Charge-Separation-Type Ionic Crystals with Mixed AuCo and AuNiCo Hexanuclear Complexes.

Treatment of a digold(I) metalloligand, [Au(dppe)(d-Hpen)] (HL; d-Hpen = d-penicillamine, dppe = 1,2-bis(diphenylphosphino)ethane), with a 1:1 mixture of Co(OAc) and Ni(OAc) under aerobic conditions resulted in the formation of three types of hexanuclear complexes: [Co(L)], [NiCo(L)], and [Ni(L)]. The addition of NaNO, MNO (M = K, Rb, Cs), and M(NO) (M = Ca, Sr, Ba) to the reaction mixture led to co-crystallization of [Co(L)] and [NiCo(L)] as a solid solution to form the charge-separation (CS)-type ionic crystals , , and , respectively, while [Ni(L)] independently crystallized as a single species (). In , [Co(L)] and [NiCo(L)] cations assemble in a 1:2 ratio to form a cationic supramolecular octahedron accommodating 4 HO ions, while 10 nitrate ions are packed in each hydrophilic tetrahedral interstice of the crystal to form an anionic adamantane cluster. The overall structures of and are very similar to that of , having a CS-type structure composed of cationic supramolecular octahedra with a +12 charge and anionic inorganic clusters with a -10 charge. However, contains M ions in place of the HO ions in , and furthermore, a novel rhombic dodecahedron cluster composed of 14 nitrate ions, which encapsulates two M ions, is formed in each hydrophilic tetrahedral interstice in .