectra, respectively, in both the solid and the solution states at 77 K.
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Affiliation(s)
- Sanjib Kar
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai-400076, India
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Ghumaan S, Sarkar B, Patra S, Parimal K, van Slageren J, Fiedler J, Kaim W, Lahiri GK. 3,6-Bis(2′-pyridyl)pyridazine (L) and its deprotonated form (L − H+)−as ligands for {(acac)2Run+} or {(bpy)2Rum+}: investigation of mixed valency in [{(acac)2Ru}2(μ-L − H+)]0and [{(bpy)2Ru}2(μ-L − H+)]4+by spectroelectrochemistry and EPR. Dalton Trans 2005:706-12. [PMID: 15702181 DOI: 10.1039/b417530a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crystallographically characterised 3,6-bis(2'-pyridyl)pyridazine (L) forms complexes with {(acac)2Ru} or {(bpy)2Ru2+}via one pyridyl-N/pyridazyl-N chelate site in mononuclear Ru(II) complexes (acac)2Ru(L), 1, and [(bpy)2Ru(L)](ClO4)2, [3](ClO4)2. Coordination of a second metal complex fragment is accompanied by deprotonation at the pyridazyl-C5 carbon {L --> (L - H+)-} to yield cyclometallated, asymmetrically bridged dinuclear complexes [(acac)2Ru(III)(mu-L - H+)Ru(III)(acac)2](ClO4), [2](ClO4), and [(bpy)2Ru(II)(mu-L - H+)Ru(II)(bpy)2](ClO4)3, [4](ClO4)3. The different electronic characteristics of the co-ligands, sigma donating acac- and pi accepting bpy, cause a wide variation in metal redox potentials which facilitates the isolation of the diruthenium(III) form in [2](ClO4) with antiferromagnetically coupled Ru(III) centres (J = -11.5 cm(-1)) and of a luminescent diruthenium(II) species in [4](ClO4)3. The electrogenerated mixed-valent Ru(II)Ru(III) states 2 and [4]4+ with comproportionation constants Kc > 10(8) are assumed to be localised with the Ru(III) ion bonded via the negatively charged pyridyl-N/pyridazyl-C5 chelate site of the bridging (L - H+)- ligand. In spectroelectrochemical experiments they show similar intervalence charge transfer bands of moderate intensity around 1300 nm and comparable g anisotropies (g1-g3 approximatly 0.5) in the EPR spectra. However, the individual g tensor components are distinctly higher for the pi acceptor ligated system [4]4+, signifying stabilised metal d orbitals.
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Affiliation(s)
- Sandeep Ghumaan
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai, 400076, India
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Tetrazine derived mononuclear RuII(acac)2(L) (1), [RuII(bpy)2(L)](ClO4)2 (2) and [RuII(bpy)(L)2](ClO4)2 (3) (L=3-amino-6-(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine, acac=acetylacetonate, bpy=2,2′-bipyridine): syntheses, structures, spectra and redox properties. Polyhedron 2005. [DOI: 10.1016/j.poly.2004.11.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Shono J, Nimura Y, Hashimoto T, Shimizu K. A Novel Tetra Nuclear Ruthenium Complex Containing Deltoid Core Topology, [Ru4(μ3-O)2]8+, Incorporating Simultaneous O,O- and γ-C Bonded Bridging Acetylacetone Units. CHEM LETT 2004. [DOI: 10.1246/cl.2004.1422] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Patra S, Sarkar B, Ghumaan S, Fiedler J, Kaim W, Lahiri GK. Isovalent and Mixed-Valent Diruthenium Complexes [(acac)2RuII(μ-bpytz)RuII(acac)2] and [(acac)2RuII(μ-bpytz)RuIII(acac)2](ClO4) (acac = Acetylacetonate and bpytz = 3,6-Bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine): Synthesis, Spectroelectrochemical, and EPR Investigation. Inorg Chem 2004; 43:6108-13. [PMID: 15360263 DOI: 10.1021/ic049346r] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The title compounds involving the structurally characterized bridging ligand bpytz were characterized, showing very strong electrochemical stabilization of the mixed-valent RuIIRuIII state (Kc = 10(13.9)) but no detectable (epsilon < 20 M(-1) cm(-1)) intervalence charge-transfer band in the infrared region. In situ reduction of the neutral precursor produces a diruthenium(II) complex of the bpytz radical anion according to EPR spectroscopy, whereas oxidation of the mixed-valent form leads to a diruthenium(III) species.
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Affiliation(s)
- Srikanta Patra
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai-400076, India
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Patra S, Sarkar B, Ghumaan S, Fiedler J, Kaim W, Lahiri GK. The triruthenium complex [{(acac)2RuII}3(L)] containing a conjugated diquinoxaline[2,3-a:2′,3′-c]phenazine (L) bridge and acetylacetonate (acac) as ancillary ligands. Synthesis, spectroelectrochemical and EPR investigation. Dalton Trans 2004:754-8. [PMID: 15252496 DOI: 10.1039/b316007f] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The compound [[(acac)2Ru]3(L)] (1) undergoes three well-separated one-electron oxidation and reduction processes. The EPR results indicate electron removal from the ruthenium(II) centres on oxidation and the occupation of a largely L-based molecular orbital on reduction. In spite of well-separated (DeltaE > or = 340 mV) oxidation no obvious intervalence charge transfer bands were detected in the Vis, NIR or IR regions, suggesting very weak electronic coupling between the metal centres in the mixed-valent intermediates 1+ and 1(2+). The separated (DeltaE > or = 540 mV) stepwise reduction produces weak near-infrared features associated with partially occupied pi* orbitals of L, the unusually high g anisotropy in the EPR spectrum of 1- is attributed to the occupation of a degenerate MO by the unpaired electron.
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Affiliation(s)
- Srikanta Patra
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai
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39
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Kar S, Pradhan B, Sinha RK, Kundu T, Kodgire P, Rao KK, Puranik VG, Lahiri GK. Synthesis, structure, redox, NLO and DNA interaction aspects of [{(L′–‴)2RuII}3(μ3-L)]3+and [(L′)2RuII(NC5H4S−)]+[L3−= 1,3,5-triazine-2,4,6-trithiolato, L′–‴ = arylazopyridine]. Dalton Trans 2004:1752-60. [PMID: 15252573 DOI: 10.1039/b403332a] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The trinuclear complexes [(L'-'")2RuII)3(mu3-L)](ClO4)3, [1] (ClO4)3-[3](ClO4)3 (L = trianionic form of 1,3,5-triazine-2,4,6-trithiol; N(p)C(5)H(4)N=N(a)-C6H4(R), R = H (L'), m-Me (L"), p-Me (L'")) and the analogous mononuclear complex [(L')2RuII(NC5H4S-)]ClO4 [4] ClO4 were synthesized. Crystal structures of [1](ClO4)3 and [4]ClO4 were determined. [1](3+)-[3](3+) exhibit three successive oxidative couples corresponding to Ru(II)Ru(II)Ru(III)<==>Ru(II)Ru(II)Ru(II); Ru(II)Ru(III)Ru(III)<==>Ru(II)Ru(II)Ru(III); Ru(III)Ru(III)Ru(III)<==>Ru(II)Ru(III)Ru(III) where the mixed valent states are moderately coupled. The complexes display multiple reductions associated with the azo functions of the ancillary ligands (L'-'"). The energy of the Ru(II)-based lowest energy MLCT transitions (533-558 nm) involving the pi* level of azoimine chromophore of L'-'" varies depending on the nuclearity as well as substituents in the ligand framework and follows the order: [1](3+) > [2](3+) > [3](3+) > [4](+). The complexes exhibit reasonably high third-order non-linear optical properties with gamma= (0.90-2.45) [times] 10(-29) esu. The interactions of the trinuclear complexes [((L')2RuII)3(mu3-L)]3+[1]3+, [((bpy)2RuII)3((mu3-L)]3+[5]3+ and [((phen)2RuII)3((mu3)-L)]3+[6]3+(bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline) with the circular and linear forms of p-Bluescript DNA show reduced ethidium bromide fluorescence on gel electrophoresis.
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Affiliation(s)
- Sanjib Kar
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India
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Patra S, Miller TA, Sarkar B, Niemeyer M, Ward MD, Lahiri GK. An unusual dinuclear ruthenium(III) complex with a conjugated bridging ligand derived from cleavage of a 1,4-dihydro-1,2,4,5-tetrazine ring. Synthesis, structure, and UV-vis-NIR spectroelectrochemical characterization of a five-membered redox chain incorporating two mixed-valence states. Inorg Chem 2003; 42:4707-13. [PMID: 12870962 DOI: 10.1021/ic034131n] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of [Ru(acac)(2)(CH(3)CN)(2)] with 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,4-dihydro-1,2,4,5-tetrazine (H(2)L) results in formation of an unexpected dinuclear complex [(acac)(2)Ru(III)(L(1))Ru(III)(acac)(2)] (1) in which the bridging ligand [L(1)](2)(-) contains an (-)HN[bond]C[double bond]N[bond]N[double bond]C[bond]NH(-) unit arising from two-electron reduction of the 1,4-dihydro-1,2,4,5-tetrazine component of H(2)L. The crystal structure of complex 1 confirms the oxidation assignment of the metal ions as Ru(III) and clearly shows the consequent arrangement of double and single bonds in the bridging ligand, which acts as a bis-bidentate chelate having two pyrazolyl/amido chelating sites. Cyclic voltammetry of the complex shows the presence of four reversible one-electron redox couples, assigned as two Ru(III)/Ru(IV) couples (oxidations with respect to the starting material) and two Ru(II)/Ru(III) couples (reductions with respect to the starting material). The separation between the two Ru(III)/Ru(IV) couples (Delta E(1/2) = 700 mV) is much larger than that between the two Ru(II)/Ru(III) couples (Delta E(1/2) = 350 mV) across the same bridging pathway, because of the better ability of the dianionic bridging ligand to delocalize an added hole (in the oxidized mixed-valence state) than an added electron (in the reduced mixed-valence state), implying some ligand-centered character for the oxidations. UV-vis-NIR spectroelectrochemical measurements were performed in all five oxidation states; the Ru(II)-Ru(III) mixed-valence state of [1](-) has a strong IVCT transition at 2360 nm whose parameters give an electronic coupling constant of V(ab) approximately 1100 cm(-1), characteristic of a strongly interacting but localized (class II) mixed-valence state. In the Ru(III)-Ru(IV) mixed-valence state [1](+), no low-energy IVCT could be detected despite the strong electronic interaction, possibly because it is in the visible region and obscured by LMCT bands.
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Affiliation(s)
- Srikanta Patra
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai-400076, India
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