Sequestering and metamorphosis of molecular nitrogen at ambient conditions: role of bonding and back-bonding DOI Creative Commons
Ratan Logdi, Arijit Bag, Ashwani K. Tiwari

et al.

Published: July 20, 2022

The optical absorbance behavior of a molecule during the reaction is yet to be explored due deficiency in appropriate theoretical and experimental tools. In present study, Intrinsic Reaction Coordinate (IRC) trapping methodology implemented new approach capture electronic motion nitrogen activation by heterocyclic carbenes. This technique acts as Handycam (Molecular Handycam) shoot photographs electrons event chemical beyond Born-Oppenheimer approximation. use newly designed molecular analyse electron flow at frontier orbitals adduct formation with carbene corroborated that −N 2 reaction, operates σ −acceptor π −donor where bonding back processes occur before after transition state reaction. There significant time delay between process, implying back-bonding not simultaneous for this These findings ameliorate DFT-based designing carbenes model congenial catalyst sequestering atmospheric its metamorphosis ammonia an ambient metal-free condition. It also brought light absorption may change along path. Though nitrogen, carbene−N are non-responsive visible light, evanescent region observed

Language: Английский

Ambiphilic singlet carbenes: Electron donors and acceptors DOI
Hyunho Kim, Eunsung Lee

Bulletin of the Korean Chemical Society, Journal Year: 2022, Volume and Issue: 43(12), P. 1328 - 1341

Published: Sept. 10, 2022

Abstract The isolation of cyclic(alkyl)(amino)carbenes (CAACs) and N , ′‐diamidocarbenes (DACs) has opened up new avenues in the field carbene chemistry due to their unique properties. CAACs are strong σ‐donors π‐acceptors, whereas DACs extremely π‐acceptors. ambiphilicity carbenes can facilitate applications such as small molecule activation catalysis. Since DACs, several ambiphilic have been synthesized, thereby advancing development chemistry. This review summarizes most relevant findings on until 2022.

Language: Английский

Citations

24
Bicyclic (alkyl)(amino)carbene (BICAAC) in a dual role: activation of primary amides and CO2towards catalyticN-methylation DOI Creative Commons
Nimisha Gautam, Ratan Logdi,

P Sreejyothi

et al.

Chemical Science, Journal Year: 2023, Volume and Issue: 14(19), P. 5079 - 5086

Published: Jan. 1, 2023

Herein, we report the first catalytic methylation of primary amides using CO2 as a C1 source. A bicyclic (alkyl)(amino)carbene (BICAAC) exhibits dual role by activating both amide and to carry out this transformation which enables formation new C-N bond in presence pinacolborane. This protocol was applicable wide range substrate scopes, including aromatic, heteroaromatic, aliphatic amides. We successfully used procedure diversification drug bioactive molecules. Moreover, method explored for isotope labelling 13CO2 few biologically important detailed study mechanism carried with help spectroscopic studies DFT calculations.

Language: Английский

Citations

14
Cyclic (Alkenyl)(Amino)Carbene (SMeCAenAC): Introducing a Member to the Cyclic (Alkyl)(Amino)Carbenes Family Featuring a Narrow Energy Gap DOI
Chinmoy Majumder, Ankita Sharma, Bindusagar Das

et al.

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 17, 2025

Herein, we report the carbene-like activity of a nonisolable, highly ambiphilic cyclic (alkenyl)(amino)carbene (SMeCAenAC, 3), which is stabilized as [(SMeCAenAC)(H)N(SiMe3)2] (4). This protected form (4) stable in air and moisture. Compound 4 can be used carbene source through deamination upon heating to 130-140 °C. Moreover, density functional theory (DFT) calculations indicate that SMeCAenAC has smallest singlet-triplet gap (37.05 kcal/mol) narrow highest occupied molecule orbital (HOMO)-lowest unoccupied molecular (LUMO) (3.92 eV) among (alkyl)(amino)carbenes (CAACs). The precursor (3) synthesized on multigram scale with good yield. SMeCAenAC-coordinated copper complex showed excellent efficiency catalytic addition phenols electron-deficient olefins. study also highlights [SMeCAenAC-H]OTf for metal-free catalysis, property uniquely characteristic an carbene, even though formation free was not achieved.

Language: Английский

Citations

0
Versatile chemistry of six-membered NHC with boranes: bromination at sp3 borane, activation of the B–H bond of HBpin, and ring expansion of NHC DOI
Gargi Kundu,

Ruchi Dixit,

Srinu Tothadi

et al.

Dalton Transactions, Journal Year: 2022, Volume and Issue: 51(38), P. 14452 - 14457

Published: Jan. 1, 2022

The NHC·borane chemistry has been majorly restricted to imidazol-2-ylidene classes of carbenes. In our previous communication, we reported the synthesis 6-SIDipp·BH3 [6-SIDipp = 1,3-di(2,6-diisopropylphenyl) tetrahydropyrimidine-2-ylidene] and its electrophilic substitution reaction with iodine. Here, have shown selective bromination a 6-SIDipp stabilized sp3 B-H bond. Treatment 1.2 equivalents N-bromosuccinamide gives mixture mono- disubstituted products 6-SIDipp·BH2Br (1) 6-SIDipp·BHBr2 (2). However, reactions alkyl bromides or carbon tetrabromide resulted in selectively. Exploration BHCl2 9-BBN (9-borabicyclo[3.3.1]nonane) led mono-6-SIDipp adducts 3 6a. Furthermore, 6a undergoes ring expansion afford seven-membered product, 6b, under mild conditions. Unlike 9-BBN, bond HBpin oxidative addition upon 6-SIDipp, epitomizing first example (7) insertion at NHCs. analogous reactivity HBcat tetrahydropyrimidinium salt B(cat)2 as counteranion (8).

Language: Английский

Citations

16
Air and Water Stable Bicyclic (alkyl)(amino)Carbene Stabilized Phosphenium Cation: Reactivity and Selective Fluoride Ion Affinity DOI Open Access
Ritu Yadav, Ankita Sharma, Bindusagar Das

et al.

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(62)

Published: Aug. 15, 2024

Abstract The synthesis and reactivity of an air water stable Bicyclic (alkyl)(amino)carbene (BICAAC) stabilized phosphenium cation (1) is reported. Air are rare in the literature. Compound 1 obtained by reaction BICAAC with Ph 2 PCl THF followed anion exchange LiOTf. reduction oxidation yielded corresponding α‐radical phosphine species (2) oxide (3) respectively. All compounds well characterized single crystal X‐ray diffraction studies. Lewis acidity 3 determined conducting fluoride ion affinity experiments using UV‐Vis spectrophotometry multinuclei NMR spectroscopy. Compounds exhibited selective binding to but did not interact other halides (Cl − Br ). Quantum chemical calculations were performed understand structure nature bonding interactions these compounds, as comprehend specific over halide ions.

Language: Английский

Citations

3
A Boron-Nitrogen Double Transborylation Strategy for Borane-Catalyzed Hydroboration of Nitriles DOI

Subham Pradhan,

Raman Vijaya Sankar,

Chidambaram Gunanathan

et al.

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(18), P. 12386 - 12396

Published: Aug. 31, 2022

Organoborane-catalyzed hydroboration of nitriles provides N,N-diborylamines, which act as efficient synthons for the synthesis primary amines and secondary amides. Known nitrile methods are dominated by metal catalysis. Simple metal-free using diborane [H-B-9-BBN]2 a catalyst pinacolborane turnover reagent is reported. The reaction monomeric H-B-9-BBN with leads to hydrido-bridged diborylimine intermediate; subsequent sequential double hydroboration-transborylation pathway involving B-N/B-H σ bond metathesis proposed.

Language: Английский

Citations

14
Comparing B–H Bond Activation in NiIIX(NNN)-Catalyzed Nitrile Dihydroboration (X = Anionic N-, C-, O-, S-, or P-donor) DOI
Saeed Ataie, R. Tom Baker

Inorganic Chemistry, Journal Year: 2022, Volume and Issue: 61(49), P. 19998 - 20007

Published: Dec. 1, 2022

One of the key steps in many metal complex-catalyzed hydroboration reactions is B-H bond activation, which results hydride formation. Anionic ligands that include multiple lone pairs electrons, cooperation with a center, have notable potential redox-neutral activation through metal-ligand cooperation. Herein, using an easily prepared NpyridineNimineNpyrrolide ligand (L2)-, series divalent NiIIX(NNN) complexes were synthesized, X = bromide (2), phenoxide (3), thiophenoxide (4), 2,5-dimethylpyrrolide (5), diphenylphosphide (6), and phenyl (7). The characterized 1H 13C NMR spectroscopy, mass spectrometry, X-ray crystallography employed as precatalysts for nitrile dihydroboration. Superior activity phenoxy derivative (3) [vs thiophenoxy (4) or (7)] suggests occurs at Ni-X (vs Ni-Npyrrolide) bond. Furthermore, stoichiometric treatment 2-7 showed no reaction, whereas pinacolborane (HBpin) gave same Ni-H complex 2, 3, 5. Considering only 5 successfully catalyzed dihydroboration, we suggest catalytic cycle involves conventional inner sphere pathway initiated by substrate insertion into Ni-H.

Language: Английский

Citations

11
B–N/B–H Transborylation: borane-catalysed nitrile hydroboration DOI Creative Commons
Filip S. Meger, Alexander C. W. Kwok, Franziska Gilch

et al.

Beilstein Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 18, P. 1332 - 1337

Published: Sept. 26, 2022

The reduction of nitriles to primary amines is a useful transformation in organic synthesis, however, it often relies upon stoichiometric reagents or transition-metal catalysis. Herein, borane-catalysed hydroboration give reported. Good yields (48-95%) and chemoselectivity (e.g., ester, nitro, sulfone) were observed. DFT calculations mechanistic studies support the proposal double B-N/B-H transborylation mechanism.

Language: Английский

Citations

10
Tropylium tetrafluoroborate promoted hydroboration of nitriles, imines and amides DOI
Son H. Doan, Thành Vinh Nguyễn

Green Chemistry, Journal Year: 2022, Volume and Issue: 24(19), P. 7382 - 7387

Published: Jan. 1, 2022

A new organocatalytic approach to reduce nitriles, imines or amides with pinacolborane amines is reported.

Language: Английский

Citations

8
Adducts of Bicyclic (Alkyl)(Amino)Carbene with ECl3 and Three Electron Reduction Thereof: Syntheses of BICAAC Stabilized E−E Bonded Compounds (E=P, Sb) DOI
Manu Adhikari, Sandeep Kumar Thakur, Sanjay Singh

et al.

European Journal of Inorganic Chemistry, Journal Year: 2023, Volume and Issue: 26(30)

Published: Aug. 14, 2023

Abstract The stoichiometric reaction of bicyclic (alkyl)(amino)carbene (BICAAC) with group 15 chlorides, ECl 3 (E=P, Sb) to form the Lewis adducts BICAAC:ECl (E=P ( 1 ), Sb 2 )) has been investigated in present work. BICAAC smoothly reacts PPhCl [BICAAC:PPhCl ] which on ‐ situ two electron reduction equivalents KC 8 afforded phosphinidene complex, BICAAC=P‐Ph ). Complete dechlorination BICAAC‐ECl and leads three‐electron afford low‐valent trans bent bis(BICAAC)E complexes 4 ) 5 )). These are first examples pnictogens all have characterized by different spectroscopic techniques their solid‐state structure elucidated single crystal X‐ray diffraction.

Language: Английский

Citations

4