Donors such as amine and phenolic groups, when positioned ortho to a nitro group, are always involved in intramolecular hydrogen bonding.
在硝基邻位上存在的氢键给体如胺基，酚基时，总与硝基形成分子内氢键。
2
The invention relates to a hair dyeing method starting from a composition comprising at least one ortho-diphenol, one metal salt, hydrogen peroxide, (bi)carbonate and a basifying agent.