199462-45-8Relevant academic research and scientific papers
Synthesis and reactivity of bis(alkoxysilylamido)yttrium η2-pyridyl and η2-α-picolyl compounds
Duchateau, Robbert,Brussee, Edward A. C.,Meetsma, Auke,Teuben, Jan H.
, p. 5506 - 5516 (2008/10/08)
The synthesis and reactivity of bis(alkoxysilylamido)yttrium pyridyl and α-picolyl complexes [Me2Si(NCMe3)(OCMe3)]2YR (R = η2-(C,N)-2-NC5H4 (1); R = η2-(C,N)-CH2-2-NC5H4 (2); R = η2-(C,N)-C(H)Me-2-NC5H4 (3); R = η2-(C,N)-C(H)Me-2-NC5H3-6-Me (4)) is reported. 1-4 have been prepared by C-H activation of pyridine and the corresponding methyl (ethyl) and dimethyl-substituted pyridines from [Me2Si(NCMe3)(OCMe3)]2YCH(SiMe 3)2 and by salt metathesis with the appropriate lithium salts from [Me2Si(NCMe3)(OCMe3)] 2YCl·THF. The molecular structure of 2 shows that the picolyl group is bonded to yttrium in an η3-aza-allylic fashion. With dihydrogen, stepwise hydrogenation of the pyridyl fragment of 1 has been observed, finally yielding the 2,3-dihydropyridyl complex [Me2Si(NCMe3)(OCMe3)]2Y-NC 5H8 (7). Compound 1 inserts ethene to form the α-methylpicolyl derivative 4. Polymerization of ethene was not observed. The pyridyl compound 1 reacts with PhC≡CH to yield the corresponding acetylide pyridine complex [Me2Si(NCMe3)(OCMe3)] 2YC≡CPh·Py (8). The complexed pyridine can be substituted by THF to give [Me2Si(NCMe3)(OCMe3)] 2YC≡CPh·THF (9), which easily loses THF and forms the base-free acetylide [Me2Si(NCMe3)(OCMe3)]2-YC≡CPh (10). Compounds 1 and 2 readily insert nitriles yielding imido-pyridine complexes. The imido-pyridine complexes that contain α-hydrogen readily undergo a 1,3-H shift affording the corresponding enamido-pyridine compounds. With CO, the pyridyl compound 1 gives a dipyridylketone complex {[Me2Si(NCMe3)(OCMe3)] 2Y}{μ,η2,η2-(N,N',O)-OC(2-NC 5H4)2} (15).
