Figure 6.

ATR‐FTIR spectra of the photodecomposition of 1 (2 mm)+5′‐GMP (2 mol equiv) under 420 nm irradiation. A) Full spectral range, 3800–645 cm⁻¹, including main peak assignments. Refer to Figure S20 in the Supporting Information for a full description of peak vibrations. B) ATR‐FTIR spectra, 2200–1950 cm⁻¹, highlighting the decrease and shifts in ν _asym(N₃) at 2031 cm⁻¹ to 2046 cm⁻¹ and the appearance of a new peak at 2164 cm⁻¹. C) ATR‐FTIR spectra, 1850–1150 cm⁻¹, highlighting the decrease in ν(CO) at 1697 cm⁻¹, ν _sym(N₃) at 1271 cm⁻¹ and ν(CC,CN_{pyr breathing}) at 1178 cm⁻¹, as well as the increase of several (new) peaks at 1172, 1670, 1643, 1610, 1570, 1500, 1406 and 1358 cm⁻¹. D) ATR‐FTIR spectra, 1190–640 cm⁻¹, highlighting the increase of the broad ν_asym(PO₃ ²⁻) peak at 1076 cm⁻¹ and the shift of ν(PO) from 777 cm⁻¹ to 768 cm⁻¹. Notations used: ν=stretch, δ=in‐plane angle bending, sym=symmetric, asym=antisymmetric, pur breathing=purine breathing mode and arrows indicate direction of change to the vibration throughout irradiation.