Straightforward, multigram synthesis of the new diamidediamine proligand H 2 N 2 NNA [N 2 NNA = (2-NC 5 H 4 )-CH 2 N(CH 2 CH 2 NSiMe 3 ) 2 ] is described along with a preliminary survey of the five-and six-coordinate, neutral and cationic, single-and multiply-bonded complexes of groups 3, 4 and 5 that it can support; the related bis(alkoxide)diamine proligand H 2 O 2 NNA is also described where H 2 O 2 NNA = (2-NC 5 H 4 )CH 2 N(CH 2 CMe 2 OH) 2 .

New group 4 compounds supported by the tetradentate diamide-diamine ligand N2NN‘ are reported (N2NN‘ = (2-C5H4N)CH2N(CH2CH2NSiMe3)2) along with some comparative studies with the new bis(alkoxide)-diamine ligand O2NN‘ (O2NN‘ = (2-C5H4N)CH2N(CH2CMe2O)2). Reaction of the previously described ZrCl2(N2NN‘) (1) with 2 equiv of MeLi or PhCH2MgCl gave ZrR2(N2NN‘) (R = Me (2) or CH2Ph (3)). Reaction of 1 with 1 equiv of RCH2MgCl gave the monoalkyl analogues ZrCl(R)(N2NN‘) (R = CH2Ph (6) or CH2SiMe3 (7)). Reaction of Zr(CH2R)4 (R = SiMe3 or CMe3) with H2N2NN‘ in C6D6 gave the corresponding Zr(CH2R)2(N2NN‘), 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 BArF 3 (ArF = C6F5) in benzene led to the cyclometalated cation [Zr{(2-NC5H4)CH2N(CH2CH2NSiMe3)(CH2CH2NSiMe2CH2−)}]+ via SiMe3 group C−H activation, but in the presence of THF the methyl cation [ZrMe(THF)(N2NN‘)]+ was formed. Reaction of 6 with BArF 3 gave the chloride cation [ZrCl(N2NN‘)]+. Reaction of Li2N2NN‘ with Ti(NR)Cl2(py)3 gave the five-coordinate imides Ti(NR)(N2NN‘) (R = tBu or Ar (15), Ar = 2,6-C6H3 iPr2). Zirconium imides Zr(NAr)(N2NN‘) and Zr(NtBu)(py)(N2NN‘) (18) were prepared by sequential reaction of 1 with LiCH2SiMe3 (2 equiv) and the appropriate amine and pyridine for the latter. Reaction of 1 with LiNHtBu (2 equiv) gave Zr(NHtBu)2(N2NN‘). Reaction of 18 with piperidine gave Zr(NHtBu)(NC5H10)(N2NN‘) (19) via N−H bond activation. For comparative purposes the group 5 imides M(NtBu)Cl(N2NN‘) (M = Nb (20) or Ta (21)) were prepared from Li2N2NN‘ and the corresponding M(NtBu)Cl3(py)2. Reaction of 2-aminomethylpyridine with an excess of isobutylene oxide afforded H2O2NN‘ (22). Reaction of H2O2NN‘ (1 or 2 equiv) with Ti(NMe2)4 gave Ti(O2NN‘)2, which reacted with TiCl4(THF)2 to form TiCl2(O2NN‘). Reaction of H2O2NN‘ with Zr(CH2SiMe3)2Cl2(Et2O)2, Zr(NMe2)4, or Zr(CH2SiMe3)4 gave ZrX2(O2NN‘) (X = Cl, NMe2, or CH2SiMe3 (27)). Reaction of 27 with BArF 3 in the presence of THF formed [Zr(CH2SiMe3)(THF)(O2NN‘)]+ , but in the absence of a Lewis base the μ-alkoxide-bridged dimer [Zr2(CH2SiMe3)2(O2NN‘)2]2+ was formed. The compounds 3, 6, 15, 19, 21, 22, and 27 were crystallographically characterized.

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