Herbert Binder

Transition metal complexes with sulfur ligands: Part CXLIV. Square planar nickel complexes with NiS4 cores in three different oxidation states: synthesis, X-ray structural and spectroscopic studies

Abstract The reaction of ‘buS2’2−=3,5-ditertiarybutyl-1,2-benzenedithiolate(2−) with Ni(ac)2·4H2O and subsequently AsPh4Cl, yielded (AsPh4)2[Ni(‘buS2’)2] (1). Complex 1 is extremely air sensitive and oxidized rapidly to give (AsPh4)[Ni(‘buS2’)2] (2). The anion of 2 could be further oxidized by iodine to give neutral [Ni(‘buS2’)2] (3). Complexes 1, 2 and 3 contain nickel in the formal oxidation states +2, +3 and +4, and could be completely characterized by X-ray structure determination and spectroscopic methods. The results indicate that the oxidation of 1→2→3 concerns electrons residing in molecular orbitals having [NiS4] character. No evidence could be obtained for an involvement of the benzene rings or an electron delocalization beyond the [NiS4] core. This conclusion corresponds with the reactivity of 3 versus 2 and 1 towards protons and CO. While 3 is inert to the attack of H+ and CO, 2 and 1 exhibit rapid reactions to give ‘buS2’H2 and either nickel–chloro complexes or Ni(CO)4.

Thionocarbonat-fixierung durch vib-metallcarbonyle: Chemie, spektroskopie und molekülstruktur

Abstract The pentacarbonyl thionocarbonate metal complexes III, IV, and V are synthesized under photochemical conditions from Cr(CO) 6 , Mo(CO) 6 , W(CO) 6 , and thionocarbonates I in THF. Reactions of the new complexes are described, and spectroscopic properties (IR, NMR, MS, and ESCA) discussed. The crystal structure of IIIa was determined by single crystal X-ray techniques.

(μ2)2-dimercaptotetraborane(10), H2B(μ2-SR)2B3H6

Abstract B4H10 reacts with mercaptans by splitting off H2 to form H2B(μ2-SR)2B3H6 III. An unstable adduct B4H10 RSH I was identified as a precursor of III. The 11B NMR spectra of III showed that the B1,3 signals coalesce at 70°C indicating a rapid inversion. On cooling however, the exo-exo, endo-endo and exoendo invertomers were detected.

A phosphorus–tin cage molecule with an extremely shielded 31P nucleus: P4[Sn(C6H5)2]3

The structure of the compound P4[Sn(C6H5)2]3 was deduced from the 119Sn and 31P NMR spectra and it was shown to be a structural analogue of the hetero‐nortricyclene P4S3. The apical phosphorus atom exhibits an extremely negative 31P chemical shift of ‐554.65 ppm, and the basal phosphorus atoms also resonate at high field strengths. The 31P spectrum includes all tin satellite signals of the [mono‐117/119Sn] isotopomers. The spectra are analyzed as A2A′MX spin systems (A, M=31P; X=117/119Sn). The 31P data for analogous tricyclic cage molecules are presented and discussed.