New group 4 organometallic and imido compounds of diamide-diamine and related dianionic O2N2-donor ligands

New group 4 compounds supported by the tetradentate diamide-diamine ligand N 2 NN' are reported (N 2 NN' = (2-C5H4N)CH2N(CH2CH2NSiMe3)2) along with some comparative studies with the new bis(alkoxide)-diamine ligand O 2 NN' (O 2 NN' = (2-C 5 H 4 N)CH 2 N(CH 2 -CMe 2 O) 2 ). Reaction of the previously described ZrCl 2 (N 2 NN') (1) with 2 equiv of MeLi or PhCH 2 MgCl gave ZrR 2 (N 2 NN') (R = Me (2) or CH 2 Ph (3)). Reaction of 1 with 1 equiv of RCH 2 MgCl gave the monoalkyl analogues ZrCl(R)(N 2 NN') (R = CH 2 Ph (6) or CH 2 SiMe 3 (7)). Reaction of Zr(CH 2 R) 4 (R = SiMe 3 or CMe 3 ) with H 2 N 2 NN' in C 6 D 6 gave the corresponding Zr(CH 2 R) 2 (N 2 NN'), but these decomposed over several hours. Reaction of 1 with allylmagnesium chloride gave ZrCl{(2-NC5(6-C3H5)H4)CH2N(CH2CH2NSiMe3) 2 }, in which the pyridyl group has undergone nucleophilic attack. Reaction of 2 with BAr F 3 (Ar F = C 6 F 5 ) in benzene led to the cyclometalated cation [Zr{(2-NC 5 H 4 )CH2N(CH2CH2NSiMe3)(CH2CH2NSiMe2CH2-)}] + via SiMe 3 group C-H activation, but in the presence of THF the methyl cation [ZrMe-(THF)(N 2 NN')] + was formed. Reaction of 6 with BAr F 3 gave the chloride cation [ZrCl(N 2 -NN')] + . Reaction of Li 2 N 2 NN' with Ti(NR)Cl 2 (py) 3 gave the five-coordinate imides Ti(NR)(N 2 NN') (R = t Bu or Ar (15), Ar = 2,6-C 6 H 3 i Pr 2 ). Zirconium imides Zr(NAr)(N 2 NN') and Zr(N t Bu)-(py)(N 2 NN') (18) were prepared by sequential reaction of 1 with LiCH 2 SiMe 3 (2 equiv) and the appropriate amine and pyridine for the latter. Reaction of 1 with LiNH t Bu (2 equiv) gave Zr(NH t Bu) 2 (N 2 NN'). Reaction of 18 with piperidine gave Zr(NHtBu)(NC 5 H 1 0 )(N 2 NN') (19) via N-H bond activation. For comparative purposes the group 5 imides M(N t Bu)Cl-(N 2 NN') (M = Nb (20) or Ta (21)) were prepared from Li 2 N 2 NN' and the corresponding M(N t -Bu)Cl 3 (py) 2 . Reaction of 2-aminomethylpyridine with an excess of isobutylene oxide afforded H 2 O 2 NN' (22). Reaction of H 2 O 2 NN' (1 or 2 equiv) with Ti(NMe 2 ) 4 gave Ti(O 2 NN') 2 , which reacted with TiCl 4 (THF) 2 to form TiCl 2 (O 2 NN'). Reaction of H 2 O 2 NN' with Zr(CH 2 SiMe 3 ) 2 -Cl 2 (Et 2 O) 2 , Zr(NMe 2 ) 4 , or Zr(CH 2 SiMe 3 ) 4 gave ZrX 2 (O 2 NN') (X = Cl, NMe 2 , or CH 2 SiMe 3 (27)). Reaction of 27 with BAr F 3 in the presence of THF formed [Zr(CH2SiMe3)(THF)(02NN')]+, but in the absence of a Lewis base the /<-alkoxide-bridged dimer [Zr2(CH2SiMe3)2(O 2 NN') 2 ] 2 + was formed. The compounds 3, 6, 15, 19, 21, 22, and 27 were crystallographically characterized.