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Computational Study of Structural and Reactive Properties of Imidazolidine, Piperazine, and Their N,N-Dinitro Derivatives.

ADA225247

Publication Date	1990
Personal Author	Murray, J. S.; Redfern, P. C.; Lane, P.; Politzer, P.; Willer, R. L.
Page Count	16
Abstract	Structural features, relative stabilities and reactive properties of the five- and six-membered diaza alicyclic systems imidazolidine and piperazine and their N,N-dinitro derivatives have been studied using an ab initio self-consistent-field molecular orbital approach at the 3-21G level. Both imidazolidine and 1,3-dinitroimidazolidine have puckered geometries, while the most stable conformers of the pipperazines are chairs. For both piperazine and 1,4-dinitropiperazine, there are three chair conformers that are very close in energy, one of which has a calculated non-zero dipole moment. Our results are therefore consistent with the experimentally determined non-zero dipole moments for these two molecules. Imidazolidine and piperazine are found to have an added degree of stability relative to the analogous cycloalkanes, which may be due to omega-conjugation of the amine lone pairs. The introduction of nitro groups results in a greater degree of ring flattening in 1,3-dinitroimidazolidine than in 1,4-dinitropiperazine. The large negative regions in the electrostatic potentials of imidazolidine and piperazine, attributed to the ring nitrogen lone pairs and indicative of attractive sites for electrophiles, are greatly diminished in strength and size by substitution of nitro groups for the amine hydrogens. Keywords: Reprints. (KR)
Keywords	Imidazoles Piperazines Computations Reprints Structural properties Chemical derivatives Molecular orbitals
Source Agency	Non Paid Reprints
NTIS Subject Category	99F - Physical & Theoretical Chemistry
Corporate Authors	New Orleans Univ., LA. Dept. of Chemistry.
Supplemental Notes	Pub. in Jnl. of Molecular Structure (Theochem), v207 p177-191 1990.
Document Type	Journal Article
Title Note	Journal article.
NTIS Issue Number	199024
Contract Number	N00014-85-K-0217

Computational Study of Structural and Reactive Properties of Imidazolidine, Piperazine, and Their N,N-Dinitro Derivatives.

Computational Study of Structural and Reactive Properties of Imidazolidine, Piperazine, and Their N,N-Dinitro Derivatives.
ADA225247

Publication Date	1990
Personal Author	Murray, J. S.; Redfern, P. C.; Lane, P.; Politzer, P.; Willer, R. L.
Page Count	16
Abstract	Structural features, relative stabilities and reactive properties of the five- and six-membered diaza alicyclic systems imidazolidine and piperazine and their N,N-dinitro derivatives have been studied using an ab initio self-consistent-field molecular orbital approach at the 3-21G level. Both imidazolidine and 1,3-dinitroimidazolidine have puckered geometries, while the most stable conformers of the pipperazines are chairs. For both piperazine and 1,4-dinitropiperazine, there are three chair conformers that are very close in energy, one of which has a calculated non-zero dipole moment. Our results are therefore consistent with the experimentally determined non-zero dipole moments for these two molecules. Imidazolidine and piperazine are found to have an added degree of stability relative to the analogous cycloalkanes, which may be due to omega-conjugation of the amine lone pairs. The introduction of nitro groups results in a greater degree of ring flattening in 1,3-dinitroimidazolidine than in 1,4-dinitropiperazine. The large negative regions in the electrostatic potentials of imidazolidine and piperazine, attributed to the ring nitrogen lone pairs and indicative of attractive sites for electrophiles, are greatly diminished in strength and size by substitution of nitro groups for the amine hydrogens. Keywords: Reprints. (KR)
Keywords	Imidazoles Piperazines Computations Reprints Structural properties Chemical derivatives Molecular orbitals
Source Agency	Non Paid Reprints
NTIS Subject Category	99F - Physical & Theoretical Chemistry
Corporate Authors	New Orleans Univ., LA. Dept. of Chemistry.
Supplemental Notes	Pub. in Jnl. of Molecular Structure (Theochem), v207 p177-191 1990.
Document Type	Journal Article
Title Note	Journal article.
NTIS Issue Number	199024
Contract Number	N00014-85-K-0217