Figure 2.

ATR‐FTIR spectra of the photodecomposition of 1 (2 mm in water) under 420 nm irradiation. A) Full spectral range, 3700–640 cm⁻¹. B) Second derivative spectra, 3650–2950 cm⁻¹, highlighting rapid decrease in ν(OH_Pt‐OH) at 3350 cm⁻¹ in the first few minutes. C) Second derivative spectra, 2100–1980 cm⁻¹, highlighting the decrease and shifts in ν _sym(N₃) at 2048/2033 cm⁻¹ to 2023 cm⁻¹ and 2044 cm⁻¹ sequentially prior to complete disappearance. D) Second derivative spectra, 1650–640 cm⁻¹, highlighting decrease in ν _sym(N₃) at 1271 cm⁻¹ and increase in δ(OH_Pt‐OH) at 1381 cm⁻¹ and 1334 cm⁻¹. Notations used: ν=stretch, δ=in‐plane angle bending, γ=out‐of‐plane angle bending, sym=symmetric and asym=antisymmetric. The labelling of pyridine modes is given in Wilson's notations, as described previously.9