Platinum bimetallic complexes

A zerovalent platinum bimetallic complex Pt2(dppm)3 will also catalyze the oxidation of CO to CO2 using either O2 or NO as oxidant. " Again, no comment can be made regarding the reaction mechanism. Oxidation of CO on platinum metal surfaces involves the reaction of chemisorbed atomic oxygen, but it is unlikely that such species are formed under the mild conditions of temperature used in these examples. In the conversion of the coordinated carbonyl in IrCl(CO)PN (PN = o-(diphenylphosphino)-A,A-dimethylaniline) to CO2 though it has been tentatively suggested that a metallocyclic intermediate is formed (23) ... 

While today the construction of such bidentate phosphine ligands with the use of an assembly metal is referred to as supramolecular chemistry, this is not to say that there are no examples in older literature utilizing this principle. Actually, there are many and using as a search term hetero bimetallic complexes (a named coined in the early 1980s) leads us to a plethora of complexes. For instance in complex 29, reported by Rauchfuss in 1982, one would consider copper as the assembly metal and platinum as the potential catalytic metal [70]. 

Extension of these ligands to the triphosphorus compound (EtO)2PO 2PO allows bimetallic platinum(II) complexes to be synthesized where the phosphonato P coordinates to one platinum, and the phosphite P atoms chelate to the second platinum(II) center.1485... 

A handful of bimetallic complexes with bridging ancillary ligands have also been reported, of which four are based on platinum. These include [(K2-pzTp)Pt(nl-C3H4Me)]2( T-dppb) (243, Section III.B.2), obtained by treatment of pzTpPt(r 3-C3H4Me) (225) with Vi equiv. 

Bimetallic alkenes, with platinum heterobimetallic complexes, 8, 637 homobimetallic complexes, 8, 635 Bimetallic complexes... 

As part of an effort to build covalently linked multicomponent assemblies for light-chemical energy conversion schemes, the Pt(diimine)(tdt) chromo-phore has been incorporated into bimetallic complexes with platinum(II) and mthenium(II) diimine chromophores using dipyridocatecholate (dpcat) or... 

It is difficult to find direct bonding interaction between the ferrocene iron and the second transition metal in the hetero-bimetallic complexes. Only the mono-triphenylphosphine palladium and platinum compounds fc[E2M(PPh3)] (E = O, M = Pd (Scheme 5-14) [79] E = S, M = Pd [268, 269], and Pt [269]) appear to... 

Abstract Square-planar palladium(II) and platinum(II) complexes with a high-lying filled d 2 orbital can act as metalloligands for Lewis-acidic metal centers such as d ° and s cations. This behavior is promoted by hard ligands such as a-bound hydrocarbyl ligands. A wide diversity of structural motifs based on this kind of donor-acceptor metal-metal bonds has been discovered in the last decades. This chapter reviews the coordination chemistry of metalloligands derived from alkyl, aryl, alkynyl, and carbene complexes of palladium(II) and platinum(II). The specific reactivity of the resulting bimetallic complexes is also addressed. 

A number of iron-platinum bimetallic clusters with isocyanide ligands have been studied those, such as 129, bridged by a dppm ligand have proved to be versatile (Scheme 30). " Both charged, 129, and uncharged, 130, complexes are possible, depending on the reaction route taken Fe-Pt bond lengths are typically 2.80 A. 

The chemistry of bimetallic complexes, in particular species containing hydrocarbyl bridging ligands, has experienced a notable development in recent years.Several reviews on the subject have appeared, and therefore only salient examples having 7 -olefinic platinum-bonding interactions will be considered here. 

Some similar bimetallic acylamino complexes are also known with transition metal ions, e.g., with vanadium(II) [67], palladium(II) [68], and especially platinum(II) [69]. In the Cambridge Structural Database [39] only one trimetallic structure is found in which three iron(II) ions are bridged by a total number of six acylamino ligands [70]. 

Other one-pot preparations of bimetallic nanoparticles include NOct4(BHEt3) reduction of platinum and ruthenium chlorides to provide Pto.sRuo.s nanoparticles by Bonnemann et al. [65-67] sonochemical reduction of gold and palladium ions to provide AuPd nanoparticles by Mizukoshi et al. [68,69] and NaBH4 reduction of dend-rimer—PtCl4 and -PtCl " complexes to provide dend-rimer-stabilized PdPt nanoparticles by Crooks et al. [70]. 

Ru(bipy)3 formed in this reaction is reduced by the sacrificial electron donor sodium ethylenediaminetetra-acetic acid, EDTA. Cat is the colloidal catalyst. With platinum, the quantum yield of hydrogenation was 9.9 x 10 . The yield for C H hydrogenation was much lower. However, it could substantially be improv l by using a Pt colloid which was covered by palladium This example demonstrates that complex colloidal metal catalysts may have specific actions. Bimetalic alloys of high specific area often can prepared by radiolytic reduction of metal ions 3.44) Reactions of oxidizing radicals with colloidal metals have been investigated less thoroughly. OH radicals react with colloidal platinum to form a thin oxide layer which increases the optical absorbance in the UV and protects the colloid from further radical attack. Complexed halide atoms, such as Cl , Br, and I, also react... 

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