Highly strained, ring-tilted [1]ferrocenophanes containing group 16 elements in the bridge: synthesis, structures, and ring-opening oligomerization and polymerization of [1]thia- and [1]selenaferrocenophanes

Synthesis of the first sulfur- and selenium-bridged [1]ferrocenophanes showed that these species have tilt angles of 31 degrees and 26 degrees respectively. Evidence for the high degree of ring strain was further provided by nuclear magnetic resonance chemical shifts of the ipso-carbon atoms in the [1]chalcogenaferrocenophanes. Data indicate that ring-opening polymerization reactions are less efficient in the formation of poly(ferrocenyl chalcogenides). Detailed studies of physical properties will be made when higher molecular weight samples of become available.