Tetrahydridozincate

The properties and uses of lithium tetrahydridozincate(2-) are similar to those of lithium trihydrozincate(l -). It decomposes at 136° to give lithium hydride and zinc metal. 

The predominant interplanar spacing and the corresponding relative intensities of the x-ray (nickel-filtered CuKa) diffraction pattern (estimated visually) are d = 5.02 A (m) 4.25 A (s) 3.84 A (vs) 3.65 A (m)  

Shriver, The Manipulation of Air-Sensitive Compounds, McGraw-Hill Book Company, New York, 1969. 

One route to Zn—H bonds involves metathesis of a hydride with Zn—X or Zn—R (R = alkyl) bonds.1 A second route, used in the preparation of anionic zinc hydride complexes, involves donor-acceptor interaction between H- and diorganozinc.2 For example3 

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The reaction of methyllithium with dimethylzinc in 1 1 and 2 1 molar ratios in diethyl ether solution produces lithium tri- and tetramethyl-zincates.1 Two equivalents of lithium trimethylzincate( 1 -) react with three equivalents of lithium tetrahydridoaluminate(l -), and one equivalent of lithium tetramethylzincate(2 —) reacts with two equivalents of lithium tetra-hydridoaluminate(l —) to give lithium trihydridozincate( 1 -) and lithium tetrahydridozincate(2 —), respectively, in quantitative yields. Both reactions proceed in diethyl ether at room temperature and are complete within 5 min. The compounds are air-sensitive and therefore must be prepared in an airfree atmosphere (nitrogen or argon). They may be used as reducing agents in organic syntheses. 

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