Correction to “Chemically Recyclable, High Molar Mass Polyoxazolidinones via Ring-Opening Metathesis Polymerization”

In our original publication, the ¹³C NMR spectra that were used for microstructure assignment and quantification lacked resolution of all eight signals that arise from a mixture of E- and Z-alkenes as well as head-to-tail (HT), head-to-head (HH), and tail-to-tail (TT) regioisomeric linkages. The signal-to-noise of the original band-selective HMBC NMR spectra showed HT cross peaks for the more prominent ¹³C NMR peaks and did not show these cross peaks for the lower intensity ¹³C NMR peaks, leading us to our original peak assignments. Subsequently acquired spectra for P3 detected two overlapping peaks at 130.02 and 129.97 ppm that were previously not resolved. A band-selective HMBC spectrum using a higher field instrument (900 vs 500 MHz in our original publication) indicated the microstructures in our original publication were assigned incorrectly from the lower resolution spectra. The major versus minor peaks in the ¹³C NMR spectra arise from differences in alkene geometry rather than from regiochemistry, as originally reported. The microstructure of P3 consists of 67% HT and 33% HH+TT linkages (quantified from the peaks at 130.02 and 129.97 ppm) as well as 86% E- and 14% Z-alkenes (assigned from the relative intensity of the peaks in the IR spectrum and quantified using all peaks). Newly acquired ¹³C NMR spectra of P2 and P4 unfortunately did not have an analogous increase in resolution, even when acquired on a 900 MHz instrument. While the lower resolution for these polymers prevents the assignment of regiochemistry, the alkene geometry has been corrected to 84% and 78% E-alkenes for P2 and P4, respectively. The overall conclusions of the work are not affected except for the microstructure analysis. In the main text, this section should now read: “Because these Oxa-fused COE monomers are unsymmetrical, we attempted to characterize the regioregularity of enchainment for M2–M4 using IR and NMR spectroscopies. There was insufficient resolution in the ¹³C NMR spectra to characterize the regioselectivity of M2 and M4, but M3 showed 67% head-to-tail enchainment (see Section S2E for more details)”. In the Supporting Information, this section (Section S2E) on page S11 should now read “We therefore acquired a quantitative ¹³C NMR spectrum using a 20 s relaxation delay (Figure S14D,E), which determined P3 contains 67% HT and 33% HH+TT linkages as well as 86% E- and 14% Z-alkenes.” On page S12, this section should now read “An analogous analysis was performed for P2 ... and P4 ... to determine the microstructure. While the regiochemistry of enchainment could not be determined due to insufficient resolution in the ¹³C NMR spectra, P2 was found to have 84% E-alkenes and P4 to have 78% E-alkenes”. Figure S13. Band-selective HMBC (900 and 226 MHz, CDCl₃) of P3 with correlations highlighted with solid (E-alkenes) and dashed (Z-alkenes) lines. Correlations on the nitrogen (H) side are in blue, on the oxygen (T) side in red, and between sides in purple for the HT regioisomer. Figure S14. Partial ¹³C NMR spectrum (151 MHz, CDCl₃) of P3 acquired with (A) 2 s, (B, D, E) 20 s, and (C) 30 s relaxation delays using the Bruker zgig30 pulse sequence and (A–C) 128 or (D, E) 1275 scans. The peaks in Part D were fit in MestReNova using a generalized Lorentzian peak shape with the integrals for the peaks at 130.02 and 129.97 ppm (used to quantify regiochemistry) given in Table S8. The deconvoluted peaks are shown in blue, the sum in pink, and the residuals in red. The peaks in Part E were integrated using the standard integration feature in MestReNova for the quantification of the alkene geometry. The corrected versions of Figures S13, S14, S19, and S25, along with the corrected captions for Figures S20 and S26 are presented here. New Table S8 tabulates the integrations of the deconvoluted quantitative ¹³C NMR peaks for P3, and new Figure S49 shows unresolved alkene peaks for P2 and P4 in the ¹³C NMR spectra using a 900 MHz instrument. Figure S19. Band-selective HMBC spectrum (500 and 126 MHz, CDCl₃) of P2. Figure S20. Partial ¹³C NMR (151 MHz, CDCl₃, 20 s relaxation delay) spectrum of olefin region of P2 used to quantify the ratio of E- and Z-alkenes. Figure S25. Band-selective HMBC spectrum (500 and 126 MHz, CDCl₃) of P4. Figure S26. Partial ¹³C NMR (151 MHz, CDCl₃, 60 s relaxation delay) spectrum of olefin region of P4 used to quantify the ratio of E- and Z-alkenes. Determined in MestReNova from line fitting with a generalized Lorentzian peak shape. Normalized by the number of C atoms (i.e., 1 for HT or 2 for TT). Figure S49. Partial ¹³C NMR spectra (226 MHz, CDCl₃) of (A) P2 and (B) P4 showing the alkene peaks were unresolved even at a higher field. The higher field spectra were recorded on a Bruker 900 MHz Avance III instrument with a TCI cryoprobe [(¹H, 900 MHz), (¹³C, 226 MHz)] at 22 °C. This article has not yet been cited by other publications.