Fig. 1.

2D ¹H-¹³C HETCOR solid state NMR spectrum of [2/SiO_{2- (700)}] contacted with ¹³C dilabeled ethene. This spectrum was acquired under eDUMBO-1_12.5 (44) homonuclear decoupling (F₁) and SPINAL-64 (45) heteronuclear decoupling (F₂) at ν₁^H = 100 kHz. The contact time for CP and the recycle delay were 500 μs and 2 s, respectively. A total of 48 t₁ points with 512 scans each were collected. A scaling factor (λ_exp) of 0.54 was used in F₁ for eDUMBO-1_12.5 homonuclear decoupling. Asterisks indicate spinning side bands of the alkylidene resonance [W] = CH₂. The ¹³C CP MAS spectrum (512 scans) recorded with a CP step of 500 μs and a recycle delay of 2 s is indicated above the 2D plot. To the left of the 2D plot is shown the ¹H single pulse spectrum (eight scans). Dashed and dotted correlations correspond to the methylidene [W]=CH₂ and metallacyclobutane [W](CH₂CH₂CH₂) moieties in 4 and 5, respectively.