Hydride ligands synthesis

Hydrogen cyanide reactions catalysts, 6,296 Hydrogen ligands, 2, 689-711 Hydrogenolysis platinum hydride complexes synthesis, 5, 359 Hydrogen peroxide catalytic oxidation, 6, 332, 334 hydrocarbon oxidation iron catalysts, 6, 379 reduction... 

Scheme 3. The synthesis of 8 and 9. (i) p-loluenesulfonic acid, ClljCh (ii) CHjCyi IiO (iii) H SCVMeC. N, -30°C. The location of the hydride ligands in 8 are not known with certainty.

The hydride iron carbonyl anion, [HFe(CO)4] , has a structure that is best described as a distorted tbp with the hydride ligand occupying an axial site. The anion is fluxional both in solution and in the solid state.113 The main use is found in organic synthesis and catalysis.114 A typical reaction is the reduction of olefins... 

The ammonia addition complexes of diborane are revealed as true coordination compounds of boron in which hydride ligands are replaced systematically by ammonia molecules. It is worthwhile to note that the analogy is a formal one and has no implications relative to geometry. It simply demonstrates the similar formulas of members of two substitution series. The particular divalent and trivalent cations [HB(NH3)3] and [B(NH3)4]" have not, to the best of my knowledge, been reported as yet, but I confidently predict that both a trivalent and divalent cation of boron will be prepared in the near future. Chelation phenomena, as described in subsequent discussions, may well be helpful in achieving this goal. An earlier, tentative report (19) from my laboratory of the divalent cation [HB(NH3)3]+2 was later shown by us to be in error. More sophisticated methods of synthesis appear to be required. 

It is noteworthy that while the electron rich Cp 2SmH is only moderately stable in solution, the analogous more strained dinuclear bridging complex is less stable and must be kept under hydrogen in order to record the NMR spectrum [2]. The synthesis of a samarium hydride supported by a calix-tetrapyrrolyl system was recently published [9] (Scheme 2), with the hydride ligand bonded to one samarium and to two lithium atoms. This cage affords an efficient protection against bimolecular collisions and the complex is described as thermally robust. 

Several general review articles [19-41] dealing mostly with the synthesis of new actinide complexes confirm the broad and rapidly expanding scope of this field. Those reviews dealt with the structure, stability, and reactivates of complexes with cyclopentadienyl, dienyls (pentadienyl, cyclohexadienyl, indenyl, phospholyl), cyclooctatetraenyl, arene ligands, hydrocarbyls, and hydrides ligands. 

---