STABILIZATION OF LITHIUM BOROHYDRIDE WITH NITROGEN DONOR, CHELATING LIGANDS - SYNTHESES AND SOLID-STATE STRUCTURES OF [HC(3,5-ME(2)PZ)(3)]LI(ETA(3)-BH4), ([H2C(3,5-ME(2)PZ)(2)]LI(MU-ETA(3)-BH4))(2), AND ([4,4'-ME(2)BIPY]LI(MU-ETA(3)-BH4))(2) (PZ = PYRAZOLYL, BIPY = BIPYRIDYL)
Dl. Reger et al., STABILIZATION OF LITHIUM BOROHYDRIDE WITH NITROGEN DONOR, CHELATING LIGANDS - SYNTHESES AND SOLID-STATE STRUCTURES OF [HC(3,5-ME(2)PZ)(3)]LI(ETA(3)-BH4), ([H2C(3,5-ME(2)PZ)(2)]LI(MU-ETA(3)-BH4))(2), AND ([4,4'-ME(2)BIPY]LI(MU-ETA(3)-BH4))(2) (PZ = PYRAZOLYL, BIPY = BIPYRIDYL), Inorganic chemistry, 36(27), 1997, pp. 6266-6269
The reaction of HC(3,5-Me(2)pz)(3) and LiBH4 in THF yields [HC(3,5-Me(
2)pz)(3)]Li(eta(3)-BH4) (pz = pyrazolyl). In the solid state, the boro
hydride ligand is tridentate with an octahedral arrangement about the
lithium. A similar reaction using HC(pz)(3) yields the insoluble ionic
compound {[HC(pz)(3)](2)Li}(BH4). Reaction of equimolar amounts of Li
BH4 and H2C(3,5-Me(2)pz)(2) yields {[H2C(3,5-Me(2)pz)(2)]Li(mu-eta(3)-
BP4)}(2). This complex is a centrosymmetric dimer in the solid state h
aving two bridging [eta(3)-BH4](-) ligands. For each [eta(3)-BH4](-) l
igand, there is one mu(3)-H and two mu(2)-H atoms. A similar reaction
with H2C(pz)(2) yields {[H2C(pz)(2)]Li(BH4)}(2) and with 4,4'-dimethyl
-2,2'-bipyridine (4,4'-Me(2)bipy) yields {[4,4'-Me(2)bipy]Li(mu-eta(3)
-BH4)}(2). The structure of {[4,4'-Me(2)bipy]Li(mu-eta(3)-BH4)}(2) in
the solid state is similar to that of {[H2C(3,5-Me(2)pz)(2)]Li(mu-eta(
3)-BH4)}(2), except the Li2B2 central core is not planar and both mu(3
)-H atoms are on the same side of this core.