Rearrangements versus ligand exchange reactions of organocobalt polymer having cobaltacyclopentadiene moieties in the main chain

✍ Scribed by Ikuyoshi Tomita; Akinori Nishio; Takeshi Endo

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 155 KB
• Volume: 12
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199810/11)12:10/11<735::aid-aoc780>3.0.co;2-l

✦ Synopsis

The rearrangement reaction of an organocobalt polymer with cobaltacyclopentadiene moieties in the main chain (1) was carried out to yield a new polymer bearing (h 5 -cyclopentadienyl) (h 4cyclobutadiene)cobalt moieties in the main chain (2). For instance, a polymer (2) containing pure h 4 -cyclobutadienecobalt units was obtained as a yellow powder in 79% yield by the reaction of 1 in tetrahydrofuran (THF) at 110 °C for 1 h in a sealed tube. The polymer (2) obtained was soluble in organic solvents such as chloroform, THF and N,N-dimethylformamide and was quite stable under air. It showed good thermal stability and a weight loss of 5% was observed at 482 °C by thermogravimetric analysis (TGA). On the other hand, displacement of the triphenylphosphine ligands on the main chain of the organocobalt polymer (1), without rearrangement of the cobaltacyclopentadiene rings, was observed when the reaction was carried out in the presence of appropriate ligands such as P(n-Bu) 3 . The resulting ligand-exchanged polymer showed different properties in comparison with 1. For instance a polymer bearing tri-n-octylphosphine is soluble in n-hexane, which is a poor solvent for 1.