Synthesis and Characterization of New Triangulo Derivatives of Pt^IPt^IPt^II, Including the First Platinum Cluster Binding Both Ethylene and CO

Abstract

The terminal hydride in the (PtPtPtII)-Pt-I-Pt-I triangulo cluster Pt-3(mu-PBu2t)(3)(H)(CO)(2) (1) may be removed by one-electron oxidants such-as [Cp2Fe]PF6. Under carbon monoxide the reaction affords the symmetrical, cationic derivative [Pt-3(mu-PBu2t)(3)(CO)(3)]PF6 (2). By operating with an-excess of the suitable ligand, we also prepared [Pt-3(mu-PBu2t)(3)(CO)(2)(NCCH3)]PF6 (3) and [Pt-3(mu-PBu2t)(3)(CO)(2)(CH2 =CH2)]PF6 (4). New neutral triangular precursors were obtained by substitution of the CO ligands contained in 1 with isocyanides. The hydrides Pt-3(mu-PBu2t)(3)-, (H)(CNR)(2) (5, R = CH2Ph; 6, R = C6H4-p-CH3; 7,R = Bu-t) were isolated by this route. Complex 7 reacts with chloroform to give Pt-3(mu-PBu2t)(3)(Cl)(CNBut)(2), (8), which, under an excess of CNBut, yields the cationic derivative [Pt-3(mu-PBu2t)(3)(CNBut)(3)]Cl (9). The new triangulo clusters were characterized by multinuclear NMR spectroscopy and, as far as 4 and 7 are concerned, by single-crystal X-ray diffraction

Assembling Metal Clusters with Covalent Linkers: Synthesis and Structure of a Quasi‐Planar Pt18 Dendrimer Containing Five Clusters Connected by σ‐Alkynyl Spacers

“…[20] Several structures with predefined molecular shape can therefore be engineered through the combination of these building blocks with well-chosen s-alkynyl spacers, one of which is shown in Scheme 1. The trinuclear precursor {Pt 3 }Cl (2) [{Pt 3 } = Pt 3 (mPtBu 2 ) 3 (CO) 2 ] was easily prepared from [{Pt 3 }(CO)]-(CF 3 SO 3 ) (1) [18] and a chloride salt. Coupling two equivalents of 2 with 1,3,5-triethynylbenzene, [21] under the classical Sonogashira conditions, [22] 2 (4), [19] we obtained (in 85 % yield) the title compound [({Pt 3 }-CC) 2 -C 6 H 3 -CC] 4 {Pt 6 } (6), as an orange, microcrystalline solid that was thermally and air stable.…”

“…The spectroscopic characterization of a linear analogue of complex 6 has also been recently described. [27] Experimental Section [Pt(m-PtBu 2 )(CO)] 3 (CF 3 SO 3 ) (1), [18] [Pt 6 (m-PtBu 2 ) 4 (CO) 6 ](CF 3 SO 3 ) 2 (4), [19] and 1,3,5-triethynylbenzene [21] were prepared as previously described.…”

“…In this paper we show that tri-and hexanuclear platinum clusters with sizable bridging phosphide groups are suitable precursors to ordered materials. Indeed, the bulky PtBu 2 ligands in [Pt 3 (m-PtBu 2 ) 3 (L) 2 (X)]n+ [18] and [Pt 6 (m-PtBu 2 ) 4 -(CO) 4 (X) 2 ]2n+ [19] (X = neutral ligand, n = 1; X = monoanionic ligand, n = 0; L = neutral ligand) impart remarkable thermal and chemical stability to the {Pt x (m-P) y } cores and leave a limited number of reactive sites properly positioned to build ordered structures. Moreover, they force alkynyl ligands to bind the polynuclear system with s,h 1 -rather than p,h 2 -interactions.…”

Formation and characterization of a benzoquinolate triplatinum cluster containing a μ3-PPh2 bridging system and two Pt–Pt bonds

“…The ability of the bridging phosphido (l-PR 2 ) ligands to form a great number of clusters and polynuclear complexes of transition metals is attributed to the stability of the M-P bonds and to their flexible coordination to the metal centres, allowing a wide range of distances and bond angles, depending on the electronic environment of the metals involved in the polynuclear arrays [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…The most common is the cyclic triangular array with three bridging phosphido ligands [14,[17][18][19][20][21][22][23][24][25][26], while complexes with linear [19,[27][28][29] or bent [7,[29][30][31] disposition of the three metal centres, with or without M-M bonds, are less common. These phosphido Pt 3 clusters are usually linked through bridging ligands of type l-PR 2 , and only rarely contain triply bridging (l 3 -PR 2 ) ligands connecting the platinum centres.…”