Triangular ruthenium clusters

Such systems exhibit characteristic mass spectra and nuclear magnetic resonance (NMR) spectral patterns (Fig. 11) facilitating their identification. A detailed discussion can be found in a comprehensive review article on such triangular ruthenium clusters (39). 

Figure 9. Scheme showing a strategy to connect triangular ruthenium clusters via BL. 

Among the several species shown in Fig. 12, two special classes of compounds were systematically studied (31, 38, 39), consisting of tetrasubstituted pyridylpor-phyrins coordinated with four ruthenium-polypyridines (here denoted tetraruthe-nated pyridylporphyrin, TRPyP) or triangular ruthenium clusters (here denoted tetracluster pyridylporphyrin, TCPyP) (Fig. 13). 

It has been several decades since oxo-centered triruthenium-carboxylate complexes with triangular cluster frameworks of Ru3(p3-0)(p-00CR)6 (R = alkyl or aryl) were first isolated [1,2]. In the early 1970s, the first oxo-centered triruthenium complex was structurally characterized by Cotton through X-ray crystal structural determination [3]. Since then, oxo-centered trinuclear ruthenium-carboxylate cluster complexes with general formula [Ru30(00CR)6(L)2L ]n+ (R = aryl or alkyl, L and... 

The Pt2Ru4(CO)i8 cluster reacts with H2 to form Pt3Ru6(CO)2i(/i3-H)-(jt-H)3 in which the platinum and ruthenium atoms are arranged in triangular layers of the pure elements.10 This complex can be converted to Pt3Ru6(CO)20(/i3-C2Ph2X/i-H)2 by reaction with diphenylacetylene.10 The latter complex was found to be an active catalyst for the hydrogenation... 

Fig. 19. Ru6C(CO),5(PhCsCH) (45, 46). The six ruthenium atoms define a slightly distorted octahedron, with the carbide carbon at the center (mean Ru-C — 2.04(2) A). The phenylacetylene ligand is bound to one triangular face of the cluster. Ru-Ru bond lengths fall into two groups those on the face bearing the acetylene average 2.80(4) A, and the remaining metal-metal bonds average 2.92(5) A.

The simplest bonding mode found in trinuclear hydrocarbon-substituted clusters of osmium and ruthenium is the 7 -vinyl coordination in which one carbon center is formally cr-bound to one metal atom in the triangular core and the alkene/alkyne unit is formally vr-bound to an adjacent metal, so that the ligand donates three electrons to the cluster. Vinyl complexes are generally prepared by alkyne insertion into [Os3(/U-H)2(GO)io] or by the oxidative addition of an alkene to [Os3(GO)io(NGMe)2l or [Os3(GO)i2], and may be considered to be intermediates in reactions to other hydrocarbon-containing cluster products. A list of reported 77 -vinyl- and the related 77 -acetylide-substituted complexes is presented in Table 1. The related 77 -vinylidene-substituted clusters, in which one carbon atom of the ligand is cr-bonded to two metal centers and the alkene unit is formally vr-bound to the third metal center, can be prepared by the thermal conversion of an 77 -vinyl cluster (Scheme 3). The 77 -vinylidene formally donates four electrons to the cluster core. 

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