Structure determination of methyl nicotinate and methyl picolinate by gas electron diffraction combined with ab initio calculations

Hajime Kiyono, Ryosuke Tatsunami, Teruyo Kurai, Hiroshi Takeuchi, Toru Egawa, Shigehiro Konaka

研究成果: Article査読

12 被引用数 (Scopus)

抄録

The molecular structures of isomers, methyl nicotinate and methyl picolinate, have been studied by gas electron diffraction. The samples were heated to 341-343 K by using a high-temperature nozzle to get enough vapor pressure. HF/6-31G* ab initio calculations were carried out, and structural constraints were taken from their results. Vibrational amplitudes and shrinkage corrections were calculated from the harmonic force constants given by normal coordinate analyses. The principal structural parameters of the s-trans conformer of methyl nicotinate are as follows (angle brackets mean averaged values): 〈rg(N-C)〉 = 1.337(7) Å; 〈rg(C-C)ring〉 = 1.402(3) Å; rg(Cring-C(=O)) = 1.480(12) Å; rg(C=O) = 1.199(7) Å; 〈rg(C-O)〉 = 1.380(11) Å; ∠αCNC = 119.0(14)°; 〈∠αNCC) = 122.8(11)°; ∠α(N=)C-Cring-C(=O) = 118.3(12)°; ∠αCring-C=O = 121.5(12)°; ∠αCring-C-O = 115.6(10)°. Those of the s-trans conformer of methyl picolinate are as follows: 〈rg(N-C)〉 = 1.344(7) Å; 〈rg(C-C)ring〉 = 1.398(4) Å; rg(Cring-C(=O)) = 1.497(11) Å; rg(C=O) = 1.209(7) Å; 〈rg(C-O)〉 = 1.380(11) Å; ∠αCNC = 117.2(12)°; 〈∠αNCC〉 = 123.9(12)°; ∠αN-C-C(=O) = 115.1(10)°; ∠αCring-C=O = 121.0(12)°; ∠αCring-C-O = 115.1(12)°. The structural parameters of the two isomers and methyl isonicotinate have been compared and their similarity and differences have been discussed.

本文言語English
ページ(範囲)1405-1411
ページ数7
ジャーナルJournal of Physical Chemistry A
102
8
DOI
出版ステータスPublished - 1998 2 19
外部発表はい

ASJC Scopus subject areas

  • 物理化学および理論化学

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