189184-22-3Relevant academic research and scientific papers
C-H and C-S bond cleavage in cyclopentadienyltitanium phenoxide thiolate complexes
Firth, Andrea V.,Stephan, Douglas W.
, p. 2183 - 2188 (2018/12/02)
The thiolate complexes CpTi(OC6H3-2,6-i-Pr2)(SR)Cl (R) Et, 1; t-Bu, 2; CH2Ph, 3; Ph, 4) were prepared. Attempts to methylate 1-4 and thus obtain the potentially reactive alkyltitanium thiolate derivatives were unsuccessful. Thiolation of CpTi(OC6H3-2,6-i-Pr2)-(Me)Cl (5) with 1,1-dimethylethanethiol in the presence of base afforded the species CpTi-(OC6H3-2,6-i-Pr2)(Me)(SCMe3) (6). The analogous species CpTi(OC6H3-2,6-i-Pr2)(Me)(SCH2-Me) (7) is unstable, liberating methane and yielding the dimeric product of C-H bond activation, [CpTi(OC6H3-2,6-i-Pr2)(μ-SCHMe)]2 (8). In a related thermolysis of CpTi(OC6H3-2,6-i-Pr2)(SBn)2 (9), the dimer species [CpTi(μ-S)(OC6H3-2,6-i-Pr2)]2 (10) and (PhCH2)2S are obtained. In contrast, thermolysis of the closely related species CpTi(OC6H3-2,6-i-Pr2)-((SCH2)2C6H4) (11) and CpTi(OC6H3-2,6-i-Pr2)(SCH2Me)2 (12) resulted in no reaction, suggesting a radical process is operative in the formation of 10. Reduction of 2 with LiPCy2 gave (PCy2)2 and the S-C bond cleavage product [CpTi(OC6H3-2,6-i-Pr2)(μ3-S)]3TiCp (13). These pathways of C-H and C-S bond activation are discussed and the implications considered.
