Nanocrystals of the three‐dimensional, spin‐crossover, porous coordination framework [Fe(pz)Pt(CN)4]⋅n H2O (pz=pyrazine; n≤2.5) have been synthesized from water‐in‐oil microemulsions. The surfactant‐free nanocrystals readily desorb water and the resulting anhydrous compounds exhibit thermally induced electronic bistability accompanied by a pronounced color change (see picture; HS=high spin, LS=low spin) close to room temperature.

Adamantane substituted with two to four 4-cyanophenyl groups was used for preparation of a new series of robust Porous Covalent Triazine-based Framework (PCTF) materials. Novel adamantane PCTFs were synthesized in good yields (>80%) by the trimerization reaction of 1,3-bis-, 1,3,5-tris-and 1,3,5,7tetrakis(4-cyanophenyl)adamantane, respectively, in the presence of ZnCl 2 (Lewis acid condition) and CF 3 SO 3 H (strong Brønsted acid condition). From N 2 adsorption isotherms, the Lewis acid condition gives higher surface areas than the strong Brønsted acid condition. The amorphous nano-to microporous frameworks (>50% micropore fraction) exhibit excellent thermal stabilities (>450 C) with BET surface areas up to 1180 m 2 g À1 . A very similar ultramicropore size distribution between 4 and 10 Å was derived from CO 2 adsorption isotherms with a "CO 2 on carbon based slit-pore model". At 1 bar the gases H 2 (at 77 K), CO 2 (at 273 and 293 K) and CH 4 (at 273 K) are adsorbed up to 1.24 wt%, 58 cm 3 g À1 and 20 cm 3 g À1 , respectively. Gas uptake increases with BET surface area and micropore volume which in turn increase with the number of cyano groups in the monomer. From single component adsorption isotherms, IAST-derived ideal CO 2 :N 2 , CO 2 :CH 4 and CH 4 :N 2 selectivity values of up to 41 : 1, 7 : 1 and 6 : 1, respectively, are calculated for p / 0 at 273 K. The adamantane PCTFs have isosteric heats of adsorption for CO 2 of 25-28 kJ mol À1 at zero loading and most of them also >25 kJ mol À1 over the entire adsorption range which is well above the heat of liquefaction of bulk CO 2 or the isosteric enthalpy of adsorption for CO 2 on activated carbons.

MIL-101(Cr), one of the most important prototypical MOFs, is well investigated and widely used in many scientific fields. With regard to MOF synthesis in general, the addition of a modifier is commonly used to improve the properties of the products. The effect of inorganic (mineral) and organic acid modifiers was thoroughly investigated in the synthesis of MIL-101(Cr) and HNO3 could increase the yield to over 80% of a product with average SBET > 3200 m(2) g(-1) in repeated experiments (from an average of 50% in most published syntheses) in small-scale laboratory synthesis. The large-scale synthesis could use the finding of HNO3 addition and produce MIL-101(Cr) in >100 g quantities with yields near 70% and BET-surface areas near 4000 m(2) g(-1). The addition of acetic acid (CH3COOH) together with seeding could decrease the reaction temperature, the lowest being 160 °C (from typically 220 °C in published procedures), with still relatively good yield and BET surface area of the product. The use of other strong inorganic or weak carboxylic acids as modulators typically caused a decrease in yield and porosity.

The reaction of the rigid spacer 4,4'-bipyrazole (H(2)BPZ) with late transition metals, either following conventional routes or under solvothermal conditions, afforded the coordination polymers [M(BPZ)]·Solv (M = Zn, 1; Co, 2; Cd, 3; Hg, 4; Cu, 5; Ni, 6; Pd, 7; Solv = DMF, 3; MeCN, 5 and 6; H(2)O, 7), [Cu(H(2)BPZ)(2)(NO(3))(2)] (8), and [Cd(H(2)BPZ)(CH(3)COO)(2)] (9). State-of-the-art laboratory powder diffraction methods allowed to disclose the isomorphous character of 1 and 2, as well as of 5 and 6, which feature 3D porous networks containing 1D channels of square and rhombic shape, respectively. 3, crystallizing in the relatively rare P6(1)22 space group, consists of homochiral helices of octahedral Cd(II) ions, packing in bundles mutually linked by "radial", nonplanar BPZ ligands. Finally, the dense species 8 and 9 contain parallel 2D layers of square and rectangular meshes, respectively. Thermogravimetric analyses witnessed the relevant thermal robustness of all the [M(BPZ)] materials [except the mercury(II) derivative], which are stable in air at least up to 300 °C, with the zinc(II) derivative decomposing only around 450 °C. Variable-temperature powder diffraction experiments highlighted the permanent porosity of 1-3, 5, and 6, retained along consecutive temperature cycles in all cases but 3. When probed with N(2) at 77 K, 1-3 and 5-7 showed Brunauer-Emmett-Teller and Langmuir specific surface areas in the ranges 314(2)-993(11) and 509(16)-1105(1) m(2)/g, respectively.

The ditopic ligands 3,5-dimethyl-pyrazolate-4-carboxylate,-Me 2 pzCO 2 -, and 4-(3,5-dimethyl-1H-pyrazol-4yl)benzoate, -Me 2 pzC 6 H 4 CO 2 -, combine a pyrazolate and carboxylate functionality in axial orientation and lead to porous cobalt or zinc azolate-carboxylate frameworks that have the same cubic pcu-a topology and {M 4 (μ 4 -O)} nodes (M = Co, Zn) as MOF-5 and other IRMOFs. The microporous networks [M 4 (μ 4 -O)(Me 2 pzCO 2 ) 3 ] (M = Co, Zn) with the short linker exhibit a solvent-induced gate effect, evidenced by gas desorption hysteresis due to small pore apertures of 2.8 Å diameter together with small amounts of high-boiling solvent remaining in the activated samples. For [Co 4 (μ 4 -O)(Me 2 pzCO 2 ) 3 ], the low-pressure H 2 storage capacity (1.7 wt%, 1 bar , 77 K) is higher than for MOF-5, and the CO 2 uptake of 20.8 wt% puts it among the top MOFs for low-pressure CO 2 sorption even though the BET surface is less than 1000 m 2 g −1 . The analysis of the magnetic properties of [Co 4 (μ 4 -O)(Me 2 pzCO 2 ) 3 ] takes into account the distribution of tetrahedra resulting from the disorder of the pyrazolate-carboxylate linker. An antiferromagnetic coupling observed for [Co 4 (μ 4 -O)(Me 2 pzCO 2 ) 3 ] arises from the interactions of the cobalt(II) ions through the combined μ 4 -O + syn-syn carboxylate and μ 4 -O + pyrazolate bridges.

The two-dimensional spin crossover (SCO) polymers 2 M(CN) 4 ] (M II = Ni(1), Pd(2), Pt(3)) were nanostructured in the form of nanocrystals and nanoparticles, and their chemical, structural, and physical characterization was carried out using different experimental methods (powder X-ray diffraction, magnetic susceptibility measurements, M€ ossbauer and infrared spectroscopy, transmission and scanning electronic microscopy, etc.). Surfactant-free nanocrystals of average dimensions 400 Â 400 Â 30 nm (1a, 1a*, 2a, 3a) were synthesized from water in oil microemulsions (w/o) while nanoparticles of average size 200 Â 100, 100 Â 60, and 70 Â 30 nm were obtained in poly(vinylpyrrolidone) (PVP) coating polymer (1b-1d, 2b, 2b 0 , and 3b). The spin crossover process is drastically influenced by the dimensions of the crystal/particle. Nanocrystals of 1-3 exhibit a quasi complete first-order spin transition centered within the interval 200-225 K, while PVP-coated nanoparticles undergo continuous second order spin transition at much lower temperatures (ca. 160 K).

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The p-carborane cluster analogue of p-mercaptobenzoic acid, 1-HS-12-COOH-1,12-C 2 B 10 H 10 , has been synthesized and characterized using nuclear magnetic resonance spectroscopy, single-crystal X-ray diffraction analysis, quantum-chemical calculations, and scanning tunneling microscopy. The single-crystal structure and selected packing aspects are discussed and presented in comparison with the two-dimensional periodic arrangements. Scanning tunneling micrographs, recorded under ambient conditions, are used to compare pure monolayers of 1-HS-1,12-C 2 B 10 H 11 to coadsorbed monolayers of both the parental precursor and carboxyl-functionalized pcarboranethiolate on Au{111}. Monolayers of both constituents are further characterized by X-ray photoelectron spectroscopy, which shows good agreement between the stoichiometry of each pure monolayer and the nominal stoichiometries of the respective molecules. Results indicate that most of the molecules of both derivatives adsorb as thiolates but that a small fraction of each adsorbs as thiols, without complete SH bond scission, and consequently are labile relative to desorption. Wetting-angle measurements confirm the hydrophilic character of monolayers containing the carboxylic acid constituents. Mixed self-assembled monolayers with functionalized constituents of high axial symmetry provide a convenient basis for grafting two-and three-dimensional structures.