1
|
Swatiputra AA, Mukherjee D, Dinda S, Roy S, Pramanik K, Ganguly S. Electron transfer catalysis mediated by 3d complexes of redox non-innocent ligands possessing an azo function: a perspective. Dalton Trans 2023; 52:15627-15646. [PMID: 37792473 DOI: 10.1039/d3dt02567e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
It was first reported almost two decades ago that ligands with azo functions are capable of accepting electron(s) upon coordination to produce azo-anion radical complexes, thereby exhibiting redox non-innocence. Over the past two decades, there have been numerous reports of such complexes along with their structures and diverse characteristics. The ability of a coordinated azo function to accept one or more electron(s), thereby acting as an electron reservoir, is currently employed to carry out electron transfer catalysis since they can undergo redox transformation at mild potentials due to the presence of energetically accessible energy levels. The cooperative involvement of redox non-innocent ligand(s) containing an azo group and the coordinated metal centre can adjust and modulate the Lewis acidity of the latter through selective ligand-centred redox events, thereby manipulating the capacity of the metal centre to bind to the substrate. We have summarized the list of first row transition metal complexes of iron, cobalt, nickel, copper and zinc with redox non-innocent ligands incorporating an azo function that have been exploited as electron transfer catalysts to effectuate sustainable synthesis of a wide variety of useful chemicals. These include ketazines, pyrimidines, benzothiazole, benzoxazoles, N-acyl hydrazones, quinazoline-4(3)H-ones, C-3 alkylated indoles, N-alkylated anilines and N-alkylated heteroamines. The reaction pathways, as demonstrated by catalytic loops, reveal that the azo function of a coordinated ligand can act as an electron sink in the initial steps to bring about alcohol oxidation and thereafter, they serve as an electron pool to produce the final products either via HAT or PCET processes.
Collapse
Affiliation(s)
- Alok Apan Swatiputra
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | - Debaarjun Mukherjee
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | - Soumitra Dinda
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | - Subhadip Roy
- Department of Chemistry, The ICFAI University Tripura, Tripura 799210, India
| | - Kausikisankar Pramanik
- Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata - 700032, India
| | - Sanjib Ganguly
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| |
Collapse
|
2
|
Tripathy SK, van der Meer M, Sahoo A, Laha P, Dehury N, Plebst S, Sarkar B, Samanta K, Patra S. A dinuclear [{(p-cym)Ru(II)Cl}2(μ-bpytz˙(-))](+) complex bridged by a radical anion: synthesis, spectroelectrochemical, EPR and theoretical investigation (bpytz = 3,6-bis(3,5-dimethylpyrazolyl)1,2,4,5-tetrazine; p-cym = p-cymene). Dalton Trans 2018; 45:12532-8. [PMID: 27435992 DOI: 10.1039/c6dt01995a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The reaction of the chloro-bridged dimeric precursor [{(p-cym)Ru(II)Cl}(μ-Cl)]2 (p-cym = p-cymene) with the bridging ligand 3,6-bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine (bpytz) in ethanol results in the formation of the dinuclear complex [{(p-cym)Ru(II)Cl}2(μ-bpytz˙(-))](+), [1](+). The bridging tetrazine ligand is reduced to the anion radical (bpytz˙(-)) which connects the two Ru(II) centres. Compound [1](PF6) has been characterised by an array of spectroscopic and electrochemical techniques. The radical anion character has been confirmed by magnetic moment (corresponding to one electron paramagnetism) measurement, EPR spectroscopic investigation (tetrazine radical anion based EPR spectrum) as well as density functional theory based calculations. Complex [1](+) displays two successive one electron oxidation processes at 0.66 and 1.56 V versus Ag/AgCl which can be attributed to [{(p-cym)Ru(II)C}2(μ-bpytz˙(-))](+)/[{(p-cym)Ru(II)Cl}2(μ-bpytz)](2+) and [{(p-cym)Ru(II)Cl}2(μ-bpytz)](+)/[{(p-cym)Ru(III)Cl}2(μ-bpytz)](2+) processes (couples I and II), respectively. The reduction processes (couple III-couple V), which are irreversible, likely involve the successive reduction of the bridging ligand and the metal centres together with loss of the coordinated chloride ligands. UV-Vis-NIR spectroelectrochemical investigation reveals typical tetrazine radical anion containing bands for [1](+) and a strong absorption in the visible region for the oxidized form [1](2+), which can be assigned to a Ru(II) → π* (tetrazine) MLCT transition. The assignment of spectroscopic bands was confirmed by theoretical calculations.
Collapse
Affiliation(s)
- Suman Kumar Tripathy
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar - 751007, India.
| | - Margarethe van der Meer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34-36, D-14195 Berlin, Germany.
| | - Anupam Sahoo
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar - 751007, India.
| | - Paltan Laha
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar - 751007, India.
| | - Niranjan Dehury
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar - 751007, India.
| | - Sebastian Plebst
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34-36, D-14195 Berlin, Germany.
| | - Kousik Samanta
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar - 751007, India.
| | - Srikanta Patra
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar - 751007, India.
| |
Collapse
|
3
|
Gong T, Yang X, Fang JJ, Sui Q, Xi FG, Gao EQ. Distinct Chromic and Magnetic Properties of Metal-Organic Frameworks with a Redox Ligand. ACS APPLIED MATERIALS & INTERFACES 2017; 9:5503-5512. [PMID: 28084723 DOI: 10.1021/acsami.6b15540] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An electron-deficient and potentially chromic ligand has been utilized to impart redox activity, photo- and hydrochromism, and solvotomagnetism to metal-organic frameworks (MOFs). A pair of MOFs were constructed from the flexible zwitterionic viologen-tethered tetracarboxylate linker N,N'-bis(3,5-dicarboxylatobenzyl)-4,4'-bipyridinium (L2-): [Co3(L)(N3)4] (1) and [Mn2(L)(N3)2(H2O)2]·3H2O (2). Both compounds show three-dimensional frameworks in which mixed azido- and carboxylato-bridged chains are connected through the electron-deficient viologen moieties. The chain in 1 is built from alternating bis(azide) and (azide)bis(carboxylate) bridges, while that in 2 contains uniform (azide) (carboxylate) bridges. The MOFs shows the characteristic redox properties of the viologen moieties. The redox activity affords the MOFs with different chromic properties, owing to subtle differences in chemical environments. 1 shows reversible photochromism, which is related to the radical formation through photoinduced electron transfer from azide-carboxylate to viologen according to UV-vis, X-ray photoelectron, and electron spin resonance spectroscopy and DFT calculations. 2 is nonphotochromic for lack of appropriate pathways for electron transfer. Unexpectedly, 2 shows a novel type of solid-state hydrochromism. Upon the removal and reabsorption of water, the compound shows remarkable color change because of reversible electron transfer accompanying a reversible structural transformation. The radical mechanism is distinct from those for traditional hydrochromic inorganic and organic materials. Magnetic studies indicate ferro- and antiferromagnetic coupling in 1 and 2, respectively. What's more, 2 shows marked magnetic response to the removal of water molecules owing to the formation of radicals. The compound illustrates a unique material exhibiting dual responses (color and magnetism) to water.
Collapse
Affiliation(s)
- Teng Gong
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200062, China
| | - Xiao Yang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200062, China
| | - Jia-Jia Fang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200062, China
| | - Qi Sui
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200062, China
| | - Fu-Gui Xi
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200062, China
| | - En-Qing Gao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200062, China
| |
Collapse
|
4
|
Heterotetranuclear Complexes of Reduced and Non-reduced Bridging 1,2,4,5-Tetrazine Ligands with 1,1′-Bis(diphenylphosphanyl)-ferrocene-copper(I). Z Anorg Allg Chem 2015. [DOI: 10.1002/zaac.201400564] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
5
|
Jana R, Mobin SM, Schwederski B, Fiedler J, Kaim W. Variable coordination of redox-active TCNB in discrete and polymeric ferrocenylcopper(I) complexes: structures and spectroelectrochemical behaviour. Dalton Trans 2013; 42:16142-50. [PMID: 24022668 DOI: 10.1039/c3dt51360b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,2,4,5-Tetracyanobenzene (TCNB) was reacted with [Cu(dppf)(CH3CN)2](BF4) and [Cu(dchpf)(CH3CN)](BF4), dppf = 1,1'-bis(diphenylphosphino)ferrocene and dchpf = 1,1'-bis(dicyclohexylphosphino)ferrocene, to produce a heterotetranuclear metallamacrocycle 1, {[Cu(dppf)(μ-TCNB)](BF4)}2, and a heterooctanuclear complex 2, [{Cu(dchpf)}4(μ4-TCNB)](BF4)4. Complex 1 is the first example of a structurally characterised discrete transition metal complex of TCNB. Upon crystallisation attempts, compound 2 formed the structurally identified coordination polymer 3, {[Cu(dchpf)(μ-TCNB)]2(BF4)2}n. Structural and spectroscopic analyses confirmed the redox-innocent behaviour of TCNB in 1, 2 and 3. However, the soluble compounds 1 and 2 could be oxidised and reduced spectroelectrochemically (UV-vis, IR, and EPR). The oxidation occurs invariably at the ferrocene sites without notable splitting of redox potentials. Reduction involves the TCNB bridging ligands to produce radical complexes. As a variably bridging acceptor component of supramolecular structures the TCNB ligand thus adopts an intermediate position between the highly electron transfer-active TCNE, TCNQ and TCNQF4 systems and the numerous redox-innocent bridges.
Collapse
Affiliation(s)
- Rajkumar Jana
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring55, D-70550 Stuttgart, Germany.
| | | | | | | | | |
Collapse
|
6
|
Mondal P, Ehret F, Bubrin M, Das A, Mobin SM, Kaim W, Lahiri GK. A Diruthenium Complex of a “Nindigo” Ligand. Inorg Chem 2013; 52:8467-75. [DOI: 10.1021/ic400390b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Prasenjit Mondal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai
400076, India
| | - Fabian Ehret
- Institut
für Anorganische
Chemie, Universität Stuttgart, Pfaffenwaldring
55, D-70550 Stuttgart, Germany
| | - Martina Bubrin
- Institut
für Anorganische
Chemie, Universität Stuttgart, Pfaffenwaldring
55, D-70550 Stuttgart, Germany
| | - Amit Das
- 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
| | - Wolfgang Kaim
- Institut
für Anorganische
Chemie, Universität Stuttgart, Pfaffenwaldring
55, D-70550 Stuttgart, Germany
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai
400076, India
| |
Collapse
|
7
|
Zhao Y, Li Y, Qin Z, Jiang R, Liu H, Li Y. Selective and colorimetric fluoride anion chemosensor based on s-tetrazines. Dalton Trans 2012; 41:13338-42. [DOI: 10.1039/c2dt31641b] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
8
|
Roy S, Sarkar B, Duboc C, Fiedler J, Sarper O, Lissner F, Mobin S, Lahiri G, Kaim W. Heterohexanuclear (Cu3Fe3) Complexes of Substituted Hexaazatrinaphthylene (HATN) Ligands: Twofold BF4−Association in the Solid and Stepwise Oxidation (3e) or Reduction (2e) to Spectroelectrochemically Characterized Species. Chemistry 2009; 15:6932-9. [DOI: 10.1002/chem.200802655] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
9
|
Das A, Sarkar B, Duboc C, Strobel S, Fiedler J, Záliš S, Lahiri G, Kaim W. Das ungeradzahlig elektronenkonfigurierte Komplexion [Ruk(NOm)(Qn)(terpy)]2+mit zwei idealtypischen “nicht-unschuldigen” Liganden. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900767] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
10
|
Das A, Sarkar B, Duboc C, Strobel S, Fiedler J, Záliš S, Lahiri G, Kaim W. An Odd-Electron Complex [Ruk(NOm)(Qn)(terpy)]2+with Two Prototypical Non-Innocent Ligands. Angew Chem Int Ed Engl 2009; 48:4242-5. [DOI: 10.1002/anie.200900767] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|