| Abstract: | A synthetic approach to the sandwich complex Cp′′′Co(η4‐P4)] ( 2 ) containing a cyclo‐P4 ligand as an end‐deck was developed. Complex 2 is the missing homologue in the series of first‐row cyclo‐Pn sandwich complexes, and shows a unique tendency to dimerize in solution to form two isomeric P8 complexes (Cp′′′Co)2(μ,η4:η2:η1‐P8)] ( 3 and 4 ). Reactivity studies indicate that 2 and 3 react with further Cp′′′Co] fragments to give (Cp′′′Co)2(μ,η2:η2‐P2)2] ( 5 ) and (Cp′′′Co)3P8] ( 6 ), respectively. Furthermore, complexes 2 , 3 , and 4 thermally decompose forming 5 , 6 , and the P12 complex (Cp′′′Co)3P12] ( 7 ). DFT calculations on the P4 activation process suggest a η3‐P4 Co complex as the key intermediate in the synthesis of 2 as well as in the formation of larger polyphosphorus complexes via a unique oligomerization pathway. |
