Competition between 3d metals(II) and palladium(II) in the reaction of heterobimetallic complexes Pd(μ-OOCMe)4M(OH2) (M=Ni, Co, Mn) with azobenzene

Transformation of Methyl Linoleate to its Conjugated Derivatives with Simple Pd(OAc)2/Lewis Acid Catalyst

“…In previous studies, it has been observed by UV-Vis spectra that adding non-redox metal salts like Sc(OTf) 3 or Al(OTf) 3 to Pd(OAc) 2 in acetonitrile would generate the new Pd(II) species, and it was further evidenced by NMR studies [33][34][35]. Taken together with the facts that heterobimetallic Pd(II) dimers having an acetate bridge with bivalent or trivalent metal ions, including Ba 2+ , Sr 2+ , Ca 2+ , Mn 2+ , Co 2+ , Ni 2+ , Cd 2+ , Zn 2+ Ce 3+ , Nd 3+ , Eu 3+ and Ce 4+ , have been widely reported [45][46][47][48], we proposed the formation of the heterobimetallic Pd(II)/Sc(III) or Pd(II)/Al(III) dimer having an acetate bridge as the key species for Wacker-type oxidation, olefin isomerization and oxidative coupling reactions [33][34][35]. In the present studies, the UV-Vis kinetics of Pd(OAc) 2 /Sc(OTf) 3 in toluene/t-BuOH solvent also indicated the formation of the new Pd(II) species.…”

Paramagnetic Metal–Metal Bonded Heterometallic Complexes

“…To support the two metals, research groups have focused on providing either a 3-fold symmetric or a 4-fold symmetric coordination environment. The groups of Lu and Thomas have both utilized 3-fold symmetric ligand scaffolds to support a variety of unique heterobimetallic species. − Some of these species have found success in catalytic transformations and small molecule activation, ,,,,, cross-coupling reactions, ,,, and C–H activation. , Detailed description of their reactivity is described elsewhere. ,, In addition to these 3-fold symmetric species, the groups of Vargaftik, Doerrer, Zamora, and Berry have synthesized heterobimetallic compounds supported by four ligands in a paddlewheel arrangement, affording structures with C 4 symmetry. − Remarkably, the compounds comprising this section display a wide range of magnetic behavior, sometimes counterintuitive and surprising.…”

“…Heterobimetallic compounds with C 4 symmetry were reported first, following the earlier work of Lippert, Kinoshita, and Matsumoto described in section . Vargaftik and co-workers found in 2005 that carboxylate ligands could be used to support heterobimetallic compounds having Pd–M (M = Mn, Co, Ni, Cu), − and later Pt–Co, cores. Doerrer and co-workers have reported a suite of Pt–M compounds (M = Fe, Co, Ni) supported by thiocarboxylate ligands. − Berry and co-workers recently reported a Pd–Fe complex supported by mercaptopyridine ligands …”

“…Both Doerrer and Berry laboratories have taken advantage of similar HSAB principles to form C 4 symmetric compounds using the ligands shown in Figure . The Doerrer and Zamora groups have used thiocarboxylate ligands tba and SAc, while the Berry group has used 2-thiopyridone (PyS). ,,− , Interestingly, Vargaftik and co-workers have shown conclusively that HSAB ligand design is not absolutely necessary to support heterobimetallic compounds containing Pd or Pt–their group has utilized the simple acetate ligand. − …”

“…Brandon and Claridge reported in 1968 that palladium­(II) acetate and other metal acetate salts react together to form heterobimetallic PdM­(OAc) 4 compounds . Vargaftik and co-workers have successfully characterized compounds B1 – B9 (see Tables – for compound labels) crystallographically and shown that they have the C 4 -symmetric paddlewheel-type arrangement of ligands with a direct heterometallic metal–metal interaction. − As metal–metal bonding in the Pd 3 (OAc) 6 trimer is minimal, and there are no metal–metal bonds in the first-row transition metal acetates, formation of the partial heterometallic metal–metal bond likely provides the thermodynamic driving force for the preparation of these compounds. It is notable that only the transition metals Mn, Co, Ni, and Cu react successfully with Pd 3 (OAc) 6 .…”