fenolaattiryhmä
The fenolaattiryhmä, a Finnish term, translates to "phenolate group" in English. It refers to the anionic form of a phenol, where the hydroxyl group (-OH) attached to an aromatic ring has lost its proton (H+). This deprotonation results in a negatively charged oxygen atom bonded to the ring. Phenolate ions are significantly more resonance-stabilized than simple alkoxide ions due to the delocalization of the negative charge into the pi system of the aromatic ring. This increased stability makes phenols more acidic than alcohols, and their conjugate bases, phenolates, are consequently weaker bases than alkoxides. Fenolaattiryhmä plays a crucial role in various chemical reactions and biological processes. For instance, phenolates are important intermediates in reactions like the Williamson ether synthesis and can act as nucleophiles or ligands in coordination chemistry. In biological contexts, the phenolate form of certain amino acid residues, such as tyrosine, is involved in enzyme catalysis and protein structure. The specific properties and reactivity of a fenolaattiryhmä are influenced by the substituents present on the aromatic ring. Electron-withdrawing groups generally increase the acidity of the parent phenol, leading to a more stable phenolate, while electron-donating groups have the opposite effect.