Browsing by Subject "radical"

Article

Catalytic oxidation of N -phenylamidrazones to 1,3-Diphenyl-1,4-dihydro-1, 2,4-benzotriazin-4-yls: An improved synthesis of blatters radical

Koutentis, Panayiotis Andreas; Lo Re, D. (2010)

Blatters radical, 1,3-diphenyl-1,4-dihydro-1,2,4-benzotriazin-4-yl (1a, R =H), and several of its C-7 substituted analogues (R =CF3, Cl, Br, I, Me, OMe) were prepared in good-to-excellent yields through catalytic oxidation ...

Article

Characterization and magnetic properties of a "super stable" radical 1,3-diphenyl-7-trifluoromethyl-1,4-dihydro-1,2,4-benzotriazin-4-yl

Constantinides, Christos P.; Koutentis, Panayiotis Andreas; Krassos, H.; Rawson, J. M.; Tasiopoulos, Anastasios J. (2011)

1,3-Diphenyl-7-trifluoromethyl-1,4-dihydro-1,2,4-benzotriazin-4-yl (4), prepared in SSSShigh yield via the catalytic oxidation of the corresponding amidrazone 5 by using Pd/C (1.6 mol ss%) and 1,8-diazabicyclo[5.4.0]undec-7-ene ...

Article

Direct detection of Fe(IV)=O intermediates in the cytochrome aa3 oxidase from Paracoccus denitrificans[H2O2 reaction

Pinakoulaki, Eftychia; Pfitzner, U.; Ludwig, B.; Varotsis, Constantinos (2003)

We report the first evidence for the formation of the "607- and 580-nm forms" in the cytochrome oxidase aa3/H2O2 reaction without the involvement of tyrosine 280. The pKa of the 607-580-nm transition is 7.5. The 607-nm ...

Article

Electron affinities of a homologous series of tertiary alkyl radicals and their C-H bond dissociation energies (BDEs)

Petrou, Panayiotis S.; Nicolaides, Athanassios V. (2009)

Heats of formation have been derived from G3(MP2)//B3LYP and G3MP2B3(+) atomization energies for tert-butyl radical (6R), cubyl radical, bicyclooctyl radical (1R), and tricyclo[3.3.n.03,7]alk-3(7)-yl (n=0-3, 2R-5R) radicals, ...

Article

A magnetostructural investigation of an abrupt spin transition for 1-phenyl-3-trifluoromethyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl

Constantinides, Christos P.; Berezin, Andrey A.; Zissimou, Georgia A.; Manoli, Maria; Leitus, G. M.; Bendikov, M.; Probert, M. R.; Rawson, J. M.; Koutentis, Panayiotis Andreas (2014)

1-Phenyl-3-trifluoromethyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl is the first example of a hydrazyl radical that shows a reversible sharp spin transition fully completed within 5(1) K. The nominally first-order transition ...

Article

Of ortho-conjugatively linked reactive intermediates: The cases of ortho-phenylene-(bis)nitrene, -carbenonitrene, and -(bis)carbene

Nicolaïdes, Andrew N.; Nakayama, T.; Yamazaki, K.; Tomioka, H.; Koseki, S.; Stracener, L. L.; McMahon, R. J. (1999)

ortho-Phenylene-bisnitrene (2) and -carbenonitrene (3) were generated in an inert matrix at low temperature, characterized by IR spectroscopy, and identified with the help of DFT calculations. Their thermal and photochemical ...

Article

Perchlorophenalenyl radical

Koutentis, Panayiotis Andreas; Chen, Y. Z.; Cao, Yun Zhen; Best, T. P.; Itkis, M. E.; Beer, L.; Oakley, R. T.; Cordes, A. W.; Brock, C. P.; Haddon, R. C. (2001)

We report the preparation and solid-state characterization of the perchlorophenalenyl radical (1). The radical is initially obtained as a yellow-green solid by reduction of the perchlorophenalenium salt (12+). This solid ...

Article

Phenyl radical, cation, and anion. The triplet-singlet gap and higher excited states of the phenyl cation

Nicolaïdes, Andrew N.; Smith, D. M.; Jensen, F.; Radom, L. (1997)

High-level ab initio molecular orbital calculations have been carried out for the phenyl cation (1), the phenyl radical (2), and the phenyl anion (3). Our best estimate for the heat of formation (ΔH(f298)) of the phenyl ...

Article

Ring opening of the cyclopropylcarbinyl radical and its N- and O- substituted analogues: A theoretical examination of very fast unimolecular reactions

Smith, D. M.; Nicolaïdes, Andrew N.; Golding, B. T.; Radom, L. (1998)

High level ab initio molecular orbital calculations have been used to examine the ring opening of the cyclopropylcarbinyl radical and its heterosubstituted analogues. The applicability of various theoretical techniques to ...

Article

Route to benzo- and pyrido-fused 1,2,4-triazinyl radicals via N ′-(Het)aryl- N ′-[2-nitro(het)aryl]hydrazides

Berezin, Andrey A.; Zissimou, Georgia A.; Constantinides, Christos P.; Beldjoudi, Yassine; Rawson, J. M.; Koutentis, Panayiotis Andreas (2014)

A two-step route to 1,3-disubstituted benzo- and pyrido-fused 1,2,4-triazinyl radicals is presented. The route involves the N′-(2-nitroarylation) of easily prepared N′-(het)arylhydrazides via nucleophilic aromatic substitution ...

Article

Spin-triplet excitons in 1,3-diphenyl-7-(fur-2-yl)-1,4-dihydro-1,2,4- benzotriazin-4-yl

Constantinides, Christos P.; Carter, E.; Murphy, D. M.; Manoli, Maria; Leitus, G. M.; Bendikov, M.; Rawson, J. M.; Koutentis, Panayiotis Andreas (2013)

7-(Fur-2-yl)benzotriazinyl 1 is the first example of a hydrazyl radical dimer with a thermally accessible triplet state. The triplet exciton (|D| = 0.018 cm-1, |E| = 0.001 cm-1) was observed by solid-state VT-EPR spectroscopy ...