Polymeric hydrides

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Kakiuchi (1994) Hydrogen Inorganic chemistry in Encyclopedia of Inorganic Chemistry, ed. R.B. King, Wiley, Chichester, vol. 3, p. 1444 - An up-to-date account including detailed discussion of isotopes and isotope effects. 

Desiraju and T. Steiner (1999) The Weak Hydrogen Bond in Structural Chemistry and Biology, Oxford University Press, Oxford - A well-illustrated and referenced account of modern views of hydrogen bonding. 

Desiraju (1996) Accounts of Chemical Research, vol. 29, p. 441 - The C-H---0 hydrogen bond structural implications and supramolecular design . 

Emsley (1980) Chemical Society Reviews, vol. 9, p. 91 - A review of strong hydrogen bonds. 

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The solid polymeric hydride sometimes decomposes explosively into its elements on exposure to air. 

The polymeric hydride is relatively stable to water, but reacts violently with alkali, evolving hydrogen. 

Keywords Density functional theory, olefin polymerization, -hydride elimination,... 

A number of indium trialkyls have been prepared, starting from the trimeihyl, and some diaryl compounds are known, such as the diphenyl bromide. The lower trialkyls are tetramers. Like aluminum, indium forms a polymeric hydride. (lnHil , from which lelrahydroindates. such as the lithium compound, LilnHj. can be derived. 

With LiAlFLj, a polymeric hydride (SiH2) is formed and with Grignardcom-pounds the corresponding alkyl compounds can be obtained ... 

The antisymmetric vTi H vibration for this compound is seen as an intense broad absorption at 1450 cm-1 (22). In contrast, treatment of a saturated hexane solution of (i7-C5H5)2Ti(CH3)2 (4) with H2 at 0°C gave a gray-green, presumably polymeric hydride, [(C5H5)2TiHl (6), having a characteristic vT1 H absorption at 1140 cm-1 (23,24). 

Chain Propagation. In the chain propagation step, an olefin molecule reacts with a tertiary butyl carbonium ion as postulated by Whitmore (1934). This addition reaction produces a larger carbonium ion which then either undergoes isomerization or abstracts a hydride from an isobutane molecule. (Under some circumstances, the larger carbonium ion may add a second molecule of olefin this reaction will be discussed under "Polymerization".) Hydride abstraction regenerates a chain-carrying, tertiary butyl carbonium ion and also forms a molecule of isoparaffin. Reactions follow ... 

The compound readily decomposes to Tl, LiH, and H2 above 30 °C, whereas in ether solntions a polymeric hydride is formed after a few hours at 0 °C (equation 2) ... 

Polymeric hydrides (white solids) are formed by Be and Al. In BeH2 (Figure 9.13), each Be centre is tetrahedral, giving a chain structure in which multi-centre bonding of the type described for B2H5 is present. The structure of AIH3 consists... 

All the elements of Group 13 (boron group) form polymeric hydrides (MH3)j . The monomers MH3 are strong Lewis acids and are unstable. Borane (BH3) achieves... 

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