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 2 pen) is reported. The reaction of [Au 2 Cl 2 (dppe)] (dppe=1,2‐bis(diphenylphosphino)ethane) with d ‐H 2 pen in a 1:1 ratio gave [Au 4 (dppe) 2 ( d ‐pen) 2 ] ([ 1 ]), in which two [Au 2 (dppe)] 2+ 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) 2 afforded [Au 4 Cu(dppe) 2 ( d ‐pen) 2 ] 2+ ([ 2 ] 2+ ), in which a Cu II ion is chelated by the two coordination arms in [ 1 ] to form an Au I 4 Cu II bicyclic metallocage. A similar reaction using Cu(NO 3 ) 2 was accompanied by the ring expansion of [ 1 ] to [Au 8 (dppe) 4 ( d ‐pen) 4 ], leading to the production of [Au 8 Cu 2 (dppe) 4 ( d ‐pen) 4 ] 4+ ([ 3 ] 4+ ). In [ 3 ] 4+ , two Cu II ions are each chelated by the two coordination arms to form an Au I 8 Cu II 2 tricyclic metallocage, accommodating a nitrate ion. The use of Ni(NO 3 ) 2 or Ni(OAc) 2 instead of Cu(NO 3 ) 2 commonly gave a tricyclic metallocage of [Au 8 Ni 2 (dppe) 4 ( d ‐pen) 4 ] 4+ ([ 4 ] 4+ ), but a water molecule was accommodated inside the Au I 8 Ni II 2 metallocage.