Analysis of carbon-carbon spin-spin couplings, 1JCC in 3-substituted thiophenes;: Comparison with 1JCC couplings in 2-substituted derivatives

被引:0
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作者
Kamienska-Trela, K [1 ]
Dabrowski, A [1 ]
Nieczyporuk, E [1 ]
Wójcik, J [1 ]
机构
[1] Polish Acad Sci, Inst Organ Chem, PL-01224 Warsaw, Poland
来源
XXXII POLISH SEMINAR ON NUCLEAR MAGNETIC RESONANCE AND ITS APPLICATIONS, PROCEEDINGS | 2000年 / 29卷
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中图分类号
O64 [物理化学(理论化学)、化学物理学]; O56 [分子物理学、原子物理学];
学科分类号
070203 ; 070304 ; 081704 ; 1406 ;
摘要
The measurements of (1)J(CC) couplings performed for a series of variously substituted 3-thiophenes have shown that the magnitude of both (1)J(C2C3) and (1)J(C3C4) couplings strongly depends on the electronegativity of the first atom of the substituent attached to the carbon atom 3, whereas only a small substitutent effect is observed for the (1)J(C4C5) coupling. The coupling values for (1)J(C2C3) vary from 51.5 Hz in 3-trimethylstannyl derivative up to 78.0 Hz in the 3-methoxy compound. The corresponding values for (1)J(C3C4) are 46.0 and 68.9 Hz, respectively. A comparison of the data obtained for 3-substituted thiophenes with those obtained recently by us for analogously 2-substituted derivatives revealed that the influence of the substituent on the (1)J(C2C3) couplings is in most cases very close, i. e. within 0-3 Hz.
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页码:161 / 163
页数:3
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