Organylselenoacetylene und selenocyanate; 77Se- und 13C-NMR-chemische verschiebungen und 77Se- 13C-spin-kopplungskonstanten

⁷⁷Se and ¹³C NMR chemical shifts and ⁷⁷Se-¹³C spinspin coupling constants of mono- and bis(organylseleno)acetylenes and organyl selenocyanates are shown. The changes of ⁷⁷Se chemical shifts caused by variation of the organyl groups are well reflected by known increments. The δ(⁷⁷Se) and ¹J(⁷⁷Se¹³C) values of the investigated compounds are discussed in relation to the corresponding alkyl- and vinyl-selenides. The ¹J(⁷⁷Se¹³C) values of the selenoacetylenes and selenocyanates as well as alkyl- and vinyl-selenides are linearly dependednt (i) on ¹J(¹³C¹H) values of the corresponding hydrocarbons, hydrogen cyanide respectively and (ii) on the product of the s-characters of the coupled Se and C atoms. These linear correlations prove the predominance of the Fermi contact term for changes of the one-bond ⁷⁷Se¹³C coupling in dependence on hybridization.