Ring-to-Cage Structural Conversion via Template Effect in a Gold(I) Metallosupramolecular System.

A unique example of a ring-to-cage structural conversion in a multinuclear gold(I) coordination system with d-penicillamine (d-H pen) is reported. The reaction of [Au Cl (dppe)] (dppe=1,2-bis(diphenylphosphino)ethane) with d-H pen in a 1:1 ratio gave [Au (dppe) (d-pen) ] ([1]), in which two [Au (dppe)] units are linked by two d-pen S atoms in a cyclic form so as to have two bidentate-N,O coordination arms. The subsequent reaction of [1] with Cu(OTf) afforded [Au Cu(dppe) (d-pen) ] ([2] ), in which a Cu ion is chelated by the two coordination arms in [1] to form an Au Cu bicyclic metallocage. A similar reaction using Cu(NO ) was accompanied by the ring expansion of [1] to [Au (dppe) (d-pen) ], leading to the production of [Au Cu (dppe) (d-pen) ] ([3] ). In [3] , two Cu ions are each chelated by the two coordination arms to form an Au Cu tricyclic metallocage, accommodating a nitrate ion. The use of Ni(NO ) or Ni(OAc) instead of Cu(NO ) commonly gave a tricyclic metallocage of [Au Ni (dppe) (d-pen) ] ([4] ), but a water molecule was accommodated inside the Au Ni metallocage.