Synthesis, Characterization, and Ethylene Polymerization of Group IV Metal Complexes with Mono-Cp and Tridentate Aryloxide or Arylsulfide Ligands

Abstract

Half-sandwich titanium and zirconium complexes with tridentate dianionic aryloxide or arylsulfide ligands [R-2-{(2-XC6H4)NCH}C6H2O]2- ([XNOR]2-, R = H, X = O (L1); R = 4-Me-6-Bu t (R‘), X = O (L2); R = H, X = S (L3); R = 4-Me-6-Bu t (R‘), X = S (L4)) have been prepared. Reactions of CpMCl3 (M = Ti, Zr) with sodium salts of the aryloxide or arylsulfide ligands (L1−L4) afford CpTi[XNOR]Cl [R = H, X = O (1); R = 4-Me-6-Bu t (R‘), X = O (2); R = H, X = S (3); R = 4-Me-6-Bu t (R‘), X = S (4)] and CpZr[ONOR]Cl [R = H (5)], respectively. Complexes 1−5 were characterized by IR and 1H NMR spectra and elemental analyses, and their molecular structures have been determined by X-ray diffraction methods. The coordination properties of these complexes have been investigated in the solid state and compared to related systems. When activated by excess methylaluminoxane (MAO), these complexes can be used as catalysts for ethylene polymerization and exhibited moderate activities. The activities of arylsulfide complexes 3 and 4 are higher than those of their analogues, aryloxide complexes 1 and 2, and zirconium complex 5 is much more active than titanium complexes 1−4.

TiIV Complexes of Redox‐Active Schiff Bases

“…Table 1 As previously hypothesized, [11a] the coordination geometry and nuclearity seem highly influenced by steric hindrance. Indeed, monomeric structures similar to (IЈ)Ti-(OtBu) 2 have previously been reported for CpTi(IЈ)Cl [19] and for CpTi(L)Cl and LTi(OiPr) 2 obtained from the 3-tertbutyl-5-methylsalicylaldehyde analogue of H 2 I (H 2 L). [20] These displayed similarly distorted square pyramidal geometries where three of the four basal positions were occu- pied by the ONS ligand, and the OR groups were nonequivalent.…”

“…This distortion seems to be a general phenomenon with ONS ligands Ϫ L 2 Ti species also showed this [20] Ϫ but is apparently much reduced or absent in ONO analogues. [19,21] Its origin is likely to be the significantly longer Ti-S bond [2.40 Å in CpTi(IЈ)Cl vs. 1.89 Å for the equivalent bond in the ONO analogue], [19] as well as perhaps the greater steric demand of the sulfur atom and its poorer π-overlap with the imino portion.…”

Synthesis, characterization, and catalytic activities in syndiospecific polymerization of styrene for half-sandwich titanium complexes with non-Cp tridentate dianionic ligands MeN(CH2CR2O−)2

“…Cp ring exhibits highly regular pentahapto coordination. The distance between the Cp (centroid) and Ti ranges 2.129(5) Å which are similar to those observed for other structurally characterized Cp-Ti complexes [5][6][7][8][9][10][11].…”

“…1, fall in a range observed for other known Ti-Cp complexes [5][6][7][8][9][10][11]. The average Ti-O distance of 1.856(5) Å and the Ti-Cl distance of 2.3392(15) Å are similar to those observed for other structurally characterized titanium complexes [5][6][7][8][9][10][11]15].…”

“…Until now, many organometallic precursors have been evaluated for their sPS catalytic behavior as well as the influence of their structure on physical properties of obtained sPS polymers [2,3]. In the case of poly(aolefin) catalysis, a number of Cp 0 Ti(L) n X 3Àm type complexes with one Cp ligand and a second non-Cp ligand have widely been explored in order to elucidate the relationship between structures of catalysts and catalytic activities [4]; however, there are relatively few reports for the syndiospecific polymerization of styrene using half-sandwich titanocene complexes containing one bi-, tri-, or tetradentate ligand (non-Cp type ligand) in replace of chlorides in [7], Cp * TiCl[(OCH 2 CH 2 ) 2 NMe] [8], CpTiCl(OPhCH@NPhOMe) [9], Cp * TiCl((OCH(R)CH 2 ) 2 -NAr) [10], and CpTiCl[(R-2-{2-XC 6 H 4 }N@CH)C 6 H 2 O] [11]. Recently, we have reported Cp * TiCl(DEA-Me) (1) having the tridentate N-methyldiethanolateamine ligand could be used as a good precursor for syndiospecific polymerization of styrene in the presence of MAO [8].…”