Transition-Metal-Promoted Reactions of Boron Hydrides. 7. Platinum(II) Bromide Catalyzed Cage Growth and Dehydrocoupling Reactions of Diborane with Small Polyhedral Carboranes and Boranes: Synthesis of a New Arachno Carborane, 5,6-C2B6H12, and the Diborane-Coupled Compounds 2:1', 2'-(1,6-C2B4H5)(B2H5) and 2:1',2'-(B5H8)(B2H5).

摘要

Platinum dibromide has been found to promote cage growth and dehydorcoupling reactions between diborane and small, polyhedral carboranes and boranes, yielding either larger single-cage compounds or bridge-substituted diborane-polydehral carborane/borane complexes. For the catalyzed reaction of diborane with 1,5-C2B3H5, a cage growth reaction occurs to give the new arachno carborane, 5,6-C2B6H12. For 1,6-C2B4H6 and B5H9, cage growth reactins do not take place but instead the coupled diborane-polyhedral cage species 2:1', 2'-(1,6-C2B4H5)(B2H5) and 2:1', 2'-(B5H8)(B2H5) are obtained.