Gold(I)-Gold(III)-4,4′-bpy-phosphine complexes: Synthesis and multinuclear NMR study

Abstract

Silver assisted de-bromination gives [Au2(dppm/dppe/dppa) (OTf)2], which on reaction with 4,4′-bpy and gold(I) phosphines in CH2Cl2 medium, by the self assembly technique, leads to [(PPh3)Au(4,4′-bpy)Au(PPh3)], (1a–1d,2), [{Au2(dppm/dppe/dppa)}{(4,4-bpy)Au(PPh3)}2](NO3)4, (3), [{Au4(dppm/dppe/dppa)2(4,4-bpy)2}](OTf)4, (4), [{(PPh3)AuI(4,4′-bpy)}2AuIII(C6F5/Mes)](NO3)3, (5) [dppm/dppe/dppa =diphenyl phosphino-methane(a), –ethane(b), ammine(c), C6F5/Mes pentafluorophenyl/mesitylene]. The maximum molecular peak of the corresponding molecule is observed in the ESI mass spectrum. Ir spectra of the complexes show –C=C–, –C=N–, as well as phosphine, mesitylene and pentafluorophenyl stretching. The 1H-NMR spectra as well as 31P(1H)-NMR suggest solution stereochemistry, proton movement and phosphorus proton interaction. Considering all the moities there are a lot of carbon atoms in the molecule reflected by the 13C(H)-NMR spectrum. In the 1H–1H COSY spectrum of the present complexes and contour peaks in the 1H–13C-HMQC spectrum, assign the solution structure and stereoretentive transformation in each step.