CH2POOH2

CH2POOH2 is a shorthand notation used in organic and organophosphorus chemistry to denote the phosphonomethyl group, written structurally as -CH2-P(=O)(OH)2. In this arrangement a methylene group is bonded to a phosphorus atom bearing a phosphoryl oxo (P=O) and two hydroxyl groups. This moiety is the phosphonic acid fragment that appears in a number of bioactive and synthetic compounds.

Chemistry and properties: The phosphorus is in the +5 oxidation state and the group forms a tetrahedral center. The CH2P(=O)(OH)2 fragment is highly polar and water-soluble. Phosphonic acids have two acidic protons: pKa1 around 1–2 and pKa2 around 7–8, so deprotonation occurs in aqueous solution depending on pH. The group can be esterified to give phosphonate esters, and the C–P bond allows attachment to various organic cores. It is relatively stable under neutral conditions but hydrolyzes under strong acid or base to yield the parent phosphonic acid.

Occurrence and applications: The phosphonomethyl motif is present in several agrochemicals and biochemical reagents. Glyphosate, N-(phosphonomethyl)glycine, contains this group attached to a glycine backbone, and AMPA (aminomethylphosphonic acid) features the same phosphonomethyl unit with an amino substituent. The motif is also used in the synthesis of ligands, catalysts, and materials, where the strong chelating ability of phosphonates is exploited. Some organisms produce natural phosphonate compounds, illustrating the biological relevance of P–C bonds in this chemistry.

Name and related groups: The fragment is commonly referred to as the phosphonomethyl group. Related phosphorus-oxygen chemistry includes methylphosphonic acid (CH3P(=O)(OH)2) and other phosphonate derivatives.