Deuterated

Deuterated refers to molecules in which at least one hydrogen atom has been replaced by deuterium (2H, D), a stable isotope with one proton and one neutron. Deuterium is heavier than protium, the most common hydrogen isotope, and this mass difference causes small changes in vibrational frequencies, bond strengths, and nuclear magnetic resonance properties. In NMR spectroscopy, deuterium has a distinct resonance and deuterated solvents such as CDCl3 and C6D6 are used to minimize background signals and provide a deuterium lock.

Applications and effects: Deuteration is widely used to trace chemical and biological pathways through isotopic labeling. It can slow reaction rates via the kinetic isotope effect, aiding mechanistic studies. In pharmaceutical development, deuterated drugs may exhibit altered metabolic stability, potentially affecting clearance and toxicity. In analytical chemistry, deuterated standards improve accuracy in mass spectrometry and chromatography.

Methods: Deuteration is achieved by exchanging labile hydrogens with deuterium from D2O or deuterated reagents, or by catalytic hydrogen–deuterium exchange using deuterium gas (D2) or deuterated reagents. Non-exchangeable positions can be labeled via de novo synthesis with deuterated precursors. Some methods employ enzymatic or photochemical processes to introduce deuterium.

Examples: Common deuterated solvents include CDCl3, C6D6, and DMSO-d6. Heavy water, D2O, is used as a neutron moderator and as a solvent in some NMR applications, though ingestion at high levels can disrupt biological processes. Deuterated compounds are generally stable and non-radioactive.