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An experimental and theoretical study of dinitrogen related chemistry : = Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	An experimental and theoretical study of dinitrogen related chemistry :/
其他題名:	Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions.
作者:	Chen, Grace Shiahuy.
面頁冊數:	1 online resource (288 pages)
附註:	Source: Dissertations Abstracts International, Volume: 59-04, Section: B.
Contained By:	Dissertations Abstracts International59-04B.
標題:	Organic chemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9737904click for full text (PQDT)
ISBN:	9780591479065

An experimental and theoretical study of dinitrogen related chemistry : = Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions.
Chen, Grace Shiahuy.

An experimental and theoretical study of dinitrogen related chemistry :Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions. - 1 online resource (288 pages)

Source: Dissertations Abstracts International, Volume: 59-04, Section: B.

Thesis (Ph.D.)--University of Missouri - Columbia, 1996.

Includes bibliographical references

Deamination reactions play an important role in synthetic organic chemistry and their pathways often involve highly unstable, reactive aliphatic diazonium ions. It is the goal to utilize the power of modern ab initio theory coupled to laboratory experimentation to gain a better understanding of the electronic structures of these reactive intermediates. The first crystal structures of aliphatic diazonium ions, β,β-diethoxy- and β,β-dichlorovinyldiazonium ions, were determined and their electronic structures were investigated by ab initio theory. Both experimental and theoretical results indicate that β,β-disubstituted vinyldiazonium ions are better described as disubstituted carbenium ions. However, for the close system, the group VIA trisubstituted carbenium ions C(XH)3+ (X = O, S, Se, Te), the results of the electronic structure analyses show only the trihydroxy carbenium ion has a positively charged C-center together with highly polarized C-O bonds. For all heavier homologues (X = S, Se, Te), the central C-atom carries a negative charge and all the X atoms have positive charge. The results show the umpolung of the C-X bonds for the heavier homologues. Potential conjugative interactions are pivotal to discussions of the stereochemistry and of the electronic structure of para-substituted acetophenone azines. With a series of symmetric para-substituted acetophenone azines, the stereochemistry and the electronic structures are investigated experimentally and theoretically. Unlike the case of parent system, formaldazine, which prefers N-N s-trans conformation, all the results indicate that the symmetric para-substituted acetophenone azines assume N-N gauche conformations and the phenyl rings are twisted out the best plane without indication of conjugation in the solid state, in solution, and in the gas phase. Furthermore, the structural analyses demonstrate that there are no significant manifestations of N-N conformation and of phenyl conjugation effects even with push and pull substituents on the asymmetric para-substituted acetophenone azines. The Natural Population Analysis (NPA) shows that there is no charge transfer in the asymmetric azines. Asymmetrical azines with acceptor and donor groups in the para positions on opposing ends of the molecule can be excellent candidates of novel nonlinear optical (NLO) materials. Some azines have the values of the first hyperpolarizability, β, 5 to 6 times of the value of para-nitroaniline in the EFISH measurements.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9780591479065Subjects--Topical Terms:

523952
Organic chemistry.
Subjects--Index Terms:

carbeniumIndex Terms--Genre/Form:

542853
Electronic books.

An experimental and theoretical study of dinitrogen related chemistry : = Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions.
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100 1 $a Chen, Grace Shiahuy. $3 3705673
245 1 3 $a An experimental and theoretical study of dinitrogen related chemistry : $b Electronic structures of aliphatic diazonium ions, symmetrical and asymmetrical azines, and group via trisubstituted carbenium ions.
264 0 $c 1996
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500 $a Source: Dissertations Abstracts International, Volume: 59-04, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Glaser, Rainer.
502 $a Thesis (Ph.D.)--University of Missouri - Columbia, 1996.
504 $a Includes bibliographical references
520 $a Deamination reactions play an important role in synthetic organic chemistry and their pathways often involve highly unstable, reactive aliphatic diazonium ions. It is the goal to utilize the power of modern ab initio theory coupled to laboratory experimentation to gain a better understanding of the electronic structures of these reactive intermediates. The first crystal structures of aliphatic diazonium ions, β,β-diethoxy- and β,β-dichlorovinyldiazonium ions, were determined and their electronic structures were investigated by ab initio theory. Both experimental and theoretical results indicate that β,β-disubstituted vinyldiazonium ions are better described as disubstituted carbenium ions. However, for the close system, the group VIA trisubstituted carbenium ions C(XH)3+ (X = O, S, Se, Te), the results of the electronic structure analyses show only the trihydroxy carbenium ion has a positively charged C-center together with highly polarized C-O bonds. For all heavier homologues (X = S, Se, Te), the central C-atom carries a negative charge and all the X atoms have positive charge. The results show the umpolung of the C-X bonds for the heavier homologues. Potential conjugative interactions are pivotal to discussions of the stereochemistry and of the electronic structure of para-substituted acetophenone azines. With a series of symmetric para-substituted acetophenone azines, the stereochemistry and the electronic structures are investigated experimentally and theoretically. Unlike the case of parent system, formaldazine, which prefers N-N s-trans conformation, all the results indicate that the symmetric para-substituted acetophenone azines assume N-N gauche conformations and the phenyl rings are twisted out the best plane without indication of conjugation in the solid state, in solution, and in the gas phase. Furthermore, the structural analyses demonstrate that there are no significant manifestations of N-N conformation and of phenyl conjugation effects even with push and pull substituents on the asymmetric para-substituted acetophenone azines. The Natural Population Analysis (NPA) shows that there is no charge transfer in the asymmetric azines. Asymmetrical azines with acceptor and donor groups in the para positions on opposing ends of the molecule can be excellent candidates of novel nonlinear optical (NLO) materials. Some azines have the values of the first hyperpolarizability, β, 5 to 6 times of the value of para-nitroaniline in the EFISH measurements.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Organic chemistry. $3 523952
653 $a carbenium
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0490
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a University of Missouri - Columbia. $3 1017522
773 0 $t Dissertations Abstracts International $g 59-04B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9737904 $z click for full text (PQDT)