Thiol end-capped titanium–copper complexes: Synthesis, solid state structure and electrochemical behavior

The synthesis of acetylene, acyl–thiol and thiol end-capped titanium–copper π-tweezer complexes of the structural type {[Ti](μ-σ,π-CCR)2}CuSC6H4-4-R′ ([Ti] = (η5-C5H4SiMe3)2Ti; 3: R = SiMe3, R′ = CCH; 5a: R = SiMe3, R′ = SC(O)Me; 5b: R = tBu, R′ = SC(O)Me), {[Ti](μ-σ,π-CCSiMe3)2}CuSC6H4–C6H4-4-SH (7) and ({[Ti](μ-σ,π-CCR)2}CuSC6H4)2 (8) is described. Homobimetallic 3, 5a and 5b are accessible via the reaction of {[Ti](μ-σ,π-CCR)2}CuMe (1a: R = SiMe3, 1b: R = tBu) with stoichiometric amounts of Me(O)CS-1-C6H4-4-CCH (2) and C6H4-1,4-(SC(O)Me)2 (4), respectively. Within these reactions the copper–sulfur bond formation is accompanied by the elimination of acetone. If 1a is treated with the dithiol (HS–C6H4)2 (6) in a ratio of 1:1 or 2:1 than dinuclear 7 and tetranuclear 8 are produced upon formation of methane. Both types of reaction allow in a straightforward manner the synthesis of analytically pure samples in high yield. In addition, complex 8 is also formed, when equimolar amounts of 7 are reacted with1a. lid state structure of 5a is reported. This complex possesses a low-valent CuSC6H4-4-SC(O)Me entity with copper(I) in a planar surrounding. All other geometrical features are in agreement with the expected data relevant for Ti–Cu organometallic π-tweezer complexes. voltammetric studies were carried out with 3–8. The results are discussed with respect to intramolecular interactions between the various electrochemically active reaction sites.