Intra and Intermolecular Interaction of Conformational Equilibria in Fluorene Derivatives
Project/Area Number |
60470023
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Research Category |
Grant-in-Aid for General Scientific Research (B)
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Allocation Type | Single-year Grants |
Research Field |
有機化学一般
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Research Institution | Yamaguchi University |
Principal Investigator |
KAJIGAESHI Shoji Yamaguchi Univ. Faculty of Engineering Professor, 工学部, 教授 (90035030)
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Co-Investigator(Kenkyū-buntansha) |
NISHIDA Akiko Yamaguchi Univ. Faculty of Engineering Assistant, 工学部, 助手 (70144920)
FUJISAKI Shizuo Yamaguchi Univ. Faculty of Engineering Lecture, 工学部, 講師 (60035045)
NOGUCHI Michihiko Yamaguchi Univ. Faculty of Engineering Assistant Professor, 工学部, 助教授 (10108772)
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Project Period (FY) |
1985 – 1986
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Project Status |
Completed (Fiscal Year 1986)
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Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥7,000,000 (Direct Cost: ¥7,000,000)
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Keywords | Fluorene / Restricted rotation / Conformational equilibrium / DNMR spectrum / 分子内相互作用 |
Research Abstract |
9-Arylfuorene derivatives have a high energy barrier to the rotation about C_<sp>3-C_<sp>2 bonds, and many investigations to their conformations have been done. Now, several 9-(2-substituted phenyl)derivatives, in which the 2-substituents bear hetero atoms such as sulfur and nitrogen, were prepared and the nonbonding interactions (attraction or repulsion) between the 2-substituent and the fluorene ring or another substituent at 9-position were investigated by means of the conformational analysis. The intereting findings containing the exsistence of NH..<pi> interaction in these systems were summarized as follows: 1. 9-Substituted 9-(2-methylthiophenyl)fluorene Derivatives (1). These were classified into three cases. (1) The steric repulsion between the methylthio group and the 9-substituents makes the ap-form predominant; (2) The nonbonding interaction, e.g, hydrogen bond, between the methylthio group and the 9-substituents results in the sp-form predominantly; (3) The above interactions were competitive, and therefore, two conformers were existed in the equilibria (ap<double half arrows>sp). 2. 9-Bustituted 9-(2-methylsulfinylphenyl)fluorene Derivativesional The conformational equilibria of 2 are somewhat different from those of 1. The sp-form were predominant in most cases due to the interaction between the morw electrophilic sulfur atom and the substituents at the 9-position. 3. 9-Substituted 9-(2-dimethylaminophenyl)fluorene Derivatives (3). The predominance of the sp-form in this system was derived by the electronic repulsion between the amino group and the fluorene ring. Interestingly, in acidic media the predominant conformer of 3 was converted to the ap-form, stemmed from the attractive (NH..<pi>) interaction between the ammonium group and the <pi> electron of fluorene nuclei. The interaction was dependent of the <pi> electron density and its energy was estimated to be blow 1 kcal/mol by means of MO calculations.
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Report
(2 results)
Research Products
(6 results)