Titanium(III) hydrazide gels designed for Kubas-type hydrogen storage were synthesized from the reaction between tris(bis(trimethylsilyl)methyl) titanium and anhydrous hydrazine. The materials demonstrate a fully reversible H 2 adsorption capacity of 2.63 wt% and 36.7 kg m À3 at 298 K and 143 bar without saturation. Interaction between the adsorption center and H 2 gas was probed by electron paramagnetic resonance. † Electronic supplementary information (ESI) available: X-ray powder diffraction, elemental analysis tables, simulated X-ray photoelectron spectra for titanium and nitrogen, hydrogen adsorption isotherms at 77 K and 298 K for non-hydrogenated samples, infrared red spectra of titanium hydrazide materials and the LiCH(SiMe 3 ) 2 precursor, Ti{CH(SiMe 3 ) 2 } 3 , EPR of Ti hydrazide materials (A100-H 2 ) under Ar or H 2 . See