ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 25, Number 3
JKCSEZ 25(3)
June 20, 1981 

In contrast with pmr (only multiplets at δ6.6∼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 δ5.58 and 5.70ppm, respectively, assigned to a methine proton. This value is slightly larger than the corresponding values (δ5.05~5.30) 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.