Group 10 Nickel, Palladium and Platinum

Group 10 Nickel, Palladium, and Platinum. In homogeneous catalysis, group 10 metals have become privileged catalysts in many organic... 

Group 10 Nickel, palladium and platinum are good hydrogenation catalysts. They all tend to form more square planar complexes compared to other transition elements. 

Of the Group 10 elements, nickel, palladium and platinum, only the +2 states of Ni and Pd are well characterized in aqueous acid solutions. Their + 2/0 standard reduction potentials in acid solution are given in the Latimer diagram ... 

There are no recent comprehensive measurements of the relative activities of metals for benzene hydrogenation, and since most of the detailed work concerns only nickel, palladium and platinum a short summary of what is known about other metals is all that can be made. Quantitative measurements of seven of the metals of Groups 9 to 10 supported on silica were reported many years ago, and the low activity of the base metals has been confirmed by measurements on... 

Biphenylene underwent dimerization in the presence of phosphine complexes of Group 10 transition metals to afford tetraphenylene (2) [4]. Catalytic hydrogenation of biphenylene with phosphine complexes of rhodium, nickel, palladium, and platinum resulted in the formation of biphenyl (3) [5]. Hydrosilylation and hydroboratlon of biphenylene occurred in the presence of a palladium catalyst to give 2-silylbiphenyls and 2-borylbiphenyl 4, respectively [6]. Disilanes, a... 

Ishikawa and coworkers have studied the unique reactivity of strained cyclic disilanes (Equation 9.11) [35]. Transition metals, especially those of Group 10, readily insert into the Si—Si bond of disilacyclobutene 118 and can catalyze the addition of that bond across a variety of unsaturated acceptors. In the case of Ni(0)-catalyzed reactions of 118 with trimethylsilyl alkynes, insertion was found to occur both in a 1,2-and in a 1,1-fashion. The latter of these pathways implies a 1,2-silyl-migration, presumably occurring at the metal center. A nickel vinylidene intermediate was therefore proposed, though efforts to prove its existence were inconclusive. Similar vinylidene intermediates have been proposed by Ishikawa and coworkers to account for migrations observed in related palladium- and platinum-catalyzed reactions [36]. 

A member of the first transition series of the group 10 elements, nickel, seems to have less of a tendency to form dinuclear or oligo-nuclear complexes compared with palladium and platinum. This is probably the consequence of the higher stability of the octahedral terms of nickel(II). The known quadruply bridged dinickel complexes are those of carboxylates, dithiocarboxylates, 1,3-diphenyltriazen (Hdpt), thiobenzoate, and A(,A( -di-p-tolylformamidinate (form). 

Rapid exchange of ethene and propene on iron and nickel films appears to proceed in this way. Very detailed studies by Japanese scientists using microwave spectroscopy have identified the structure of propene-di formed in reaction of propene with deuterium over metals of Groups 10 and 11, either supported on silica or as powders. Interpretation of the results is somewhat difficult because although addition and exchange show very similar kinetics, and are therefore thought to have the same intermediates, the locations of the deuterium atom in the propene-di are not entirely as expected by the alkyl reversal mechanism. Except on palladium and platinum, the major initial product was propene-2-di " this could arise if... 

Palladium is the middle element in group 10 of the transition elements (periods 4, 5, and 6). Many of its properties are similar to nickel located above it and platinum just below it in this group. 

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