Selenocarbonyl complexes structur

The reactions of selenocarbonyl compounds with electrophiles are also well-established procedures. Alkylations or acylations of the selenium atom of selenoamides409 or selenoureas410 are known. Selenonium salts are formed initially they can then be converted into diselenides, selenazoles, or cyclic selenides depending on their structure. Reactions of selenocarbonyls with bromine and iodine have also been widely exploited. Selenocarbonates, sele-nothiocarbonates,411-415 and selenoureas416-418 can be employed, the reaction of 209 with 1 equiv. bromine led to the hypervalent 10-Se-3 complex 210, whereas an excess of bromine gave rise to a cleavage of the carbon-selenium double bond and formation of product 211 (Scheme 64). 

Selenocarbonyl compounds can form different metal complexes and some general structures are shown in Figure 9. 

Studies on the chemistry of selenocarbonyl compounds have been increasingly reported din ing the past decade. Initially, the focus had been mainly on the development of new synthetic methods for the preparation of selenocarbonyl compoimds. The various achievements have allowed the evaluation of a wide range of applications. X-ray molecular structures of some derivatives have been disclosed. Selenocarbonyl compoimds that are relatively stable but still retain high reactivity have exhibited unique reactions. The present review outlines the characteristic features of selenocarbonyl compounds. Their syntheses and reactions are classified on the basis of reaction patterns rather than the substituents adjacent to selenocarbonyl group. Several types of metal complexes having selenocarbonyl groups are described as well. 

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