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Hydrogen complex transition metal hydride

There exist two broad families of complex transition metal hydrides. The first contains hydrogen bonded to transition elements only and has the general composition... [Pg.1537]

The gravimetric hydrogen content of complex transition metal hydrides can reach values of more than 5 wt.% (Mg2FeH6 = 5.5 wt%), but most of these systems have a... [Pg.148]

The complex transition metal hydrides known so far show too low hydrogen contents and can therefore not be considered for hydrogen storage. [Pg.151]

A second major route to metal-metal complexes, related to the salt-elimination method described above, is elimination of neutral molecules with concurrent formation of metal-metal bonded complexes. Transition metal hydrides readily undergo these dinuclear reductive elimination reactions. The oxidative addition/reductive elimination see Oxidative Addition and Reductive Elimination) reaction of molecular hydrogen is a key reaction in this area (equation 47). [Pg.1151]

Fig. 6.18 Metal—hydrogen complexes and cation environments in complex transition metal hydrides. Small filled circles hydrogen large open circles Mg + and Ba +. Fig. 6.18 Metal—hydrogen complexes and cation environments in complex transition metal hydrides. Small filled circles hydrogen large open circles Mg + and Ba +.
Table 6.4 Hydrogen storage properties of selected complex transition metal hydrides (found and/or characterized in Geneva)... Table 6.4 Hydrogen storage properties of selected complex transition metal hydrides (found and/or characterized in Geneva)...
The characteristic part of a complex transition metal hydride is the anionic homoleptic transition metal (M) hydride complex [MmH/,]""", which is balanced by the cation A+ or A + (A = Li-Cs, Mg-Ba, Eu, Yb). The formation of an extended solid is a consequence of the attractive electrostatic Coulomb interaction between cations and complex anions, whereas within the complex, hydrogen... [Pg.251]

Two closely related reactions, (a) and (b), illustrated by Eq. (12) (Rj = HPhj, Etj, Phj, CI3, CljPh) and (13), of silicon hydrides with transition metal complexes generate compounds with Si—M bonds with elimination of hydrogen (a) cleavage of metal-metal bonds and (b) reaction with transition metal hydrides. Reactions discussed in this section are relevant to... [Pg.265]

An obvious limitation to the hydrogen-elimination method, especially for early transition metal elements, is the availability of transition metal hydrides (this applies also to the HCl elimination) or binuclear complexes. [Pg.267]

In 1931, Hieber and Leutert reported Fe(CO)4(H)2 not only as the first iron hydride complex but also as the first transition-metal hydride complex (FeH2 was reported in 1929 from FeCl2 and PhMgBr under a hydrogen atmosphere. However, it exists only in a gas phase) [2, 3]. The complex synthesized from Fe(CO)5 and OH (Scheme 1) is isolable only at low temperature and decomposes at room temperature into Fe(CO)5, Fe(CO)3, and H2. [Pg.28]

Usui, Y, Hrrano, M., Fukuoka, A. and Komiya, S. (1997) Hydrogen abstraction from transition metal hydrides by gold alkoxides giving gold-containing heterodinuclear complexes. Chemistry Letters, 26, 981. [Pg.89]

We do not know exactly where the hydrogen binds at the active site. We would not expect it to be detectable by X-ray diffraction, even at 0.1 nm resolution. EPR (Van der Zwaan et al. 1985), ENDOR (Fan et al. 1991b) and electron spin-echo envelope modulation (ESEEM) (Chapman et al. 1988) spectroscopy have detected hyperfine interactions with exchangeable hydrous in the NiC state of the [NiFe] hydrogenase, but have not so far located the hydron. It could bind to one or both metal ions, either as a hydride or H2 complex. Transition-metal chemistry provides many examples of hydrides and H2 complexes (see, for example. Bender et al. 1997). These are mostly with higher-mass elements such as osmium or ruthenium, but iron can form them too. In order to stabilize the compounds, carbonyl and phosphine ligands are commonly used (Section 6). [Pg.178]


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See also in sourсe #XX -- [ Pg.195 , Pg.196 , Pg.197 , Pg.198 , Pg.199 , Pg.200 , Pg.201 , Pg.202 ]




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Hydride hydrogenation

Hydrogen complexes

Hydrogen hydrides

Hydrogen metal hydride complexes

Hydrogen metal hydrides

Hydrogen transition

Hydrogen transition-metal hydrides

Hydrogenation complexes

Hydrogenation hydride complex

Hydrogenation metal hydrides

Hydrogenation transition metals

Metal hydrides, complex

Transition hydrides

Transition metal-hydride complexes

Transition metal-hydrides

Transition metals metallic hydrides

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