Synthesis and characterization of titanium(IV) complexes containing the diphenylphosphino- and diphenylthiophosphoryl-functionalized cyclopentadienyl ligand. Crystal and molecular structure of Ti(η5-C5H4PPh2)Cl3

The trimethylsilyl cyclopentadiene derivative C5H4(SiMe3)PPh2 (1) was treated with TiCl4 to give the air- and moisture-sensitive mono(cyclopentadienyl) compound Ti(η5-C5H4PPh2)Cl3 (4). Reaction of 4 with Mg(CH2C6H5)2(THF)2 gave Ti(η5-C5H4PPh2)(CH2C6H5)3 (5). Reactions of the lithium and thallium derivatives M{C5H4P(S)Ph2} (M=Li (2), Tl (3)) with one equiv. of TiCl4 afforded the mono(cyclopentadienyl) complex Ti{η5-C5H4P(S)Ph2}Cl3 (6), whereas reaction with 0.5 equiv. of TiCl4 gave the bis(cyclopentadienyl) complex Ti{η5-C5H4P(S)Ph2}2Cl2 (8). Compound 6 was also isolated as a minor product from the reaction of Ti{η5-C5H4P(S)Ph2}2Cl2 (8) with one equiv. of TiCl4. The major product was identified as an inseparable mixture of two compounds [Ti{η5-C5H4P(S)Ph2}2Cl2·TiCl4]n (7a and 7b). Reaction of Ti(η5-C5H5)Cl3 with 3 afforded the ‘mixed-ring’ bis(cyclopentadienyl) complex Ti{η5-C5H4P(S)Ph2}(η5-C5H5)Cl2 (9). Compounds 6–9 are very moisture-sensitive and easily decompose to form the cyclopentadiene C5H5P(S)Ph2. Structural data of these complexes indicate η5-coordination of the substituted cyclopentadienyl ligands and this coordination mode was confirmed by X-ray crystal structure analysis of compound 4.