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)(NC(5)H(10))(2)Cl(2) (2) served as starting materials for the syntheses of the iron diborane(4)yl complexes [Cl(R(2)N)B-B(NR(2))Fe(C(5)H(5))(CO)(2)] (3a, NR(2)=NC(4)H(8); 3b, NR(2)=NC(5)H(10)). Upon reaction with the anionic manganese hydride complex K[(C(5)H(4)Me)MnH(CO)(2)], the bridged borylene complexes [{(C(5)H(4)Me)Mn(CO)(2)}(2)BNR(2)] (4a, NR(2)=NC(4)H(8); 4b, NR(2)=NC(5)H(10)) were obtained with cleavage of the boron-boron bond, hydrogen migration from manganese to boron, and formation of the corresponding diboranes(6) (H(2)BNR(2))(2). All complexes were obtained as crystalline materials and fully characterized in solution by IR and multinuclear NMR spectroscopy. (C) 1999 Elsevier Science S.A. All rights reserved.