Diborane(4)yl and bridged borylene complexes from 1,2-dipyrrolidino- and 1,2-dipiperidinodiborane(4) derivatives

The 1,2-diaminodichlorodiboranes(4) B-2(NC(4)H8)(2)Cl-2 (1) and B-2(NC5H10) (2)Cl-2 (2) served as starting materials for the syntheses of the iron dibo rane(4)yl complexes [Cl(R2N)B-B(NR2)Fe(C5H5)(CO)(2)] (3a, NR2=NC4H8; 3b, NR 2=NC5H10). Upon reaction with the anionic manganese hydride complex K[(C5H4 Me)MnH(CO)(2)], the bridged borylene complexes [{(C5H4Me)Mn(CO)(2)}(2)BNR2] (4a, NR2=NC4H8; 4b, NR2=NC5H10) were obtained with cleavage of the boron-b oron bond, hydrogen migration from manganese to boron, and formation of the corresponding diboranes(6) (H2BNR2)(2). All complexes were obtained as cry stalline materials and fully characterized in solution by IR and multinucle ar NMR spectroscopy. (C) 1999 Elsevier Science S.A. All rights reserved.