A @T06446@ by which one @M03986@ (the @S06082@) is converted into another by the formation of one (and only one) two-centre @B00697@ between the substrate and another molecular entity and which involves no other changes in @C01274@ in the substrate. For example, the formation of an acyl @C00907@ by attachment of carbon monoxide to a @C00812@ (R+):
The product of an attachment may also be the @A00138@ of the two reactants, but not all adducts can be represented as the products of an attachment. (For example, the Diels–Alder @C01496@:
results in an @A00138@ of buta-1,3-diene and ethene, but the reaction cannot be described as an attachment since bonds are formed between more than two centres.)
See also:
electron attachment
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1086 [Terms] [Paper]