6533b827fe1ef96bd12859ca

RESEARCH PRODUCT

On heterocyclic systems containing bismuth(III) 2. Eight-membered heterocycles Cl/Br/I-M(CH2CH2CH2)2X 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)

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Abstract Paths to the ligands (Cl/Br-CH2CH2CH2)2NR/O/S/Se, R  Me, Bz, iPr, iBu, to the diGrignard reagents (Cl/BrMg-CH2CH2CH2)2NR/O/S, R  Me, Bz, iPr, iBu and to the eight-membered group 15 heterocycles (Cl/Br/I-As/Sb/Bi(CH2CH2CH2)2NR/S, R  Me, Bz, iBu are given. 13C-NMR, IR and Raman spectra are discussed; for the compound ClSb(CH2CH2CH2)2NMe the crystal structure analysis is given : the antimony atom is clearly Lewis acidic with ψ-trigonal-bipyramidal coordination and a transannular Sb⋯N interaction of 2.385(2) A. For such a configuration the values of the 13C-NMR chemical shifts of the α-CH2-groups (e.g. Cl-As/Sb/Bi(αCH2CH2CH2)2NMe 34.6, 25.9, 46.6 ppm) display clearly a sequence N > Bi > P ≈ As > Sb for the Pauling electronegativities of the group 15 elements : a value as high as 2.3 for bismuth is suggested.