Widely Applicable Metallacarborane Reagents for π‑Conjugated Systems

The compounds [N­(CH3)4]­[3,3′-Co­(8-(p-C6H4C2H3)-1,2-C2B9H10)­(1′,2′-C2B9H11)], [N­(CH3)4]­[3,3′-Co­(8-(p-C6H4CHO)-1,2-C2B9H10)­(1′,2′-C2B9H11)], and [N­(CH3)4]­[3,3′-Co­(8-(m-C6H4CHO)-1,2-C2B9H10)­(1′,2′-C2B9H11)] were synthesized using an easy methodology, in very good yields and large quantities, which are important requisites to be employed as starting reagents. They have been fully characterized by elemental analysis, IR, NMR, and MALDI-TOF-MS, and the crystal structures of [N­(CH3)4]­[3,3′-Co­(8-(p-C6H4C2H3)-1,2-C2B9H10)­(1′,2′-C2B9H11)] and [N­(CH3)4]­[3,3′-Co­(8-(p-C6H4CHO)-1,2-C2B9H10)­(1′,2′-C2B9H11)] were elucidated by single-crystal X-ray diffraction. These compounds, having terminal formyl and vinyl functional groups, are suitable platforms to involve the aromatic cobaltabisdicarbollide unit into extended π-conjugated systems. It is expected that these synthons will facilitate the applicability of metallacarboranes in a wide variety of different fields, where π-conjugated systems are needed to keep electronic communication.