Heteronucleare clustersysteme : XIX. Structuruntersuchungen an tetraedrischen carbonylcobalt-clustern; ein beitrag zur frage der bildung von carbonylbrücken

Abstract

The tetrahedral carbonylcobalt clusters (CO) 9Co 3CC 6H 2(CH 3) 3(II), (CO) 8P(CH) 3) 3Co 3Co(CO) 3 (III) and (CO) 7[P(CH 3) 2C 6H 5] 2Co 3Fe(H)(CO) 2P(CH 3) 2C 6H 5 (IV) were synthesized, and investigated by single-crystal X-ray diffraction methods together with the known compound (CO) 9Co 3CCl (I). The results of the structure determinations show that the mesityl-substituted methylidyne-cluster II can be arranged structurally between the non-bridged cluster I and the two CO-bridged clusters III and IV. The o-CH 3 substituents of the mesityl group act as pseudo ligands of the apical carbon atom and push the neighbouring CO ligands into the Co 3-plane: one condition for the formation of bridges as they exist in the compounds III and IV.