NI23SE12(PET3)13 - AN INTRAMOLECULAR INTERGROWTH OF NISE AND NI

The reaction of Ni(COD)2 (COD = cyclooctadiene) with Et3PSe at elevated temperature gives a mixture of Ni3Se2 and elemental Ni. When the same reagents are combined at lower temperature the cluster compound Ni23Se12(PEt3)13 is formed and can be isolated as a crystalline solid. We have determined the structure of this compound crystallographically (trigonal space group R3c, a = 17.577 (1) angstrom, c = 75.191 (6) angstrom, V = 20118 angstrom3, Z = 6). The crystallography shows the cluster to be a fusion of distorted fragments of NiSe (NiAs structure type) and hexagonally close packed elemental Ni. This cluster can be converted thermally to the same solid products (Ni3Se2 and Ni) as those resulting from the combination of Ni0 and Se0 under the more forcing conditions. This shows that the cluster is allowable as an intermediate in the molecules-to-solids conversion.