Platinum complexes trimer

Sulfur dioxide and carbon disulfide react with bis(bulky phosphine)platinum complexes to give monomeric trigonal planar [Pt(PR3)2(S02)] and trimeric complexes such as [Pt3(/u-S02)(PR3)2] and [Pt3(/i-CS2)(PR3)2] where R = Cy or But70 71... 

Most recently, Milstein and coworkers reported a new type of homogeneous catalytic reaction that generates silanones from secondary silanols under extremely mild conditions. The platinum complex (dmpe)Pt(Me)OTf) (27) (dmpe = Me2PCH2CH2PMe2, OTf = OSO2CF3 was treated with an equimolar amount of the silanol, (i-PrhSilKOII) (28), in acetone to yield a new dimeric hydrido-bridged complex 29 and the trimer 30 of diisopropylsilanone, 31 (Scheme 12)29. 

The Dalcanale group was also involved in this kind of hemicarcerand formation. For example, cavitand 21 was shown to coordinate with palladium or platinum and form the corresponding hemicarceplex containing either a solvent molecule or a single triflate counter-ion [70]. Additionally, taking advantage of their cavitand lithiation expertise, similar hosts were also synthesized by the Sherbum group. For example, they synthesized an A,C-te-pyridyl derivative and showed that reaction with platinum complexes led to cyclic dimers and trimers [71]. 

The trimeric platinum(O) complex [Pt3(CNBu )6] undergoes a double oxidative addition reaction with 2,2-bis(disilanyl)dithiane to give tetrakis(organosilyl)bis(/-butylisocyanide)platinum(IV) complexes.53 The Si—Ge bonds in bis(silylgermyl)dithiane are also cleaved by [Pt3(CNBu )6] giving analogous platinum(IV) complexes with Pt—Si and Pt—Ge bonds.53... 

The products of electrochemical oxidation of conjugated dienes are considerably affected by the reaction conditions such as the material of the electrode, the supporting electrolyte and the solvent. The oxidation of butadiene with a graphite or carbon-cloth anode in 0.5 M methanolic solution of NaClCU mainly yields dimerized products along with small amounts of monomeric and trimeric compounds (equation 5)1. The use of platinum or glassy carbon mainly gives monomeric products. Other dienes such as isoprene, 1,3-cyclohexadiene, 2,4-hexadiene, 1,3-pentadiene and 2,3-dimethyl-l,3-butadiene yield complex mixtures of isomers of monomeric, dimeric and trimeric compounds, in which the dimeric products are the main products. 

The [Hg3(OH)2]4+ cation has a zigzag structure 78 the [Hg(OH)]+ cation, in its chlorate and bromate salts, is an infinite chain analogue (17).79 A related cyclic /x-hydroxo trimer (18) is found in a platinum(II)-diaminocyclohexane complex.69... 

The complex [Pt 4(CH3COO)8] (1), which is a tetrameter of plat-inum(II) acetate, was first found by Skapski and co-workers in a study aiming at the isolation of pure platinum(II) acetate (24-26). They revealed that pure platinum acetate obtained using the silver acetate method (27) has an unusual tetrameric structure (Fig. 1). The structure is totally different from the trimeric structure known for palladium(II) acetate, [PdgCCHgCOOle] (28). 

A number of planar platinum(II) complexes, [Pt(oxime)2(NH3)2]Cl2 and [Pt(oxime)4]Cl2, have been isolated,which have been shown to function as stronger protonic acids than the corresponding free oximes in some cases neutralized species such as [Pt(Hato)(ato)2] can be readily obtained. Dimeric compounds with the formula [M(ato)Me2]2, where M = B, A1 or Ga, with the ato (acetoximato) group bridging have been reported. Similarly, in the trimeric palladium(II) complexes [Pd(acetato)(acetoximato)]3, both the acetato and acetoximato groups have been shown to bridge the three palladium atoms which constitute an equilateral triangle. ... 

The paucity of complexes with O-donors arises because Pd(II) and Pt(II) are soft metal centres (see Table 7.9). We noted above the instability of the tetraaqua ions. Reaction of [PtCl4] with KOH and excess Hacac gives monomeric [Pt(acac)2]. PaUadium(II) and platinum(II) acetates are trimeric and tetrameric respectively. The Pd atoms in [Pd(02CMe)2]3 are arranged in a triangle with each Pd—Pd (non-bonded, 310-317 pm) bridged by two... 

Interest in metal complexes containing polyfluoroalkyl- and polyfluoro-aryl-acetylenes as ligands has continued to be high, and has included compounds of platinum, palladium, gold, iridium, rhodium, - ruthenium, cobalt, - - nickel, molybdenum, and iron. These are reviewed in detail elsewhere in the Report (see Chapter 5). Such complexes may acquire usefulness for organic synthesis in due course thus significant amounts of hexakis(trifiuoromethyl)benzene are formed when perfluorobut-2-yne is incorporated into certain cobalt and nickel complexes. Similarly, the interesting compound hexakis(pentafluorophenyl)benzene was isolated in 40—70% yield hy trimerization of perfluorodiphenylacetylene over 7C-cyclopentadienylrhodium dicarbonyl in toluene. ... 

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