Ammonia-Borane Derived BN Fragments Trapped on Bi- and Trimetallic Titanium(III) Systems.

Titanium(III) complexes containing unprecedented (NH2BH2NHBH3)(2-) and {N(BH3)(3)}(3-) ligands have been isolated, and their structures elucidated by a combination of experimental and theoretical methods. The treatment of the trimethyl derivative [TiCp*Me-3] (Cp*=eta(5)-C5Me5) with NH3BH3 (3 equiv) at room temperature gives the paramagnetic dinuclear complex [{TiCp*(NH2BH3)}(2)(mu-NH2BH2NHBH3)], which at 80 degrees C leads to the trinuclear hydride derivative [{TiCp*(mu-H)}(3){mu(3)-N(BH3)(3)}]. The bonding modes of the anionic BN fragments in those complexes, as well as the dimethylaminoborane group trapped on the analogous trinuclear [{TiCp*(mu-H)}(3)(mu(3)-H)(mu(3)-NMe2BH2)], have been studied by X-ray crystallography and density functional theory (DFT) calculations.