A x [W 6 I 14 ] compounds with A = Na, K, Rb, or Cs are prepared from W 3 I 12 and alkali iodides (AI). Crystal structures were solved and refined for Na[W 6 I 14 ] and A 2 [W 6 I 14 ] compounds with A = K, Rb and Cs on the basis of powder and single-crystal XRD diffraction. All compounds behave stable in air and can be dissolved in polar organic solvents making them [a]
Upon reaction of the dipyrido-anellated guanidinium salt 1 with one equivalent of CpNa we were able to synthesize the dipyrido-anellated diaminofulvalene 4 in one step in 33% isolated yield. This shortens the initial route that applies a literature-known fulvalene synthesis via uronium salt 3 by two steps and avoids the need for a sacrificial equivalent of CpNa. Although the X-ray structure analysis reveals a shorter exocyclic double bond than observed in the diaminofulvalene V, a theoretical analysis based upon DFT calculations shows a stronger zwitterionic character for the dipyridofulvalene 4.
The highly dipolar fulvalene 1 reacts with pentacarbonyl iron(0) and hexacarbonyl tungsten(0) complexes under irradiation with UV light. The cyclopentadienyl complexes 2 and 3 formed are analysed by means of NMR and IR spectroscopy as well as X-ray analysis. They are the first zwitterionic carbonyl complexes of fulvenes or ful-2228 valenes. In the case of iron, the dinuclear complex 2 consisting of a dicarbonyliron(+I)-tetracarbonylferrat(-I) moiety is formed, whereas in the case of tungsten, the mononuclear tricarbonyl tungsten(0) complex 3 is obtained.
The synthesis of a η-coordinated LiCp complex by simple addition of a Li-salt in benzene is presented. A strongly zwitterionic fulvalene serves as the Cp-precursor. Evidence for the coordination of Li was obtained by the characterisitic Li NMR chemical shifts, variable temperature experiments in solution and by X-ray structure analysis in the solid state.
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