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A crystalline hydrogen-bonded framework with permanent porosity, built by rod-like struts and engineered to bear ultra-fast molecular rotors between two triple bonds, offers the possibility of controlling the rotational rates upon CO2 adsorption. CO2 enters the pores from the gas phase and reduces the rotational rates from the extremely fast regime of 107 Hz at 216 K to 105 Hz. The CO2-rotor interaction was evident from the 2H NMR response to the dynamics of the rotors in contact with CO2 in the crystal structure.

Porous crystalline dipeptides absorb, reversibly from the gas phase, a series of volatile fluorinated ethers in use as anesthetics. Their vapor pressure was considerably reduced, with favorable guest capture and release. Variable channel sizes were customized for selective sorption and pressure thresholds were observed in the narrowest pores. 1H, 13C and 19F MAS NMR coupled with ab initio conformational analysis and grand canonical Monte Carlo simulations highlight the guest loading and arrangement adopted in the congruent nanochannels, suggesting how the anesthetics can accommodate in biochemical receptors.

Supramolecular chemistry finds in solid-state NMR spectroscopy a privileged characterization method, especially in a variety of multidimensional experiments. Several applications of solid-state NMR to inclusion compounds, host–guest systems, cocrystals, polymeric self-assembly, and porous materials have been realized. Gases and volatile molecules were detected in supramolecular adducts by NMR as well, providing accurate information about their interaction with the solid transport properties and anisotropic behavior. In ordered systems, the results are complementary to XRD and, thus, NMR is regarded as a structural method, but it is also sensitive to amorphous phases, complex molecular aggregates, interfaces, and overall dynamics.

Porous molecular materials represent a new front in the endeavor to achieve high-performance sorptive properties and gas transport. Self-assembly of polyfunctional molecules containing multiple charges, namely, tetrahedral tetra-sulfonate anions and bifunctional linear cations, resulted in a permanently porous crystalline material exhibiting tailored sub-nanometer channels with double helices of electrostatic charges that governed the association and transport of CO2 molecules. The charged channels were consolidated by robust hydrogen bonds. Guest recognition by electrostatic interactions remind us of the role played by the dipolar helical channels in regulatory biological membranes. The systematic electrostatic sites provided the perfectly fitting loci of complementary charges in the channels that proved to be extremely selective with respect to N2 (S = 690), a benchmark in the field of porous molecular materials. The unique screwing dynamics of CO2 travelling along the ultramicropores with a step-wise reorientation mechanism was driven by specific host-guest interactions encountered along the helical track. The unusual dynamics with a single-file transport rate of more than 106 steps per second and an energy barrier for the jump to the next site as low as 2.9 kcal mol-1 was revealed unconventionally by complementing in situ13C NMR anisotropic line-shape analysis with DFT modelling of CO2 diffusing in the crystal channels. The peculiar sorption performances and the extraordinary thermal stability up to 450 °C, combined with the ease of preparation and regeneration, highlight the perspective of applying these materials for selective removal of CO2 from other gases.

The conversion of low-energy light into photons of higher energy based on sensitized triplet–triplet annihilation (sTTA) upconversion is emerging as the most promising wavelength-shifting methodology because it operates efficiently at excitation powers as low as the solar irradiance. However, the production of solid-state upconverters suited for direct integration in devices is still an ongoing challenge owing to the difficulties concerning the organization of two complementary moieties, the triplet sensitizer, and the annihilator, which must interact efficiently. This problem is solved by fabricating porous fluorescent nanoparticles wherein the emitters are integrated into robust covalent architectures. These emitting porous aromatic framework (ePAF) nanoparticles allow intimate interaction with the included metallo-porphyrin as triplet sensitizers. Remarkably, the high concentration of framed chromophores ensures hopping-mediated triplet diffusion required for TTA, yet the low density of the framework promotes their high optical features without quenching effects, typical of the solid state. A green-to-blue photon upconversion yield as high as 15% is achieved: a record performance among annihilators in a condensed phase. Furthermore, the engineered ePAF architecture containing covalently linked sensitizers produces full-fledge solid-state bicomponent particles that behave as autonomous nanodevices.

Porous metal–organic frameworks (MOFs) and porous coordination polymers (PCPs) are ideal substrates for gas storage and separation. In particular, the complexation of transition metals with pyrazole-based ligands boosts both thermal and chemical stability of the resulting MOFs, making these materials superior candidates for practical and industrial applications. The introduction of fluorinated groups in MOFs can result in more hydrophobic structures with improved performances under humid conditions in real-life applications such as CO2 capture from flue gas. We synthesized three 1,4-bis(1H-pyrazol-4-ylethynyl)benzene (H2BPEB) derivatives, bearing one, two (in adjacent positions) and four fluorine atoms on the central aromatic core. These struts were exploited to build Zn(II), Ni(II) and Fe(III) architectures. Gas absorption and separation abilities of such resulting structures were extensively investigated towards N2, CO2 and CH4.

The enormous interest manifested in recent years for porous materials has generated efficient systems for adsorbing gases of great interest for energy and the environment, such as CO2, CH4 and H2. Our project is based on the design of porosity in combination with switchable dynamics and flexibility for gaining control over gas capture and selectivity. This approach is made possible by fabricating tetrahedral building blocks and rotor-on-axel molecular struts. The interaction of tetrahedral-shaped polyanions with linear difunctional organic cations (CPOS-5) produced tailored sub-nanometer channels with double helices of electrostatic charges governed the association and transport of CO2 molecules.1 The unique screwing dynamics of CO2 travelling along the ultramicropores with a single-file 106 step/s transport rate was revealed by in-situ 13C-NMR combined with CO2 DFT modelling. Highly symmetrical tetrahedral elements were designed to construct swellable porous adamantoid frameworks through co-operation of hydrogen bonds mounted on conformationally flexible groups.2 The flexibility of the porous crystals manifests itself in response to stimuli of selected gases: the contact with CO2, Xe and hexane triggers the enlargement of channel cross-section and capacity. The accomodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light XRD, combined with Molecular Dynamics and DFT calculations. 129Xe NMR highlights gas dynamics while receiving the encoding of the shape and orientation of each visited cage. Ultra-fast molecular rotors were realized in porous crystals by engineering crystalline frameworks containing rod-like linkers as amphidynamic elements.3 The porous frameworks promise access to the control of rotary motion by chemical and physical stimuli. Rotor dynamics as fast as 1011 Hz (in the regime of conventional liquids) in properly designed porous crystals was hampered by a gas or vapor diffused to the cavities, such as CO2, iodine and hydrocarb

In recent years the interest manifested for porous materials has generated efficient systems for adsorbing gases of great interest for energy and the environment, such as CO2, CH4 and H2. Our project is based on the design of porosity in combination with switchable dynamics and flexibility for gaining control over gas capture and selectivity. This approach is made possible by fabricating tetrahedral building blocks and rotoron- axel molecular struts. The interaction of tetrahedral-shaped polyanions with linear difunctional organic cations (CPOS-5) produced tailored sub-nanometer channels with double helices of electrostatic charges governed the association and transport of CO2 molecules.1 The unique screwing dynamics of CO2 travelling along the ultramicropores with a single-file 106 step/s transport rate was revealed by in-situ 13C-NMR combined with CO2 DFT modelling (Figure 1). Highly symmetrical tetrahedral elements were designed to construct swellable porous adamantoid frameworks through co-operation of hydrogen bonds mounted on conformationally flexible groups.2 The flexibility of the porous crystals manifests itself in response to stimuli of selected gases: the contact with CO2, Xe and hexane triggers the enlargement of channel cross-section and capacity. The accomodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light XRD, combined with Molecular Dynamics and DFT calculations. 129Xe NMR highlights gas dynamics while receiving the encoding of the shape and orientation of each visited cage. Ultra-fast molecular rotors were realized in porous crystals by engineering crystalline frameworks containing rod-like linkers as amphidynamic elements.3 The porous frameworks promise access to the control of rotary motion by chemical and physical stimuli. Rotor dynamics as fast as 1011 Hz (in the regime of conventional liquids) in properly designed porous crystals was hampered by a gas or vapor diffused to the cavities, such as CO2, iodine and hydroca

Background and Purpose - As a reliable scoring system to detect the risk of symptomatic intracerebral hemorrhage after thrombectomy for ischemic stroke is not yet available, we developed a nomogram for predicting symptomatic intracerebral hemorrhage in patients with large vessel occlusion in the anterior circulation who received bridging of thrombectomy with intravenous thrombolysis (training set), and to validate the model by using a cohort of patients treated with direct thrombectomy (test set). Methods - We conducted a cohort study on prospectively collected data from 3714 patients enrolled in the IER (Italian Registry of Endovascular Stroke Treatment in Acute Stroke). Symptomatic intracerebral hemorrhage was defined as any type of intracerebral hemorrhage with increase of ≥4 National Institutes of Health Stroke Scale score points from baseline ≤24 hours or death. Based on multivariate logistic models, the nomogram was generated. We assessed the discriminative performance by using the area under the receiver operating characteristic curve. Results - National Institutes of Health Stroke Scale score, onset-to-end procedure time, age, unsuccessful recanalization, and Careggi collateral score composed the IER-SICH nomogram. After removing Careggi collateral score from the first model, a second model including Alberta Stroke Program Early CT Score was developed. The area under the receiver operating characteristic curve of the IER-SICH nomogram was 0.778 in the training set (n=492) and 0.709 in the test set (n=399). The area under the receiver operating characteristic curve of the second model was 0.733 in the training set (n=988) and 0.685 in the test set (n=779). Conclusions - The IER-SICH nomogram is the first model developed and validated for predicting symptomatic intracerebral hemorrhage after thrombectomy. It may provide indications on early identification of patients for more or less postprocedural intensive management.

Two novel pillared Zn(II)-based Metal-Organic Frameworks were de novo synthesized exploiting N,N′-(1,1′-biphenyl)-4,4′-diylbis-4-pyridinecarboxamide (bpba) and its fluorinated analogous N,N′-(perfluoro-1,1′-biphenyl-4,4′-diyl)diisonicotinamide (F-bpba) as suitable pillar linkers and 2,6-naphthalene dicarboxylic acid as carboxylic ligand. The resulting heteroleptic MOFs, namely, PUM210, [Zn4(bpba)1.5·(ndc)4·(H2O)]n and PUM210F, [Zn3(F-bpba)1·(ndc)3·(DMF)]n, feature an uncommon truncation of the Zn(II) paddle-wheel nodes along the pillaring direction. PUM210 and PUM210F exhibit a polycatenated architecture, resulting in microporous channels decorated by amide moieties. The activated forms show a permanent porosity and a selective adsorption of CO2 over N2. Moreover, the partially transmetalated Cu-PUM210 and Cu-PUM210F were obtained by convenient transmetalation protocol and their adsorption propriety toward CO2 were subsequently investigated.

The present study focuses on the assembly of organo-cations with organo-anions in water. The anions, characterized by symmetric moieties (carbon-, adamantane-, or calixarene-based) functionalized with directional hydrogen bond (HB) acceptor functions (tetra-sulfonate moieties), are combined with planar guanidinium or terephtalimidamide cations as hydrogen bond donors, the purpose being to integrate water molecules into the lattice. The imbalance between the charge on the two components, and the considerable number of HB donor and acceptor sites, promotes the insertion of water into the structures. In the reported structures, a part of the water molecules serves as a structural linker between the anions and cations, while the remaining molecules cluster into channels and cavities in a loose association with the supramolecular matrix framework.

In the search for flexible molecular crystals endowed with porosity, we achieved the fabrication of expandable crystalline prototypal structures, which allow the absorption of gases, without modifying the crystal architecture. The design brings together highly symmetrical tetrahedral elements to construct swellable porous adamantoid frameworks through co-operation of eight surrounding hydrogen bonds mounted on conformationally flexible groups. The flexibility of the porous crystals manifests itself in response to stimuli of selected gases, which promote reversible conformational changes, inducing breathing in the molecular structure. The backbone of the reticular construction is based on the formation of the carboxylic dimers, which project outwards from the tetrahedral molecular core to consolidate the 3D framework. Contact with proper gases such as CO2, Xe and hexane triggers a 56-70% enlargement of the channel cross-section. The accommodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light X-ray diffraction, combined with molecular dynamics and density functional theory (DFT) theoretical calculations. Rare experimental observations of xenon dynamics, in which Xe diffuses along the channels and experiences different chamber orientations in the crystal, were gathered by analysing 129Xe NMR chemical shift anisotropy profiles, which encode the shape and orientation of each visited cavity along the channel. The jump rate and activation energy experienced was uniquely established by exploring Xe atoms in their diffusional path. Nitrogen showed a low affinity to the matrix and was unable to enlarge the pores, thus it was excluded from the restrictive pores of the empty crystal. Given the properties of molecular crystals, it is possible to outline some advantageous aspects, such as simple design, easy self-assembly, solubility, reversible gas uptake and absence of metal ions, and they can thus be considered for eco-friendly gas capture and separat

A challenging issue is the dynamics of nanoporous solids after the insertion of molecular rotors in their building blocks and promises access to the control of rotary motion by chemical and physical stimuli.[1] The combination of porosity with ultra-fast rotor dynamics was discovered in molecular crystals, covalent organic frameworks and MOFs by 2H spin-echo NMR spectroscopy and T1 relaxation times.[2-5] The rotors, as fast as 1011 Hz at 150 K, are exposed to the crystalline channels, which absorb CO2 and I2 from the gas phase, even at low pressures. Interestingly, the rotor dynamics can be switched on and off by vapor absorption/desorption, showing a remarkable change of material dynamics, which, in turn, produces a modulated physical response. Novel mesoporous organosiloxane frameworks allowed us to realize periodic architectures of fast molecular rotors on which C-F dipoles are mounted.[6] These dipolar rotors showed not only rapid dynamics (109 Hz at 325 K) in solid-state NMR experiments, but also a dielectric response typical of a fast dipole reorientation. Moreover, crystals with permanent porosity were exploited in an unusual way to decorate crystal surfaces with regular arrays of dipolar rotors. The inserted molecules carry alkyl chains which are included as guests into the channel-ends.[7] The rotors stay at the surface due to a bulky molecular stopper which prevents the rotors from entering the channels. The host-guest relationships were established by 2D solid-state NMR and GIAO HF ab initio calculations. In a final example, flexible molecular crystals were fabricated by a series of shape-persistent azobenzene tetramers that form porous molecular crystals in their trans configuration. The efficient trans→cis photoisomerization of the azobenzene units converts the crystals into a non-porous phase but crystallinity and porosity are restored upon Z→E isomerization promoted by visible light irradiation or heating. We demonstrated that the photoisomerization e

Nanoporous materials are excellent candidates for the fabrication of molecular rotors in the solid state and promise access to the control of rotary motion by chemical and physical stimuli.[1] The combination of remarkable porosity with fast rotor dynamics was discovered in molecular crystals, covalent organic frameworks and metal-organic frameworks (MOFs) by 2H spin-echo NMR spectroscopy and spin lattice T1 relaxation times.[2-4] A microporous MOF engineered to contain in its scaffold rod-like ligands [1,4-bis(1H-pyrazol-4-ylethynyl)benzene] (BPEB) showed extremely rapid 180° flip reorientation of the central p-phenylene unit with rotational rates of 1011 Hz at 150 K. Molecular rotors are exposed to the crystalline channels, which absorb CO2 and I2 even at low pressure. Interestingly, dynamics could be tuned by gas absorption/desorption, showing a remarkable change of material dynamics, which, in turn, produces a modulated NMR response. Crystal-pore accessibility of the MOF allowed the CO2 molecules to enter the cavities and control the molecular rotor spinning speed down to 105 Hz at 150 K (Figure). This strategy enabled the regulation of rotary motion by gas diffusion in the channels and the determination of the energetics of rotary dynamics in the presence of CO2, enlarging perspectives in the field of sensors and gas detection. Moreover, the insertion of dipoles onto molecular rotors in mesoporous organosilica architectures permits to obtain fast molecular rotors containing dynamic C-F dipoles. The dipolar rotors show not only rapid dynamics of the aromatic rings (109 Hz at 325 K) in the solid state NMR experiments, but also dielectric response typical of a fast dipole-reorientation under the stimuli of an applied electric field.[5] Regular arrays of dipolar molecular rotors can be also mounted on crystal surfaces in an unusual way, exploiting the formation of surface inclusion compounds. Guest molecule is comprised of a rotator, a stopper and a shaft: 2D 1H-13

This study reports and analyses how different countries are measuring the contribution of bioeconomy (BE) to their overall economy or country objectives. The focus is on Argentina, Australia, Germany, Malaysia, the Netherlands, South Africa and the United States of America. The countries selected from six continents differ in terms of level of economic development and have different bioeconomy strategies. From the sample countries and available literature, general conclusions on constraints and opportunities of bioeconomy for countries with different income level and biomass availability are drawn. The paper shows that different sets of sectors and subsectors are considered ‘bioeconomy’ by the countries analysed. The sectors included in the bioeconomy strategy often reflect the objectives and priorities identified by the country, and comparative advantages linked; for instance, to endowment in biomass resources, historical economic specialisation, and past investments in research and development ( R&D ). Some regional efforts to harmonize the measurement of bioeconomy exists. For example, since the launch of the European Commission (EC) strategy for the bioeconomy in 2012, the EC Joint Research Centre (JRC) has been monitoring jobs and turnover in the European Union bioeconomy for all the member states and sectors.

High surface area 3D polymers represent one of the most promising classes of porous materials because of their high gas uptake and stability to thermal and chemical degradation. A series of porous organic polymers with aromatic building units have been synthesized and compared to explore their high-pressure performance as adsorbents of gases of relevant importance for energy and the environment. Particular attention was paid to methane storage up to pressures as high as 180 bar at ambient temperature. Porous polymers were prepared starting from a wide choice of spatially expanded aromatic monomers: a systematic change in the number of rings, variable size and shape was taken under consideration. The high number of rings (up to 6), which act as multiple reactive sites and form a number of connections between the multi-dentate nodes, result in an extensive cross-linked framework. Condensation was obtained by two alternative synthetic routes, viz., Yamamoto cross-coupling and Friedel-Crafts alkylation reactions. The structural characteristics and high stability of the porous polymers, even to mechanical compression, were carefully determined by several methods, including 1D and 2D solid state NMR, FT IR and thermal analyses. The CH4 uptake in the porous polymers allowed an understanding of the incremental response to pressure, up to extremely high values, and the exploitation of the extensive pressure range to customize the gas adsorption/desorption cycles for storage and transportation. Owing to the notable presence of large mesopores and network flexibility, combined with high surface area, a remarkable gain at high pressure was achieved, ensuring a highly competitive uptake/delivery efficiency. At 180 bar, adsorption values up to 445 cm3 STP g-1 were measured for porous organic polymers such as carbazolyl- and triptycene-based materials. The benchmark of these materials PAF1 reaches the value of 916 cm3 STP g-1 of adsorbed CH4, exceeding the performance of most of t

A metal organic framework (MOF) engineered to contain in its scaffold rod-like struts featuring ultrafast molecular rotors showed extremely rapid 180 ° flip reorientation with rotational rates of 1011 Hz at 150 K. Crystal-pore accessibility of the MOF allowed the CO2 molecules to enter the cavities and control the rotor spinning speed down to 105 Hz at 150 K. Rotor dynamics, as modulated by CO2 loading/unloading in the porous crystals, was described by proton T1 and 2H NMR spectroscopy. This strategy enabled the regulation of rotary motion by the diffusion of the gas within the channels and the determination of the energetics of rotary dynamics in the presence of CO2

The fabrication of porous architectures for the confinement of gases and polymer chains to pores is a challenging research area. The matrices range from fully-organic and metal-organic frameworks to porous molecular crystals of synthetic and biological origin, such as dipeptides.[1] We were mostly intrigued in comparing the matrices depending on the nature of the interactions, pore shape, surface area and pore capacity. Like gases, flexible polymer chains can diffuse inside the galleries undergoing severe steric requirements which tune their conformations, dynamics and properties. Fast-1H, 19F and 2D hetero-correlated MAS NMR spectroscopies played a key role in determining the host-guest interactions at the interfaces and the relationships between the components. A few case studies will be highlighted. A peculiar kind of porous crystalline solid derives from the use of hard and soft interactions in a hierarchical construction. Primary supramolecular toroidal structures are formed by robust metal-organic bonds: they can self-assemble four-by-four into the shape of Platonic solids, held together by van der Waals and coulombic interactions.[2] Anions play a major role in modulating the architectures. The 3D crystalline structures are permanently porous and able to entrap reversibly vapors and gases. In a further example, 1,3-butadiene vapors could be separated from other C4 hydrocarbon by a MOF matrix [3], which provides structural flexibility and unique guest-responsive accommodation. Regarding the relevant issue of manipulating and transforming polymer chains in a confined environment, we varied the conducting properties of polyacrylonitrile chains by thermal transformation into graphitized nanofibers.[4] Moreover, isolation of single polysilane chains increased the rate of carrier mobility in comparison with that in the bulk state due to the elimination of the slow interchain hole-hopping.[5] The main chain conformation of polysilane could be controlled by changing

A challenging issue is the dynamics of porous solids and the insertion of molecular rotors in their building blocks, promising access to the control of rotary motion by chemical stimuli. The combination of porosity with ultra-fast rotor dynamics was discovered in molecular crystals and covalent frameworks, by 2H spin-echo NMR spectroscopy and T1 relaxation times.[1-3] The rotors, as fast as 107 Hz at 200 K, are exposed to the crystalline channels, which absorb CO2 and I2 vapors even at low pressure. Interestingly, the rotor dynamics can be switched on and off by vapor absorption/desorption, showing a remarkable change of material dynamics. Novel mesoporous organosiloxane frameworks allowed to realize periodic architectures of fast molecular rotors containing dynamic C-F dipoles in their structure.[4] The dipolar rotors showed not only the rapid dynamics of the aromatic rings (ca. 5108 Hz at 325 K), as detected by solid-state NMR spectroscopy, but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Crystals with permanent porosity were exploited in an unusual way to decorate crystal surfaces with regular arrays of dipolar rotors. The inserted molecules carry alkyl chains which are included as guests into the channel-ends.[5] The rotors stay at the surface due to a bulky molecular stopper which prevents the rotors from entering the channels. The host-guest relationships were established by 2D solid-state NMR and GIAO HF ab initio calculations. Flexible molecular crystals were fabricated by a series of shape-persistent azobenzene tetramers that form porous molecular crystals in their trans configuration. The efficient trans→cis photoisomerization of the azobenzene units converts the crystals into a non-porous phase but crystallinity and porosity are restored upon Z→E isomerization promoted by visible light irradiation or heating. We demonstrated that the photoisomerization enables reversible on/off switchin

Molecular rotors, especially when bearing dipoles, are a challenging research field entailing a number of useful phenomena, such as switchable ferroelectricity, and the fabrication of dynamic elements of molecular motors in solids. The combination of remarkable porosity with ultra-fast rotor dynamics was discovered by our group in molecular crystals and covalent frameworks, by 2H spin-echo NMR spectroscopy and T1 relaxation times [1-3]. Molecular rotors, as fast as 107 Hz at 200 K, are exposed to the crystalline channels, which absorb CO2 and I2 vapors even at low pressure. Interestingly, the rotor dynamics could be controlled by I2 absorption/desorption, showing a remarkable change of material dynamics and suggesting the use of porous crystals in sensing and pollutant management. Novel mesoporous organosiloxane frameworks, obtained by a self-assembly process, allowed to realize periodic architectures of fast molecular rotors containing dynamic C-F dipoles in their structure (Fig. 1a) [4]. The dipolar rotors showed not only the rapid dynamics of the aromatic rings (ca. 5x108 Hz at 325 K) (Fig. 1b), but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Molecular rotors were mounted on crystal surfaces exploiting the formation of surface inclusion compounds. Guest molecules engineered as three segments comprising a shaft, a stopper, and a rotator can interact with a porous crystal and insert the shaft into the bulk crystal, while the rotator lies on the surface[5]. The host-guest relationships were established by 2D solid state NMR and low rotational barriers were found by dielectric spectroscopy.

ConspectusMolecules and materials can show dynamic structures in which the dominant mechanism is rotary motion. The single mobile elements are defined as "molecular rotors" and exhibit special properties (compared with their static counterparts), being able in perspective to greatly modulate the dielectric response and form the basis for molecular motors that are designed with the idea of making molecules perform a useful mechanical function. The construction of ordered rotary elements into a solid is a necessary feature for such design, because it enables the alignment of rotors and the fine-tuning of their steric and dipolar interactions. Crystal surfaces or bulk crystals are the most suitable to adapt rotors in 2D or 3D arrangements and engineer juxtaposition of the rotors in an ordered way. Nevertheless, it is only in recent times that materials showing porosity and remarkably low density have undergone tremendous development.The characteristics of large free volume combine well with the virtually unhindered motion of the molecular rotors built into their structure. Indeed, the molecular rotors are used as struts in porous covalent and supramolecular architectures, spanning both hybrid and fully organic materials. The modularity of the approach renders possible a variety of rotor geometrical arrangements in both robust frameworks stable up to 850 K and self-assembled molecular materials. A nanosecond (fast dynamics) motional regime can be achieved at temperatures lower than 240 K, enabling rotor arrays operating in the solid state even at low temperatures. Furthermore, in nanoporous materials, molecular rotors can interact with the diffusing chemical species, be they liquids, vapors, or gases. Through this chemical intervention, rotor speed can be modulated at will, enabling a new generation of rotor-containing materials sensitive to guests. In principle, an applied electric field can be the stimulus for chemical release from porous materials.The effort needed t

The separation of 1,3-butadiene from C4hydrocarbon mixtures is imperative for the production of synthetic rubbers, and there is a need for a more economical separation method, such as a pressure swing adsorption process. With regard to adsorbents that enable C4gas separation, [Zn(NO2ip)(dpe)]n(SD-65; NO2ip=5-nitroisophthalate, dpe=1,2-di(4-pyridyl)ethylene) is a promising porous material because of its structural flexibility and restricted voids, which provide unique guest-responsive accommodation. The 1,3-butadiene-selective sorption profile of SD-65 was elucidated by adsorption isotherms, in situ PXRD, and SSNMR studies and was further investigated by multigas separation and adsorption–desorption-cycle experiments for its application to separation technology.