Journal ArticleDOI
Photoinduced C−N Bond Cleavage in 2-Azido-1,3-diphenyl-propan-1-one Derivatives: Photorelease of Hydrazoic Acid
Rodney F. Klima,Abhijit V. Jadhav,Pradeep N. D. Singh,Mingxin Chang,Christine Vanos,Jagadis Sankaranarayanan,Mai Vu,Nazarin Ibrahim,Elaine Ross,Shaun Mccloskey,Rajesh S. Murthy,Jeanette A. Krause,Bruce S. Ault,Anna D. Gudmundsdottir +13 more
Reads0
Chats0
TLDR
The characterization of 1-n was supported by isotope labeling, IR spectroscopy, and molecular modeling and the irradiation of azides 1 in argon matrices at 14 K lead to the formation of the corresponding triplet alkyl nitrenes (1-n), via intramolecular energy transfer from T2K.Abstract:
Photolysis of 3-azido-1,3-diphenyl-propan-1-one (1a) in toluene yields 1,3-diphenyl-propen-1-one (2), whereas irradiation of 3-azido-2,2-dimethyl-1,3-diphenyl-propan-1-one (1b) results in the formation of mainly 2,2-dimethyl-1,3-diphenyl-propan-1-one. Laser flash photolysis (308 nm) of 1a,b in acetonitrile reveals a transient absorption (λmax = ∼310 nm) due to the formation of radicals 4a and 4b, respectively, which have lifetimes of ∼14 μs at ambient temperature. TD−DFT calculations (B3LYP/6-31+G(d)) reveal that the first and second excited states of the triplet ketone (T1K (n,π*) and T2K (π,π*)) in azide 1a are almost degenerate, at ∼74 and 76 kcal/mol above the ground state (S0), respectively. Similarly, azide 1b has T1K and T2K 75 and 82 kcal/mol above S0, respectively. The calculated transition state for cleaving the C−N bond is located 71 and 74 kcal/mol above S0 in azides 1a and 1b, respectively. The calculated bond dissociation energies for breaking the C−N bond are 55 and 58 kcal/mol for azides 1...read more
Citations
More filters
Journal ArticleDOI
Iodide-catalyzed synthesis of N-nitrosamines via C-N cleavage of nitromethane.
TL;DR: An iodide-catalyzed process to synthesize N-nitrosamines has been developed using TBHP as the oxidant and the mild catalytic system succeeded in cleaving the carbon-nitrogen bond in nitromethane.
Journal ArticleDOI
Selective Formation of Triplet Alkyl Nitrenes from Photolysis of β-Azido-Propiophenone and Their Reactivity
Pradeep N. D. Singh,Sarah M. Mandel,Jagadis Sankaranarayanan,Sivaramakrishnan Muthukrishnan,Mingxin Chang,Rachel M. Robinson,Paul M. Lahti,Bruce S. Ault,Anna D. Gudmundsdottir +8 more
TL;DR: In this paper, photolysis of β-azido propiophenone derivatives, with built-in sensitizer units, leads to selective formation of triplet alkyl nitrenes, which are persistent intermediates that do not abstract H-atoms from the solvent but do decay by dimerizing with another triplet nitrene to form azo products, rather than reacting with an azide precursor.
Journal ArticleDOI
Intramolecular H-atom abstraction in gamma-azido-butyrophenones: formation of 1,5 ketyl iminyl radicals.
Sivaramakrishnan Muthukrishnan,Jagadis Sankaranarayanan,Rodney F. Klima,Tamara C. S. Pace,Cornelia Bohne,Anna D. Gudmundsdottir +5 more
TL;DR: DFT-TD calculations were used to support the proposed mechanism for formation of the 1,5 ketyl iminyl radicals, and the biradicals were characterized with transient spectroscopy.
Journal ArticleDOI
TBAI-catalyzed selective synthesis of sulfonamides and β-aryl sulfonyl enamines: coupling of arenesulfonyl chlorides and sodium sulfinates with tert-amines.
Hongmei Jiang,Hongmei Jiang,Xiaoyue Tang,Zhihui Xu,Huixian Wang,Han Kang,Xiaolan Yang,Yuanyuan Zhou,Yong-Lai Feng,Xianyong Yu,Qingwen Gui,Qingwen Gui +11 more
TL;DR: A simple, practical and metal-free method has been developed for the synthesis of sulfonamides and β-arylsulfonyl enamines via the selective cleavage of C-N and C-H bonds through the iodine-catalyzed oxidation of arenesulfonyL chlorides and sodium sulfinates with tert-amines.
Journal ArticleDOI
C–N bond dissociation energies: An assessment of contemporary DFT methodologies
TL;DR: In this paper, the authors used the CBS-QB3 method to provide the theoretical benchmark values for estimating the energetic C-N bond dissociation energies and showed that the three hybrid meta GGA functionals, BB1K, MPWB1K and M06-2X, can reproduce the experimental values well.
References
More filters
Journal ArticleDOI
Density‐functional thermochemistry. III. The role of exact exchange
TL;DR: In this article, a semi-empirical exchange correlation functional with local spin density, gradient, and exact exchange terms was proposed. But this functional performed significantly better than previous functionals with gradient corrections only, and fits experimental atomization energies with an impressively small average absolute deviation of 2.4 kcal/mol.
Journal ArticleDOI
Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density
TL;DR: Numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, show that density-functional formulas for the correlation energy and correlation potential give correlation energies within a few percent.
Journal ArticleDOI
Quantum mechanical continuum solvation models.
TL;DR: This paper presents a meta-modelling procedure called "Continuum Methods within MD and MC Simulations 3072", which automates the very labor-intensive and therefore time-heavy and expensive process of integrating discrete and continuous components into a discrete-time model.
Journal ArticleDOI
An improved algorithm for reaction path following
TL;DR: In this article, a second order algorithm for finding points on a steepest descent path from the transition state of the reactants and products is presented. But the points are optimized so that the segment of the reaction path between any two adjacent points is given by an arc of a circle, and the gradient at each point is tangent to the path.
Journal ArticleDOI
Reaction Path Following in Mass-Weighted Internal Coordinates
TL;DR: In this article, the authors extended their previous algorithm for following reaction paths downhill to use mass-weighted internal coordinates, which has the correct tangent vector and curvature vectors in the limit or small step size but requires only the transition vector and the energy gradients.