Six-Membered Aromatic Polyazides: Synthesis and Application

Tuning Green Explosives through SNAr Chemistry

Reactivity and regioselectivity of SNAr-type fluorine substitution with azide in polyfluorosubstituted nitrobenzenes was studied both theoretically and experimentally. The obtained polyazido-substituted nitrobenzene derivatives were extensively characterized by NMR, IR, HPLC, X-ray, and DFT methods. It was found that the substitution with the azide nucleophile occurs first at the para- and the ortho-positions to the NO2-group and that transazidation reactions also occur here. Thermal decomposition of prepared azidonitrobenzenes was studied both in controlled (kinetic decay) and uncontrolled (explosion) modes. In case of the controlled thermal decomposition of ortho-azidonitrobenzenes, benzofuroxans were found as major products of the reaction unless another azido group was adjacent to the furoxan moiety. The bursting power of azidonitrobenzenes was found to rise gradually with the number of the azide substituents in the aromatic ring.

Molecular Magnets: The Synthesis and Characterization of High-Spin Nitrenes

Among all C‐, N‐, and O‐centered polyradicals, high‐spin nitrenes possess the largest magnetic anisotropy and are of considerable interest as multi‐level molecular spin systems for exploration of organic molecular magnetism and quantum information processing. Although the first representatives of quintet and septet nitrenes were obtained almost 50 years ago, the experimental and theoretical studies of these highly reactive species became possible only recently, owing to new achievements in molecular spectroscopy and computational chemistry. Meanwhile, dozens of various quintet dinitrenes and septet trinitrenes were successfully characterized by IR, UV/Vis, and EPR spectroscopy, thus providing important information about the electronic structure, magnetic properties and reactivity of these compounds.

Recent advances in chemistry of high-spin nitrenes

Experimental and theoretical studies on aromatic nitrenes bearing from three to six unpaired electrons and having quartet, quintet, sextet or septet ground spin states, published in the last 15 years are analyzed. A comparative analysis of the magnetic properties of high-spin nitrenes and all other known high-spin organic molecules is performed. Promising areas of practical application of high-spin nitrenes as molecular magnets and as qubits and qudits for quantum computations are discussed.

The bibliography includes 214 references.

EPR spectroscopy of multicomponent, multispin molecular system obtained by the photolysis of 2,4,6-triazido-3-cyano-5-fluoropyridine in solid argon

Complex multicomponent, multispin molecular system, consisting of a septet trinitrene, two quintet dinitrenes, and three triplet mononitrenes, was obtained by the photolysis of 2,4,6-triazido-3-cyano-5-fluoropyridine in solid argon. To identify these paramagnetic products, electron paramagnetic resonance spectroscopy in combination with line-shape spectral simulations and density functional theory calculations was used. The products of the photolysis was found to be triplet 2,4-diazido-3-cyano-5-fluoropyridyl-6-nitrene (D_T  = 1.000 cm^-1 , E_T  = 0), triplet 2,4-diazido-3-cyano-5-fluoropyridyl-2-nitrene (D_T  = 1.043 cm^-1 , E_T  = 0), triplet 2,6-diazido-3-cyano-5-fluoropyridyl-4-nitrene (D_T  = 1.128 cm^-1 , E_T  = 0 cm^-1 ), quintet 4-azido-3-cyano-5-fluoropyridyl-2,6-dinitrene (D_Q  = 0.211 cm^-1 , E_Q  = 0.0532 cm^-1 ), quintet 2-azido-3-cyano-5-fluoropyridyl-4,6-dinitrene (D_Q  = 0.208 cm^-1 , E_Q  = 0.0386 cm^-1 ), and septet 3-cyano-5-fluoropyridyl-2,4,6-trinitrene (D_S  = -0.1017 cm^-1 , E_S  = -0.0042 cm^-1 ) in a 38:4:7:22:14:4 ratio, respectively.

Synthesis of Geminal Azido-Halo Compounds and α-Azidoalkyl Esters from Aldehydes via α-Azido Alcohols

α-Azido alcohols are generated by treating aldehydes with hydrazoic acid in chloroform. These adducts are transformed into geminal azido-halo compounds through the reaction with phosphorus trichloride or phosphorus tribromide, whereas α-azidoalkyl esters are isolated after interaction with acyl chlorides.

13 C and 15 N NMR spectra of high-energy polyazidocyanopyridines

¹³ C and ¹⁵ N NMR spectra of high-energy 2,4,6-triazidopyridine-3,5-dicarbonitrile, 2,3,5,6-tetraazidopyridine-4-carbonitrile and 3,4,5,6-tetraazidopyridine-2-carbonitrile are reported. The assignment of signals in the spectra was performed on the basis of density functional theory calculations. The molecular geometries were optimized using the M06-2X functional with the 6-311+G(d,p) basis set. The magnetic shielding tensors were calculated by the gauge-independent atomic orbital method with the Tao-Perdew-Staroverov-Scuseria hybrid functional known as TPSSh. In all the calculations, a polarizable continuum model was used to simulate solvent effects. This approach provided accurate predictions of the ¹³ C and ¹⁵ N chemical shifts for all the three compounds despite complications arising due to non-coplanar arrangement of the azido groups in the molecules. It was found that the ¹⁵ N chemical shifts of the N_α atoms in the azido groups of 2,4,6-triazidopyridines correlate with the ¹³ C chemical shifts of the carbon atoms attached to these azido groups. Copyright © 2016 John Wiley & Sons, Ltd.