5- -2,2 bipyridine, reaction with platinum complexes

Dendrimers containing a- and metal-bipyridine-bonded platinum and palladium complexes have been prepared.323-327 Puddephatt and co-workers have generated dendrimers containing both palladium and platinum complexes coordinated to bidentate ligands, 276.325 Dendrimer 276 was synthesized via oxidative-addition of a C—Br bond to a platinum complex to form the dendrimer core. Subsequent reaction with metal complexes gave homo- or heterometallic materials. 

Platinum (260-262) and palladium (262,263) complexes have been incorporated into dendrimeric materials. Polymers incorporating both platinum and palladium units coordinated to bipyridine ligands have been reported by Pudde-phatt and co-workers (114) (262). These dendrimers were prepared via oxidative addition of a C—Br bond to a platinum complex, giving the core molecule. Further reaction with platinum or palladium complexes resulted in the homo- or heterometallic materials, respectively. 

Despite the interest in B(C6Fs)3 as a Lewis acid catalyst for organic reactions or a co-catalyst for olefinic polymerizations, little is known of its reaction with water. There is a report of the compound [NHEt3][HOB(C6F5)3] [158] and of the platinum complex, [Pt[HOB(C6Fs)3 Me(Bu2bpy)](Bu2bpy = 4,4 -di-ferf-butyl-2,2 -bipyridine),... 

Some platinum metals, especially ruthenium but also rhenium, osmium, and iridium, form luminescent complexes with nitrogen-containing ligands, e.g., 2,2 -bipyridine (bpy). These complexes may participate in redox reactions with concomitant chemiluminescence in three different ways. 

A platinum complex with a bipyridine as the most widely used ligand is easily prepared in high yields by reaction with Pt(Me)2(DMSO)2 in toluene to give an air- and moisture-stable product. The ligand exchange reactions proceed easily with other ligands such as phosphine, CO, and pyridine derivative, as shown in Eq. (7.8) [48]. 

Recent studies indicate the reaction of platina-/3-diketone with bipyridines via oxidative addition yields the diacyl hydrido Pt(IV) complex. Further ligand abstraction may result in H bond bridged dimer and a double-deck dimer through Pt Pt interaction (Scheme 17). On the other hand, the prototype of unsupported cis- diacyl platinum(II) species was obtained either via nucleophilic addition to cationic acyl carbonyl complexes or CO insertion into a trans acyl alkyl complex (Scheme 18). In the latter process for propionyl methyl or acetyl ethyl complex. 

A series of complexes with bipyridine ligands has also been described <2003EJI2749, 2004EJI4484, 20060M2074>.The reaction between 6,6 -diphenyl-2,2 -bipyridine 124 and [Pt(Me)2(DMSO)2] was carried out with a platinum/ligand ratio of 2 1 in toluene at 80 °C (Equation 44). The reaction was slow and led to the isolation of a yellow product that was insoluble in the reaction medium, was stable in air, and had high thermal stability <2006OM2253>. 

Complex 2 (Eq. 1) and complex 11 in the reaction sequence shown in (Eq. 3) reported by James and coworkers [15] appear to be the only isolated bis(alkynyl) platinum(IV) complexes. Complex 11, assumed to have the configuration shown by analogy with 2 and related Ptl2Me2(bpy) (bpy = 2,2 -bipyridine), was obtained in quantitative yield and is stable over weeks in the solid state but slowly decomposes in solution by reductive elimination to form 12 (Eq. 3). The reaction of (Eq. 3) can be viewed as a suitable model for the chemistry of (Eq. 2), implicating Pt ... 

Several other recent reviews contain material relevant to this section. An article by Blandamer and Burgess on the thermodynamics, kinetics, and mechanisms of solvation, solvolysis, and substitution in nonaqueous solvents contains a contribution on the controversial dissociative mechanism for isomerization of square-planar molecules. This is outlined in Section 5.5. A review of ligand substitution reactions at low-valency transition-metal centers contains sections on five-coordinate metal carbonyl complexes and on ML4 complexes (mainly tetrahedral configurations with L being a tertiary phosphine), as well as on acid- and base-catalyzed reactions. A review by Constable " surveying the reactions of nucleophiles with complexes of chelating heterocyclic imines contains a sizable section on square-planar palladium and platinum derivatives. Most discussion centers on [Pt(bipy)2] and [Pt(phen)2] (bipy = 2,2 -bipyridine phen = 1,10-phenanthroline). The metal center, ligand, or both are susceptible to nucleophilic attack and the mechanisms involved are critically assessed. 

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