Dissymmetrical trans-Ethynyl-Butadiynyl Adducts on a Diruthenium Core: Synthesis, Characterization, and Selective Deprotection
摘要:
Reactions between the ethynyl complexes (4,0)-[Ru-2(aP)(4)](C2SiR3) (ap is 2-anilinopyridinate, R = Pr-i (1a) and CH3 (1b)) and LiC4SiMe3 result in the formation of dissymmetrical ethynyl-butadiynyl adducts trans-(4,0)-(Me3SiC4)[Ru-2(ap)(4)](C2SiR3) (R = Pr-i (2a) and CH3 (2b)). Treating 2b with K2CO3 in MeOH/THF leads to trans-(HC4)[Ru-2(ap)(4)](C2SiMe3) (3b) and trans-(HC4)[Ru-2(ap)(4)](C2H) (4) in 86% and ca. 10% yields, respectively, and the former can be quantitatively converted to 4 using NaOH. Treating 2a with NaOH in MeOH/THF yields trans-(HC4)[Ru-2(ap)(4)]((C2SiPr3)-Pr-i) (3a) only. Single-crystal structural analysis of 2a and 3b revealed that the Ru-Ru unit and the axial alkynyl ligands are approximately collinear in both molecules. Rich redox chemistry was revealed for all the compounds through voltammetric study: compound 1 exhibits reversible one-electron oxidation and reduction, and compounds 2-4 exhibit one one-electron oxidation and two one-electron reductions. All the ethynyl-butadiynyl adducts (2-4) exhibit an intense charge-transfer absorption of around 1035 nm, revealing a HOMO-LUMO gap of 1.20 eV.
Dissymmetrical trans-Ethynyl-Butadiynyl Adducts on a Diruthenium Core: Synthesis, Characterization, and Selective Deprotection
摘要:
Reactions between the ethynyl complexes (4,0)-[Ru-2(aP)(4)](C2SiR3) (ap is 2-anilinopyridinate, R = Pr-i (1a) and CH3 (1b)) and LiC4SiMe3 result in the formation of dissymmetrical ethynyl-butadiynyl adducts trans-(4,0)-(Me3SiC4)[Ru-2(ap)(4)](C2SiR3) (R = Pr-i (2a) and CH3 (2b)). Treating 2b with K2CO3 in MeOH/THF leads to trans-(HC4)[Ru-2(ap)(4)](C2SiMe3) (3b) and trans-(HC4)[Ru-2(ap)(4)](C2H) (4) in 86% and ca. 10% yields, respectively, and the former can be quantitatively converted to 4 using NaOH. Treating 2a with NaOH in MeOH/THF yields trans-(HC4)[Ru-2(ap)(4)]((C2SiPr3)-Pr-i) (3a) only. Single-crystal structural analysis of 2a and 3b revealed that the Ru-Ru unit and the axial alkynyl ligands are approximately collinear in both molecules. Rich redox chemistry was revealed for all the compounds through voltammetric study: compound 1 exhibits reversible one-electron oxidation and reduction, and compounds 2-4 exhibit one one-electron oxidation and two one-electron reductions. All the ethynyl-butadiynyl adducts (2-4) exhibit an intense charge-transfer absorption of around 1035 nm, revealing a HOMO-LUMO gap of 1.20 eV.