Journal of the Korean Chemical Society (대한화학회지)

Korean Chemical Society (대한화학회)
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Paramagnetic Deshielding Effects by Aryl Groups of Triaryl-9-thioxanthenylphosphonium Perchlorate

삼아릴-9-티오크잔테닐포스포니움 과염소산염의 아릴기에 의한 상자기성 벗김 효과

  • Kwang Hyun Ahn (Department of Chemistry, College of Natural Science, Seoul National University) ;
  • Kyong Tae Kim (Department of Chemistry, College of Natural Science, Seoul National University)
  • 안광현 (서울대학교 자연과학대학 화학과) ;
  • 김경태 (서울대학교 자연과학대학 화학과)
  • Published : 1981.06.30
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Abstract

In contrast with pmr (only multiplets at ${\delta}6.6$∼7.8 ppm) spectrum of triphenyl-9-thioxanthenylphosphonium perchlorate and tri-o-methoxyphenyl-9-thioxanthenylphosphonium perchlorate, tri-n-butyl-9-thioxanthenylphosphonium perchlorate and tribenzyl-9-thioxanthenylphosphonium perchlorate showed a doublet at ${\delta}5.58$ and 5.70ppm, respectively, assigned to a methine proton. This value is slightly larger than the corresponding values (${\delta}5.05$~5.30) of 9-arylthioxanthenes but clearly differentiated from those of aromatic protons. This result implys that the downfield shift of a methine proton of triaryl-9-thioxanthenylphosphonium perchlorate is not due to inductive effects of an electron deficient phosphorus atom but paramagnetic deshielding effects by three aryl groups on phosphorus.

삼페닐-9-티오크잔텐닐포스포니움 과염소산염과 삼-오르토-메톡시페닐-9-티오크잔텐닐포스포니움 과염소산염과는 대조적으로 삼-n-부틸-9-티오크잔텐닐포스포니움 과염소산염과 삼벤질-9-티오크잔텐닐포스포니움 과염소산염은 각각 ${\delta}5.58$ppm과 ${\delta}5.70$ ppm 에서 methine 양성자에 해당하는 이중상을 보여주었다. 이 값은 9-아릴티오크잔틴의 상응값 (${\delta}5.05$~5.30)보다 다소 큰 값이나 방향족화합물의 양성자의 값과는 분명히 차이가 난다. 이 결과는 삼아릴-9-티오크잔텔닐포스포니움 과염소산염의 methine 양성자가 낮은 장으로 이동한 원인이 전자가 부족한 인원자에 의한 유발 효과때문이 아니라 인에 결합된 세개의 아릴기의 상자기성 벗김 효과에 의한 것임을 의미한다.

Keywords

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