Synthesis, Structure, and Reactivity of RuII Complexes with Trimethylsilylethinylamidinate Ligands

The mononuclear amidinate complexes [(?6-cymene)-RuCl(1a)] (2) and [(?6-C6H6)RuCl(1b)] (3), with the trimethylsilyl-ethinylamidinate ligands [Me3SiC=CC(N-c-C6H11)2] (1a) and[Me3SiC=CC(N-i-C3H7)2] (1b) were synthesized in high yields by salt metathesis. In addition, the related phosphane complexes[(?5-C5H5)Ru(PPh3)(1b)] (4a) [(?5-C5Me5)Ru(PPh3)(1b)] (4b), and [(?6-C6H6)Ru(PPh3)(1b)](BF4) (5-BF4) were prepared by ligand exchange reactions. Investigations on the removal of the trimethyl-silyl group using [Bu4N]F resulted in the isolation of [(?6-C6H6)Ru(PPh3){(N-i-C3H7)2CC=CH}](BF4) (6-BF4) bearing a terminal alkynyl hydrogen atom, while 2 and 3 revealed to yield intricate reaction mixtures. Compounds 1a/b to 6-BF4 were characterized by multinuclear NMR (1H, 13C, 31P) and IR spectroscopy and elemental analyses, including X-ray diffraction analysis of 1b, 2, and 3.