Solvation of polymeric organolithium compounds. Stoichiometry and heats of interaction of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with poly(styryl)lithium and poly(isoprenyl)lithium

The enthalpies of interaction of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with poly‐(isoprenyl)lithium and poly(styryl)lithium were measured as a function of R ([base]/[Li]) by using high‐dilution solution calorimetry at 25°C. Both polymeric organolithiums exhibit initial exothermic enthalpies of interaction with TMEDA (R ≃ 0.1) of ca. −13 kcal/mole. The concentration dependencies show a break (decrease) in the plot of ΔH vs. R at ca. R = 0.5 for poly(isoprenyl)lithium and at ca. R = 1.0 for poly(styryl)lithium.