Synthesis and Reactivity Studies of Iminoboryl Complexes

A range of new iminoborylcomplexes of the type [L<sub><i>n</i></sub>M−B≡N−R], which are isoelectronic with σ-alkynyl complexes [L<sub><i>n</i></sub>M−C≡C−R], was obtained by systematically varying the metal M, the coligands L, and the nitrogen bound substituent R. Selected examples include, for example, <i>trans</i>-[(Cy<sub>3</sub>P)<sub>2</sub>(Br)Pt(B≡N<i>i</i>Bu)], which is characterized by a sterically less demanding N−R group or the unprecedented rhodium species <i>cis,mer</i>-[(Br)<sub>2</sub>(Me<sub>3</sub>P)<sub>3</sub>Rh(B≡NSiMe<sub>3</sub>)]. All compounds were fully characterized in solution by multinuclear NMR spectroscopy and, where appropriate, in the solid state by X-ray crystallography. Subsequent reactivity studies revealed that particularly the combination of smaller N−R groups with Pt−B linkages of increased stability opens up opportunities for novel reactivity patterns of this class of compounds. Within the scope of these study, we inter alia succeeded in synthesizing the unusual bridged boryl species 1,4-<i>trans</i>-[{(Cy<sub>3</sub>P)<sub>2</sub>(Br)Pt(B{NH<i>i</i>Bu}NH)}<sub>2</sub>C<sub>6</sub>H<sub>4</sub>] and a complex bearing both an acetylide ligand and an iminoboryl ligand, respectively.