Diphosphetane-diyles: Diradical or Huckel-aromatic ? from orbital and structural isomerism to radical cations and anionic carbenes

The synthesis, crystal structure and bonding properties of various diphosph etane-diyles are discussed and compared with those of other valence isomers . Experimental studies revealed that interconversion of different isomers a re possible. Furthermore, it will be shown that diphosphetane-diyles can se rve as building blocks in organo phosphorus as well as metal organic chemis try.