Reactions of boranes and metallaboranes with phosphines*
Lawrence Barton, Oleg Volkov, Mitsuhiro Hata, Paul McQuade, and Nigam
P.Rath
Department of Chemistry and Biochemistry and the Center
for Molecular
Electronics, University of Missouri-St.Louis, St.Louis, MO 63121, USA
Abstract: This paper reports extensions of the well-established
field of phosphine�borane chemistry. Linked clusters, for example, {[(PPh3)2(CO)OsB4H7-3-BH2-PPh2]2
[(Fe(C5H4)2]}, are formed in reactions
of rigid backboned bidentate phosphines with {2,2,2-(PPh3)2(CO)-nido-2-OsB5H9].
Reaction of bidentate phosphines with the unsaturated clusters [8,8-PPh3)2-nido-8,7-RhSB9H10]
and [9,9-(PPh3)2-nido-9,7,8-RhC2B8
H11] leads to the isolation of novel species such as {1-(PPh3)[1,3-(�-dppm)]-closo
-1,2-RhSB9H8},with a dppm molecule bridging adjacent metal and boron
vertices in the cage, [1,1-(�2-dppe)-3-(�1-dppm)-closo-1,2-RhSB
9H8], a mixed ligand system, and {9,9-�2-[(�2-BH3)PPh2PCH2
PPh2]-nido- 9,7,8-RhC2B8H11} which contains a bidentate dppm
BH3 moiety. The formation of bidentate phosphine-linked main group transition-metal
moieties such as [BH3PPh2(CH)nPPh2IrCp*Cl2] is also described
as is an example of a bidentate phosphine-polyhedral borane adduct [NR4][B11H12(dppm)] in which the borane cage is isoelectronic with
[B11H14]�. Finally, a novel oxidative coupling reaction promoted
by Cp2ZrCl2/n-BuLi to form the new nonaborane cage system, arachno
-B9H11(PPh3)2, an unusual homolog of the well-known species B10H12(PPh3)2, is reported.
*Lecture presented at the XIth International Meeting
on Boron Chemistry (IMEBORON XI), Moscow, Russia, 28 July - 2 August
2002. Other presentations are published in this issue,
pp. 1157-1355.
