Role of the chemical structure of metal–organic framework compounds in the adsorption of hydrogen

Some aspects of the formation and structural features of low nuclearity heterometallic carboxylates

Heterometallic carboxylate complexes are of paramount interest in pure and applied coordination chemistry. Despite that plurality of such type compounds have been published to date, synthetic aspects of their chemistry often remain in the shadow of intriguing physical properties manifesting by these species. Present review summarizes reliable data on direct synthesis of low nuclearity molecular compounds as well as coordination polymers on their base with carboxylate-bridged {M2Mg} (M = Co2+, Ni2+, Cd2+), {M2Li2} (M = Co2+, Ni2+, Zn2+, VO2+), {M2Ln2} and {M2Ln} (M = Cu2+, Zn2+, Co2+) metal cores. Structural features and stabilization factors are considered and principal outcomes are confirmed by quantum-chemical calculations. Particular attention is paid to consideration of ligand-exchange reactions that allow controllable modification of heterometallic metal core under mild conditions giving diverse molecular complexes with modified ligand environment or Metal-Organic Frameworks with permanent porosity.

Characterization of MOFs. 2. Long and Local Range Order Structural Determination of MOFs by Combining EXAFS and Diffraction Techniques

This chapter provides an elementary introduction to X‐ray and neutron scattering theory, written with a didactic perspective. At the beginning, the scattering process is introduced in a general way and then a differentiation between crystalline samples and amorphous samples is made, leading to the Bragg equation or to the Debye equation and to the Pair Distribution Function (PDF) approach, respectively. Advantages and disadvantages of the use of X‐rays or neutrons for scattering experiments are underlined. The basics of Extended X‐ray Absorption Fine Structure (EXAFS) spectroscopy are also reported. Starting from these basics, five examples have been selected from the recent literature where the concepts described in the first didactic part have been applied to the understanding of the structure of different MOFs materials.