Exploring the Optimal Synthetic Pathways towards µ-Carbido Diruthenium(IV) Bisphthalocyaninates

Series of substituted µ‐carbido diruthenium(IV) bisphthalocyaninates [Pc*Ru]₂(µ‐C) [where Pc* = tetra‐tert‐butyl‐, octa‐n‐butoxy‐, tetra‐15‐crown‐5‐ and hexa‐n‐butoxy‐mono‐(15‐crown‐5)‐substituted ligands] were synthesized using two alternative approaches – (i) direct metalation of phthalocyanines with Ru₃(CO)₁₂ in refluxing o‐dichlorobenzene where [Pc*Ru]₂(µ‐C) are formed as by‐products together with monomeric complexes [Pc*Ru](CO) and (ii) dimerization of [Pc*Ru](CO) by dichlorocarbene generated in situ from chloroform and bases (KOH or NMe₄OH), which affords target complexes in high yield. Application of the appropriate base – NMe₄OH was found to be crucial in the case of synthesis of crown‐substituted µ‐carbido dimers. Reaction of Ru₃(CO)₁₂ with the phthalocyanine bearing bulky mesityloxy‐groups yielded solely monomeric complex which could not be dimerized under any studied conditions. Therefore, the influence of nature of peripheral substituents in phthalocyanines on their reactivity in metalation and dimerization reactions was revealed.