Triamidoamine chemistry of zirconium

The reactions of H-3(NN3') (NN3' = N((CH2CH2NSiBuMe2)-Me-t)(3)) with [Zr(CH 2Ph)(4)] and [Zr(NMe2)(4)] give the azazirconatranes [Zr(NN3')(CH2Ph)] and [Zr(NN3')(NMe2)], respectively. The reaction of [Li-3(NN3')(THF)(3)] with [ ZrCl4(THF)(2)] fails to yield [Zr(NN3')Cl] cleanly, but this compound is ac cessible by reaction of [Zr(NN3')(CH2Ph)] with BCl3 or of [Zr(NN3')(NMe2)] with SiMe3Cl. The molecular structures of [Zr(NN3')X] (X = CH2Ph, NMe2, Cl) show that the triamidoamine ligands adopt the usual S-fold symmetric arran gement to give approximately trigonal-bipyramidal complexes. Attempted subl imation of [Zr(NN3')(CH2Ph)] or its treatment with Ha leads to clean conver sion to the metallacyclic complex [Zr{N((CH2CH2NSiBuMe2)-Me-t)(2)(CH2CH2NSi BuMeCH2)-Me-t}] via deprotonation of a silylmethyl group and elimination of toluene. The molecular structure of this complex contrasts with those abov e in that the tert-butyldimethylsilyl groups adopt an upright conformation as a consequence of the presence of the metallacyclic unit. The dihedral an gles N-ax-Zr-N-eq-Si are in the range 173.8-177.2 degrees. Exposure of the metallacycle to D-2 gas leads to deuteration of all three Me2Si groups via sequential deuteriolysis/sigma-bond metathesis. The less acidic (BuSi)-Bu-t and backbone CH2 groups are unaffected.