Silver(I) acetylides stabilized by η2-alkynes: Synthesis, reaction chemistry and solid state structures

Individual synthetic routes to heterobimetallic Ti(IV)–Ag(I) acetylides of type {[Ti](μ-σ,π-CCR1)2}AgCCR2 ([Ti] = (η5-C5H4SiMe3)2Ti: R1 = SiMe3: 6, R2 = SiMe3; 7, R2 = Ph. R1 = tBu: 8, R2 = SiMe3; 9, R2 = Ph. [Ti] = (η5-C5H5)2Ti): 10, R1 = tBu, R2 = SiMe3) including (i) the reaction of {[Ti](μ-σ, π-CCR1)2}AgNO3 ([Ti] = (η5-C5H4SiMe3)2Ti): 1, R1 = SiMe3; 2, R1 = tBu. [Ti] = (η5-C5H5)2Ti: 3, R1 = tBu) with LiCCR2 (4, R2 = SiMe3; 5, R2 = Ph) and (ii) treatment of [Ti](CCSiMe3)2 ([Ti] = (η5-C5H4SiMe3)2Ti) (11) with [AgCCR2] (12, R2 = SiMe3; 13, R2 = Ph) are described. The reactions of 1–3 with 4 or 5 appeared to be sensitive towards stoichiometry because an excess of 4 or 5 resulted in the formation of [(Ag(CCR2)2)Li(OEt2)]n (14) and [Ti](CCR1)2. Coordination polymer 14 is also accessible, when, for example, [AgCCSiMe3] (12) is treated with 1 eq. of LiCCSiMe3 (4) in diethyl ether. tanium(IV)–silver(I) acetylides 6–10 are stable in the dark and at low temperature, while on exposure to light and on heating they decompose to give R2CC–CCR2 together with [Ti](CCR1)2 and elemental silver. xes 6–10 contain a mono-nuclear AgCCR2 entity stabilized by the chelate-bonded organometallic π-tweezer molecule [Ti](CCSiMe3)2, which was evinced by structure determination of 7 in the solid state. In 14 linear [Me3SiCC–Ag–CCSiMe3]− units are connected by [Li(OEt2)]+ building blocks forming a coordination polymer.