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Goswami B, Khatua M, Devi A, Hans S, Chatterjee R, Samanta S. Ligand redox controlled amine dehydrogenation and imine hemilability in singlet diradical azo-aromatic Ni(II) complexes: characterization of the electron transfer series of azo-imine complexes of Ni(II). Dalton Trans 2024; 53:10250-10260. [PMID: 38829194 DOI: 10.1039/d3dt03414c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Herein, using azo-amine (H2L) and azo-imine (L1-3) ligands, singlet diradical Ni(II) complexes [1] and [2] were synthesized from Ni(0)(COD)2 in THF. In separate reactions, homoleptic NiII complexes, [3a]2+-[3c]2+, were synthesized from [NiII(H2O)6](ClO4)2 and L1-3, respectively. All these complexes were characterized thoroughly. The X-ray structures of [1] and [2] showed that the amine side arm in [1] and the imine side arm in [2] are de-coordinated. The dN-N lengths in these two complexes were found to be ∼1.32 Å, which corresponds to the one-electron reduced azo-bond length. These complexes, [1] and [2], showed 1H NMR signals characteristic of diamagnetic compounds. These studies, along with DFT calculations, indicated that the unpaired spins on ligands coupled antiferromagnetically with the two unpaired spins on NiII to result in s = 0 ground states. Complex [1] showed ligand-based redox-induced dehydrogenation of the distal amine side arm to result in L1. Complexes [3a]2+-[3c]2+ have dN-N lengths of ∼1.27 Å and dC-N lengths of ∼1.28 Å. In cyclic voltammetry, complex [3a]2+ showed four well-resolved reversible reductive waves at 0.5 V to -1.6 V in dichloromethane. The first two waves became irreversible when they were measured in acetonitrile solution. The electron transfer series of [3a]2+ was further characterized by spectro-electrochemistry, EPR, and DFT calculations. These showed that all the reductions were associated with the ligand. It was further probed by redox events in complexes [3b]2+ and [3c]2+. While the electron donor -OMe group on the phenyl ring of the azo moiety in [3b]2+ showed a prominent cathodic shift of the potentials, the -F substitution on the phenyl group on the imine side arm of [3c]2+ has almost no effect. It has to be noted here that the oxidation of [2] by two electrons returns it back to complex [3a]2+. Reduction of [3a]2+ by two electrons also resulted in complex [2], indicating reversible ligand redox-induced hemilability of the imine moiety between [3a]2+ and [2]. Moreover, characterization of the electron transfer series of [3a]2+ and [2] has shown superior redox non-innocent behaviour and coordination ability of the azo-pyridine moiety in nickel(II) complexes over the imino-pyridine moiety of the ligand.
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Affiliation(s)
- Bappaditya Goswami
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Manas Khatua
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Ambika Devi
- Department of Chemistry, Indian Institute of Technology Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India.
| | - Shivali Hans
- Department of Chemistry, Indian Institute of Technology Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India.
| | - Robindo Chatterjee
- Department of Chemistry, Indian Institute of Technology Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India.
| | - Subhas Samanta
- Department of Chemistry, Indian Institute of Technology Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India.
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Kamal, Samanta S. Noninnocent Azo-Aromatic Cobalt(II)-Catalyzed sp 3 C-H Alkylation of Fluorenes with Alcohols. J Org Chem 2024; 89:1910-1926. [PMID: 38205792 DOI: 10.1021/acs.joc.3c02657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Herein, employing well-defined redox noninnocent cobalt(II) complexes an efficient sp3 C-H alkylation of fluorenes using alcohols as alkylating agents to result in alkylated fluorenes is reported. The catalytic protocol was versatile with various fluorenes and benzyl alcohols. It also showed very good functional group tolerance with both alcohols and fluorenes. Moreover, an efficient single-step and simultaneous di C-C as well as both C-C and the C-N alkylation reaction of fluorenes was observed with this catalytic protocol. Such selective single-step dialkylation of fluorenes is indeed beneficial. Several control experiments, deuterium labeling, and 1H NMR kinetic studies have revealed a ligand radical-based borrowing hydrogen mechanism involving the azo-aromatic complexes of cobalt as catalysts for the alkylation of fluorenes.
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Affiliation(s)
- Kamal
- Department of Chemistry, Indian Institute of Technology (IIT) Jammu, Jagti, Jammu, Jammu & Kashmir 181221, India
| | - Subhas Samanta
- Department of Chemistry, Indian Institute of Technology (IIT) Jammu, Jagti, Jammu, Jammu & Kashmir 181221, India
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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.
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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.
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Khatua M, Goswami B, Hans S, Kamal, Mazumder S, Samanta S. Hemilabile Amine-Functionalized Efficient Azo-Aromatic Cu-Catalysts Inspired by Galactose Oxidase: Impact of Amine Sidearm on Catalytic Aerobic Oxidation of Alcohols. Inorg Chem 2022; 61:17777-17789. [DOI: 10.1021/acs.inorgchem.2c03087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manas Khatua
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur, Kolkata 741246, India
| | - Bappaditya Goswami
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur, Kolkata 741246, India
| | - Shivali Hans
- Department of Chemistry, Indian Institute of Technology Jammu Jagti, Jammu 181221, India
| | - Kamal
- Department of Chemistry, Indian Institute of Technology Jammu Jagti, Jammu 181221, India
| | - Shivnath Mazumder
- Department of Chemistry, Indian Institute of Technology Jammu Jagti, Jammu 181221, India
| | - Subhas Samanta
- Department of Chemistry, Indian Institute of Technology Jammu Jagti, Jammu 181221, India
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Zorina-Tikhonova EN, Matyukhina AK, Chistyakov AS, Vologzhanina AV, Korlyukov AA, Gogoleva NV, Novikova VA, Belova EV, Ugolkova EA, Starikova AA, Korchagin DV, Babeshkin KA, Efimov NN, Kiskin MA, Eremenko IL. Synthesis, structure, magnetic properties and thermal behaviour of Ba–M II (M II = Mn, Co, Cu, and Zn) allylmalonates. NEW J CHEM 2022. [DOI: 10.1039/d2nj03751c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A series of Ba-MII complexes with allylmalonic acid anions [BaMII(Amal)2(H2O)3]n (MII = Mn, Co, Cu, and Zn) were synthesized. The magnetic measurements revealed slow magnetic relaxation in non-zero field (HDC = 1500 Oe) for CoII ions.
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Affiliation(s)
- Ekaterina N. Zorina-Tikhonova
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Anna K. Matyukhina
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Aleksandr S. Chistyakov
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Anna V. Vologzhanina
- A.N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, Vavilova str. 28, 119334 Moscow, Russian Federation
| | - Alexander A. Korlyukov
- A.N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, Vavilova str. 28, 119334 Moscow, Russian Federation
| | - Natalia V. Gogoleva
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Veronika A. Novikova
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
- Chemistry Department, Lomonosov Moscow State University, Leninsky gory, 1-3, 1119991 Moscow, Russian Federation
| | - Ekaterina V. Belova
- Chemistry Department, Lomonosov Moscow State University, Leninsky gory, 1-3, 1119991 Moscow, Russian Federation
| | - Elena A. Ugolkova
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Alyona A. Starikova
- Institute of Physical and Organic Chemistry, Southern Federal University, prosp. Stachki 194/2, Rostov-on-Don 344090, Russian Federation
| | - Denis V. Korchagin
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Ac. Semenov prosp. 1, Chernogolovka, Moscow region 142432, Russian Federation
| | - Konstantin A. Babeshkin
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Nikolay N. Efimov
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Mikhail A. Kiskin
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
| | - Igor L. Eremenko
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russian Federation
- A.N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, Vavilova str. 28, 119334 Moscow, Russian Federation
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