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A method of storing gas comprises providing a recipient for receiving the gas and providing a porous gas storage material. The gas storage material comprises a cross-linked polymeric framework and a plurality of pores for gas sorption. The cross-linked polymeric framework comprises aromatic ring-containing monomeric units comprising at least two aromatic rings. The aromatic ring-containing monomeric units are linked by covalent cross-linking between aromatic rings to form a stable, rigid nanoporous material for storing the gas at pressures significantly greater than the atmospheric pressure, for example in excess of 100 bar. A possible application is the storage and transportation of compressed natural gas. Also claimed are methods for producing a porous gas storage material, porous gas storage materials and the use of a gas storage material.

In this study, we show how the combination of metal ions, counter-anions and opportunely functionalized and preorganized ligands gives rise to two distinct supramolecular isomers, coordination polymeric chains and hexameric macrocycles. The hexamers then aggregate to form a cubic structure exhibiting permanent microporosity. The supramolecular assemblies are formed with Ag+, thioether functionalized bis(pirazolyl)methane ligands and CF3SO3-/PF6- as the counter-anions. Five different ligands were prepared by modifying the peripheral thioether moiety with naphthyl, methoxy, m-Me, p-Me and F groups (LSNf, LSPhOMe, LSPhm-Me, LSPhp-Me, and LSPhF). Helicoidal coordination polymeric chains are formed with CF3SO3- (general formula [Ag(L)]n(CF3SO3)n), whereas macrocyclic hexamers are formed with PF6- (general formula [Ag(L)]6(PF6)6). The macrocycles self-assemble into ordered capsules with the shape of a tetrahedron, and the overall framework is sustained by Ag+⋯(PF6-)⋯Ag+ contacts. The capsules generate a highly symmetric structural arrangement, which is characterized by permanent microporosity arising from two distinct types of microporous chambers in the structure. The gas absorption isotherms show that the materials can selectively adsorb CO2 and N2O over CH4 and N2. The modulation of the microporosity of the materials is achieved by the different thioether functionalization of the ligands LSNf, LSPhOMe, LSPhm-Me, and LSPhF. The diffusion and localization of the gas molecules within the cavities were investigated by 2D 1H-13C solid state NMR on samples loaded with enriched 13CO2, showing that both types of cavities are accessible to guest molecules from the gas phase.(Figure Presented).

Porous organic frameworks perform a variety of functions, owing to their extremely large surface areas, but the dynamics of the structural elements have never been explored. Our discovery of ultra-fast molecular rotors (106 Hz at 225 K) in their architectures allows us to look at them from a new perspective. The constructive elements are robust struts and rapid rotors, resulting in a dynamic material whose motion can be frozen or released at will. The rotational motion can be actively regulated in response to guests. As the temperature is increased, the rotors spin ever faster, approaching free-rotational diffusion at 550 K. The unusual combination of remarkable nanoporosity with fast dynamics is intriguing for engineering oscillating dipoles and producing responsive materials with switchable ferroelectricity, and for applications spanning from sensors to actuators, which capture and release chemicals on command.

Our work was aimed at performing polymerizations in porous materials and controlling solid state reactions of the new adducts with polymers. The project exploits the unprecedented potentials of porous materials presently in use, which range from fully-organic covalent frameworks and metal-organic frameworks to porous molecular crystals of biological origin, while the properties induced to the polymers include stereochemistry, chain alignment and morphology. The extraordinary surface areas (> 5000 m2/g) and pore capacity exhibited by porous aromatic frameworks (PAFs) interconnected by covalent bonds, allow sorption of a large amount of monomers to form high-molecular-mass polymers tightly interwoven with the porous matrix [1]. Polyacrylonitrile (PAN) obtained by this way could undergo in-situ thermal transformation to conductive, semi-conductive polymers and carbon nano-fibers. PAN was also synthesized in the form of isotactic polymer within the nanochannels of dipeptide crystals which were used as sacrificial polymerization vessels [2]. The crystalline matrix sublimed away over 250 °C after a polymer intramolecular reaction to yield a rigid 'ladder' polymer, which retained the morphology of the crystal scaffold. In a third example, the metal-organic host framework can participate with two reactive vinyl pendant groups in the polymerization, resulting in a cross-linked network [3]. The crystal scaffold of the host was removed except at cross-linking points, which act as clipping points for the aligned polymer chains. Although the polymer chains are atactic, they are kept in register by the molecular clips and chain-periodicity was ascertained by XRD and TEM. An intriguing aspect of porous crystalline frameworks is the dynamics of molecular elements in the pore-walls. Since these mobile elements behave as rotors and are exposed collectively to the structural voids in the porous material, their motion could be switched on and off by intervening molecular species migrat

Our work was aimed at performing polymerizations in porous materials and controlling solid state reactions of the new adducts with polymers. The project exploits the unprecedented potentials of porous materials presently in use, which range from fully-organic covalent frameworks and metal-organic frameworks to porous molecular crystals of biological origin, while the properties induced to the polymers include stereochemistry, chain alignment and morphology. The extraordinary surface areas (> 5000 m2/g) and pore capacity exhibited by porous aromatic frameworks (PAFs) interconnected by covalent bonds, allow sorption of a large amount of monomers to form high-molecular-mass polymers tightly interwoven with the porous matrix [1]. Polyacrylonitrile (PAN) obtained by this way could undergo in-situ thermal transformation to conductive, semi-conductive polymers and carbon nano-fibers. PAN was also synthesized in the form of isotactic polymer within the nanochannels of dipeptide crystals which were used as sacrificial polymerization vessels [2]. The crystalline matrix sublimed away over 250 °C after a polymer intramolecular reaction to yield a rigid 'ladder' polymer, which retained the morphology of the crystal scaffold. In a third example, the metal-organic host framework can participate with two reactive vinyl pendant groups in the polymerization, resulting in a cross-linked network [3]. The crystal scaffold of the host was removed except at cross-linking points, which act as clipping points for the aligned polymer chains. Although the polymer chains are atactic, they are kept in register by the molecular clips and chain-periodicity was ascertained by XRD and TEM. An intriguing aspect of porous crystalline frameworks is the dynamics of molecular elements in the pore-walls. Since these mobile elements behave as rotors and are exposed collectively to the structural voids in the porous material, their motion could be switched on and off by intervening molecular species migrat

Porous materials are an attractive playground for the confinement of polymers and polymerization reactions to take place. We explored the use of porous hosts of various nature from synthetic to biological origin. This approach enables to achieve intriguing molecular architectures and morphologies. Within the family of natural hosts, we proposed for the first time the use of dipeptides as crystalline hosts for in situ polymerization: they provide ideal spaces for orienting polymer microstructure during its formation, mimicking enzymes. Exclusively 1,4-trans diene polymers and isotactic polycryloniltrile were synthesized as the output of the rigorous order of the crystalline structure. In the case of PAN the curing treatment results in a carbon nanofibrils which retain the crystal morphology. Moreover, prompted by the exceptional absorption properties of porous organic polymers with BET surface areas of 5500 m2/g, we realized the confined polymerization of acrylonitrile to yield bi-continuous phase materials with extended interfaces. The porous aromatic frameworks can be envisaged as a cradle for thermally activated chemical reactions of confined PAN. Solid state 2D NMR could describe the intimacy of the nanophases and polymer confinement. Optical absorption of the cured nanocomposites in the visible and near-infrared spectra could be tuned as a function of the thermal treatment and the energy gap falls in the range of semiconductor. Interestingly, through CH∙∙∙pi interactions, the molecular recognition of specific blocks of triblock copolymers and amphidynamic molecules by a host molecule promotes the formation of hierarchical periodic structures and surface inclusion compounds, respectively. The formation of the supramolecular architectures was followed by in situ synchrotron XRD while specific intermolecular interactions were highlighted by fast-1H MAS NMR and GIAO HF ab initio calculations.

The first example of a porous molecular crystal containing rotors is presented. The permanently porous crystal architecture is sustained by rotor-bearing molecular rods which are connected through charge-assisted hydrogen bonds. The rotors, as fast as 108 Hz at 240 K, are exposed to the crystalline channels, which absorb CO2 and I2 vapors at low pressure. The rotor dynamics could be switched off and on by I2 absorption/desorption, showing remarkable change of material dynamics by the interaction with gaseous species and suggesting the use of molecular crystals in sensing and pollutant management.

Chain alignment can significantly influence the macroscopic properties of a polymeric material, but no general and versatile methodol. has yet been reported to obtain highly ordered cryst. packing of polymer chains, with high stability. Here, we disclose a strategy that relies on ordered crosslinks' to produce polymeric materials that exhibit a cryst. arrangement. Divinyl crosslinkers (2,5-divinyl-terephthalate) were first embedded, as substitutional ligands, into the structure of a porous coordination polymer (PCP), [Cu(terephthalate)triethylenediamine0.5]n. A representative vinyl monomer, styrene, was subsequently polymd. inside the channels of the host PCP. The polystyrene chains that form within the PCP channels also crosslink with the divinyl species. This bridges together the polymer chains of adjacent channels and ensures that, on selective removal of the PCP, the polymer chains remain aligned. Indeed, the resulting material exhibits long-range order and is stable to thermal and solvent treatments, as demonstrated by X-ray powder diffraction and transmission electron microscopy

Ivory has always been considered one of the most attractive and valuable biological gem materials. It is tooth dentin, or the yellowish white, calcified, extremely elastic tissue that forms the tusks of several mammalian species. Microscopic examination of the surface in all possible directions is needed to a successful identification of cut and polished samples of ivory, but sometimes it is not enough. Supplemental techniques should be used for assisting discrimination of elephant (both Loxodonta africana and Elephas maximus) ivory and wholly mammoth (Mammuthus primigenius) ivory, because from a textural standpoint they can be remarkably similar. To provide the key identifying features of these two types of ivory is nowadays of special significance, due to the fact that elephant ivory trade and import and export are illegal, whereas wholly mammoth tusks may be legally exported and manufactured. Both materials are formed primarily by nanocrystals of biological calcium orthophosphate that are embedded in a type I collagen matrix. By exploiting 1H, 13C and 31P magic angle spinning (MAS) NMR we investigated the composition of several elephant and mammoth ivory specimens. 13C MAS NMR spectra confirmed the presence of the CO32- group associated to the carbonated hydroxyapatite in both ivory types. In the collagen structure no differences have been highlighted. Quantitative 31P MAS NMR spectra revealed important features about the inorganic matrix. The high resolution allowed us to achieve the simultaneous detection of the signal assigned to the bulk PO43- groups of the hydroxyapatite phase and of minor side peaks ascribed to unprotonated surface sites POx (PO, PO2- and PO32-) and to protonated sites POxH on the surface of the nano-sized crystals of the hydroxyapatite.

Molecular crystals of dipeptides containing open channels can selectively absorb CO2 over N2 and CH4, as shown by experimental and simulated isotherms. The efficient CO2 capture enabled separation from methane and allowed the direct observation by 2D MAS NMR of CO2 sequestered in the peptide-based biozeolites. © 2013 The Royal Society of Chemistry

Molecular rotor systems have been one of most challenging topics in the last years. Inspiring to biological molecular machines based on rotor systems, such as ATP-synthase, chemists have tried to reproduce functional nanodevices based on molecular rotors. One of the main targets in this research field was the attainment of materials wherein molecular rotors are organized in such a way that the free space around them is maximized and the rotational barrier is as low as possible. In this work we present a first example of highly-ordered materials wherein molecular rotors are linked to the framework through robust covalent bonds, which confer both thermal and chemical stability to the final material. We have chosen Periodic Mesoporous Organosilica (PMO) systems with crystal-like pore walls, such as p-phenyl, diphenylene and p-divinylphenylensilica, to study the rotational properties of the organic linkers pivoted between two siloxane layers. In these materials, organic moieties are organized at molecular level in the pore walls with the adjacent organic linkers posed at a distance greater than the sum of van der Waals radii. We have explored the dynamics of the molecular rotors by 2H NMR spectroscopy on the deuterated aromatic moieties. In fact, 2H NMR spectroscopy is a method of choice to determine the mechanism of motion. Rotational frequencies as fast as 108 Hz were estimated at room temperature and energy activation barriers of about 10 kcal/mol were calculated. Interestingly, we demonstrated for the first time that the rotational motion could be controlled by the presence of guest molecules diffused-in the mesopores and the materials change from a 2D rotational glass to a 2D rotational fluid behavior by increasing the temperature. In conclusion, these materials could find applications as gas-sensor systems or carriers for controlled release of stored molecules.

Research towards the fabrication of materials containing molecular rotors mounted on surfaces or arranged in ordered 3D arrays is presently very intense. The organization of individual rotors into ordered arrays in solids can provide the necessary juxtaposition to make them operate as devices and to realize materials that could express useful functions in the fields of electronics, optoelectronics, and nanofluidics. Molecular rotors in bulk materials require both a large free volume and low energy barriers that allow rotation of the organic elements about their pivotal bonds. The fulfillment of these criteria has been accomplished in low-density organic crystals by reducing the interactions of the mobile elements and protecting them in closed molecular capsules. We present periodic mesoporous organosilicas (PMOs) containing large nanochannels and ordered arrays of molecular moieties covalently linked to a robust siloxane framework which behave as molecular rotors. Connection of the organic elements to the siloxane layers through a virtually barrierless C-Si bond dictates their regularity, separating them one from the other and enabling the realization of highly mobile organic moieties. The highly porous hybrid materials are endowed with extremely low density and high surface area, thus the molecular rotors have the advantage of being easily accessible from the surrounding space through the open pores. The dynamics of the p-phenylene moieties in p-phenyl, diphenylene and divinylbenzene hybrid materials was studied by 2H solid-state NMR spectroscopy on the deuterated compounds. The spin–echo spectra provide the mechanism of reorientation of the C-D vectors and the motional averaging for frequencies that overcome the MHz regime. Consequently, variable-temperature solid-state 2H spin–echo NMR spectra were recorded to determine the reorientation rate and the mechanism of motion of p-phenylene rings in the porous materials. The 2H NMR spectral profiles of the deuterated m

Porous materials which present open nanochannels of cross-sections ranging from 0.3 to 4 nm. were investigated. Particular attention has been given to microporous frilly-org. substances of synthetic or biol. origin. In the latter family, a no. of dipeptides crystallize in hexagonal lattices with permanent porosity and modulated pore sizes. The affinity towards CO2 and relevant gases, such as methane and hydrogen, and their absorption efficiency was proved for the first time, even under mild conditions. Moreover, mixt. sepns. has been tested successfully, due to the pronounced selectivity (e.g. CO2 vs N2 and CH4). Also, porous org. networks of extremely high surface area (>6000m2/g were prepd. and studied.).

The dynamics of p-phenylene-d4 rotators in hierarchically ordered periodic mesoporous p-divinylbenzenesilica have been elucidated by deuterium solid-state NMR spectroscopy. The mesoporous material, characterized by a honeycomb lattice structure, has arrays of alternating p-divinylbenzene and siloxane layers forming the ordered walls of the mesoscopic channels. NMR expts. revealed a non-Arrhenius temp. dependence of the rotator dynamics, with rates ranging from 103 to 108 Hz between 215 K and 305 K. The regime of motion changes drastically at ∼280 K, indicating a dynamical transition with a corresponding change in heat capacity. At room temp. and above, the rotators comprise a highly mobile fluid-like rotational phase within the org. layers of the walls. However, cooling slightly below room temp. results in rigid glass-like org. layers with markedly slower dynamics. Exploiting the rotational behavior, above and below the transition, represents a means to elicit a very significant thermal response within a narrow temp. range.

The rational design of synthetic supramolecular architectures based on well-defined structure-directing forces and hydrogen bonding is still a challenge. We present a supramolecular cage assembled through 72 hydrogen bonds which is constructed from two kinds of hexagonal molecular tiles forming a truncated octahedron, one of the thirteen Archimedean polyhedra (Science 2011, 333, 436). The framework displays an extraordinary ability to encapsulate a wide range of differently charged species, not observed otherwise. By the exploitation of the same kind of interactions, orientation of polyconjugated guest molecules is obtained in tunable host cavities. The framework host architectures can be controlled systematically in a manner that enables the regulation of the guest orientation and aggregation (J. Am. Chem. Soc. 2010, 132, 14603). The effects of the distinct packing motifs is manifested as bathochromic shifts in the absorption and emission spectra of the guests as interpreted by ab initio TDDFT calculations. Interestingly, through CH∙∙∙pi interactions, the molecular recognition of specific blocks of triblock copolymers by a host molecule promotes the formation of hierarchical periodic structures. The formation of the supramolecular architectures is followed by in situ synchrotron X-ray diffraction while the specific CH∙∙∙pi intermolecular interactions are highlighted by fast-1H MAS NMR and GIAO HF ab initio calculations (J. Am. Chem. Soc. 2011, 133, 8982). Moreover, weak intermolecular interactions play a key role in modulating the dynamics of molecular rotors in amphidynamic materials. Indeed, the precise engineering of highly-organized porous silica scaffolds supporting organic elements allows the fabrication of fast molecular rotors (k>108 Hz) entirely exposed to the guest molecules which act as regulators (Angew. Chemie Int. Ed. 2010, 49, 1760).

Interpenetrated nanocomposites were formed by polymerization of acrylonitrile in a ultrahigh surface area (>5000 m2 g−1) porous framework. The resulting material realizes a hyperextended interface with uniform interdigitation of the two structures at the size limit of the individual molecular moieties. The confined poly(acrylonitrile) chains could be transformed into light-absorbing polyconjugated ladder polymers.

A novel porous tubular 1D-MOF, built from Cu(II), 1,2-bis(4-pyridyl)ethane and P,P′-diphenyl-diphosphinate, has been prepared by an easy and direct self-assembly process in either needle microcrystal or nanorod form depending on the synthesis conditions. The CO2 absorption kinetics drastically increased from the micrometric crystals to the nanorods. The selectivity towards other gases and polar solvents was also investigated. © 2012 The Royal Society of Chemistry.

We describe an approach to regular triangular arrays of dipolar molecular rotors based on insertion of dipolar rotator carrying shafts as guests into channels of a host, tris(o-phenylenedioxy)cyclotriphosphazene (TPP). The rotor guests can either enter the bulk of the host or stay at or near the surface, if a suitable stopper is installed at the end of the shaft. Differential scanning calorimetry, solid-state NMR, and powder X-ray diffraction were used to examine the insertion of a dipolar rotor synthesized for the purpose, 1-n-hexadecyl-12-(2,3-dichlorophenyl)-p-dicarba-closo-dodecaborane, and it was found that it forms a surface inclusion compound. Rotational barriers from 1.2 to 9 kcal/mol were found by dielectric spectroscopy and were attributed to rotors inserted into the surface to different degrees, some rubbing the surface as they turn.

The motional behavior of p-phenylene-d4 rotators confined within the 2D layers of a hierarchically ordered periodic mesoporous p-divinylbenzenesilica has been elucidated to evaluate the effects of reduced dimensionality on the engineered dynamics of artificial molecular machines. The hybrid mesoporous material, characterized by a honeycomb lattice structure, has arrays of alternating p-divinylbenzene rotors and siloxane layers forming the molecularly ordered walls of the mesoscopic channels. The p-divinylbenzene rotors are strongly anchored between two adjacent siloxane sheets, so that the p-phenylene rotators are unable to experience translational diffusion and are allowed to rotate about only one fixed axis. Variable-temperature 2H NMR experiments revealed that the p-phenylene rotators undergo an exchange process between sites related by 180° and a non-Arrhenius temperature dependence of the dynamics, with reorientational rates ranging from 103 to 108 Hz between 215 to 305 K. The regime of motion changes rapidly at about 280 K indicating the occurrence of a dynamical transition. The transition was also recognized by a steep change in the heat capacity at constant pressure. As a result of the robust lamellar architecture comprising the pore walls, the orientational dynamic disorder related to the phase transition is only realized in two dimensions within the layers, that is in the plane perpendicular to the channel axis. Thus, the aligned rotors that form the organic layers exhibit unique anisotropic dynamical properties as a result of the architecture’s reduced dimensionality. The dynamical disorder restricted to two dimensions constitutes a highly mobile fluidlike rotational phase at room temperature, which upon cooling undergoes a transition to a more rigid glasslike phase. Activation energies of 5.9 and 9.5 kcal/mol respectively have been measured for the two dynamical regimes of rotation. Collectively, our investigation has led to the discovery of an orientati

The study of crystalline architectures showing permanent porosity that can absorb molecules from the gas phase or include selectively target polymer segments in the nanochannels will be addressed. The porous crystalline matrices span from dipeptide crystals (1) and molecular zeolites to metal-organic frameworks and crystalline hybrid organosilicas. The open pore structure of the nanochannels and the diffusion rates of the gases was established by hyperpolarized Xenon NMR whilst gases such as carbon dioxide and methane were observed directly by 1H and 13C NMR spectroscopy after gas diffusion into the cavities. In addition, in the crystalline pore walls of nanoporous hybrid material we recognized, for the first time, the presence of parallel and aligned molecular rotors, yielding an unsual anisotropic arrangement of surface-exposed molecular rotors in a 3D framework (2). The entrapment of molecules inside the channels could successfully regulate the fast molecular rotor dynamics.

Flexible polymer chains and a suitable aromatic host self-assemble in varied ratios to fabricate crystalline and semi-crystalline materials with robust architectures. The high melting macromolecular adducts were successfully prepared by solvent-free mechanochemical or thermal treatment of the crystalline host and few polymers with various molecular weights. This unconventional strategy has been applied for the selective confinement of copolymer blocks into crystalline inclusion compounds, thus creating novel architectures stabilized by cooperative CH•••pi interactions, as revealed by solid state NMR.

Molecular self-assembled crystalline materials are promising in several fields, including gas storage, selective recognition and modulation of functions of active molecules. The tandem X-ray diffraction and solid state NMR approach allowed us to study amphipathic or amphidynamic materials i.e. crystalline structures that exhibit an intrinsic duality within the same periodic architecture [1-4]. In particular, we realized self-assembled crystalline architectures with guest molecules compartimentalized in two amphipathic nanospaces with distinct geometries and polarities [5]. The effect of these distinct environments on the NMR properties of the guest molecules is evident from chemical shift data and 2D heterocorrelated NMR techniques that could discriminate identical guest molecules embedded in distinct structural environments - one highly polar and the other nonpolar. The large magnetic susceptibility effect, due to ring currents of the aromatic host, enabled the determination of the host-guest distances and corroborated the variable-temperature crystal structure resolution. A dual behavior was also highlighted in a block copolymer. The molecular recognition of specific blocks of triblock copolymers by a host molecule led to the formation of hierarchical periodic structures [2]. The end blocks of the triblock copolymer were locked into the inclusion crystals whilst the central block was excluded, creating a new material of assembled nanocrystals regularly superimposed on one another. The formation of the supramolecular architectures was followed in situ synchrotron X-ray diffraction while fast-1H MAS NMR provided direct evidence of selective inclusion of the blocks. Notably, amphidynamic materials could be recognized in hybrid organic-inorganic crystalline materials [1]. The precise engineering of highly-organized porous materials containing organic elements pivoted on inorganic layers enabled the fabrication of fast molecular rotors entirely exposed to the guest mol

A polyphenylenevinylene derivative electroluminescent polymer was successfully incorporated into the channels of mesoporous silica SBA-15 with platelet morphology, and the obtained material was fully characterized by mean of X-ray diffraction, nitrogen physisorption porosimetry, infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), solid-state nuclear magnetic resonance (SS-NMR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy. The hybrid host-guest system displays significant pore size and volume restriction, along with luminescent properties that mimic those of the polymer in solution, as a consequence of strongly reduced aggregation of the polymer chains when confined in the SBA-15 channels. Moreover, the new composite material possesses a higher photostability than the pure polymer and represents a promising candidate for further use in the field of optoelectronic devices. © 2011 American Chemical Society.

Deep Inelastic Neutron Scattering measurements of water confined in mesoporous silica have been carried out. The experiment has been performed at room temperature on dry and on hydrated samples in order to investigate the interaction between the protons and the silanol groups of the confining surface. With this aim we could control the hydration of the pores in such a way as to adsorb 3.0 water molecules per nm2, corresponding to a 1 to 1 ratio with the silanol groups of the surface. DINS measurements directly measure the mean kinetic energy and the momentum distribution of the protons. A detailed analysis of the hydrated sample has been performed in order to separate the contributions of the protons in the system, allowing us to determine the arrangement of water molecules on the silanol groups. We find that the hydrogen bond of the water proton with the oxygen of the silanol group is much stronger than the hydrogen bonds of bulk water. © the Owner Societies. 2011.

The utility of basic sites of porous coordination polymers (PCPs) for the end-functionalization of oligo(vinylidene fluoride) (OVDF) is demonstrated. Densely arranged carboxylate moieties on the PCP pore walls act as basic sites and allow the efficient elimination reaction of the terminal group of OVDF to proceed. The progress of the reaction of an OVDF precursor in the PCP nanochannels was evidenced using solid state 19F NMR spectroscopy. From 19F and 1H NMR and IR measurements of the product isolated from the composite obtained, the terminal -CH2CF 2I moiety of OVDF was shown to be successfully converted to a -CHCF2 group. Because of the large surface area of the PCP materials, the OVDF precursor easily accessed the basic sites, resulting in a large increase in the rate of the elimination reaction. In addition, a notable effect of the porous structure of PCPs upon the elimination reaction was observed. © 2011 The Royal Society of Chemistry.

This work studied rubber-clay nanocomposites, in particular: filler-elastomer interface, multiscale clay organization in the rubber matrix, both in the absence and in the presence of C black, hybrid clay/C black filler network, dynamic-mech. properties of raw and S-cured compds. Studies performed with various techniques such as ESR spin labeling, Solid State NMR, TEM and x-ray diffraction pattern allowed to observe a nice distribution and dispersion of the layered clay, with the development of filler-matrix interface. Composites were prepd. with either intercalated or exfoliated organoclays, both in the absence and in the presence of C black, observing in the latter case the formation of a hybrid filler network formed by layered and spherical particles. Dynamic-mech. studies revealed that the replacement of a part of C black with an organoclay promotes a stronger filler-rubber interaction. The exfoliated organoclay is demonstrated as the ideal filler for compds. that have to explore a wide range of temps., as it gives rise to a better stability of properties.

Self-assembled supramol. crystals fabricated by solvent-free mechanochem. treatments of a cryst. host and a rubbery polymer are stabilized by cooperative CH....pi. interactions as revealed by 1H fast-MAS and 2-dimensional solid state NMR.

The present work describes a method to modify the surface of silica, reducing its polar character and making it compatible and dispersible into hydrocarbon based elastomers. A liquid low molar mass polybutadiene (PB) was grafted with mercaptopropyltrimethoxysilane (MPTS) via radical addition of the thiol group to the double bonds. The silanized PB was reacted with silica via thermal condensation with its silanol groups. 29Si NMR spectra showed that the condensation reaction of the trifunctional silane involved one or two alkoxy groups, while the third alkoxy group remained unreacted, probably for steric reasons. The characterization of the functionalized silica particles was performed by contact angle measurements and TGA analysis. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rotor speed regulation In the hybrid walls of porous p-phenylenesilica can be ach-ieved by guest uptake and removal. A graduation from slow to ultrafast motional regimes {k = 104-108 s-1) can be experienced by the molecular rotors depending on guest nature and temper-ature, as detected by solid-state spin-echo 2H NMR spectroscopy (see picture). (Figure Presented)

The y-ray-induced grafting of polybutadiene oligomers onto precipitated silica was investigated in the dose range up to 200kGy by THA,FTIR,CP/MASNMR,TEM microscopy, inverse gas chromatography (IGC), with determination of the grafting yields and the characterization of the modified silica with respect to surface energy,SiO2–oligomer interaction and morphology.The matrix EPR spectroscopy was employed for investigating the nature of the intermediate radicals in the grafting mechanism.

Dipeptide crystalline materials are proposed for the absorption of environmentally and energetically relevant gases such as carbon dioxide, methane and hydrogen. The crystalline scaffolds, held together by a network of hydrogen bonds, of L-alanyl-L-valine (AV), L-valyl-L-alanine (VA), L-isoleucyl-L-valine (IV) and L-valyl-L-isoleucine (VI) form stable nanochannel pores with internal hydrophobic surfaces and suitable cross-section that encapsulates, efficiently and selectively, guest gases. The soft nature of the interactions guarantees reversibility of the process and triggered delivery simply by reducing gas pressure. With L-isoleucyl-L-valine, showing small channel diameter (3.9 Å), at 195K and already at 250 torr CO2 absorption reaches the value of 53 cm3 (STP) g_1 (90% maximum loading). We were able to attain remarkable CO2/CH4 selectivity even at atmospheric pressure, supporting the idea that this crystalline powder can find application in methane purification from carbon dioxide. Hydrogen showed a particular affinity for the IV and VI as shown by the adsorption isotherms run up to 10 atm and 77K. The type I Langmuir profile at 77 K reached maximum loading already at pressures close to 1 atm, and an absorption capacity of 52 cm3 (STP) g-1 for IV that corresponds to 0.5 mol/mol.

Oggetti polimerici con morfologia definita a livello micrometrico e nanometrico sono stati ottenuti per replica diretta, a partire da micro-oggetti silicei di identica forma. Una silice porosa contenente nanocanali può essere sfruttata per condurre la polimerizzazione radicalica allo stato confinato di monomeri vinilici. In questo modo, micro-oggetti di silice auto-generati, dotati di forma definita (tubi, giroidi, coni), sono stato usati come nano reattori per preparare nanocompositi polimerici, che mantengono le strutture geometriche iniziali. La trascrizione della forma originale risulta completa anche dopo la dissoluzione della matrice inorganica, permettendo per la prima volta la creazione di inusuali micro-oggetti polimerici con porosità su scala nanometrica. L’alto grado di controllo sulla geometria e sulla porosità, messo a punto con questa nuova strategia di replica, apre nuove prospettive nel campo dei materiali polimerici. Grazie alla loro plasticità i microoggetti possono essere assemblati in micromacchine funzionali o impiegati per il confinamento di macromolecole biologiche, come il DNA.

A new aluminum naphthalenedicarboxylate Al(OH)(1,4-NDC)·2H2O compound has been synthesized. The crystal structure exhibits a three-dimensional framework composed of infinite chains of corner-sharing octahedral Al(OH)2O4 with 1,4-naphthanedicarboxylate ligands forming two types of channels with squared-shape cross-section. The large channels present a cross-section of 7.7 × 7.7 Å2, while the small channels are about 3.0 × 3.0 Å2. When water molecules are removed, no structural transformation occurs, generating a robust structure with permanent porosity and remarkable thermal stability. 2D 1H−13C heteronuclear correlation NMR measurements, together with the application of Lee-Goldburg homonuclear decoupling, were applied, for the first time, to porous coordination polymers revealing the spatial relationships between the 1H and 13C spin-active nuclei of the framework. To demonstrate the open pore structure and the easy accessibility of the nanochannels to the gas phase, highly sensitive hyperpolarized (HP) xenon NMR, under extreme xenon dilution, has been applied. Xenon can diffuse selectively into the large nanochannels, while the small ones show no substantial uptake of xenon due to severe restrictions along the channels that prevent the diffusion. Two-dimensional exchange experiments showed the exchange time to be as short as 15 ms. Through variable-temperature HP 129Xe NMR experiments we were able to achieve an unprecedented description of the large nanochannel space and surface, a physisorption energy of 10 kJ mol−1, and the chemical shift value of xenon probing the internal surfaces. The large pore channels are straight, parallel, and independent, allowing one-dimensional anisotropic diffusion of gases and vapors. Their walls are composed of the naphthalene moieties that create an unique environment for selective sorption. These results prompted us to measure the storage capacity toward methanol, acetone, benzene, and carbon dioxide. The selective adsorption of