The six‐coordinate complexes [TiX4(L‐L)] [X = Cl or Br; L‐L = Ph2PCH2PPh2, Ph2P(CH2)2PPh2, Ph2P(CH2)3PPh2, o‐C6H4(PPh2)2, o‐C6H4(PMe2)2, Ph2As(CH2)2AsPh2, o‐C6H4(AsMe2)2 or MeC(CH2AsMe2)3] and the eight‐coordinate complexes [TiX4(L‐L)2] [L‐L = o‐C6H4(PMe2)2 or o‐C6H4(AsMe2)2] have been prepared and characterised by solution 1H and 31P{1H} NMR spectroscopy, IR and UV/Visible spectroscopy and microanalyses. The crystal structures of [TiCl4{o‐C6H4(PMe2)2}], [TiCl4{o‐C6H4(PMe2)2}2], [TiBr4{o‐C6H4(PMe2)2}2], [TiBr4{o‐C6H4(AsMe2)2}2] and [TiBr4{MeC(CH2AsMe2)3}] are described and permit detailed comparisons to be made between the six‐ and eight‐coordinate species and between the phosphane and arsane species. The crystal structure of the zwitterionic [TiCl5(Ph2PCH2PHPh2)] is also reported.
published as an Advance Article on the web Antimony(III) halides form highly unusual infinite one-or two-dimensional networks when coordinated to dithio-or diseleno-ether ligands or macrocyclic selenoethers. The structures adopted are contrasted with those observed for related bismuth(III) species.
Reaction of TiCl 4 with L-L [L-L = MeE(CH 2 ) n EMe; E = S or Se, n = 2 or 3, PhE(CH 2 ) 2 EPh or o-C 6 H 4 (EMe) 2 ] in anhydrous n-hexane solution under an N 2 atmosphere results in the rapid formation of [TiCl 4 (L-L)] as yellow, orange or red solids. Analogous bromo and iodo species, [TiX 4 (L-L)] [X = Br; L-L = MeE(CH 2 ) n EMe or o-C 6 H 4 (EMe) 2 ; X = I; L-L = MeSe(CH 2 ) 2 SeMe or o-C 6 H 4 (SeMe) 2 ], were obtained as intense orange or red coloured solids by treatment of TiX 4 with L-L in CH 2 Cl 2 solution. Crystallographic studies on [TiCl 4reveal a distorted octahedral arrangement with the coordinated group 16 donor ligand adopting the form in the first three cases and the meso form in the fourth example. These studies also reveal a trans influence series of Cl > S ≈ Se on Ti(). Solution NMR studies show that the chloro-compounds undergo rapid pyramidal inversion at ambient temperature, while the bromo and iodo species also undergo rapid ligand dissociation/chelate ring-opening. At low temperature these processes are slowed significantly, such that in most of the chloro and bromo species it is possible to identify both the meso and invertomers, although ligand exchange is still rapid at 200 K for the iodo species. The potential of these compounds as sources of titanium sulfide or titanium selenide phases via controlled decomposition is also discussed briefly. Finally, the dinuclear species, [Cl 3 Ti{MeS(CH 2 ) 2 SMe}] 2 (µ-O), formed by partial hydrolysis of [TiCl 4 {MeS(CH 2 ) 2 SMe}], has also been identified crystallographically.
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