Syntheses and Characterization of Titanium(IV) and Titanium(III) Complexes with (2-Dimethylphosphino)ethane-1-thiolate and (3-Dimethylphosphino)propane-1-thiolate as Ligands
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- 作者：Kazutaka Matsuzaki ; Hiroyuki Kawaguchi ; Peter Voth ; Kyoko Noda ; Sumitaka Itoh ; Hideo D. Takagi ; Kazuo Kashiwabara ; and Kazuyuki Tatsumi
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：August 25, 2003
- 年：2003
- 卷：42
- 期：17
- 页码：5320 - 5329
- 全文大小：186K
- 年卷期：v.42,no.17(August 25, 2003)
- ISSN：1520-510X
文摘
Reactions of Cp2TiCl2 (Cp = 
5-cyclopentadienide) with 2 or 1 equiv of hybrid P-S ligands (L), (CH3)2P(CH2)nS-(n = 2, dmpet; n = 3, dmppt), produced new dicyclopentadienyltitanium(IV) complexes with L, Cp2Ti(L-
S)2(1, L = dmpet; 2, L = dmppt) and [Cp2Ti(L-2S,P)]BPh4 (3, L = dmpet; 4, L = dmppt). The Ti(III) complexes,Cp2Ti(L-2S,P) (5, L = dmpet; 6, L = dmppt), were prepared by the reaction of Cp2Ti(3-C3H5) with 1 equiv of L.The structures of complexes 1-6 were confirmed by X-ray diffraction analyses. It was found that complexes 3 and5 were isostructural around Ti(IV) and Ti(III) centers: the Ti(IV)-S bond length in 3 (2.3498(9) Å) is shorter by 0.14Å than Ti(III)-S in 5 (2.4877(7) Å), while Ti(IV)-P (2.534(1) Å) was merely 0.05 Å shorter than Ti(III)-P (2.5844(7)Å). The redox potential between 3 and 5 in acetonitrile was -1.14 V vs the ferricinium/ferrocene couple. Aheterobimetallic complex that has the frame of complex 1, [Cp2Ti(dmpet)2Cu]PF6 (7), was also isolated and structurallycharacterized: the Ti-Cu distance (2.95(1) Å) was shorter than that in [Cp2Ti(SC2H4PPh2)2Cu]BF4, previously reportedby White and Stephan. Structural characterization was also carried out for Cp*Ti(dmpet-S)2(dmpet-2S,P) (8) andCpTiCl2(dmppt-2S,P) (9), which were obtained by the reactions of Cp*(or Cp)TiCl3 (Cp* = 5-C5Me5-) withn equiv (n = 1-3) of L. The mutual site-exchange reaction between phosphorus atoms on a coordinated dmpetin the 2S,P mode and on two other coordinated dmpet's in the S mode within complex 8 was analyzed by thevariable-temperature 31P{1H} dynamic NMR method. The kinetic parameters for this process, kex298 = 1.9 × 105s-1, 
H
= 48 kJ mol-1, and S = 17 J mol-1 K-1, as well as the rather long Ti(IV)-P distance (2.652(1) Å),indicate the fluxional nature of the coordination geometry in complex 8.
5-cyclopentadienide) with 2 or 1 equiv of hybrid P-S ligands (L), (CH3)2P(CH2)nS-(n = 2, dmpet; n = 3, dmppt), produced new dicyclopentadienyltitanium(IV) complexes with L, Cp2Ti(L-S)2(1, L = dmpet; 2, L = dmppt) and [Cp2Ti(L-2S,P)]BPh4 (3, L = dmpet; 4, L = dmppt). The Ti(III) complexes,Cp2Ti(L-2S,P) (5, L = dmpet; 6, L = dmppt), were prepared by the reaction of Cp2Ti(3-C3H5) with 1 equiv of L.The structures of complexes 1-6 were confirmed by X-ray diffraction analyses. It was found that complexes 3 and5 were isostructural around Ti(IV) and Ti(III) centers: the Ti(IV)-S bond length in 3 (2.3498(9) Å) is shorter by 0.14Å than Ti(III)-S in 5 (2.4877(7) Å), while Ti(IV)-P (2.534(1) Å) was merely 0.05 Å shorter than Ti(III)-P (2.5844(7)Å). The redox potential between 3 and 5 in acetonitrile was -1.14 V vs the ferricinium/ferrocene couple. Aheterobimetallic complex that has the frame of complex 1, [Cp2Ti(dmpet)2Cu]PF6 (7), was also isolated and structurallycharacterized: the Ti-Cu distance (2.95(1) Å) was shorter than that in [Cp2Ti(SC2H4PPh2)2Cu]BF4, previously reportedby White and Stephan. Structural characterization was also carried out for Cp*Ti(dmpet-S)2(dmpet-2S,P) (8) andCpTiCl2(dmppt-2S,P) (9), which were obtained by the reactions of Cp*(or Cp)TiCl3 (Cp* = 5-C5Me5-) withn equiv (n = 1-3) of L. The mutual site-exchange reaction between phosphorus atoms on a coordinated dmpetin the 2S,P mode and on two other coordinated dmpet's in the S mode within complex 8 was analyzed by thevariable-temperature 31P{1H} dynamic NMR method. The kinetic parameters for this process, kex298 = 1.9 × 105s-1, H = 48 kJ mol-1, and S = 17 J mol-1 K-1, as well as the rather long Ti(IV)-P distance (2.652(1) Å),indicate the fluxional nature of the coordination geometry in complex 8.