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Karmakar H, Anga S, Panda TK, Chandrasekhar V. Aluminium alkyl complexes supported by imino-phosphanamide ligand as precursors for catalytic guanylation reactions of carbodiimides. RSC Adv 2022; 12:4501-4509. [PMID: 35425514 PMCID: PMC8981115 DOI: 10.1039/d2ra00242f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 01/13/2023] Open
Abstract
Herein, we report the synthesis, characterisation, and application of three aluminium alkyl complexes, [κ2-{NHIRP(Ph)NDipp}AlMe2] (R = Dipp (2a), Mes (2b); tBu (2c), Dipp = 2,6-diisopropylphenyl, Mes = mesityl, and tBu = tert-butyl), supported by unsymmetrical imino-phosphanamide [NHIRP(Ph)NDipp]- [R = Dipp (1a), Mes (1b), tBu (1c)] ligands as molecular precursors for the catalytic synthesis of guanidines using carbodiimides and primary amines. All the imino-phosphanamide ligands 1a, 1b and 1c were prepared in good yield from the corresponding N-heterocyclic imine (NHI) with phenylchloro-2,6-diisopropylphenylphosphanamine, PhP(Cl)NHDipp. The aluminium alkyl complexes 2a, 2b and 2c were obtained in good yield upon completion of the reaction between trimethyl aluminium and the protic ligands 1a, 1b and 1c in a 1 : 1 molar ratio in toluene via the elimination of methane, respectively. The molecular structures of the protic ligands 1b and 1c and the aluminium complexes 2a, 2b and 2c were established via single-crystal X-ray diffraction analysis. Complexes 2a, 2b and 2c were tested as pre-catalysts for the hydroamination/guanylation reaction of carbodiimides with aryl amines to afford guanidines at ambient temperature. All the aluminium complexes exhibited a high conversion with 1.5 mol% catalyst loading and broad substrate scope with a wide functional group tolerance during the guanylation reaction. We also proposed the most plausible mechanism, involving the formation of catalytically active three-coordinate Al species as the active pre-catalyst.
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Affiliation(s)
- Himadri Karmakar
- Department of Chemistry, Indian Institute of Technology Hyderabad Kandi Sangareddy 502285 Telangana India +91 40 2301 6032 +91 40 2301 6036
| | - Srinivas Anga
- Tata Institute of Fundamental Research Hyderabad Gopanpally 500107 Hyderabad India
| | - Tarun K Panda
- Department of Chemistry, Indian Institute of Technology Hyderabad Kandi Sangareddy 502285 Telangana India +91 40 2301 6032 +91 40 2301 6036
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad Gopanpally 500107 Hyderabad India
- Department of Chemistry, IIT Kanpur Kanpur 208016 India
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2
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Anga S, Karmakar H, Panda TK, Chandrasekhar V. Alkali metal complexes of an unsymmetrical imino–phosphanamidinate (N-P-N) ligand. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.122091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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3
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Anga S, Acharya J, Chandrasekhar V. An Unsymmetric Imino-Phosphanamidinate Ligand and its Y(III) Complex: Synthesis, Characterization, and Catalytic Hydroboration of Carbonyl Compounds. J Org Chem 2021; 86:2224-2234. [PMID: 33290079 DOI: 10.1021/acs.joc.0c02383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An imino-phosphanamide ligand, [NHIiPr2Me2P(Ph)NH-2,6-iPr2C6H3] (LH), containing two different N-substituents was prepared by the direct reaction of the lithium salt of N-heterocyclic imine (NHI) with phenylchloro-2,6-diisopropylphenyl phosphanamine, PhP(Cl)NH-2,6-iPr2-C6H3. Reaction of LH with Y(N(SiMe3)2)3 afforded the heteroleptic complex, [{L}Y(N(SiMe3)2)2] (1), by elimination of HN(SiMe3)2. Compound 1 was characterized by multinuclear NMR and X-ray crystallography. In the complex, the Y(III) center was found to be tetracoordinate in a distorted tetrahedral geometry. The ligand, imino-phosphanamidinate, [L]-, functions in a chelating manner, and its coordination to Y(III) results in a distorted 4-membered YPN2 ring. As a proof of principle of its activity, 1 was used as a precatalyst for the hydroboration of various aldehydes and ketones using HBpin as the hydrogen source. The hydroboration reaction was rapid and clean even with low catalyst loadings (0.01-0.1 mol %). In addition, a very good functional group tolerance was observed in these reactions.
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Affiliation(s)
- Srinivas Anga
- Tata Institute of Fundamental Research Hyderabad, Gopanpally 500046, Hyderabad, India
| | - Joydev Acharya
- Tata Institute of Fundamental Research Hyderabad, Gopanpally 500046, Hyderabad, India.,Department of Chemistry, IIT Kanpur, Kanpur 208016, India
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally 500046, Hyderabad, India.,Department of Chemistry, IIT Kanpur, Kanpur 208016, India
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Feuerstein TJ, Goswami B, Rauthe P, Köppe R, Lebedkin S, Kappes MM, Roesky PW. Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence. Chem Sci 2019; 10:4742-4749. [PMID: 31160950 PMCID: PMC6510313 DOI: 10.1039/c9sc00629j] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/11/2019] [Indexed: 12/22/2022] Open
Abstract
Alkali metal complexes of an enantiopure iminophosphonamide bearing chiral centers at both nitrogen atoms are described. They show bright phosphorescence and thermally activated delayed fluorescence (TADF).
The enantiomerically pure ligand P,P-diphenyl-N,N′-bis((R)-1-phenylethyl)phosphinimidic amide (1; (R)-HPEPIA) was synthesized and subsequently deprotonated with alkali metal precursors to yield dimeric complexes [M2{(R)-PEPIA}2] (M = Li (2), Na (3), K (4), Rb (5)). The cesium compound [M{(R)-PEPIA}] (6) crystallized as a cocrystal composed of dimeric ([Cs2{(R)-PEPIA}2] (6d) and 1D-polymeric ([Cs{(R)-PEPIA}]n) (6p) species in a 1 : 1 ratio. The coordination polymer 6p features a unique sinus-shaped configuration of repeating –Cs–N–P–N–Cs–N–P–N– units. Unusual photoluminescence (PL) properties were found for solid 1–6: in contrast to the fluorescent ligand 1, the alkali metal complexes show phosphorescence at low temperatures (<100 K) and thermally activated delayed fluorescence (TADF) above ∼150 K. The latter provides for PL quantum yields up to 36% (3) at ambient temperature. DFT calculations support that both 1 and 2–6d have similar singlet and triplet excited states with energy separations of a few tens of meV. The strongly enhanced intersystem crossing (ISC) in the metal complexes, resulting in TADF, is attributed to their dimeric structure. This suggests that the fluorophore dimerization may serve as a tool to effect ISC for the design of TADF emitters.
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Affiliation(s)
- Thomas J Feuerstein
- Institute for Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15 , 76131 Karlsruhe , Germany .
| | - Bhupendra Goswami
- Institute for Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15 , 76131 Karlsruhe , Germany .
| | - Pascal Rauthe
- Institute for Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15 , 76131 Karlsruhe , Germany .
| | - Ralf Köppe
- Institute for Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15 , 76131 Karlsruhe , Germany .
| | - Sergei Lebedkin
- Institute of Nanotechnology , Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 , Eggenstein-Leopoldshafen , Germany
| | - Manfred M Kappes
- Institute of Nanotechnology , Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 , Eggenstein-Leopoldshafen , Germany.,Institute of Physical Chemistry , Karlsruhe Institute of Technology (KIT) , Fritz-Haber-Weg. 2 , 76131 Karlsruhe , Germany
| | - Peter W Roesky
- Institute for Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15 , 76131 Karlsruhe , Germany .
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5
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Lawrence SR, Cordes DB, Slawin AMZ, Stasch A. Mechanistic insights of anionic ligand exchange and fullerene reduction with magnesium( i) compounds. Dalton Trans 2019; 48:16936-16942. [DOI: 10.1039/c9dt03976g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exchange of anionic ligands on the Mg22+ ion via an associative mechanism can be facile and depends on ligand sterics and shape.
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Affiliation(s)
| | - David B. Cordes
- EaStCHEM School of Chemistry
- University of St Andrews
- St Andrews
- UK
| | | | - Andreas Stasch
- EaStCHEM School of Chemistry
- University of St Andrews
- St Andrews
- UK
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6
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Pick FS, Leznoff DB, Fryzuk MD. Redox behaviour of ([fc(NPiPr2)2]Fe)2, formation of an iron–iron bond and cleavage of azobenzene. Dalton Trans 2018; 47:10925-10931. [DOI: 10.1039/c8dt00828k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The redox behaviour of the dimeric tetrairon complex, ([fc(NPiPr2)2]Fe)2 (where fc(NPiPr2)2 = 1,1′-(C5H4NPiPr2)2Fe) has been investigated.
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Affiliation(s)
- Fraser S. Pick
- Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
| | - Daniel B. Leznoff
- Deprtment of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada V5A 1S6
| | - Michael D. Fryzuk
- Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
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7
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Prashanth B, Bawari D, Singh S. Heteroleptic Iminophosphonamide In(III) Complexes: Source of Mild Lewis Acid Indium Centers. ChemistrySelect 2017. [DOI: 10.1002/slct.201700026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Billa Prashanth
- Department of Chemical Sciences; Indian Institute of Science Education and Research Mohali; Knowledge City, Sector-81, SAS Nagar, Mohali 140306 Punjab India
| | - Deependra Bawari
- Department of Chemical Sciences; Indian Institute of Science Education and Research Mohali; Knowledge City, Sector-81, SAS Nagar, Mohali 140306 Punjab India
| | - Sanjay Singh
- Department of Chemical Sciences; Indian Institute of Science Education and Research Mohali; Knowledge City, Sector-81, SAS Nagar, Mohali 140306 Punjab India
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8
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Hawley AL, Ohlin CA, Fohlmeister L, Stasch A. Heavier Group 13 Metal(I) Heterocycles Stabilized by Sterically Demanding Diiminophosphinates: A Structurally Characterized Monomer-Dimer Pair For Gallium. Chemistry 2016; 23:447-455. [DOI: 10.1002/chem.201604495] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Andrew L. Hawley
- School of Chemistry; Monash University; 17 Rainforest Walk Melbourne Victoria 3800 Australia
| | - C. André Ohlin
- School of Chemistry; Monash University; 17 Rainforest Walk Melbourne Victoria 3800 Australia
- Department of Chemistry; Umeå University; Linnaeus väg 10 Umeå 907 36 Sweden
| | - Lea Fohlmeister
- School of Chemistry; Monash University; 17 Rainforest Walk Melbourne Victoria 3800 Australia
| | - Andreas Stasch
- School of Chemistry; Monash University; 17 Rainforest Walk Melbourne Victoria 3800 Australia
- EaStCHEM School of Chemistry; University of St Andrews; North Haugh St Andrews KY16 9ST UK
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López Ortiz F, García López J, Casimiro M, Iglesias MJ. Diastereoselective Ortho Lithiation of Phosphinimidic Amides: A Multinuclear Magnetic Resonance and Computational Study. J Org Chem 2016; 81:11095-11103. [DOI: 10.1021/acs.joc.6b02083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Fernando López Ortiz
- Área
de Química
Orgánica, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - Jesús García López
- Área
de Química
Orgánica, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - María Casimiro
- Área
de Química
Orgánica, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - María José Iglesias
- Área
de Química
Orgánica, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
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Prashanth B, Srungavruksham NK, Singh S. Mononuclear Neutral Boron Hydrides Affordable as [N,N’] Chelates of Iminophosphonamides. ChemistrySelect 2016. [DOI: 10.1002/slct.201600746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Billa Prashanth
- Department of Chemical Sciences; Indian Institute of Science Education and Research Mohali; Knowledge City, Sector-81, SAS Nagar Mohali 140306, Punjab India
| | - Nagarjuna Kumar Srungavruksham
- Department of Chemical Sciences; Indian Institute of Science Education and Research Mohali; Knowledge City, Sector-81, SAS Nagar Mohali 140306, Punjab India
| | - Sanjay Singh
- Department of Chemical Sciences; Indian Institute of Science Education and Research Mohali; Knowledge City, Sector-81, SAS Nagar Mohali 140306, Punjab India
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Fohlmeister L, Stasch A. Ring-Shaped Phosphinoamido-Magnesium-Hydride Complexes: Syntheses, Structures, Reactivity, and Catalysis. Chemistry 2016; 22:10235-46. [PMID: 27271460 DOI: 10.1002/chem.201601623] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Indexed: 11/10/2022]
Abstract
A series of magnesium(II) complexes bearing the sterically demanding phosphinoamide ligand, L(-) =Ph2 PNDip(-) , Dip=2,6-diisopropylphenyl, including heteroleptic magnesium alkyl and hydride complexes are described. The ligand geometry enforces various novel ring and cluster geometries for the heteroleptic compounds. We have studied the stoichiometric reactivity of [(LMgH)4 ] towards unsaturated substrates, and investigated catalytic hydroborations and hydrosilylations of ketones and pyridines. We found that hydroborations of two ketones with pinacolborane using various Mg precatalysts is very rapid at room temperature with very low catalyst loadings, and ketone hydrosilylation using phenylsilane is rapid at 70 °C. Our studies point to an insertion/σ-bond metathesis catalytic cycle of an in situ formed "MgH2 " active species.
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Affiliation(s)
- Lea Fohlmeister
- School of Chemistry, Monash University, 17 Rainforest Walk, Melbourne, Victoria, 3800, Australia
| | - Andreas Stasch
- School of Chemistry, Monash University, 17 Rainforest Walk, Melbourne, Victoria, 3800, Australia. .,School of Chemistry, University of St Andrews, North Haugh, St. Andrews, KY16 9ST, UK.
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12
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Lichtenberg C. Aminotroponiminates: Alkali Metal Compounds Reveal Unprecedented Coordination Modes. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00042] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Crispin Lichtenberg
- Institut für Anorganische
Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Fernández Sáez N, García López J, Iglesias MJ, López Ortiz F. Derivatization of (quinolin-8-yl)phosphinimidic amides via ortho-lithiation revisited. Dalton Trans 2015; 44:11504-13. [PMID: 26030882 DOI: 10.1039/c5dt01392e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
5The direct ortho-lithiation of N-H containing (quinolin-8-yl)phosphinimidic amides by reaction with 1 equiv. of n-BuLi described by Wang and co-workers has been re-examined. The multinuclear magnetic resonance ((1)H, (2)H, (7)Li, (13)C, (15)N and (31)P) study of the species formed in the monolithiation of N-(tert-butyl)-P,P-diphenyl-N'-(quinolin-8-yl)phosphinimidic amide 5 with n-BuLi in THF showed that proton abstraction occurred exclusively and quantitatively at the NH. The combination of the NMR results with a DFT study made it possible to describe the structure of the N-lithiated species 9 as a dimer consisting of an eight-membered ring showing two lithium ions triply coordinated to nitrogen atoms corresponding to the deprotonated amine and aminoquinoline moieties of different monomers. The formation of a polymer featuring the same coordination mode couldn't be excluded. In addition, optimized conditions for the efficient derivatization of 5 via ortho-lithiation were realised. The reaction of 5 with 2.4 equiv. of t-BuLi in THF in the temperature range of -80 °C to 25 °C for 3 h afforded a N,C(ortho)-dilithiated species that was trapped with a series of electrophiles leading to new functionalized ortho derivatives of 5 in good yields.
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Affiliation(s)
- Nerea Fernández Sáez
- Área de Química Orgánica, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain.
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Böttcher T, Jones C. Extremely bulky secondary phosphinoamines as substituents for sterically hindered aminosilanes. Dalton Trans 2015. [DOI: 10.1039/c5dt02504d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The synthesis of a series of extremely bulky secondary amines with a phosphine function, Ar†(PR2)NH (Ar†= C6H2{C(H)Ph2}2Pri-2,6,4; R = Ph, NEt2, NPri2) is described. Deprotonation with eithern-BuLi or KH yields the respective alkali metal amides. Reactions with a series of chlorosilanes allows access to monomeric molecular compounds bearing the extremely bulky amino substituentsviasalt elimination.
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Affiliation(s)
| | - Cameron Jones
- School of Chemistry
- Monash University
- Melbourne
- Australia
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