Diphosphastannylenes: Precursors for Phosphorus–Phosphorus Coupling?

The preparation of the secondary phosphane (Ph){C 6 H 3 ‐2,6‐(CH 2 NMe 2 ) 2 }PH ( 1 ), a potentially base‐stabilized ligand, and the sterically protected carbaborane‐based phosphane ( o ‐CH 3 C 2 B 10 H 10 ) 2 PH ( 2 ) is reported. Reaction of Sn{N(SiMe 3 )} 2 with 1 gives the diphosphastannylene [(Ph){(C 6 H 3 ‐2,6‐CH 2 NMe 2 ) 2 }P] 2 Sn ( 3 ) in high yield. In contrast, the room‐temperature reaction of 2 with Sn{N(SiMe 2 )} 2 does not proceed. By applying elevated temperatures, the heteroleptic amidophosphastannylene {( o ‐CH 3 C 2 B 10 H 10 ) 2 P}{(SiMe 3 ) 2 N}Sn ( 4 ) was formed, instead of the expected diphosphastannylene {( o ‐CH 3 C 2 B 10 H 10 ) 2 P} 2 Sn. The thermal decomposition of compounds 3 and 4 was also studied. The thermal decomposition of 3 produced the new phosphorus–phosphorus‐bonded compound 5 , an unprecedented 1,2‐diphosphol‐type molecule.