Some investigations of organotellurium chemistry

Abstract

Diaryl ditellurides, Rote, (R = Ph, p-CH3,C6H4, p-CH30C6H4) , P-C2H5OC6H4, p-PhOC6H4 and 1-Naphthyl were prepared. The IR and Raman spectra of these compounds between 400-40 on™ | are presented. Detailed assignments of the spectra of PhoTe, are attempted. The tellurium-telluriun stretching frequency in all cases is identified between 167-187 cm’. The evidence from these spectroscopic data suggested that the structure of diaryl ditellurides have Cy skeletal symmetry. There is no evidence to support previous claims that. diphenyl ditelluride readily dissociates into radicals in solution, Attempts to prepare unsymmetrical diaryl ditellurides were unsuccessful. The infrared and where possible the Raman spectra between 400-40 cm-1 of five classes of aryltelluriumn trihalides, RTeX, (R = Ph, p-CHzC¢Hy» p-CHz0C GH, p-C 5H, OC 6H, aand p-PhOC 6H, (X = Cl, Br and I) are presented. The tellurium-halogen vibrational modes are indicated and . detailed assignments for spectra of Phiexs are offered. The low frequency data and other physical evidence suggested the compounds are associated to some degree with dimeric structures the most probable for chlorides and iodides in which the tellurium atom has coordination number five. There is evidence that some bromides, notably PhTebr,, (p-CH3C ¢H, )TeBr., and (p-PhOC ¢H, )TeBrz are more associated. The structures are best described as involving donor-acceptor interaction between X” and RTeX+2. The infrared and Raman spectra of aryltelluriumn oxyhalides, RTeOX (R = Ph, P-CoH,OC EH, x = Cl, ary) ete presented. The tellurium oxygen vibrational modes of the compounds are assigned. p-Phenetyltellurium trichloride Was: hydrolysed with 40% sodium ekiouats solution, the products obtained are RTeOOH, and (RTeO) 0 when the previous one was acidified with dilute acetic acid. The assignment of tellurium oxygen vibrational modes of these products are also given. PhTeCl, and (p~C 5H, OC EH, )TeC1, both reacted with pyridine in benzene gave RTeCly PyH*. The mechanism of hydrolysis of aryltellurium trihalides with water is suggested. The micro-analysis method of tellurium in organotellurium compounds by atomic absorption spectroscopy is developed. The compounds were decomposed with concentrated nitric acid and perchloric acid, and the absorption of aqueous solutions was recorded. Telluric acid AR grade is used as a standard,