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De S, Dutta S, Koley D. Theoretical Insights into Aluminum-Catalyzed Cyanosilylation of Aldehydes and Ketones. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00242] [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)
- Sriman De
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, India
| | - Sayan Dutta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, India
| | - Debasis Koley
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, India
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Tang J, Luo Q, Zeng D, Zhang N. Thermodynamic and Kinetic Studies on the Conversion of Solvent-Shared to Contact Ion Pairs in Sparingly Soluble MF 2 (M = Mg 2+ and Ca 2+) Aqueous Solutions: Implications for Understanding Supersaturated Behavior and Association Constant Determination. J Phys Chem B 2022; 126:1566-1578. [PMID: 35167281 DOI: 10.1021/acs.jpcb.1c09135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The thermodynamic and kinetic behaviors of Mg2+-F- ion pairing in aqueous solution are investigated theoretically and experimentally and are contrasted to those of Ca2+-F-. Thermodynamically, similar to CaFx(H2O)142-x (x = 1 and 2), MgF(H2O)y+ (y = 14-20) contact ion pairs (CIPs) are more stable than their solvent-shared ion pairs (SSIPs), whereas the CIPs and SSIPs of MF2(H2O)y are almost isoenergetic. However, in kinetics, the conversion of SSIPs to CIPs for M2+-F- (M = Mg2+ and Ca2+) ion pairing must overcome a high energy barrier due to the strong hydration of Mg2+ and F-. The kinetics dominate after the thermodynamics and kinetics are balanced, which hinders the formation of M2+-F- CIPs in practical MF2 aqueous solutions (less than or equal to saturated concentrations). This result is also supported by the 19F nuclear magnetic resonance spectra of saturated MF2 solutions. Although the interaction between Mg2+ and F- is slightly stronger than that between Ca2+ and F- due to the smaller radius of Mg2+, the formation of Mg2+-F- CIPs needs to go through two rate-limiting steps, the dehydration and entrance of F- (i.e., via exchange mode) with a higher energy barrier, due to the ability of strongly bound water molecules and rigorous octahedral coordinated configuration of Mg2+, while the formation of Ca2+-F- CIPs only goes through a single rate-limiting step, the entrance of F- (i.e., via swinging mode) with a lower energy barrier, due to the flexible coordination configuration of Ca2+. This is responsible for precipitation in MgF2 aqueous solution requiring a larger supersaturation degree and a lower precipitation rate than in CaF2. These kinetic factors lead to the association constants previously reported for MF+ determined by a fluoride ion-selective electrode (ISE) combined with the titration method, where the MF2 solutions were always unsaturated at the titration end point, which actually corresponds to those of the ligand process going from completely free M2+ and F- to their SSIPs. A possible strategy to accurately determine the association constants of MF+ and MF2(aq) CIPs by fluoride ISEs is proposed. The present results suggest that judging the formation of M2+-F- CIPs in practical solutions from a theoretical calculation perspective requires significant consideration of the kinetic factors, except for the thermodynamic factors.
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Affiliation(s)
- Jianfeng Tang
- College of Science, Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. China
| | - Qiongqiong Luo
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China
| | - Dewen Zeng
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China
| | - Ning Zhang
- College of Science, Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. China
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Goossen LJ, Koley D, De S, Sivendran N. Isomerization of Functionalized Olefins Using the Dinuclear Catalyst [PdI(μ-Br)(PtBu3)]2: A Mechanistic Study. Chemistry 2021; 27:15226-15238. [PMID: 34387372 PMCID: PMC8596456 DOI: 10.1002/chem.202102554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Indexed: 11/13/2022]
Abstract
In a combined experimental and computational study, the isomerization activity of the dinuclear palladium(I) complex [PdI(μ‐Br)(PtBu3)]2 towards allyl arenes, esters, amides, ethers, and alcohols has been investigated. The calculated energy profiles for catalyst activation for two alternative dinuclear and mononuclear catalytic cycles, and for catalyst deactivation are in good agreement with the experimental results. Comparison of experimentally observed E/Z ratios at incomplete conversion with calculated kinetic selectivities revealed that a substantial amount of product must form via the dinuclear pathway, in which the isomerization is promoted cooperatively by two palladium centers. The dissociation barrier towards mononuclear Pd species is relatively high, and once the catalyst enters the energetically more favorable mononuclear pathway, only a low barrier has to be overcome towards irreversible deactivation.
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Affiliation(s)
- Lukas J Goossen
- Ruhr-Universität Bochum, Organische Chemie I, Universitätsstraße 150, ZEMOS 2/27, 44801, 44801 Bochum, GERMANY
| | - Debasis Koley
- IISER-K: Indian Institute of Science Education and Research Kolkata, Chemical Sciences, Campus Rd, 741 246, Mohanpur, Nadia, INDIA
| | - Sriman De
- IISER-K: Indian Institute of Science Education and Research Kolkata, Chemical Sciences, Campus Rd, 741 246, Mohanpur, Nadia, INDIA
| | - Nardana Sivendran
- Ruhr-Universität Bochum: Ruhr-Universitat Bochum, Chemistry and Biochemistry, Universitätsstr. 150, ZEMOS, 44795, Bochum, GERMANY
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Bisai MK, Ajithkumar VS, Gonnade RG, Sen SS. Access to a Variety of Ge(II) and Sn(II) Compounds through Substitution of Hypersilyl Moiety. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00306] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Milan Kumar Bisai
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - V. S. Ajithkumar
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rajesh G. Gonnade
- Physical and Material Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sakya S. Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Parvin N, Sen N, Muhasina PV, Tothadi S, Parameswaran P, Khan S. The diverse reactivity of NOBF 4 towards silylene, disilene, germylene and stannylene. Chem Commun (Camb) 2021; 57:5008-5011. [PMID: 33949489 DOI: 10.1039/d1cc01034d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The reactivity of NOBF4 towards silylene, disilene, germylene, stannylenes has been described. Smooth syntheses of compounds of composition [PhC(NtBu)2E(= O → BF3)N(SiMe3)2, E = Si (3) and Ge (4)] were accomplished from the corresponding tetrylenes. An unusual heterocycle (10) featuring B, Sn, N, P, and O atoms was obtained from the reaction with a stannylene, while a 1,2-vicinal anti addition of fluoride was observed with a disilene (12).
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Affiliation(s)
- Nasrina Parvin
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr Homi Bhabha Road, Pashan, Pune-411008, India.
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Takahashi S, Ishii A, Nakata N. Interconversion between a silaimine and an aminosilylene supported by an iminophosphonamide ligand. Chem Commun (Camb) 2021; 57:3203-3206. [PMID: 33687409 DOI: 10.1039/d1cc00667c] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The reaction of a chlorosilylene, supported by an iminophosphonamide ligand, with KN(SiMe3)2 resulted in the formation of a silaimine instead of the expected aminosilylene. However, this silaimine exists in equilibrium with the corresponding aminosilylene, which was experimentally demonstrated using variable-temperature NMR spectroscopy and a trapping reaction with elemental selenium to give a silaselenourea.
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Affiliation(s)
- Shintaro Takahashi
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan.
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Lee E, Pietrasiak E. Activation of C–F, Si–F, and S–F Bonds by N-Heterocyclic Carbenes and Their Isoelectronic Analogues. Synlett 2020. [DOI: 10.1055/s-0040-1707106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Reactions involving C–F, Si–F, and S–F bond cleavage with N-heterocyclic carbenes and isoelectronic species are reviewed. Most examples involve activation of aromatic C–F bond via an SNAr pathway and nucleophilic substitution of fluorine in electron-deficient olefins. The mechanism of the C–F bond activation depends on the reaction partners and the reaction can proceed via addition–elimination, oxidative addition (concerted or stepwise) or metathesis. The adducts formed upon substitution find applications in organic synthesis, as ligands and as stable radical precursors, but in most cases, their full potential remains unexplored.1 Introduction1.1 The C–F Bond1.2 C–F Bond Activation: A Short Summary1.3 C–F Bond Activation: A Special Case of SNAr1.4 N-Heterocyclic Carbenes (NHCs)1.5 The Purpose of this Article2 C–F bond Activation in Acyl Fluorides3 Activation of Vinylic C–F Bonds4 Activation of Aromatic C–F Bonds5 X–F Bond Activation (X = S or Si)6 C–F Bond Activation by Main Group Compounds Isoelectronic with NHCs7 Conclusions and Outlook
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Affiliation(s)
- Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology
- Division of Advanced Materials Science, Pohang University of Science and Technology
| | - Ewa Pietrasiak
- Department of Chemistry, Pohang University of Science and Technology
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Zitz R, Pöcheim A, Baumgartner J, Marschner C. A 1,5-Oligosilanylene Dianion as Building Block for Oligosiloxane Containing Cages, Ferrocenophanes, and Cyclic Germylenes and Stannylenes. Molecules 2020; 25:E1322. [PMID: 32183200 PMCID: PMC7144727 DOI: 10.3390/molecules25061322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/05/2020] [Accepted: 03/11/2020] [Indexed: 11/16/2022] Open
Abstract
Starting out from dipotassium 1,5-oligosiloxanylene diide 2, a 3,7,10-trioxa-octasilabicyclo[3.3.3]undecane was prepared, which represents the third known example of this cage structure type. Reaction of 1,3-dichlorotetramethyldisiloxane with 1,1'-bis[bis(trimethylsilyl)potassiosilyl]ferrocene gave a ferrocenophane with a disiloxane containg bridge. The compound can be further derivatized by conversion into a 1,5-oligosilanyl diide. Reacting 1,5-oligosiloxanylene diide 2 with SnCl2 or GeCl2·dioxane in the presence of PMe3 gave cyclic disilylated tetrylene PMe3 adducts. Release of the base-free stannylene led to a dimerization process which gave a bicyclic distannene as the final product. Abstraction of the PMe3 from the cyclic disilylated germylene PMe3 adduct with B(C6F5)3 caused oxidative addition of the germylene into a para-C-F bond of Me3P·B(C6F5)3.
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Affiliation(s)
| | | | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria; (R.Z.); (A.P.)
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria; (R.Z.); (A.P.)
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Dutta S, De S, Bose S, Mahal E, Koley D. Cooperative Donor-Acceptor Interactions in Stabilizing Carbene-Borane and Carbene-Alane Compounds: A Theoretical Insight. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.201901163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Sayan Dutta
- Department of Chemical Sciences; Indian Institute of Science Education and Research (IISER) Kolkata; 741 246 Mohanpur India
| | - Sriman De
- Department of Chemical Sciences; Indian Institute of Science Education and Research (IISER) Kolkata; 741 246 Mohanpur India
| | - Sanjoy Bose
- Department of Chemical Sciences; Indian Institute of Science Education and Research (IISER) Kolkata; 741 246 Mohanpur India
| | - Eti Mahal
- Department of Chemical Sciences; Indian Institute of Science Education and Research (IISER) Kolkata; 741 246 Mohanpur India
| | - Debasis Koley
- Department of Chemical Sciences; Indian Institute of Science Education and Research (IISER) Kolkata; 741 246 Mohanpur India
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Kundu G, De S, Tothadi S, Das A, Koley D, Sen SS. Saturated N-Heterocyclic Carbene Based Thiele's Hydrocarbon with a Tetrafluorophenylene Linker. Chemistry 2019; 25:16533-16537. [PMID: 31609519 DOI: 10.1002/chem.201904421] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/06/2019] [Indexed: 01/24/2023]
Abstract
The synthesis of a SIPr [1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene] derived Kekulé diradicaloid with a tetrafluorophenylene spacer (3) has been described. Two synthetic routes have been reported to access 3. The cleavage of C-F bond of C6 F6 by SIPr in the presence of BF3 led to double C-F activated compound with two tetrafluoro borate counter anions (2), which upon reduction by lithium metal afforded 3. Alternatively, 3 can be directly accessed in one step by reacting SIPr with C6 F6 in presence of Mg metal. Compounds 2 and 3 were well characterized spectroscopically and by single-crystal X-ray diffraction studies. Experimental and computational studies support the cumulenic closed-shell singlet state of 3 with a singlet-triplet energy gap (ΔES-T ) of 23.7 kcal mol-1 .
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Affiliation(s)
- Gargi Kundu
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), New Ghaziabad, 201002, India
| | - Sriman De
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, India
| | - Srinu Tothadi
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Abhishek Das
- Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata, 700032, India
| | - Debasis Koley
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), New Ghaziabad, 201002, India
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Guru MM, De S, Dutta S, Koley D, Maji B. B(C 6F 5) 3-catalyzed dehydrogenative cyclization of N-tosylhydrazones and anilines via a Lewis adduct: a combined experimental and computational investigation. Chem Sci 2019; 10:7964-7974. [PMID: 31853352 PMCID: PMC6839809 DOI: 10.1039/c9sc02492a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 07/05/2019] [Indexed: 12/19/2022] Open
Abstract
Tris(pentafluorophenyl)borane-catalyzed dehydrogenative-cyclization of N-tosylhydrazones with aromatic amines has been disclosed. This metal-free catalytic protocol is compatible with a range of functional groups to provide both symmetrical and unsymmetrical 3,4,5-triaryl-1,2,4-triazoles. Mechanistic experiments and density functional theory (DFT) studies suggest an initial Lewis adduct formation of N-tosylhydrazone with B(C6F5)3 followed by sequential intermolecular amination of the borane adduct with aniline, intramolecular cyclization and frustrated Lewis pair (FLP)-catalyzed dehydrogenation for the generation of substituted 1,2,4-triazoles.
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Affiliation(s)
- Murali Mohan Guru
- Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur-741246 , India . ;
| | - Sriman De
- Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur-741246 , India . ;
| | - Sayan Dutta
- Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur-741246 , India . ;
| | - Debasis Koley
- Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur-741246 , India . ;
| | - Biplab Maji
- Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur-741246 , India . ;
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Zhang X, Li P, Wang B, Cao Z. Mechanistic Features in Al(I)-Mediated Oxidative Addition of Aryl C-F Bonds: Insights From Density Functional Theory Calculations. Front Chem 2019; 7:596. [PMID: 31552218 PMCID: PMC6733912 DOI: 10.3389/fchem.2019.00596] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/12/2019] [Indexed: 11/13/2022] Open
Abstract
The oxidative addition of a range of robust aryl C–F bonds to a single Al(I) center supported by a (NacNac)− bidentate ligand ((NacNac)− = [ArNC(Me)CHC(Me)NAr]− and Ar = 2,6–Pr2iC6H3) have been explored by density functional theory calculations. Our calculations demonstrate that the Al(I) center-mediated C–F insertion generally proceeds via the concerted mechanism that involve both the donation (nAl→σC-F*) and back-donation (σF(p)→πAl(p)*) interactions. In addition, the predicted free energy barriers for the C–F bond activation show good agreement with the experimental information available. Finally, the comparative studies show that B(I) is the most active among group III metals (B, Al, Ga), thus supplying a testable prediction for experiments.
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Affiliation(s)
- Xiangfei Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.,School of Chemistry and Pharmaceutical Engineering, Huanghuai University, Zhumadian, China
| | - Ping Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Zexing Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
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Mondal T, Dutta S, De S, Koley D. Computational Exploration of Mechanistic Avenues in C-H Activation Assisted Pd-Catalyzed Carbonylative Coupling. J Org Chem 2019; 84:257-272. [PMID: 30525639 DOI: 10.1021/acs.joc.8b02630] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The detailed mechanism of the intermolecular Pd-catalyzed carbonylative coupling reaction between aryl bromides and polyfluoroarenes relying on C(sp2)-H activation was investigated using state-of-the-art computational methods (SMD-B3LYP-D3(BJ)/BS2//B3LYP-D3/BS1). The mechanism unveils the necessary and important roles of a slight excess of carbon monoxide: acting as a ligand in the active catalyst state, participating as a reactant in the carbonylation process, and accelerating the final reductive elimination event. Importantly, the desired carbonylative coupling route follows the rate-limiting C-H activation process via the concerted metalation-deprotonation pathway, which is slightly more feasible than the decarboxylative route leading to byproduct formation by 1.2 kcal/mol. The analyses of the free energies indicate that the choice of base has a significant effect on the reaction mechanism and its energetics. The Cs2CO3 base guides the reaction toward the coupling route, whereas carbonate bases such as K2CO3 and Na2CO3 switch toward an undesired decarboxylative path. However, K3PO4 significantly reduces the C-H activation barrier over the decarboxylation reaction barrier and can act as a potential alternative base. The positional influence of a methoxy substituent in bromoanisole and different substituent effects in polyfluoroarenes were also considered. Our results show that different substituents impose significant impact on the desired carbonylative product formation energetics. Considering the influence of several ligands leads to the conclusion that other phosphine and N-heterocyclic carbene, such as P nBuAd2 and IMes, can be used as an efficient alternative than the experimentally reported P tBu3 ligand exhibiting a clear preference for C-H activation (ΔΔ⧧ GLS) by 7.1 and 10.9 kcal/mol, respectively. We have also utilized the energetic span model to interpret the experimental results. Moreover, to elucidate the origin of activation barriers, energy decomposition analysis calculations were accomplished for the critical transition states populating the energy profiles.
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Affiliation(s)
- Totan Mondal
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
| | - Sayan Dutta
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
| | - Sriman De
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
| | - Debasis Koley
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
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Dutta S, Mondal T, De S, Rudra K, Koley D. Strengths of different Lewis bases in stabilizing titanium fluorides: A theoretical insight. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Bakthavachalam K, Dutta S, C A, Raghavendra B, Haridas A, Sen SS, Koley D, Ghosh S. Cyclometallation of a germylene ligand by concerted metalation-deprotonation of a methyl group. Dalton Trans 2018; 47:15835-15844. [PMID: 30358780 DOI: 10.1039/c8dt03166e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The reaction of [CH{(CMe)(2,6-iPr2C6H3N)}2]GeCl with LiN(SiMe3)2 was previously reported, which led to the formation of a hetero-fulvene type germylene, [CH{(CMe)(C[double bond, length as m-dash]CH2)(2,6-iPr2C6H3N)}2]Ge through the deprotonation of the C-H bond from the methyl substituents. In this paper, we attempted the analogous reaction with (Dipp)NCMeCHCOMeGeCl using LiN(SiMe3)2 which gave rise to a metathesis product, (Dipp)NCMeCHCOMeGeN(SiMe3)2 (2). However, the reactions of 2 with [M2Cl2(μ-Cl)2(η5-Cp*)2] (M = Rh and Ir) resulted in cyclometallated Rh and Ir complexes through the activation of the C-H bond from the germylene ligand. The complexes were characterized by single crystal X-ray analysis, which authenticated the presence of Ge-Rh and Ge-Ir bonds. DFT studies have been performed to understand the mechanism.
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Affiliation(s)
- K Bakthavachalam
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
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Dutta S, Maity B, Thirumalai D, Koley D. Computational Investigation of Carbene–Phosphinidenes: Correlation between 31P Chemical Shifts and Bonding Features to Estimate the π-Backdonation of Carbenes. Inorg Chem 2018. [DOI: 10.1021/acs.inorgchem.8b00174] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sayan Dutta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, India
| | - Bholanath Maity
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, India
| | - D. Thirumalai
- Department of Chemistry, Thiruvalluvar University, Serkkadu, Vellore 632 115, India
| | - Debasis Koley
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, India
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Bakewell C, Ward BJ, White AJP, Crimmin MR. A combined experimental and computational study on the reaction of fluoroarenes with Mg-Mg, Mg-Zn, Mg-Al and Al-Zn bonds. Chem Sci 2018; 9:2348-2356. [PMID: 29719707 PMCID: PMC5897846 DOI: 10.1039/c7sc05059c] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 01/19/2018] [Indexed: 11/21/2022] Open
Abstract
Through a combined experimental and computational (DFT) approach, the reaction mechanism of the addition of fluoroarenes to Mg–Mg bonds has been determined as a concerted SNAr-like pathway in which one Mg centre acts as a nucleophile and the other an electrophile.
Through a combined experimental and computational (DFT) approach, the reaction mechanism of the addition of fluoroarenes to Mg–Mg bonds has been determined as a concerted SNAr-like pathway in which one Mg centre acts as a nucleophile and the other an electrophile. The experimentally determined Gibbs activation energy for the addition of C6F6 to a Mg–Mg bond of a molecular complex, ΔG‡298 K(experiment) = 21.3 kcal mol–1 is modelled by DFT with the ωB97X functional, ΔG‡298 K(DFT) = 25.7 kcal mol–1. The transition state for C–F activation involves a polarisation of the Mg–Mg bond and significant negative charge localisation on the fluoroarene moiety. This transition state is augmented by stabilising closed-shell Mg···Fortho interactions that, in combination with the known trends in C–F and C–M bond strengths in fluoroarenes, provide an explanation for the experimentally determined preference for C–F bond activation to occur at sites flanked by ortho-fluorine atoms. The effect of modification of both the ligand coordination sphere and the nature and polarity of the M–M bond (M = Mg, Zn, Al) on C–F activation has been investigated. A series of highly novel β-diketiminate stabilised complexes containing Zn–Mg, Zn–Zn–Zn, Zn–Al and Mg–Al bonds has been prepared, including the first crystallographic characterisation of a Mg–Al bond. Reactions of these new M–M containing complexes with perfluoroarenes were conducted and modelled by DFT. C–F bond activation is dictated by the steric accessibility, and not the polarity, of the M–M bond. The more open coordination complexes lead to enhanced Mg···Fortho interactions which in turn lower the energy of the transition states for C–F bond activation.
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Affiliation(s)
- Clare Bakewell
- Department of Chemistry , Imperial College London , South Kensington , London , SW7 2AZ , UK .
| | - Bryan J Ward
- Department of Chemistry , Imperial College London , South Kensington , London , SW7 2AZ , UK .
| | - Andrew J P White
- Department of Chemistry , Imperial College London , South Kensington , London , SW7 2AZ , UK .
| | - Mark R Crimmin
- Department of Chemistry , Imperial College London , South Kensington , London , SW7 2AZ , UK .
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Sen SS, Roesky HW. Silicon-fluorine chemistry: from the preparation of SiF2to C–F bond activation using silylenes and its heavier congeners. Chem Commun (Camb) 2018; 54:5046-5057. [DOI: 10.1039/c8cc01816b] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The feisty nature of silicon(ii) fluorides has been harnessed by two cyclic alkyl amino carbene (cAAC) ligands and (cAAC)2SiF2has been isolated at room temperature and structurally characterized.
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Affiliation(s)
- Sakya S. Sen
- Inorganic Chemistry and Catalysis Division
- CSIR-National Chemical Laboratory
- Pune 411008
- India
| | - Herbert W. Roesky
- Institute of Inorganic Chemistry
- Georg-August University
- Goettingen
- Germany
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