ChemInform Abstract: New Oligomeric Tungsten-Selenium Anions: Synthesis and Characterization by 77Se NMR and X-Ray Diffraction Techniques.

ChemInform Abstract

Four new oligomeric anions of the W-Se system, W₃Se₉^2-, W₂Se₉^2-, and W2Se1^2-0 (two isomers) have been prepared as shown in the scheme. The structure of (III) (triclinic, P1, Z=1) is closely related to that of the analogous, W₃S₉^2- species. In the mixed crystal (IV) (P1, Z=2), the W₂Se₉^2- and W2Se1^2-0 ions are present in the same cell with occupancies of 0.66 and 0.34, respectively. W₂Se₉^2- has approximate Cs symmetry with square-pyramidal coordination about the W atoms. The major isomer of (V) (P1, Z=2) is identical with that found in (IV) and its structure closely resembles the analogous W2S1^2-0 ion. The minor isomer of (V) has no known sulfide analogue.