New Diamide−Diamine Ligands and their Zirconium and Hafnium Dichloride and Bis(dimethylamide) Complexes

• Published in: Inorganic chemistry Vol. 41; no. 5; pp. 1110 - 1119
• Main Authors: Skinner, Michael E. G, Li, Yahong, Mountford, Philip
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11.03.2002
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic011043z

The multigram syntheses of the protio ligands (2-NC5H4)CH2N(CH2CH2NHSiMe2R)2 (R = Me, H2N2NN‘ 3; R = tBu, H2N2NN* 4) are described via reactions of the previously reported (2-NC5H4)CH2N(CH2CH2NH2)2 (1). A new synthesis of 1 is reported starting from 2-aminomethylpyridine and N-tosylaziridine, proceeding via (2-NC5H4)CH2N(CH2CH2NHTs)2 (2). Reaction of H2N2NN‘ or H2N2NN* with nBuLi gives good yields of the dilithiated derivatives Li2N2NN‘ and Li2N2NN*. Reaction of H2N2NN‘ or H2N2NN* with [MCl2(CH2SiMe3)2(Et2O)2] gives the cis-dichloride complexes [MCl2(L)] (L = N2NN‘, M = Zr 7 or Hf 8; L = N2NN*, M = Zr 9). The corresponding reactions of H2N2NN‘ or H2N2NN* with [Zr(NMe2)4] afford the bis(dimethylamide) derivatives [Zr(NMe2)2(L)] (L = N2NN‘ 10 or N2NN* 11). All of these protonolysis reactions proceed smoothly and in good yields. Attempts to prepare the titanium complexes [Ti(X)2(N2NN‘)] (X = Cl or NMe2) were unsuccessful. The X-ray crystal structures of (2-NC5H4)CH2N(CH2CH2NHTs)2·EtOH, [ZrCl2(N2NN‘)]·0.5C6H6, [Zr(NMe2)2(N2NN‘)], and [Zr(NMe2)2(N2NN*)] are reported.