Nuclear magnetic resonance hydrides

Boron s electron deficiency does not permit conventional two-electron bonds. Boron can form multicenter bonds. Thus the boron hydrides have stmctures quite unlike hydrocarbons. The B nucleus, which has a spin of 3/2, which has been employed in boron nuclear magnetic resonance spectroscopy. 

Solid State Nuclear Magnetic Resonance Study of Heavy Metal Hydrides... 

Craig, P.J., D. Mennie, M.I. Needham, O.F.X. Donard, and F. Martin. 1993. Mass spectroscopic nuclear magnetic resonance evidence confirming the existence of methyl mercury hydride. J. Organomet. Chem. 447 5-8. 

Solid-state nuclear magnetic resonance (NMR) has been extensively used to assess structural properties, electronic parameters and diffusion behavior of the hydride phases of numerous metals and alloys using mostly transient NMR techniques or low-resolution spectroscopy [3]. The NMR relaxation times are extremely useful to assess various diffusion processes over very wide ranges of hydrogen mobility in crystalline and amorphous phases [3]. In addition, several borohydrides [4-6] and alanates [7-11] have also been characterized by these conventional solid-state NMR methods over the years where most attention was on rotation dynamics of the BHT, A1H4, and AlHe anions detection of order-disorder phase transitions or thermal decomposition. There has been little indication of fast long-range diffusion behavior in any complex hydride studied by NMR to date [4-11]. 

In general, on reaction with lithium aluminum hydride, secondary sulfonic esters are desulfonylated, with formation of the corresponding secondary alcohol. An exception is provided in an observation by Reist and coworkers, who treated 6-0-benzoyl-l,2-0-isopropyli-dene-5-O-p-tolylsulfonyl-a-D-glucofuranose, with lithium aluminum hydride in ether and obtained a product thought to be 6-deoxy-l,2-0-isopropylidene-y3-L-idofuranose, derived from an intermediate 5,6-anhydro-L-ido derivative later, Ryan and coworkers showed, from its nuclear magnetic resonance spectrum, that the product was 5-deoxy-l,2-0-isopropylidene-a-D- t/Zo-hexofuranose. The problem has been re-examined by Overend and coworkers the repetition experiment under the conditions of Reist and coworkers afforded 5-deoxy-... 

The cations [cis-HjRh(dppp)2] and [cis-HjRh[(-l-)-diop]2] are similar to the known [cis-H2Rh[P(CHj)3] ] and show a u(Rh-H) stretch in the IR, a pair of multi-plets in the high-field nuclear magnetic resonance (NMR) at 25°C and two resonances in the P NMR. The lower field resonance for each system is attributed to the mutually trans-P atoms, and that at higher field to the P atoms trans to the hydrides. The presence of two P resonances at all temperatures rules out a cis-trans rearrangement. Both [cis-H2Rh(dppp)2] and [cis-HjRh[(-l-)-diop]2] lose on dissolving in solution under Ar. 

When CFjCOjD is used as the acid proton, nuclear magnetic resonance (NMR) shows rapid and stereospecific exchange between the Rh hydride and the two endo positions on the six-membered ring, reflecting the reversible transfer of the Rh hydride to endo sites at the ends of the diene system . 

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