ChemInform Abstract: AB INITIO CALCULATIONS ON THE DIPHOSPHINE RADICAL CATION (P2H4+.CNTDOT.)

1985 ◽  
Vol 16 (35) ◽  
Author(s):  
D. FELLER ◽  
E. R. DAVIDSON ◽  
W. T. BORDEN
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Radical Cation

Cleavage of the radical cations of alkenes; 1-butene and 4,4-dimethyl-1-pentene. Ab initio calculations on the interaction between the allyl and alkyl radical and carbocation moieties

1991 ◽  
Vol 69 (9) ◽  
pp. 1365-1375 ◽  
Author(s):  
Xinyao Du ◽  
Donald R. Arnold ◽  
Russell J. Boyd ◽  
Zheng Shi
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Radical Cation ◽  
Alkyl Radical ◽  
Radical Cations ◽  
Molecular Orbital Calculations ◽  
Allyl Radical ◽  
Allyl Cation ◽  
Tert Butyl ◽  
Carbon Carbon Bond

Carbon–carbon bond cleavage of the radical cations of 1-butene [Formula: see text] and 4,4-dimethyl-1-pentene [Formula: see text] will generate the allyl and alkyl radical and carbocation fragments. Alternative bonding arrangements between the allyl and methyl moieties in [Formula: see text] and between the allyl and tert-butyl moieties in [Formula: see text] possible metastable intermediates or transition states preceding complete separation of the fragments, have been investigated by ab initio molecular orbital calculations. Structures were fully optimized at the UHF/6-31G* or UHF/STO-3G levels, and some of the calculations on [Formula: see text] were expanded with single point MP2/6-31G*//UHF/6-31G* computations. The C4H8+ radical cation, having a structure similar to that of 1-butene, is more stable than the separated fragments: 183 kj mol−1 lower in energy than the sum of the energies of the allyl cation and the methyl radical, and 385 kJ mol−1 lower than the sum of the energies of an allyl radical and a methyl cation, at the MP2/6-31G* level. The corresponding values at the UHF/STO-3G level are 276 and 415 kj mol−1, respectively. There is less bonding interaction between the allyl and tert-butyl moieties in [Formula: see text] The summation of the energies of the allyl radical and tert-butyl cation is 123 kj mol−1 lower than the summation of the energies of the allyl cation and tert-butyl radical, and 115 kJ mol−1 higher in energy than the bonded radical cation [Formula: see text] at the UHF/STO-3G level. These calculated values are compared with thermochemical data and with experimental results on the cleavage of these, and related, radical cations. Key words: radical cation, cleavage, ab initio calculations, electron transfer, photochemistry.

scholarly journals Das Methylviologen-Radikalkation. Synthese, Kristallstruktur und ab initio-Rechnungen von N,N′-Dimethyl-4,4′ -bipyridinium-chlorid-dihydrat / The Methylviologen Radical Cation. Synthesis, Crystal Structure and ab initio Calculations of N,N′ -Dimethyl-4,4′ -bipyridinium Chloride Dihydrate

1993 ◽  
Vol 48 (10) ◽  
pp. 1341-1347 ◽  
Author(s):  
Hans Wolkers ◽  
Ralf Stegmann ◽  
Gernot Frenking ◽  
Kurt Dehnicke ◽  
Dieter Fenske ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Radical Cation ◽  
Structural Parameters ◽  
Ion Pairs ◽  
Radical Cations ◽  
Chloride Ions ◽  
Chloride Dihydrate ◽  
Deep Blue

The title compound has been prepared by the reduction of N,N′-dimethyl-4,4′-bipyridinium dichloride with dilithium tritelluride in dimethylformamide solution. It forms deep blue crystal needles, which were characterized by a crystal structure determination. Space group Pna 21,Z = 8,3450 observed unique reflections, R = 0.045. Lattice dimensions at -70°C: a =1707.6(8), b = 2323.9(11), c = 664.6(3) pm. The N,N′-dimethyl-4,4′-bipyridinium radical cations are planar and form ion pairs in the lattice. The chloride ions together with the water molecules form an infinite network of hydrogen bridges along the crystallographic a-axis. The structural parameters of the radical cation are in excellent agreement with ab initio calculations.

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