109012-00-2Relevant academic research and scientific papers
Synthesis, characterization, and chemistry of titanium(IV), titanium(III), zirconium(IV), and hafnium(IV) complexes of phosphine sulfides and selenides. The crystal and molecular structures of Cp2Ti(SPCy2)2, Cp2Ti(S2PCy2), and Cp2Ti(Se2PPh2)
Gelmini, Lucio,Stephan, Douglas W.
, p. 1515 - 1522 (2008/10/08)
The complexes Cp2M(SPR2)2 (M = Ti, R = Cy (1); M = Zr, R = Ph (2), R = Cy (3); M = Hf, R = Ph (4), R = Cy (5)) were prepared by reaction of LiSPR2 with the appropriate metallocene dihalide. 1 crystallizes in the triclinic space group P1, with a = 7.999 (2) ?, b = 13.102 (5) ?, c = 16.626 (6) ?, α = 96.71 (3)°, β = 101.43 (3)°, γ = 91.14 (3)°, V = 1694 (1) ?3, and Z = 2. Species 2-5 could also be prepared from the reaction of Cp2M(PR2)2 (M = Zr, Hf) with elemental sulfur. Reactions of Cp2TiCl2 with LiXPR2 (X = S, R = Ph; X = Se, R = Ph, Cy) or solutions of 1 on standing yield Ti(III) species by reductive elimination of (XPR2)2. These Ti(III) complexes are formulated as Cp2TiXPR2 (X = S, R = Ph (6), Cy (7); X = Se, R = Ph (8), R = Cy (9)) on the basis of EPR data. These Ti(III) compounds are unstable and slowly convert by chalcogen atom abstraction to the complexes Cp2TiX2PR2 (X = S, R = Ph (12), R = Cy (13); X = Se, R = Ph (14), R = Cy (15)). 13 crystallizes in the orthorhombic space group Pbna, with a = 9.075 (3) ?, b = 34.052 (5) ?, c = 14.318 (5) ?, V = 4424 (3) ?3, and Z = 8. 14 crystallizes in the monoclinic space group P21/c, with a = 8.471 (3) ?, b = 29.868 (9) ?, c = 8.336 (3) ?, β = 104.47 (3)°, V = 2030 (1) ?3, and Z = 4. 12-15 as well as the analogues (X = S, R = Me (10), R = Et (11)) can also be prepared by photolysis of Cp2Ti(CO)2 in the presence of (SPR2)2 or XPR2H. Alternatively, 12-15 can be prepared by reaction of either LiXPR2 or LiX2PR2 with [Cp2TiCl]2. Complexes 2-5 slowly convert to the complexes [Cp2MX]2 (M = Zr, X = S (16), X = Se (17); M = Hf, X = S (18), X = Se (19), respectively). The preparation of 16-19 can also be achieved by direct reaction of 2-5 with Cp2M(PR2)2. The differences between the Ti chemistry and that of Zr and Hf are attributed to the ease of reduction of Ti(IV) to Ti(III).
