Insertion reactions of GaCp*, InCp* and In[C(SiMe3)3] into the Ru–Cl bonds of [(p-cymene)RuIICl2]2 and [Cp*RuIICl]4

Abstract

The first carbonyl free ruthenium/low valent Group 13 organyl complexes are presented, obtained by insertion of ER (ER = GaCp*, InCp*, In[C(SiMe₃)₃]) into the Ru–Cl bonds of [(p-cymene)RuCl₂]₂, [Cp*RuCl]₄ and [Cp*RuCl₂]₂. The compound [(p-cymene)RuCl₂]₂ reacts with GaCp*, giving a variety of isolated products depending on the reaction conditions. The Ru–Ru dimers [{(p-cymene)Ru}₂(GaCp*)₄(μ₃-Cl)₂] (1) and the intermediate [{(p-cymene)Ru}₂(μ-Cl)₂] (2) were isolated, as well as monomeric complexes [(p-cymene)Ru(GaCp*)₃Cl₂] (3), [(p-cymene)Ru(GaCp*)₂GaCl₃] (4) and [(p-cymene)Ru(GaCp*)₂Cl₂(DMSO)] (5). The reaction of [Cp*RuCl]₄ with ER gives “piano-stool” complexes of the type [Cp*Ru(ER)₃Cl] (ER = InCp* (6), In[C(SiMe₃)₃] (7), GaCp* (8)). The chloride ligand in complex 8 can be removed by NaBPh₄, yielding [Cp*Ru(GaCp*)₃]⁺[BPh₄]⁻ (9). The reaction of [Cp*RuCl₂]₂ with GaCp* however, does not lead to an insertion product, but to the ionic Ru(II) complex [Cp*Ru(GaCp*)₃]⁺[Cp*GaCl₃]⁻ (10). The ER ligands in complexes 3, 5, 6, 7 and 8 are equivalent on the NMR timescale in solution due to a chloride exchange between the three Group 13 atoms even at low temperatures. The solid state structures, however, exhibit a different structural pattern. The chloride ligands exhibit two coordination modes: either terminal or bridging. The new compounds are fully characterized including single crystal X-ray diffraction. These results point out the different reactivities of the two precursors and the nature of the neutral p-cymene and the anionic Cp* ligand when bonding to a Ru(II) centre.