Organophosphorus compounds ester bonds

Quite often, we find nonsystematic nomenclature used in the literature dealing with organophosphorus compounds. This results in unnecessary confusion, as systematic nomenclature is easy to use and understand. Nomenclature based on the oxidation state of the phosphorus center eliminates the confusion and helps to promote understanding of the chemistry as well as to facilitate communication. Table 1.1 shows structures for tricoordinate and tetracoordinate phosphorus compounds related to oxyacids with their English general names. Also noted are the names for simple esters of the parent acids. They are organized based on oxidation state and the number of bonds of the carbon-phosphorus type. 

There is a vast chemistry of organophosphorus compounds, and even for arsenic, antimony, and bismuth, the literature is voluminous. Consequently only a few topics can be discussed here. It must also be noted that we discuss only the compounds that have P—C bonds. Many compounds sometimes referred to as organophosphorus compounds that are widely used as insecticides, nerve poisons, and so on, as a result of their anticholinesterase activity, do not, in general, contain P—C bonds. They are usually organic esters of phosphates or thiophosphates examples are the well-known malathion and parathion, (EtO)2Pv(S)(0C6H4NO2). Compounds with P—C bonds are almost entirely synthetic, though a few rare examples occur in Nature. 

The use of the term organophosphorus compound has generally been limited to those materials that contain a direct carbon-phosphorus covalent bond. We continue this restriction in the present discussion. As a result, we will omit from this discussion the chemistry and nature of materials, while containing both carbon and phosphorus, that lack the direct covalent connection of the two elements. Other sources provide significant information on such materials as simple esters of phosphoric and phosphorous acid. ... 

The major part of the phosphorus-containing insecticides cannot be considered as organophosphorus compounds in the strict sense because they do not contain a P—C bond. These compounds are esters, amides, anhydrides and fluorides of phosphoric, phosphorothioic and phosphorodithioic acids. Most of them can be classified in one of the types shown in Table 1.2. 

The number of insecticides containing a P—C bond and thus considered as organophosphorus compounds in the strict sense is considerably lower. They are predominantly esters of alkane- and benzenephosphonic acids and their sulfur analogues , ... 

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