20171-65-7Relevant articles and documents
Photodissociation Dynamics of Nitrobenzene Molecular Ion on a Nanosecond Time Scale
Hwang, Wan Goo,Kim, Myung Soo,Choe, Joong Chul
, p. 9227 - 9234 (2007/10/03)
Photodissociation dynamics of nitrobenzene molecular ion has been investigated on a nanosecond time scale by mass-analyzed ion kinetic energy spectrometry.Photodissociation has been found to occur through various reaction channels.Three dissociation channels to C6H5O(1+), C6H5(1+), and NO(1+) have been observed together with a consecutive dissociation to C5H5(1+) via C6H5O(1+).The photodissociation rate constant of the molecular ion and the kinetic energy release distributions in each channel have been determined.The rate constant of the second step of the consecutive reaction has been determined in real time also.It has been found that the direct bond cleavage to C6H5(1+) occurs in competition with the rearrangement processes to C6H5O(1+) and NO(1+) on a nanosecond time scale.Statistical theories have been used to gain insight into the dynamics of the reactions.
The Ionic Hydrogen Bond and Ion Solvation. 7. Interaction Energies of Carbanions with Solvent Molecules
Meot-Ner (Mautner), Michael
, p. 3858 - 3862 (2007/10/02)
The bonding energy of a water molecule to carbanions range from 11.0 kcal/mol for c-C5H5- to 13 - 15 kcal/mol for CH2CN-, CH2CHO-, and CH2COCH3- and to 16.2 kcal/mol for HCC-.Alcohols bond to c-C5H5- more strongly, by up to 20.6 kcal/mol for the strongly acidic CF3CH2OH, and the attachment energies show an inverse linear correlation with the acidities of the alcohols.The c-C5H5- ion exhibits unusual behavior in that it bonds to the hydrogen donor H2O more weakly (11.0 kcal/mol) than to CH3CN (15.5 kcal/mol).In contrast, the more localized pyrrolide ion c-C4H4N- bonds to the two solvents by comparable strength, 15.8 and 15.7 kcal/mol, respectively.These observations indicate a specific N-*OH hydrogen bonding contribution in c-C4H4N-*H2O, and/or an unusual C-*HC type hydrogen bonding contribution in c-C5H5-*CH3CN.As to structures, correlations between ΔHoD and ΔHoacid suggest that ligands may hydrogen bond to the ? system of c-C5H5-, and to the oxygen atoms in CH2CHO- and CH3COCH2-.The latter is supported by solvent shell effects in CH3COCH2-*nH2O.
Hypovalent Radicals. 4. Gas-Phase Studies of the Ion-Molecule Reactions of Cyclopentadienylidene Anion Radical in a Flowing Afterglow
McDonald, Richard N.,Chowdhury, A.Kasem,Setser, D.W.
, p. 6491 - 6498 (2007/10/02)
The carbene anion radical, cyclopentadienylidene-.(c-C5H4-., 1), was generated by dissociative electron attachment with diazocyclopentadiene (2) in a flowing afterglow apparatus.The ion-molecule reaction of 1 with 2 produced c-C5H4N=N-c-C5H4-., c-C5H4=c-C5H4-., and c-C5H5- by coupling at Nβ and C1 of 2 and H. abstraction from 2, respectively.The PA(1) = 377 +/- 2 kcal mol-1 was determined from bracketing reactions of ROH + 1 -> RO- + c-C5H5., which gives ΔHf0(1) = 70.7 +/- 3.2 kcal mol-1.Although the H. abstraction process by 1 was observed in most of its ion-molecule reactions, 1 failed to react with CH4, C2H4, and c-C3H6 probably because of an activation barrier of (*) 3 kcal mol-1 in these cases.With dipolar CH3OH and 1, the only observed reaction was H. abstraction from the O-H bond (shown with CH3OD).This lower limit of the H. affinity of 1 gives ΔHf0(1) (*) 67.7 +/- 3 kcal mol-1, in excellent agreement with the value derived from protonation studies.The reactions of 1 with CH3X (Cl, Br) occur by H. abstraction and halide ion (SN2) displacement.Anion radical 1 adds to activated olefins H2C=CHX (CN, CO2CH3, Cl) by a nucleophilic Michael addition mechanism.The EA of the carbene c-C5H4 was bracketed by charge-transfer reactions between 1 and C6F6 and NO2.All of these and certain other results are consistent with the ?1?2 electronic configuration as the ground state of 1.The reactions of 1 with alcohols are postulated to proceed via a hydrogen-bonded complex.
