Box-like Heterometallic Macrocycles Derived from Bis-Terpyridine Metalloligands

A series of [4+2] hexanuclear heterometallic macrocycles, {[Cp* 2 Ir 2 (μ-DHNA)] 2 [Zn(pyterpy) 2 ] 2 (OTf) 2 }·(OTf) 6 ( 1a ), {[Cp* 2 Ir 2 (μ-DHNA)] 2 [Zn(pyterpy) 2 ] 2 }·(SbF 6 ) 8 ( 1a ′), {[Cp* 2 Rh 2 (μ-DHNA)] 2 [Zn(pyterpy) 2 ] 2 }·(OTf) 8 ( 1b ), {[Cp* 2 Ir 2 (μ-DHNA)] 2 [Ni(pyterpy) 2 ] 2 (OTf) 2 }·(OTf) 6 ( 2a ), {[Cp* 2 Rh 2 (μ-DHNA)] 2 [Ni(pyterpy) 2 ] 2 }·(OTf) 8 ( 2b ), {[Cp* 2 Ir 2 (μ-DHNA)] 2 [Cu(pyterpy) 2 ] 2 }·(PF 6 ) 4 (OTf) 4 ( 3a ), and {[Cp* 2 Rh 2 (μ-DHNA)] 2 [Cu(pyterpy) 2 ] 2 }·(PF 6 ) 4 (OTf) 4 ( 3b ), have been constructed by the self-assembly of half-sandwich organometallic units [(Cp* 2 M 2 (μ-DHNA)Cl 2 ] (M = Ir and Rh; Cp* = η 5 -pentamethylcyclopentadienyl; DHNA = 6,11-dihydroxy-5,12-naphthacenedione) and the metalloligands [M(pyterpy) 2 ] 2+ (M = Zn, Ni, and Cu; pyterpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine). Confirmed by single-crystal X-ray analysis, complexes 1a – 3b display hexanuclear heterometallic macrocycles with two box-like cavities. Interestingly, on the basis of the different combinations of metals, complexes 1a and 2a have the ability to encapsulate two OTf – guest anions in the molecular cavities, but differ from that of the other complexes in which all counteranions exist outside the molecular backbones. In addition, the reaction of [Cp*MCl 2 ] 2 (M = Ir and Rh) and [Ni(pyterpy) 2 ](NO 3 ) 2 leads to the formation of [2+1] trinuclear heterometallic linear molecules {Cp* 2 Ir 2 [Ni(pyterpy) 2 ]Cl 4 }(NO 3 ) 2 ( 4a ) and {Cp* 2 Rh 2 [Ni(pyterpy) 2 ]Cl 4 }(NO 3 ) 2 ( 4b ), which could be used as a kind of precursor.