Antimony-121 nuclear magnetic resonance study of hexahaloantimonate anions

Abstract

R. GARTH KIDD and H . GARTH SPINNEY. Can. J . Chem. 59.2940Chem. 59. (1981.The seven hexahaloantimonate anions in the series [SbC&Br,-,I-have been prepared and their antimony-121 nrnr spectra show that for [SbCI4Br2]-. [SbCI,Br,]-, and [SbCI2Br4]-. only the cis isomers are present in acetonitrile solution. The pairwise additivity model for central atom shielding has been used for configuration assignments. Models relevant to the higher incidence of c i~ over trans isomers are discussed. The nuclear shielding of l2ISb is the most sensitive to halogen substitution of all the elements whose halide chemical shifts have been studied. Antimony shieldings exhibit normal halogen dependence, with bromine substitution causing upjeld shifts relative to chlorine substitution. R. GARTH KIDD et H. GARTH SPINNEY. Can. J . Chem. 59, 2940Chem. 59, (1981.On a prepare les sept anions hexahaloantimonates de la serie [SbCI,Br,-,I; leurs spectres rmn du Sb-121 revelent que seuls les isomeres cis des anions [SbCI4Br2]-, [SbCl,Br,] et [SbC12Br4] sont presents en solution dans l'acetonitrile. On a utilise le modele d'additivite par paire du blindage de I'atome central pour attribuer les configurations. On discute de modeles appropries pour expliquer la presence preponderante des isomeres cis sur les isomeres truns. De tous les elements dont on a etudie les deplacements chimiques des halogenes, le blindage nucleaire du SbIZ1 est le plus sensible a la presence des halogenes. L'effet de I'halogene sur le blindage de l'antimoine est normal par rapport au chlore alors que le brome provoque un deplacement vers les champs forts.[Traduit par le journal]

Tetrachloro- and Tetrabromostibonium(V) Cations: Raman and 19F, 121Sb, and 123Sb NMR Spectroscopic Characterization and X-ray Crystal Structures of SbCl4+Sb(OTeF5)6- and SbBr4+Sb(OTeF5)6-

“…Despite their high receptivities and large dynamic chemical shift ranges, the group 15 nuclides 75 As, 121 Sb, 123 Sb, and 209 Bi have been little exploited for chemical studies because their quadrupolar nature tends to produce extremely broad resonances, owing to the efficient quadrupolar mechanism which dominates their relaxation behavior. A few NMR studies in which 75 As, ,− 121 Sb, ,,− 123 Sb, ,, and 209 Bi 34,50 nuclides have been employed clearly demonstrate their usefulness, under specific conditions, for structural characterization in solution. A number of these studies are concerned with pnicogen(V) hexahaloanions, ,− , but no tetrahalocation of a heavy pnicogen has been characterized by NMR spectroscopy.…”

“…A few NMR studies in which 75 As, ,− 121 Sb, ,,− 123 Sb, ,, and 209 Bi 34,50 nuclides have been employed clearly demonstrate their usefulness, under specific conditions, for structural characterization in solution. A number of these studies are concerned with pnicogen(V) hexahaloanions, ,− , but no tetrahalocation of a heavy pnicogen has been characterized by NMR spectroscopy.…”

Interaction of Halogenoantimonates with Aromatic Compounds in organic solvents

“…The solutions of tetraalkylammonium salts are stable under the same conditions. 12lSb-NMR measurements lead to a single antimony species in acetonitrile solutions [27,281. Surprisingly, the same behaviour has been established for Sb,Br,2-and Sb111SbzBr2,6-[ 291.…”

Chlorobromoantimonates(V): New synthesis and 121Sb‐NMR study

“…These reactions are characterized by a poor reliability : mixtures of compounds are often obtained (reactions 7', 15), slight variations of the experimental conditions lead to very different products, and, moreover, the products of a given reaction may vary surprisingly from one to another experiment (reactions 7,7', 8, 9).…”

“…SbCl,Br,-gives two moderately wide, near overlapping signals attributed to cis-1) see for comparison the newly published ref. [15] and trans-structures. The widest signal corresponds to SbCl,Br,-, which cannot be explained, even if we suppose a cis-structure (CZv) for this ion; we think that cis-trans equilibrium takes place and that the two corresponding peaks are overlapping, leading to the wide asymmetrical envelope observed.…”