Cyclopentadienyl chromium hydrazide gels for Kubas-type hydrogen storage.

Cyclopentadienyl chromium hydrazide gels were synthesized from the protonolysis reaction between bis(cyclopentadienyl) chromium and hydrazine. The amorphous products containing low valent chromium species are exploited as substrates for Kubas-type hydrogen storage. These materials demonstrate enthalpies that rise from 10 to 45 kJ mol(-1) and show a retention of 49% of the adsorption capacity at 298 K relative to 77 K, compared to values of 10-15% for most MOFs and amorphous carbons.