Phosphorus Selenium Hetrocycles

The synthesis, organic reactivity, and metal-complex formation of interesting (RP)xSey heterocycles is reviewed. These heterocycles can now be accessed through a variety of means including the simple use of elemental selenium, Ph3PSe, and the versatile (PhP)4Se. These and other reagents have now been used to make a remarkable array of P - Se heterocycles. For example, cyclic systems with, PSe4, P2Se2, CP2Se and CP2Se2 are described. Many of these compounds have been authenticated with crystal structures revealing unusual features in the structures and bonding. Interest in these compounds has grown substantially in recent years, since selenium has been found to be an essential part of some biologically active molecules and is an essential nutrient for mammals and prevents necrotic degeneration of the liver, heart, and other organs. Moreover, organoselenium compounds have been reported to have potential pharmaceutical properties especially when incorporated into biological compounds.