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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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Odigbo C, Adenipekun C, Oladosu I, Ogunjobi A. Polyethylene terephthalate (PET) biodegradation by Pleurotus ostreatus and Pleurotus pulmonarius. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:585. [PMID: 37072643 DOI: 10.1007/s10661-023-11153-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 03/20/2023] [Indexed: 05/03/2023]
Abstract
The essential properties of polyethylene terephthalate (PET), such as chemical inertness and durability that make it a suitable material for the packaging of mineral and soft drinks, have led to it becoming a major environmental pollutant and a threat to the planet. Ecologically friendly solutions such as bioremediation are now being advocated for by scientists. This paper, therefore, seeks to explore the potential capacity of Pleurotus ostreatus and Pleurotus pulmonarius in biodegrading PET plastic on two different substrates (soil and rice straw). The substrates were combined with 5% and 10% plastic before inoculation with Pleurotus ostreatus and Pleurotus pulmonarius and then left to incubate for 2 months. Biodegradation, monitored by FT-IR pointed to the formation of new peaks in the incubated plastics after 30 and 60 days unlike in the control. Changes in band intensity and shifts in the wavenumbers caused by stretching of functional groups, C-H, O-H and N-H in the band region of 2898 cm-1 to 3756 cm-1 are confirmed indicators of successful breakdown caused by contact with P. ostreatus and P. pulmonarius. The FT-IR analysis also gave an indication of N-H stretching at 3338.04 cm-1 and 3228.62 cm-1 for PET flakes incubated with Pleurotus sp. Furthermore, degradation products like hydrocarbons, carboxylic acids, alcohols, esters, and ketones were also detected in the GC-MS analysis of the decomposed PET plastic after 30 and 60 days. These compounds are formed due to chain scission caused by the fungal species. There was a discoloration of the PET flakes caused by an increase in carboxyl-terminated species as a result of enzymes secreted by the fungi in the process of biodegradation.
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Affiliation(s)
- Chioma Odigbo
- Plant Physiology and Biochemistry Section, Botany Department, University of Ibadan, Ibadan, Nigeria.
| | - Clementina Adenipekun
- Plant Physiology and Biochemistry Section, Botany Department, University of Ibadan, Ibadan, Nigeria.
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Epping RF, Vesseur D, Zhou M, de Bruin B. Carbene Radicals in Transition-Metal-Catalyzed Reactions. ACS Catal 2023; 13:5428-5448. [PMID: 37123600 PMCID: PMC10127290 DOI: 10.1021/acscatal.3c00591] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/21/2023] [Indexed: 04/08/2023]
Abstract
Discovered as organometallic curiosities in the 1970s, carbene radicals have become a staple in modern-day homogeneous catalysis. Carbene radicals exhibit nucleophilic radical-type reactivity orthogonal to classical electrophilic diamagnetic Fischer carbenes. Their successful catalytic application has led to the synthesis of a myriad of carbo- and heterocycles, ranging from simple cyclopropanes to more challenging eight-membered rings. The field has matured to employ densely functionalized chiral porphyrin-based platforms that exhibit high enantio-, regio-, and stereoselectivity. Thus far the focus has largely been on cobalt-based systems, but interest has been growing for the past few years to expand the application of carbene radicals to other transition metals. This Perspective covers the advances made since 2011 and gives an overview on the coordination chemistry, reactivity, and catalytic application of carbene radical species using transition metal complexes and catalysts.
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Affiliation(s)
- Roel F.J. Epping
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - David Vesseur
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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4
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Ramle AQ, Tiekink ER, Basirun WJ. Synthesis, functionalization and coordination chemistry of dibenzotetraaza[14]annulenes. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Roose TR, Verdoorn DS, Mampuys P, Ruijter E, Maes BUW, Orru RVA. Transition metal-catalysed carbene- and nitrene transfer to carbon monoxide and isocyanides. Chem Soc Rev 2022; 51:5842-5877. [PMID: 35748338 PMCID: PMC9580617 DOI: 10.1039/d1cs00305d] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Indexed: 11/21/2022]
Abstract
Transition metal-catalysed carbene- and nitrene transfer to the C1-building blocks carbon monoxide and isocyanides provides heteroallenes (i.e. ketenes, isocyanates, ketenimines and carbodiimides). These are versatile and reactive compounds allowing in situ transformation towards numerous functional groups and organic compounds, including heterocycles. Both one-pot and tandem processes have been developed providing valuable synthetic methods for the organic chemistry toolbox. This review discusses all known transition metal-catalysed carbene- and nitrene transfer reactions towards carbon monoxide and isocyanides and in situ transformation of the heteroallenes hereby obtained, with a special focus on the general mechanistic considerations.
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Affiliation(s)
- T R Roose
- Department of Chemistry and Pharmaceutical Sciences and Amsterdam Institute for Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
| | - D S Verdoorn
- Organic Chemistry, Aachen-Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Urmonderbaan 22, 6167RD Geleen, The Netherlands.
- Organic Synthesis Division, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | - P Mampuys
- Organic Synthesis Division, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | - E Ruijter
- Department of Chemistry and Pharmaceutical Sciences and Amsterdam Institute for Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
| | - B U W Maes
- Organic Synthesis Division, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | - R V A Orru
- Organic Chemistry, Aachen-Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Urmonderbaan 22, 6167RD Geleen, The Netherlands.
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Reek JNH, de Bruin B, Pullen S, Mooibroek TJ, Kluwer AM, Caumes X. Transition Metal Catalysis Controlled by Hydrogen Bonding in the Second Coordination Sphere. Chem Rev 2022; 122:12308-12369. [PMID: 35593647 PMCID: PMC9335700 DOI: 10.1021/acs.chemrev.1c00862] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Transition metal catalysis is of utmost importance for the development of sustainable processes in academia and industry. The activity and selectivity of metal complexes are typically the result of the interplay between ligand and metal properties. As the ligand can be chemically altered, a large research focus has been on ligand development. More recently, it has been recognized that further control over activity and selectivity can be achieved by using the "second coordination sphere", which can be seen as the region beyond the direct coordination sphere of the metal center. Hydrogen bonds appear to be very useful interactions in this context as they typically have sufficient strength and directionality to exert control of the second coordination sphere, yet hydrogen bonds are typically very dynamic, allowing fast turnover. In this review we have highlighted several key features of hydrogen bonding interactions and have summarized the use of hydrogen bonding to program the second coordination sphere. Such control can be achieved by bridging two ligands that are coordinated to a metal center to effectively lead to supramolecular bidentate ligands. In addition, hydrogen bonding can be used to preorganize a substrate that is coordinated to the metal center. Both strategies lead to catalysts with superior properties in a variety of metal catalyzed transformations, including (asymmetric) hydrogenation, hydroformylation, C-H activation, oxidation, radical-type transformations, and photochemical reactions.
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Affiliation(s)
- Joost N H Reek
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.,InCatT B.V., Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Sonja Pullen
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Tiddo J Mooibroek
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | | | - Xavier Caumes
- InCatT B.V., Science Park 904, 1098 XH Amsterdam, The Netherlands
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Guin AK, Mondal R, Chakraborty G, Pal S, Paul ND. Ruthenium-Catalyzed Dehydrogenative Functionalization of Alcohols to Pyrroles: A Comparison between Metal-Ligand Cooperative and Non-cooperative Approaches. J Org Chem 2022; 87:7106-7123. [PMID: 35583483 DOI: 10.1021/acs.joc.2c00311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Herein, we report the synthesis and characterization of two ruthenium-based pincer-type catalysts, [1]X (X = Cl, PF6) and 2, containing two different tridentate pincer ligands, 2-pyrazolyl-(1,10-phenanthroline) (L1) and 2-arylazo-(1,10-phenanthroline) (L2a/2b, L2a = 2-(phenyldiazenyl)-1,10-phenanthroline; L2b = 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline), and their application in the synthesis of substituted pyrroles via dehydrogenative alcohol functionalization reactions. In catalyst [1]X (X = Cl, PF6), the tridentate scaffold 2-pyrazolyl-(1,10-phenanthroline) (L1) is apparently redox innocent, and all the redox events occur at the metal center, and the coordinated ligands remain as spectators. In contrast, in catalysts 2a and 2b, the coordinated azo-aromatic scaffolds are highly redox-active and known to participate actively during the dehydrogenation of alcohols. A comparison between the catalytic activities of these two catalysts was made, starting from the simple dehydrogenation of alcohols to further dehydrogenative functionalization of alcohols to various substituted pyrroles to understand the advantages/disadvantages of the metal-ligand cooperative approach. Various substituted pyrroles were prepared via dehydrogenative coupling of secondary alcohols and amino alcohols, and the N-substituted pyrroles were synthesized via dehydrogenative coupling of aromatic amines with cis-2-butene-1,4-diol and 2-butyne-1,4-diol, respectively. Several control reactions and spectroscopic experiments were performed to characterize the catalysts and establish the reaction mechanism.
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Affiliation(s)
- Amit Kumar Guin
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Rakesh Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Gargi Chakraborty
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Subhasree Pal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Nanda D Paul
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
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8
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Das S, Mondal R, Guin AK, Paul ND. Ligand centered redox enabled sustainable synthesis of triazines and pyrimidines using a zinc-stabilized azo-anion radical catalyst. Org Biomol Chem 2022; 20:3105-3117. [PMID: 35088804 DOI: 10.1039/d1ob02428k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Herein, we report ligand-centered redox controlled Zn(II)-catalyzed multicomponent approaches for synthesizing pyrimidines and triazines. Taking advantage of the ligand-centered redox events and using a well-defined Zn(II)-catalyst (1a) bearing (E)-2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline (L1a) as the redox-active ligand, a wide variety of substituted pyrimidines and triazines were prepared via dehydrogenative alcohol functionalization reactions. Pyrimidines were prepared via two pathways: (i) dehydrogenative coupling of primary and secondary alcohols with amidines and (ii) dehydrogenative coupling of primary alcohols with alkynes and amidines. Triazines were prepared via dehydrogenative coupling of alcohols and amidines. Catalyst 1a is well tolerant to a wide range of substrates yielding the desired pyrimidines and triazines in moderate to good isolated yields. A series of control reactions were performed to predict the plausible mechanism, suggesting that the active participation of the ligand-centered redox events enables the Zn(II)-complex 1a to act as an efficient catalyst for synthesizing these N-heterocycles. Electron transfer processes occur at the azo-aromatic ligand throughout the catalytic reaction, and the Zn(II)-center serves only as a template.
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Affiliation(s)
- Siuli Das
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India.
| | - Rakesh Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India.
| | - Amit Kumar Guin
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India.
| | - Nanda D Paul
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India.
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9
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Mondal R, Guin AK, Chakraborty S, Paul ND. Iron-Catalyzed Metal–Ligand Cooperative Approach toward Sustainable Synthesis of Azines and N-Acylhydrazones in Air. J Org Chem 2022; 87:2921-2934. [DOI: 10.1021/acs.joc.1c02787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rakesh Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Amit Kumar Guin
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Subhajit Chakraborty
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Nanda D. Paul
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
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10
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Mondal R, Guin AK, Chakraborty G, Paul ND. Metal-ligand cooperative approaches in homogeneous catalysis using transition metal complex catalysts of redox noninnocent ligands. Org Biomol Chem 2022; 20:296-328. [PMID: 34904619 DOI: 10.1039/d1ob01153g] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Catalysis offers a straightforward route to prepare various value-added molecules starting from readily available raw materials. The catalytic reactions mostly involve multi-electron transformations. Hence, compared to the inexpensive and readily available 3d-metals, the 4d and 5d-transition metals get an extra advantage for performing multi-electron catalytic reactions as the heavier transition metals prefer two-electron redox events. However, for sustainable development, these expensive and scarce heavy metal-based catalysts need to be replaced by inexpensive, environmentally benign, and economically affordable 3d-metal catalysts. In this regard, a metal-ligand cooperative approach involving transition metal complexes of redox noninnocent ligands offers an attractive alternative. The synergistic participation of redox-active ligands during electron transfer events allows multi-electron transformations using 3d-metal catalysts and allows interesting chemical transformations using 4d and 5d-metals as well. Herein we summarize an up-to-date literature report on the metal-ligand cooperative approaches using transition metal complexes of redox noninnocent ligands as catalysts for a few selected types of catalytic reactions.
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Affiliation(s)
- Rakesh Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
| | - Amit Kumar Guin
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
| | - Gargi Chakraborty
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
| | - Nanda D Paul
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
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Zhou M, Wolzak LA, Li Z, de Zwart FJ, Mathew S, de Bruin B. Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers. J Am Chem Soc 2021; 143:20501-20512. [PMID: 34802239 PMCID: PMC8662738 DOI: 10.1021/jacs.1c10927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 12/30/2022]
Abstract
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
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Affiliation(s)
- Minghui Zhou
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lukas A. Wolzak
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Zirui Li
- Department
of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333
CC Leiden, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Simon Mathew
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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12
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Bailey GA, Buss JA, Oyala PH, Agapie T. Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence. J Am Chem Soc 2021; 143:13091-13102. [PMID: 34379389 DOI: 10.1021/jacs.1c03806] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Open-shell compounds bearing metal-carbon triple bonds, such as carbides and carbynes, are of significant interest as plausible intermediates in the reductive catenation of C1 oxygenates. Despite the abundance of closed-shell carbynes reported, open-shell variants are very limited, and an open-shell carbide has yet to be reported. Herein, we report the synthesis of the first terminal, open-shell carbide complexes, [K][1] and [1][BArF4] (1 = P2Mo(≡C:)(CO), P2 = a terphenyl diphosphine ligand), which differ by two redox states, as well as a series of related open-shell carbyne complexes. The complexes are characterized by single-crystal X-ray diffraction and NMR, EPR, and IR spectroscopies, while the electronic structures are probed by EPR studies and DFT calculations to assess spin delocalization. In the d1 complexes, the spin is primarily localized on the metal (∼55-77% Mo dxy) with delocalization on the triply bonded carbon of ∼0.05-0.09 e-. In the reduced carbide [K][1], a direct metal-arene interaction enables ancillary ligand reduction, resulting in reduced radical character on the terminal carbide (⩽0.02 e-). Reactivity studies with [K][1] reveal the formation of mixed-valent C-C coupled products at -40 °C, illustrating how productive reactivity manifolds can be engendered through the manipulation of redox states. Combined, the results inform on the electronic structure and reactivity of a new and underrepresented class of compounds with potential significance to a wide array of reactions involving open-shell species.
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Affiliation(s)
- Gwendolyn A Bailey
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Joshua A Buss
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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van Leest N, de Zwart FJ, Zhou M, de Bruin B. Controlling Radical-Type Single-Electron Elementary Steps in Catalysis with Redox-Active Ligands and Substrates. JACS AU 2021; 1:1101-1115. [PMID: 34467352 PMCID: PMC8385710 DOI: 10.1021/jacsau.1c00224] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Advances in (spectroscopic) characterization of the unusual electronic structures of open-shell cobalt complexes bearing redox-active ligands, combined with detailed mapping of their reactivity, have uncovered several new catalytic radical-type protocols that make efficient use of the synergistic properties of redox-active ligands, redox-active substrates, and the metal to which they coordinate. In this perspective, we discuss the tools available to study, induce, and control catalytic radical-type reactions with redox-active ligands and/or substrates, contemplating recent developments in the field, including some noteworthy tools, methods, and reactions developed in our own group. The main topics covered are (i) tools to characterize redox-active ligands; (ii) novel synthetic applications of catalytic reactions that make use of redox-active carbene and nitrene substrates at open-shell cobalt-porphyrins; (iii) development of catalytic reactions that take advantage of purely ligand- and substrate-based redox processes, coupled to cobalt-centered spin-changing events in a synergistic manner; and (iv) utilization of redox-active ligands to influence the spin state of the metal. Redox-active ligands have emerged as useful tools to generate and control reactive metal-coordinated radicals, which give access to new synthetic methodologies and intricate (electronic) structures, some of which are yet to be exposed.
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Affiliation(s)
- Nicolaas
P. van Leest
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Felix J. de Zwart
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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14
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Radolko J, Ehlers P, Langer P. Recent Advances in Transition‐Metal‐Catalyzed Reactions of N‐Tosylhydrazones. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100332] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jan Radolko
- Universität Rostock Institut für Chemie A.-Einstein-Str. 3a 18059 Rostock Germany
| | - Peter Ehlers
- Universität Rostock Institut für Chemie A.-Einstein-Str. 3a 18059 Rostock Germany
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Peter Langer
- Universität Rostock Institut für Chemie A.-Einstein-Str. 3a 18059 Rostock Germany
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock Albert-Einstein-Str. 29a 18059 Rostock Germany
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15
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Zhang Z, Gevorgyan V. Co-Catalyzed Transannulation of Pyridotriazoles with Isothiocyanates and Xanthate Esters. Org Lett 2020; 22:8500-8504. [PMID: 33044833 PMCID: PMC7655727 DOI: 10.1021/acs.orglett.0c03099] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An efficient radical transannulation reaction of pyridotriazoles with isothiocyanates and xanthate esters was developed. This method features conversion of pyridotriazoles into two N-fused heterocyclic aromatic systems-imino-thiazolopyridines and oxo-thiazolopyridine derivatives-via one-step Co(II)-catalyzed transannulation reaction proceeding via a radical mechanism. The synthetic usefulness of the developed method was illustrated in the synthesis of amino acid derivatives and further transformations of obtained reaction products.
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Affiliation(s)
- Ziyan Zhang
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Vladimir Gevorgyan
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
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16
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Zhou M, Lankelma M, Vlugt JI, Bruin B. Catalytic Synthesis of 8‐Membered Ring Compounds via Cobalt(III)‐Carbene Radicals. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002674] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA) Science Park 904 1098 XH Amsterdam The Netherlands
| | - Marianne Lankelma
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA) Science Park 904 1098 XH Amsterdam The Netherlands
| | - Jarl Ivar Vlugt
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA) Science Park 904 1098 XH Amsterdam The Netherlands
| | - Bas Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA) Science Park 904 1098 XH Amsterdam The Netherlands
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17
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Zhou M, Lankelma M, van der Vlugt JI, de Bruin B. Catalytic Synthesis of 8-Membered Ring Compounds via Cobalt(III)-Carbene Radicals. Angew Chem Int Ed Engl 2020; 59:11073-11079. [PMID: 32259369 PMCID: PMC7317878 DOI: 10.1002/anie.202002674] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Indexed: 12/20/2022]
Abstract
The metalloradical activation of o-aryl aldehydes with tosylhydrazide and a cobalt(II) porphyrin catalyst produces cobalt(III)-carbene radical intermediates, providing a new and powerful strategy for the synthesis of medium-sized ring structures. Herein we make use of the intrinsic radical-type reactivity of cobalt(III)-carbene radical intermediates in the [CoII (TPP)]-catalyzed (TPP=tetraphenylporphyrin) synthesis of two types of 8-membered ring compounds; novel dibenzocyclooctenes and unprecedented monobenzocyclooctadienes. The method was successfully applied to afford a variety of 8-membered ring compounds in good yields and with excellent substituent tolerance. Density functional theory (DFT) calculations and experimental results suggest that the reactions proceed via hydrogen atom transfer from the bis-allylic/benzallylic C-H bond to the carbene radical, followed by two divergent processes for ring-closure to the two different types of 8-membered ring products. While the dibenzocyclooctenes are most likely formed by dissociation of o-quinodimethanes (o-QDMs) which undergo a non-catalyzed 8π-cyclization, DFT calculations suggest that ring-closure to the monobenzocyclooctadienes involves a radical-rebound step in the coordination sphere of cobalt. The latter mechanism implies that unprecedented enantioselective ring-closure reactions to chiral monobenzocyclooctadienes should be possible, as was confirmed for reactions mediated by a chiral cobalt-porphyrin catalyst.
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Affiliation(s)
- Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA)Science Park 9041098XHAmsterdamThe Netherlands
| | - Marianne Lankelma
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA)Science Park 9041098XHAmsterdamThe Netherlands
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA)Science Park 9041098XHAmsterdamThe Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group (HomKat)Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA)Science Park 9041098XHAmsterdamThe Netherlands
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18
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Alcântara AFP, Fontana LA, Almeida MP, Rigolin VH, Ribeiro MA, Barros WP, Megiatto JD. Control over the Redox Cooperative Mechanism of Radical Carbene Transfer Reactions for the Efficient Active‐Metal‐Template Synthesis of [2]Rotaxanes. Chemistry 2020; 26:7808-7822. [DOI: 10.1002/chem.201905602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Indexed: 02/01/2023]
Affiliation(s)
- Arthur F. P. Alcântara
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
- Instituto Federal do Sertão Pernambucano Estrada do Tamboril 56200-000 Ouricuri Brazil
| | - Liniquer A. Fontana
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Marlon P. Almeida
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Vitor H. Rigolin
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Marcos A. Ribeiro
- Departamento de QuímicaUniversidade Federal do Espírito Santo Av. Fernando Ferrari, 514 29075-910 Vitória Brazil
| | - Wdeson P. Barros
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Jackson D. Megiatto
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
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19
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van Vliet KM, van Leeuwen NS, Brouwer AM, de Bruin B. Visible-light-induced addition of carboxymethanide to styrene from monochloroacetic acid. Beilstein J Org Chem 2020; 16:398-408. [PMID: 32273903 PMCID: PMC7113555 DOI: 10.3762/bjoc.16.38] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/05/2020] [Indexed: 11/23/2022] Open
Abstract
Where monochloroacetic acid is widely used as a starting material for the synthesis of relevant groups of compounds, many of these synthetic procedures are based on nucleophilic substitution of the carbon chlorine bond. Oxidative or reductive activation of monochloroacetic acid results in radical intermediates, leading to reactivity different from the traditional reactivity of this compound. Here, we investigated the possibility of applying monochloroacetic acid as a substrate for photoredox catalysis with styrene to directly produce γ-phenyl-γ-butyrolactone. Instead of using nucleophilic substitution, we cleaved the carbon chlorine bond by single-electron reduction, creating a radical species. We observed that the reaction works best in nonpolar solvents. The reaction does not go to full conversion, but selectively forms γ-phenyl-γ-butyrolactone and 4-chloro-4-phenylbutanoic acid. Over time the catalyst precipitates from solution (perhaps in a decomposed form in case of fac-[Ir(ppy)3]), which was proven by mass spectrometry and EPR spectroscopy for one of the catalysts (N,N-5,10-di(2-naphthalene)-5,10-dihydrophenazine) used in this work. The generation of HCl resulting from lactone formation could be an additional problem for organometallic photoredox catalysts used in this reaction. In an attempt to trap one of the radical intermediates with TEMPO, we observed a compound indicating the generation of a chloromethyl radical.
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Affiliation(s)
- Kaj M van Vliet
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Nicole S van Leeuwen
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Albert M Brouwer
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Bas de Bruin
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
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20
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Madarasi PK, Sivasankar C. Infrared spectroscopic detection of ketene formation from carbene and CO sources: an amide synthesis. NEW J CHEM 2020. [DOI: 10.1039/c9nj06161d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An effective methodology to detect the highly reactive ketene intermediate, which is formed in situ during the course of organic transformation.
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Affiliation(s)
| | - Chinnappan Sivasankar
- Catalysis and Energy Laboratory
- Department of Chemistry
- Pondicherry University
- Puducherry 605 014
- India
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21
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Michiyuki T, Komeyama K. Recent Advances in Four‐Coordinated Planar Cobalt Catalysis in Organic Synthesis. ASIAN J ORG CHEM 2019. [DOI: 10.1002/ajoc.201900625] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Takuya Michiyuki
- Department of Applied ChemistryGraduate School of EngineeringHiroshima University 1-4-1 Kagamiyama, Higashi-Hiroshima Hiroshima 739-8527 Japan
| | - Kimihiro Komeyama
- Department of Applied ChemistryGraduate School of EngineeringHiroshima University 1-4-1 Kagamiyama, Higashi-Hiroshima Hiroshima 739-8527 Japan
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22
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Herndon JW. The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2018. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.213051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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23
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van Vliet KM, Polak LH, Siegler MA, van der Vlugt JI, Guerra CF, de Bruin B. Efficient Copper-Catalyzed Multicomponent Synthesis of N-Acyl Amidines via Acyl Nitrenes. J Am Chem Soc 2019; 141:15240-15249. [PMID: 31465210 PMCID: PMC6764152 DOI: 10.1021/jacs.9b07140] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
![]()
Direct
synthetic routes to amidines are desired, as they are widely
present in many biologically active compounds and organometallic complexes. N-Acyl amidines in particular can be used as a starting
material for the synthesis of heterocycles and have several other
applications. Here, we describe a fast and practical copper-catalyzed
three-component reaction of aryl acetylenes, amines, and easily accessible
1,4,2-dioxazol-5-ones to N-acyl amidines, generating
CO2 as the only byproduct. Transformation of the dioxazolones
on the Cu catalyst generates acyl nitrenes that rapidly insert into
the copper acetylide Cu–C bond rather than undergoing an undesired
Curtius rearrangement. For nonaromatic dioxazolones, [Cu(OAc)(Xantphos)]
is a superior catalyst for this transformation, leading to full substrate
conversion within 10 min. For the direct synthesis of N-benzoyl amidine derivatives from aromatic dioxazolones, [Cu(OAc)(Xantphos)]
proved to be inactive, but moderate to good yields were obtained when
using simple copper(I) iodide (CuI) as the catalyst. Mechanistic studies
revealed the aerobic instability of one of the intermediates at low
catalyst loadings, but the reaction could still be performed in air
for most substrates when using catalyst loadings of 5 mol %. The herein
reported procedure not only provides a new, practical, and direct
route to N-acyl amidines but also represents a new
type of C–N bond formation.
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Affiliation(s)
- Kaj M van Vliet
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
| | - Lara H Polak
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
| | - Maxime A Siegler
- Department of Chemistry , John Hopkins University , Baltimore , Maryland 21218 , United States
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
| | - Célia Fonseca Guerra
- Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling , Vrije Universiteit Amsterdam (VU) , De Boelelaan 1083 , 1081 HV Amsterdam , The Netherlands.,Leiden Institute of Chemistry, Gorlaeus Laboratories , Úniversiteit Leiden , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
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24
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Demarteau J, Debuigne A, Detrembleur C. Organocobalt Complexes as Sources of Carbon-Centered Radicals for Organic and Polymer Chemistries. Chem Rev 2019; 119:6906-6955. [DOI: 10.1021/acs.chemrev.8b00715] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jérémy Demarteau
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Allée du 6 Août, Building B6A, Agora Square, 4000 Liège, Belgium
| | - Antoine Debuigne
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Allée du 6 Août, Building B6A, Agora Square, 4000 Liège, Belgium
| | - Christophe Detrembleur
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Allée du 6 Août, Building B6A, Agora Square, 4000 Liège, Belgium
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25
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Heins SP, Zhang B, MacMillan SN, Cundari TR, Wolczanski PT. Oxidative Additions to Ti(IV) in [(dadi)4–]TiIV(THF) Involve Carbon–Carbon Bond Formation and Redox-Noninnocent Behavior. Organometallics 2019. [DOI: 10.1021/acs.organomet.8b00930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Spencer P. Heins
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Bufan Zhang
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Samantha N. MacMillan
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Thomas R. Cundari
- Department of Chemistry, CASCaM, University of North Texas, Denton, Texas 76201, United States
| | - Peter T. Wolczanski
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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26
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Dey S, Wayland BB, Zdilla MJ. Solution and Solid State Properties for Low-Spin Cobalt(II) Dibenzotetramethyltetraaza[14]annulene [(tmtaa)Co II] and the Monopyridine Complex. Inorg Chem 2019; 58:1224-1233. [PMID: 30618250 DOI: 10.1021/acs.inorgchem.8b02644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The single-crystal X-ray structure of solvent-free (tmtaa)CoII reveals three different π-π intermacrocyclic interactions between tmtaa units (tmtaa = dibenzotetramethyltetraaza[14]annulene). Pairs of inequivalent (tmtaa)CoII units in the unit cell link into a one-dimensional π-π stacked array in the solid state. Magnetic susceptibility (χ) studies from 300 to 2 K reveal the effects of intermolecular interactions between (tmtaa)CoII units in the solid state. The effective magnetic moment per CoII center is constant at 2.83 μB from 300 to 100 K and begins to significantly decrease at lower temperatures. The magnetic data are fit to a singlet ( S = 0) ground state with a triplet ( S = 1) excited state that is 13 cm-1 higher in energy (-2 J = 13 cm-1). Toluene solutions of (tmtaa)CoII have 1H nuclear magnetic resonance (NMR) paramagnetic shifts, a solution-phase magnetic moment μeff (295 K) of 2.1 μB, and toluene glass electron paramagnetic resonance spectra that are most consistent with a low-spin ( S = 1/2) CoII with the unpaired electron located in the d yz orbital. Pyridine interacts with (tmtaa)CoII to form a five-coordinate monopyridine complex in which the unpaired electron is in the d z2 orbital. The five-coordinate complex has been structurally characterized by single-crystal X-ray diffraction, and the equilibrium constant for pyridine binding at 295 K has been evaluated by both electronic and 1H NMR spectra. Density functional theory computation using the UB3LYP hybrid functional places the unpaired electron for (tmtaa)CoII in the d yz orbital and that for the monopyridine complex in the d z2 orbital, consistent with spectroscopic observations.
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Affiliation(s)
- Soumyajit Dey
- Department of Chemistry , Temple University , 1901 Northy 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Bradford B Wayland
- Department of Chemistry , Temple University , 1901 Northy 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Michael J Zdilla
- Department of Chemistry , Temple University , 1901 Northy 13th Street , Philadelphia , Pennsylvania 19122 , United States
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27
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van Leest NP, Epping RF, van Vliet KM, Lankelma M, van den Heuvel EJ, Heijtbrink N, Broersen R, de Bruin B. Single-Electron Elementary Steps in Homogeneous Organometallic Catalysis. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2018. [DOI: 10.1016/bs.adomc.2018.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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