Current research fields of metal-organic frameworks (MOFs), which are being developed in the last 5-10 years by Russian scientific institutions and universities, are generalized. The review encompasses the design, synthesis, topological description, and prediction of MOF properties, the development of methods for their chemical engineering and modification, their investigation by modern physicochemical techniques, and the creation of functional materials based on porous frameworks (heterogeneous catalysts, highly efficient and highly selective sorbents of the new generation, conducting materials, systems for the target drug delivery).

Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc²⁻) [Co₃(btdc)₃(bpy)₂]·4DMF, 1; [Co₃(btdc)₃(pz)(dmf)₂]·4DMF·1.5H₂O, 2; [Co₃(btdc)₃(dmf)₄]∙2DMF∙2H₂O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co₃(RCOO)₆}, connected either by btdc^2– ligands (1, 3) or by both btdc^2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N₂, O₂, CO, CO₂, CH₄ adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m²⋅g⁻¹ and promising gas separation performance with selectivity factors up to 35.7 for CO₂/N₂, 45.4 for CO₂/O₂, 20.8 for CO₂/CO, and 4.8 for CO₂/CH₄. The molar magnetic susceptibilities χ_p(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μ_eff (300 K) ≈ 4.93 μ_B. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2.

Two metal–organic frameworks (MOFs), [Mg₃(btdc)₃(dmf)₄]·DMF (1) and [Mg₃(btdc)₃(dmf)₄] (2) (H₂btdc = 2,2′-bithiophene-5,5′-dicarboxylic acid; dmf = N,N-dimethylformamide), were synthesized from a similar reaction mixture at 80 °C or 130 °C, respectively. Both compounds are based on {Mg₃(RCOO)₆} trinuclear carboxylate units, serving as 6-connected nodes of the corresponding 3D frameworks. The low-temperature phase (1) adopts the frequent primitive-cubic (pcu) topology, while the high-temperature phase (2) crystallizes in the very rare sxb topology. The heating of 1 results in a facile solid-state phase transition into 2 both in DMF solvent and under solvent-free conditions, involving a significant rearrangement of bulky bithiophenedicarboxylate anions in a regular fashion. The detailed analysis of the crystal structures of both polymorphs reveals possible reaction sites and provides valuable insights into such an unprecedented topotactic process.