Bridged ferrocenes—VII

Synthesis and Ring‐Opening Polymerization of Highly Strained, Ring‐Tilted [2]Ruthenocenophanes

“…This has been confirmed in preliminary cyclic voltammetry experiments which have shown that the poly(ruthenoceny1ethylene) 7b possesses an irreversible oxidation wave at 0.60 V,["I whereas the poly(ferrocenylethy1ene) 5 (R = Me) undergoes a reversible oxidation at -0.27 V under the same condit i o n~. '~' E.yperitneiital Procedure 6a: A solution of Li,[C,H,CH,], [18] (0.95 g, 5.6 mmol) in T H F (40 mL) wasadded dropwise to a subpension of clr-[RuCl,(dinso),] 1191 (2.70 g, 5.6 mmol) in the same solvent (40 mL) at ~ 78 C. The reaction mixture was stirred at this temperature for 3 h and was then allowed to warm to room temperature over a 12 h period.…”

“…germanium, or phosphorus atom in the bridge undergo thermal ring-opening polymerization (ROP) to yield high molecular weight polymers (such as 2) . [2-61 These [llferrocenophane monomers possess strained structures in which the cyclopentadienyl ligands are significantly tilted by about[18][19][20][21][22][23][24][25][26][27]" with respect to one ar10ther.I~. ' .…”

Syntheses, Structures, and Reactivity of Radial Oligocyclopentadienyl Metal Complexes: Penta(ferrocenyl)cyclopentadienyl and Congeners

“…This outcome indicates that steric blocking of the “dangling” Cps in 3 c may be required to enforce the desired regiochemistry of annealing. Noteworthy in the 1 H NMR spectrum of 6 is the unusually deshielded resonance at δ =8.73 ppm, tentatively assigned to H14, positioned close to Fe1 (3.00 Å in the crystal) and its deshielding cone 25…”

Photocontrolled Ring‐Opening Polymerization of Strained Dicarba[2]Ferrocenophanes: A Route to Well‐Defined Polyferrocenylethylene Homopolymers and Block Copolymers

“…Additionally, dicarba[2]metallocenophanes show substantially smaller distortions at the bridging elementCp bonds compared to [1]metallocenophanes, reflected in much smaller β angles (compare 1 : β =37.0° vs. 3 : β =12.7°). Accordingly, rather than anionically‐induced ROP, metalation of 2 by using n BuLi/ N , N , N ′, N ′‐tetramethylethylenediamine (TMEDA) can be achieved, leaving the ferrocenophane moiety intact,24 while no reaction was observed between 3 a and n BuLi 25…”