Hydride complexes structures

TABLE 4.3. Strength of Intramolecular Dihydrogen Bonding in Iridium Hydride Complexes (Structure 4.3) as a Function of the Nature of the frans-Ligand Y... 

The x-ray structure obtained for one of two possible isomers of the cationic iridium hydride complex [Structure 5.9(a)] exhibited two short N-H- -H-lr contacts of 1.75 0.05 A. These distances are significantly smaller than the sum... 

Hydride Complexes of Ruthenium, Rhodium, and Iridium G. L. Geoffroy and J. R. Lehman Structures and Physical Properties of Polynuclear Carboxylates Janet Catterick and Peter Thornton... 

Fig. 1 The first X-ray crystal structures of three types of the iron hydride complexes...

In 2009, Rauchfuss and coworkers succeeded in the synthesis of the Fe- i-H-Ni complex [(CO)3Fe(pdt)(p-H)Ni(dppe)]BF4 28 (pdt = 1,3-propanedithiolate, dppe = 1,2-C2H4(PPh2)2) as a model for [NiFeJ-hydrogenases (Scheme 64) [212]. The structure of 28 was characterized by X-ray crystallographic analysis. This is the first example of an Fe-Ni thiolato hydride complex. Evolution of H2 by electrochemical reduction of CF3CO2H (pXa = 12.65) was observed in the presence of the catalytic amounts of 28. 

The great majority of platinum(I) complexes are binuclear with monofunctional or bifunctional bridging groups. However, there is also a series of unsupported dimers with the general structure shown in (12). These are generally stabilized by phosphine, carbonyl, and isocyanide ligands.17 Dimeric hydride complexes can have terminal or bridging hydrides and these are discussed above in Section 6.5.2.1.4. 

Two hydrogen bridges are present in some carbonyl hydride complexes. This is illustrated by the structure of the [H2W2(CO)8]2 anion,... 

Scheme 7 a Chain transfer through associative olefin displacement via hydride complex 1.18. b Chain transfer by concerted hydride transfer from alkyl to monomer via transition state 1.24. Note the similarity in the structures of 1.23 and 1.24... 

In 2004 Caporali investigated the hydroformylation of 1-hexene and cyclohexene using HRh(CO)(PPh3)3 [61]. The collected data indicated that the rate-determining step in the hydroformylation cycle depends upon the structure of the olefin. With an alpha-olefin like 1-hexene, the slowest step seems to be the hydrogenolysis of the acyl rhodium complex. In the presence of cyclohexene as a model for an internal olefin, the rate-determining step is the reaction of the olefin with the rhodium hydride complex (intermediate II in Fig. 6). 

Let us now consider a few non-classical hydride complexes for which molecular structures are available. 

---