Synthesis and structure of titanium diolate complexes derived from CpTiCl₃

Abstract

The compounds [C1,CpTi],(0CH2CH,CH,0) 1, [Cl,CpTi],(OCH,CMe,CH@) 2, and [CI,CpTi],-(OCHMeCH,CHMeO) 3 were prepared from the reactions of CpTiCl, and the bis-trimethylsilyl ethers of the diols. Alternatively, these species could be made from the reactions of the diol, imidazole, and CpTiCl, employing the appropriate stoichiometry. In the presence of excess diol, loss of CpH is observed. In the case of

Synthesis and Characterisation of Various Diester and Triester Adducts of TiCl4

“…[25] The bond lengths between the bridging oxygen and the titanium centres was 1.741(7) and 1.863(7) Å, showing the bonding to be covalent in nature. [26] The bridging oxygen stabilised the system and similar bridging compounds have been reported before as easier to crystallise when large stabilising ligands are removed. [24] The bond angles and distances in the two bridged titanium centres of 2b are similar to those reported.…”

“…The bridging Ti-O-Ti bond angle is 177.3(5)°which is similar to other oxo-bridged titanium chloride dimers with alkoxide ligands that are less sterically hindering. [25,26] In the presence of bulkier ligands, more acute oxo bridge angles have been reported. [27] The formation of the dimer demonstrates how air/moisture sensitive this system is and how any form of oxygen can stabilise the product.…”

Titanium Alkoxide Complexes: Condensed Phase and Gas Phase Comparisons

“…The DMPD ligand with its tertiary alkoxide groups limits the nuclearity and prevents oligomerization of its metal complexes. Further, the binding of this ligand to Ti 4+ reduces the coordination number below the optimal value of six observed in complexes that incorporate primary alkoxides as in “Ti(OEt) 4 ”, “Ti(OMe) 4 ”, and the propanediol-containing complexes [TiCl(HOCH 2 CH 2 CH 2 O)(OCH 2 CH 2 CH 2 O) 2 ] 2 and [TiCl 2 (OCH 2 CH 2 CH 2 O)(THF)] 2 . ,,,− The latter two complexes are closely related to 1 by virtue of the respective η 2 and μ,η 2 coordination patterns of their diolate ligands. If 2 equiv of HCl were removed from the monodeprotonated-diol complex above, the coordination geometry about Ti would be reduced from pseudooctahedral to the approximate trigonal bipyramidal structure of 1 .…”

Multiple bridging modes in a novel trinuclear titanium 1,3-dioxypropane compound, Ti3(methyliminodiethanolate)2(1,3-propanediolate)4

“…The nearest equivalent to this, with a similar span between Ti atoms, is the coordination of tris(hydroxymethylpropane) in a tetratitanium compound (Boyle et al, 1995), although, in this case, all the O atoms also bind two Ti atoms (" 2 -O type). The shorter TiÐO lengths of 1.750 (4) A Ê in [TiCl 2 (cyclopentadienyl)] 2 (1,3-propanediolate) (Huang & Stephan, 1995), where the TiCpCl 2 entities are only linked by the diolate, and 1.776 2 (Naiini et al, 1993), where the titanatranyl entities are linked by the pinacolate, re¯ect the less crowded four-coordinate trigonal±pyramidal titanium stereochemistry. The angles subtended at the O atom (TiÐOÐC) in these two reference structures are also quite different (158.1 and 159.6 , respectively), compared with 128.5 (2) and 129.0 (2) in (I).…”