Coordination Properties of Novel Tridentate Cyclopentadienyl Ligands in Titanium and Zirconium Complexes

New half-sandwich zirconium(IV) complexes containing salicylaldimine ligands: Synthesis, characterizations and catalytic properties

“…The 13 C NMR spectral analysis [47] on the resultant poly(ethylene-co-1-hexene)s reveals that the samples produced in the presence of each of these catalysts have relatively low 1-hexene content, and the 1-hexene content of the copolymers obtained with complex 2(1.42%) are slightly higher than those produced by complex 1(0.87%). As reported in other literatures [16][17][18][19][20][21][22][23][25][26][27][28][29][30] , half sandwich zirconium complexes bearing a variety of ligands show much poorer 1-hexene incorporation than their titanium counter parts, probably due to the difference between the zirconium and titanium metal centers. The 13 C NMR spectrum of a typical copolymer sample prepared with complex 2/Al i Bu 3 /Ph 3 CB(C 6 F 5 ) 4 system is shown in Fig.6.…”

“…Among them, some non-bridged and bridged zirconocene complexes were found to exhibit unique catalytic characteristics for the stereospecific polymerization of propylene [14,15] . Since halfsandwich titanium complexes were found to be excellent catalysts for ethylene copolymerization with α-olefins [16][17][18][19][20][21] , some half sandwich zirconium complexes bearing a benzamidinate [22] , aryloxy [23,24] , salicylaldimine [25,26] , β-diketiminate [27,28] , anilide [29][30][31][32] or imino-quinolinol [33] ligand have also been synthesized and tested as catalysts for ethylene polymerization and copolymerization with α-olefins. So far, only a few number of zirconium complexes of this type with a salicylaldimine ligand have been reported [25,26] .…”

Synthesis and reactivity of new silyl substituted monocyclopentadienyl zirconium complexes. X-ray molecular structure of [Zrη5-C5H4 (SiMe2CH2Ph)(CH2Ph)3]

“…Four different methods have been used in order to find a convenient preparative route for group 4 metal com-pounds of type [M(r/~-CsHs_nRn)C13] (see Scheme 1). Route A involves the metathetical reaction of MC14 with the appropriate main group metal cyclopentadienide in equimolar ratio [13][14][15][16][17][18]. This procedure works well for sterically crowded cyclopentadienyl groups but is found to fail for non or less bulky substituted Cp rings for which the corresponding metallocene dichloride derivatives are obtained.…”

Zirconium and Hafnium Complexes with (Allylsilyl)(η‐amidosilyl)‐η5‐cyclopentadienyl Ligands: Synthesis, Structure and Reactivity

“…Selected bond lengths and angles are given in Table 1 [36][37][38][39][40][41][42][43][44][45] The almost equal bridging Zr-Cl distances are significantly longer than the terminal Zr-Cl distance, and this last bond length again falls in the range 2.432-2.529 Å retrieved from the CSD files for similar complexes. To the best of our knowledge, the only chloro-bridged dimeric zirconium complex found in the literature containing a (amidosilyl)cyclopentadienyl moiety is (R,R)-[ZrCl(µ-Cl)] {η 5 :η 1 -C 5 Me 4 SiMe 2 NCH(Me)(Ph)} 2 , [39] where the Zr-Cl bridging bond lengths are significantly different.…”

“…The trans influence of the amido nitrogen and chlorine coordinating atoms seem similar in 6, and the bridging Zr-Cl bond lengths are not significantly different. The C1 atom that bears the amidosilyl arm is pyramidally distorted, as shown by the sum of bond angles (350.8°) as in the other chloro(amidosilyl)cyclopentadienyl complexes, [36][37][38][39][40][41][42][43][44][45] and in the doubly silylamido-bridged cyclopentadienyltitanium complex, [46] while the C4 atom that bears the allylsilyl arm is weakly pyramidally distorted (the sum of the bond angles is 359.3°). The Si1 and Si2 atoms are out of the Cp plane by -0.845(2) and 0.250(3) Å, respectively.…”