Ring-bridged hydride

With respect to catalytic olefin hydrogenation, the ring-bridged hydride is approximately 1000 times more active than (Cp2ThH2)2 for 1-hexene reduction... 

The ring-bridged (CH3)2SlCp2ThR2 complexes described in Section 7.3 undergo rapid reaction with H2 to liberate RH and to yield a hydride (eq.(75)) [68,69]. Diffraction studies Indicate that the hydride is... 

Figure 23. Molecular structure of the ring-bridged thorium hydride (CH3)2Sl[(CH3)4C5]2ThH2 2 X-ray diffraction. Relevant metrical parameters are Th-Th 3.628(1), Th-Sl = 3.478(10), 3.508(10)A, (ring center-of-gravlty)-Th-(ring center-of-gravlty) = 118 . From reference 69.

HOs3(CO)9(PPh)3)(PPh2C6H4) (Fig. 40) is produced when an ortho positioned C—H bond in the disubsti-tuted precursor, Os3(CO)io(PPh3)2, oxidatively adds to a core osmium atom. This intramolecular reaction utilizes two adjacent Os sites and creates a five-member Os-P-C-C-Os ring. The hydride bridges these same two Os atoms. 

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