Investigation of the structure of hydroxymethyl derivatives of ammelide and ammeline from their ir spectra

Comparison of the Thermal and Photochemical Reaction Pathways of Melamine on TiO2

“…Even if they are involved in the melamine decomposition pathway on TiO 2 , their contribution must be minor. Furthermore, no reaction product of ammeline, ammelide, or cyanuric acid (Figure S1, Supporting Information) is generated, because the characteristic bands of ∼1700–1800 cm –1 and/or ∼1375 cm –1 were not detected . No g-C 3 N 4 material, which has a relatively strong ∼1320 cm –1 band, was formed either. − We also investigated thermal decomposition of melamine on TiO 2 in the closed cell with 5 Torr of O 2 initially.…”

Role of Topological Charge Stabilization in Protomeric Tautomerism

“…Given that Gimarc’s original formulations are based on the simple Hückel molecular orbital method, − these aspects are sometimes neglected. To explain this situation, let us consider ammeline 39 and ammelide 40 (Figure ). − The π-electron density distribution q r of the reference hydrocarbon is shown at the bottom of Figure . From the calibrated Δ E T above, we can expect that the keto form of ammeline and the diketo form of ammelide should be the most stable tautomers.…”

“…From actual DFT calculations (Figure ), we see that these inequalities are almost correct. The product analyses of methylolation has shown that ammeline 39 behaves in a melamine-like manner and ammelide 40 behaves as cyanuric acid-like molecules, in which terminal and ring protons, respectively, are active for formaldehyde. , Keto-type ammeline 39b has also been observed by infrared spectroscopy, and is inferred from the nearly closed energies of the two tautomers. There are no reliable reports on the enol-type ammelide.…”