The “ Complex-ina-Complex ” Cations [ ( acac ) 2 M Ru 6-( pi PrC 6 H 4 Me ) 6 ( tpt ) 2 ( dhbq ) 3 ] 6 + : A Trojan Horse for Cancer Cells

The directed synthesis of organometallic cage molecules for the assembly of molecular nano-objects is a topical area of chemical research. By combining the “molecular clip” strategy developed by Stang with the “molecular paneling” strategy pioneered by Fujita, we recently synthesized trigonal-prismatic cage molecules in which six (h-arene)ruthenium or (h-pentamethylcyclopentadienyl)rhodium units are held together by two trigonal 2,4,6-tris(pyridin-4-yl)-1,3,5triazine (tpt) panels and three dichloro or oxalato bridges. We have now extended this principle to construct the larger cationic hexanuclear metalloprism [Ru6(p-iPrC6H4Me)6(tpt)2(dhbq)3] 6+ (1), which incorporates p-cymene ruthenium building blocks and is bridged by 2,5-dihydroxy-1,4-benzoquinonato (dhbq) ligands and connected by two tpt subunits (Scheme 1). The hexametallic cation 1 was prepared from the dinuclear complex [Ru2(p-iPrC6H4Me)2(dhbq)Cl2] [6] and tpt in the presence of AgO3SCF3. The cationic complex was isolated and characterized as its triflate salt 1-(OSO2CF3)6 in 75% yield. The assembly of 1 can also be achieved in the presence of [Pd(acac)2] or [Pt(acac)2] (acac= acetylacetonato) to give the “complex-in-a-complex” cations [(acac)2Pd 1] and [(acac)2Pt 1] without affecting the overall yield (Scheme 2). Cations [(acac)2Pd 1] and [(acac)2Pt 1] were both isolated as their triflate salts.