Molecular Rare‐Earth‐Metal Hydrides in Non‐Cyclopentadienyl Environments

Abstract

Molecular hydrides of the rare-earth metals play an important role as homogeneous catalysts and as counterparts of solid-state interstitial hydrides. Structurally well-characterized non-metallocene-type hydride complexes allow the study of elementary reactions that occur at rare-earth-metal centers and of catalytic reactions involving bonds between rare-earth metals and hydrides. In addition to neutral hydrides, cationic derivatives have now become available.

Hydrido Complexes of Calcium: A New Family of Molecular Alkaline‐Earth‐Metal Compounds

“…Compared to p-, [42] d-, [43] and f-block [44] metals,t he chemistry of the s-block [42j, 45] metal hydrides is still underdeveloped. Among the alkaline-earth metals,t he number of examples of molecular calcium hydrides (< 10) reflects the difficulty in isolating them compared to the hydrides of the lighter homologue magnesium (ca.…”

Molecular Magnesium Hydrides

“…Catalytic applications are promising as well. [43] We hope that this Review will inspire chemists to develop new magnesium-hydride-based materials and to find useful applications of this earthabundant element. [17d] Despite being an electropositive s-block metal, the molecular hydride chemistry of magnesium is surprisingly rich, especially with the multi-metallic hydride clusters.T he Mg À Hb onds apparently have areasonably covalent character when in suitable ligand environments.T he high Lewis acidity of Mg 2+ together with the variability of its coordination numbers help to expand the range of nuclearity and the resulting structures.T his diverse class of compounds is gradually coming of the age to allow comparison with the numerous hydride clusters of copper [42] or of the rare-earth metals.…”

“…[17d] Despite being an electropositive s-block metal, the molecular hydride chemistry of magnesium is surprisingly rich, especially with the multi-metallic hydride clusters.T he Mg À Hb onds apparently have areasonably covalent character when in suitable ligand environments.T he high Lewis acidity of Mg 2+ together with the variability of its coordination numbers help to expand the range of nuclearity and the resulting structures.T his diverse class of compounds is gradually coming of the age to allow comparison with the numerous hydride clusters of copper [42] or of the rare-earth metals. [43] We hope that this Review will inspire chemists to develop new magnesium-hydride-based materials and to find useful applications of this earthabundant element.…”

Ytterbium (II) Hydride as a Powerful Multielectron Reductant

“…An alternate strategy that completely negates the use of alkali metals is to employ the reduction chemistry of hydride ligands. Although hydride ligands in f-element complexes are more commonly associated with insertion and σ-bond metathesis, [11][12][13][14][15][16][17][18] their use as reductants is now well established. [19][20][21][22][23] For example, the two-election reduction of both COT (À 1.62 and À 1.86 V vs. SCE) and anthracene (À 1.83 and À 1.99 V vs. SCE) [24] with extrusion of H 2 gas have been reported.…”