ON HETEROCYCLIC-SYSTEMS CONTAINING BISMUTH(III) .2. 8-MEMBERED HETEROCYCLES CL BR/I-M(CH2CH2CH2)(2)X WITH LEWIS ACIDIC GROUP 15 ATOMS M =AS, SB, BI AND DONOR ATOMS X=NR, S - A CONTRIBUTION TO THE VALUE OF THE ELECTRONEGATIVITY OF BISMUTH(III)/

Paths to the ligands (Cl/Br-CH2CH2CH2)(2)NR/O/S/Se, R = Me, Bz, iPr, i Bu, to the diGrignard reagents (Cl/BrMg-CH2CH2CH2)(2)NR/O/S, R = Me, B z, iPr, iBu and to the eight-membered group 15 heterocycles (C1/Br/I-A s/Sb/Bi(CH2CH2CH2)(2)NR/S, R = Me, Bz, iBu are given. C-13-NMR, TR and Raman spectra are discussed; for the compound ClSb(CH2CH2CH2)(2)NMe t he crystal structure analysis is given: the antimony atom is clearly L ewis acidic with psi-trigonal-bipyramidal coordination and a transannu lar Sb ... N interaction of 2.385(2) Angstrom. For such a configuratio n the values of the C-13-NMR chemical shifts of the alpha-CH2-groups ( e.g. Cl-As/Sb/Bi(alpha CH2CH2CH2)(2)NMe 34.6, 25.9, 46.6 ppm) display clearly a sequence N > Bi > P approximate to As > Sb for the Paulins e lectronegativities of the group 15 elements: a value as high as 2.3 fo r bismuth is suggested.