Beiträge zur Chemie des Bors: CXCVII. Synthese, Struktur und Komplexbildung von 1,3,2,4-Diphosphadiborabicyclo[1.1.0]butanen

1,3,2,4-Diphosphadiboretanes are photochemically labile and on irradiation react to give 1,3,2,4-diphosphadibora[1.1.0]cyclobutane derivatives, provided that the substituents at the boron atoms are bulky dialkylamino groups, e.g., t-Bu2N or tmp (2,2,6,6-tetramethylpiperidino). The bicyclic ring contains a rather long PP bond (2.35 Å), indicating considerable ring strain. [(tmp)B]2P2 reactsw ith Fe2(CO)9 to produce [(tmp)B]2P2[Fe(CO)4] and [(tmp)B]2P2[Fe(CO)4]2.