A comparison of some p roperties of C=S a nd C=Se bond

There are signific ant and int eresting differences between compounds with thiocarbonyl and seleno carbonyl groups. The C =Se bond length (~ ۱. ۸ Å) is cons iderably lo nger than C=S (~ ۱.۶ Å) [۱]. As a re sult, one w ould expect the bond strengths to differ signific antly. The ʌ-bond also m ight be ex pect to be strongly affe cted in view of the orbital size m ismatch between secon d and third row atoms. On the o ther hand, s elenoamides are known to have larger rotatio nal barriers than thioam ides, where the barrier arises from the interaction nitrogen with the adjacent C=S or C=Se group [۲].

کلیدواژه ها:

Thio carbonyl gro up ، selenoc arbonyl group ، charge d istribution ، force constants