学 位 記 番 号 理工博 第

氏 名 ナラヤナン

ナエル

ラディカ

所 属 理工学研究科 分子物質化学専攻 学 位 の 種 類 博士（理学）

学 位 記 番 号 理工博 第

号 学位授与の日付 平成

年

月

日 課程・論文の別 学位規則第４条第

項該当

学 位 論 文 題 名

金属錯体の電子構造と分光学的物性

英文

論 文 審 査 委 員 主査 教 授 波田 雅彦

委員 教 授 杉浦 健一

委員 教 授 斎藤雅一

埼玉大学

【論文の内容の要旨】

Summary

Density Functional Theory (DFT) is one of the most widely used methods for electronic structure calculations of the atoms, molecules, crystals, surfaces, and their interactions. In this research work, DFT methods were applied for spectroscopic studies, bonding analysis and reaction modelling and classified as four distinct chapters.

The first chapter deals with the relative stability and selective formation of the di- µ-oxo dimetal complexes of the titanium(IV), vanadium(IV), chromium(IV) and manganese(IV) with tetradentate salen ligands bearing different degrees of steric bulk.

Two different ligands were chosen for the study, namely 3-Imino-propen-1-ol (denoted

as Ligand 1) and (R,R)- N,N′- bis(3,5-di-tert-butyl salicylidene)-1,2-cyclohexanediamine

(denoted as Ligand 2). The di-µ-oxo dimetal complexes with the least sterically

encumbered model ligand 1 preferred the M-helical structure. The enhanced stability of

the M-helical form was an intrinsic feature of di-µ-oxo dimetal complexes. In the

titanium(IV) and chromium(IV) complexes containing a practical chiral salen ligand 2, the P-helical form was found to be stable. In contrast, the corresponding vanadium(IV) and manganese(IV) complexes preferred to exist in the M-helical form.

This trend was attributed to the cooperation of the steric repulsion effects between the two bulky chiral salen ligands, structural deformation around the di-µ-oxo dimetal core and a decrease in the electronic repulsion between the phenolate oxygen atoms in the ligand.

The second chapter describe the electronic structure,

C and

Pb-NMR chemical shift of metal coordinated plumbylenes, namely monorhodioplumbole ([Rh-Pb]

), dirhodioplumbole (Rh

-Pb) and dilithioplumbole (Li

-Pb), which have a five membered ring containing lead.

The former part examined the bonding interactions in the [Rh-Pb]

and Rh

-Pb complexes using DFT calculations. In the later part, ZORA-DFT calculations were performed to discuss the

Pb- and

C- NMR chemical shifts of the atoms on the plumbole ring. The computed

Pb and

C

NMR shift could reproduce the experimental values reasonably. The importance of the relativistic effect, role of the functional, effect of solvent and dependence of exact exchange (EE) admixture were analyzed on the calculated

Pb and

C

NMR shift.

The isotropic shielding constant was decomposed into diamagnetic, paramagnetic and spin-orbit terms the role of each term on the NMR chemical shift value were analyzed.

The third chapter explored the mechanism of the monorhodioplumbole ([PbRhcod]

) catalyzed cyclotrimerization reaction of the acetylene to afford benzene.

The energy profile derived from the ([PbRhcod]

)

were compared with a simple CpRhcod catalyst to probe the role of the (plumbole)

ligand in the cyclotrimerization reaction.

The fourth chapter focuses on the simulation of the structure and the infrared

spectra of methyl acetate and its isotopologues (CD

-COO-CH

and CH

-COO-CD

) in the crystalline phase using DFT calculations.

Initially the accuracy of the pseudopotential were examined and the IR frequencies were confirmed by performing molecular calculations using a periodic model of methyl acetate and its isotopologues using SIESTA and compared them with results obtained from Gaussian 09 (all electron method) calculations. Further the structure and IR spectra of the crystalline methyl acetate were determined using SIESTA code to refine the mode assignments of the IR frequencies and probe the low frequency modes that were unavailable in the experimental studies. Finally the vibrational modes of the CD

-COO-CH

and CH

-COO-CD

in the crystalline phase were assigned for which the experimental data are not available in the interstellar medium condition.

References

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