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A state-of-the-art Rietveld refinement strategy is proposed to derive the instrumental resolution function (IRF) for a ball-mill setup for time-resolved in situ (TRIS) synchrotron XRPD.

Three new polycatenated mixed-ligand MOFs containing fluorene and naphthalene scaffolds have been solvothermally synthesized. Their solid-state luminescence has been investigated showing a Förster resonance energy transfer involving the two linkers.

Fe(III) and Mn(II) complexes with condensation product of thiosemicarbazide and 2-acetylthiazole (HL1, (E)-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide) have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. In both complexes, the thiosemicarbazone ligand is coordinated in deprotonated form through the NNS donor set of atoms. However, while Fe(III) complex is in the doublet ground state with distorted octahedral geometry, the coordination environment around Mn(II) is distorted trigonal-prismatic, and the sextet state is found to be the ground state. DFT calculations were performed to rationalize spin state preferences, and continuous shape measure describes the deviation from ideal six-coordinated polyhedral geometries in the ground and excited states. Antimicrobial activity (against a panel of Gram-negative and Gram-positive bacteria, two yeast, and one fungal strain), brine shrimp assay, and DPPH radical scavenging activity of both complexes were evaluated, and these results relate to the electronic structure of the complexes. This is the peer-reviewed, authors’ version of the article: Stojičkov, M., Zlatar, M., Mazzeo, P. P., Bacchi, A., Radanović, D., Stevanović, N., Jevtović, M., Novaković, I., Anđelković, K., Sladić, D., Čobeljić, B., Gruden, M. (2023). The interplay between spin states, geometries and biological activity of Fe(III) and Mn(II) complexes with thiosemicarbazone. Polyhedron, 237, 116389. [https://doi.org/10.1016/j.poly.2023.116389] The published version: [https://cer.ihtm.bg.ac.rs/handle/123456789/6041] Supplementary information: [https://cer.ihtm.bg.ac.rs/handle/123456789/6043]

Naphthalenediimide derivates are a class of π-conjugated molecules largely investigated in the literature and used as building blocks for metal–organic frameworks or coformers for hydrogen-bond-based cocrystals. However, their tendency to establish halogen-bond interactions remains unexplored. By using a crystalline engineering approach, we report here four new cocrystals with N,N′-di(4-pyrydyl)-naphthalene-1,4,5,8-tetracarboxidiimide and diiodo-substituted coformers, easily obtained via a mechanochemical protocol. Cocrystals were characterized via NMR, electron ionization mass spectrometry, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Crystallographic structures were then finely examined and correlated with energy framework calculations to understand the relative contribution of halogen-bond and π–π interactions toward framework stabilization., Mechanochemical synthesis allows the synthetic problems deriving from low solubility of a py-functionalized naphthalenediimide in the synthesis of halogen-bond cocrystals with iodine-containing coformers to be overcome.

The debate on the mechanisms which underpin mechanochemical reactions

Mechanochemistry has become a sustainable and attractive cost-effective synthetic technique, largely used within the frame of crystal engineering. Cocrystals, namely, crystalline compounds made of different chemical entities within the same crystal structure, are typically synthesized in bulk via mechanochemistry; however, whereas the macroscopic aspects of grinding are becoming clear, the fundamental principles that underlie mechanochemical cocrystallization at the microscopic level remain poorly understood. Time-resolved in situ (TRIS) monitoring approaches have opened the door to exceptional detail regarding mechanochemical reactions. We here report a clear example of cocrystallization between two solid coformers that proceeds through the formation of a metastable low melting binary eutectic phase. The overall cocrystallization process has been monitored by time-resolved in situ (TRIS) synchrotron X-ray powder diffraction with a customized ball milling setup, currently available at μSpot beamline at BESSY-II, Helmholtz-Zentrum Berlin. The binary system and the low melting eutectic phase were further characterized via DSC, HSM, and VT-XRPD.

Cocrystallization is an extensively used method in Crystal Engineering for tuning the properties of target compounds by pairing them with ad-hoc selected molecular partners (i.e. coformers) in a st...

Metal-organic frameworks (MOFs) give the opportunity of confining guest molecules into their pores even by a post-synthetic protocol. PUM168 is a Zn-based MOF characterized by microporous cavities that allows the encapsulation of a significant number of guest molecules. The pores engineered with different binding sites show a remarkable guest affinity towards a series of natural essential oils components, such as eugenol, thymol and carvacrol, relevant for environmental applications. Exploiting single crystal X-ray diffraction, it was possible to step-wisely monitor the rather complex three-components guest exchange process involving dimethylformamide (DMF, the pristine solvent) and binary mixtures of the flavoring agents. A picture of the structural evolution of the DMF-to-guest replacement occurring inside the MOF crystal was reached by a detailed single-crystal-to-single-crystal monitoring. The relation of the supramolecular arrangement in the pores with selective guests release was then investigated as a function of time and temperature by static headspace GC-MS analysis.

Liquid active ingredients are typically less stable than their solid analogues and they are also generally associated with storage and handling problems when considered for industrial usage. However, many synthetic and natural active ingredients are liquid or low melting solids under ambient conditions, and formulation or cocrystallization might be helpful to modulate this characteristic. As an alternative, crystalline porous matrices, such as metal–organic frameworks, can be used to encapsulate the guest molecules providing them with a crystalline environment very different to what might be observed in the pure liquid phase, thus stabilizing the active compounds in the solid state. In this work, PUM168, a flexible heteroleptic MOF, has been used to encapsulate three liquid compounds (propofol, carvacrol and menthone). The nanoconfinement of the three guests has been fully investigated via SCXRD in terms of host–guest interactions and framework rearrangement as a function of the guest loading.

A magnetic hybrid material based on the use of the mixed-ligand Metal-Organic Framework (MOF) PUM198 is proposed for the magnetic dispersive micro solid-phase extraction (MD-?SPE) of the 16 polycyclic aromatic hydrocarbons (PAHs) included in the US-EPA priority pollutants list. PUM198 is a thermally robust MOF characterized by a doubly interpenetrated microporous framework in which Zn2+ ions and carboxylate groups define 2D planes that are pillared by a bis-pyridine-bis amide ligand containing a biphenyl scaffold. PUM198 revealed to be ideal to adsorb PAHs efficiently through non-covalent interactions. A Plackett-Burman Design followed by a Central Composite Design and the multicriteria method of the desirability functions were applied to find the optimal conditions for the extraction of the investigated PAHs, resulting in a reduced solvent consumption, i.e., 50 ?L of solvent per extraction for 5 mL of sample, approximatively 3-20 times lower than those reported in previous studies, thus satisfying the principles of green analytical chemistry. Method validation proved the reliability of the method for the determination of PAHs at trace level, obtaining detection limits in the 6.7-27 ng/L range, good precision with RSDs% lower than 19% and recovery rates in the 99 (±13)-126 (±8)% range near the quantitation limit. Finally, the applicability of the method was demonstrated by analyzing underground water samples taken from contaminated sites

Time resolved in situ (TRIS) monitoring has revolutionised the study of mechanochemical transformations but has been limited by available data quality. Here we report how a combination of miniaturised grinding jars together with innovations in X-ray powder diffraction data collection and state-of-the-art analysis strategies transform the power of TRIS synchrotron mechanochemical experiments. Accurate phase compositions, comparable to those obtained by ex situ measurements, can be obtained with small sample loadings. Moreover, microstructural parameters (crystal size and microstrain) can be also determined with high confidence. This strategy applies to all chemistries, is readily implemented, and yields high-quality diffraction data even using a low energy synchrotron source. This offers a direct avenue towards the mechanochemical investigation of reactions comprising scarce, expensive, or toxic compounds. Our strategy is applied to model systems, including inorganic, metal-organic, and organic mechanosyntheses, resolves previously misinterpreted mechanisms in mechanochemical syntheses, and promises broad, new directions for mechanochemical research., Time-resolved in situ (TRIS) X-ray powder diffraction promises great potential to study mechanochemical processes. Here, the authors develop a strategy to enhance the resolution of TRIS experiments to allow deeper interpretation of mechanochemical transformations; the method is applied to a variety of model systems including inorganic, metal-organic, and organic mechanosyntheses.

In this study, a new series of extended linkers containing different polyaromatic chromophores (biphenyl, naphthalene, anthracene, fluorene, 9,9-dimethylfluorene and fluorenone) functionalized with isonicotinoyl moieties have been synthesized by Pd-catalyzed cross-coupling reactions involving isonicotinamide and the appropriate aromatic dibromide. The optimized protocol led to the isolation of the target molecules in good yield and with high purity. These were characterized by

This manuscript reports the synthesis, X-ray characterization and DFT study of three new [M(bipy)3]2[Au(CN)2]3(X) (M = Fe, Co, and Ni; bipy = 2,2′-bipyridine; X = anion) ionic compounds. These salts are composed of [M(bipy)3]2+ dications and [Au(CN)2]− anions in a 2 : 3 ratio. The positive charge is compensated by X = Cl− anions in compounds 1 (M = Fe) and 2 (M = Co) and X = OH− in 3 (M = Ni). The three tridentate bipyridine ligands define the coordination of the M2+ cation, resulting in a nearly octahedral coordination sphere. The linear dicyanoaurate(I) anions are completely surrounded by a cradle of aromatic rings with Au-ring centroid distances below the sum of van der Waals radii, evidencing the existence of a specific Au⋯π attraction. This interaction has been analyzed in terms of the role of the Au-atom (Lewis acid or Lewis base) using DFT calculations combined with the quantum theory of atoms in molecules (QTAIM), noncovalent interaction plot index (NCIplot) and natural bond orbital (NBO) computational tools. The NBO suggests that the Au⋯π interaction is an example of a coinage bond in spite of the anionic nature of the acceptor and the cationic nature of the donor.

Inclusion complexes between cyclodextrins (CDs) and active pharmaceutical ingredients (APIs) have potential for pharmaceutical formulation. Since crystallization of a given complex may result in the isolation of multiple crystal forms, it is essential to characterize these forms with respect to their structures and physicochemical properties to optimize pharmaceutical candidate selection. Here, we report the preparation and characterization of two crystallographically distinct hydrated forms of an inclusion complex between β-cyclodextrin (β-CD) and the antifungal API fluconazole (FLU) as well as temperature–concentration conditions required for their individual isolation. Determination of crystal water contents was achieved using thermoanalytical methods. X-ray analyses revealed distinct structural differences between the triclinic (TBCDFLU, space group P1) and monoclinic (MBCDFLU, space group C2) crystal forms. Removal of the crystals from their mother liquors led to rapid dehydration of the MBCDFLU crystal, while the TBCDFLU crystal was stable, a result that could be reconciled with the distinct packing arrangements in the respective crystals. This study highlights (a) the importance of identifying possible multiple forms of a cyclodextrin API complex and controlling the crystallization conditions, and (b) the need to characterize such crystal forms to determine the extent to which their physicochemical properties may differ.

4,4′-Diazopyridine (AP) is largely known for its photophysical properties, and it is extensively studied in solution as molecular switch. By contrast, AP is not similarly explored in the solid state. We here discuss the fine crystallographic interpretation of the electron density maps combined with occupancy refinement of solid solutions, cocrystals and solid solution of cocrystals of AP and some halogenated derivatives, obtained as a result of recrystallization experiments. AP halogenated derivatives are contained as impurities in the purchased starting material and present a remarkable propensity to give cocrystals or solid solutions along with AP. A new AP polymorph (AP2) has also been identified, and phase evolution as a function of temperature has been investigated by differential scanning calorimetry and variable temperature X-ray powder diffraction.

The crystalline sponge method (CSM) is primarily used for structural determination by single-crystal X-ray diffraction of a single analyte encapsulated inside a porous MOF. As the host-guest systems often show severe disorder, reliable crystallographic determination is demanding; thus the dynamics of the guest entering and the formation of nanoconfined molecular aggregates has not been in the spotlight. Now, the concept is investigated of the CSM for monitoring the structural evolution of nanoconfined supramolecular aggregates of eugenol guests with displacement of DMF inside the cavities of the flexible MOF, PUM168. The interpretation of the electron density provides a series of unique detailed snapshots depicting the supramolecular guest aggregation, thus showing the tight interplay between the host flexible skeleton and the molecular guests through the DMF-to-eugenol exchange process.

Two flexible ligands derived from iminodiacetic acid, N-methlyiminodiacetic acid (H2mida) and N-(2-hydroxyethyl)iminodiacetic acid (H2hida) have been used as ligands towards lanthanide ions. Potentiometric studies (25.0 °C, 0.50 mol L−1 Me4NCl) revealed the predominance of stable species at acidic pH values. With this information, the synthesis of the coordination compounds was afforded in aqueous solution and the polymeric solids [Sm(Hmida)2(H2O)2]ClO4·1/6NaClO4·9H2O and [Ln(hida)(H2O)2](F3CSO3)·H2O (Ln = Ho, Yb) were prepared and characterized. The samarium compound consists of a cationic 2D polymeric structure in which the ligand is protonated in the N atom, preventing coordination to the central atom. The structure presents channels along one crystallographic direction. Ho and Yb coordination compounds are isostructural. A 2D polymeric cationic network is also observed. In this case, the additional hydroxyethyl group and the unprotonated N atom participate in the coordination.

The interaction of ethylenediamine with iodic acid by the slow evaporation method at room temperature gives rise to the crystals of α-C2H10N2(IO3)2 and β-C2H10N2(IO3)2 denoted as α-EBI and β-EBI, respectively. The acentric crystal structures of both polymorphs that consist of [C2H10N2]2+ cations and [IO3]− anions connected together by N–H…O hydrogen bonds are discussed and compared. The optical properties of both polymorphs were determined using UV-vis diffuse reflectance spectroscopy (DRS) showing a wide transparency windows. The DFT calculations using the mixed B3PW91/[6–31 + (d, p), LanL2Dz] basis set of optimized geometries, dipole moment (μ), polarizability (α), first static hyperpolarizability (β), and population analysis were also reported. The experimental and theoretical IR and Raman spectra were compared, and the careful and complete assignment of the vibrational motions of both compounds was undertaken with the aid of potential energy distribution (PED) analysis. DSC and AC conductivity analysis revealed that α-C2H10N2(IO3)2 and β-C2H10N2(IO3)2 undergo a first-order phase transition around 360 K. The electrical σtot (ω, T) conductivity obeyed to Jonscher’s power law and the temperature dependence of the S(T) parameter showed that the electrical conductivity of both polymorph phases might be treated using the correlated barrier hopping (CBH) model.

The iodate salt [C2H10N2](IO3)2·4HIO3 denoted as EBITIA, was synthesized at this first time by A. M. Petrosyan et al. during the investigation the system C2H8N2 HIO3 H2O. In their study authors, have characterized the compound using iodometric titration and IR spectroscopy to determine its stocheometric composition. Later, K. Saidi et al. have studied the structural properties of the EBITIA crystal using X-ray single crystal diffraction at room temperature. In this work, this iodate salt was reproduced and was analyzed using the X-ray powder diffraction showing that the crystal structure of this compound corresponds well to the structrural model of the EBITIA. Variable temperature X-ray powder diffraction (VT-XRPD), 13C NMR, DSC and complex impedance spectroscopy (CIS) investigation were undertaken and show that the EBITIA is stable at the temperature range 303–393 K. The temperature dependence of both bulk and DC conductivities follow the Arrhenius law and the impedance data were fitted to an adequate equivalent circuit model consisting of a parallel combination of a bulk resistance and CPE. The near values of activation energies obtained from the conductivity and impedance measurements suggested that the electrical conductivity in the EBITIA may be due to the ion hopping mechanism. Moreover, the DFT calculation of the optimized geometries, vibrational wavenumbers, FOM's and Mulliken charge were also reported and were in better agreement with experiments. The complete, precise and reliable assignments of the fundamental vibrational modes were performed with the aid of potential energy distribution (PED). The optical properties of the compound were also studied using diffuse reflectance (DRS) and fluorescence spectroscopy.

Herein, four different coordination networks were isolated and structurally characterized by combining two aminocarboxylate ligands, 4,4′-[biphenyl-4,4′-diylbis(azanediyl)]dibenzoic acid and 5,5′-[biphenyl-4,4′-diylbis(azanediyl)]diisophthalic acid (H2L1 and H4L2, respectively), with different transition metals (Zn(II), Zr(IV) and Cd(II)) under solvothermal conditions. The reaction between H2L1 and Zn(NO3)2·6H2O led to two different coordination networks. In PUMflex1-Zn, which has the formula {[Zn4O(L1)3(DMF)2](DMF)5}n·(DMF)x, the ligand always displays a syn conformation (with respect to the central biphenylene scaffold), whereas in the polymorph PUMflex1.1-Zn, one of the three ligands composing the asymmetric unit adopts an anti conformation. Although the two supramolecular isomers have equivalent stoichiometry and dimensionality, they show different topologies and entanglement types: parallel polycatenation of the 63-hcb and 2-fold interpenetration of the 44-sql layers, respectively. In the case of PUMflex1-Zr, with the formula {[Zr6O4(OH)8(L1)4(H2O)2]n·(DMF)x, H2L1 exclusively adopts the syn conformation, forming 1D-chains of rugby-ball shaped aggregates (topological type 2,8C1) interconnected through H-bonds with water molecules. In contrast, H4L2 behaves as a dianionic ligand in PUMflex2-Cd, with the formula [Cd(κ2-COO)2(DMF)3(DMF)]n, forming 1D zig-zag chains connected through the N–H⋯OC(OH) H-bonds to provide planar layers of sql topology. In all cases, the ability of the amine functions to interact with the H-bond active guests is structurally highlighted by the recurrent N–H⋯ODMF interaction modelled in the X-ray structures.

The beneficial effects of transmetalation on MOFs' functional behaviours are well-known as it endows the material with novel functionalities. Even though the structural adaptation of the framework to the new metal ion has a great impact on the properties of the resulting material, this subject still remains poorly understood. Herein, we present a detailed structural study by single crystal XRD and scanning electron microscopy on the unprecedented Co-substituted form of a renowned MOF, namely IRMOF-9. The performed Zn-to-Co exchange induced profound changes in the microstructure of the crystals as well as in the framework arrangement. While the evaluation of the first suggests an unconventional transmetalation mechanism involving a phase demolition and re-growth process, the average coordination network shows a remarkable shrinking of the solid with a loss of ∼2.5% of its starting volume. This deformation comes with an increased exposure of the metal sites to the MOF cavities due to a more open disposition of the linkers, whose peculiar disorder agrees with such structural change. These results shed light on the complexity of IRMOF-9(Co), highlighting the importance of structural investigations in transmetalation studies., Dr Monica Maffini (University of Parma) is gratefully acknowledged for the ICP-OES analyses. We acknowledge Elettra-Sincrotrone for providing beamtime (Proposal 20155003) and the XRD1 beamline staff for their assistance during the experiments. Dr Stefan Wuttke is also gratefully acknowledged for the precious advice and confrontation.

In this work synthesis, characterization and crystal structures of 1, Zn(II) complex ([ZnL1(NCS)2]), with (E)-1-(2-oxo-2-(2-(quinolin-2-ylmethylene)hydrazinyl)ethyl)pyridin-1-ium chloride (HL1Cl) and 2, Bi(III) complex ([BiHL2Cl4] × 1/2CH3OH), with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL2Cl), have been reported. Zn(II) complex possesses a distorted trigonal bipyramidal geometry while surroundings around Bi(III) ion are extended pentagonal bipyramidal. Antimicrobial activity, brine shrimp assay and DPPH radical scavenging activity of both complexes, including previously synthesized complexes with HL2Cl ligand (Zn(II) and Ni(II)) and complexes with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL3Cl) (Zn(II), Cu(II), Cd(II), Co(II), Fe(III), Ni(II)), were evaluated. For the most active complexes, cytotoxic activity against five malignant cancer cell lines (HeLa, A375, MCF7, PC-3 and A549) and normal cell line HaCaT, as well as generation of reactive oxygen species (ROS), was tested. Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4675]

International audience; Among water treatment processes, ultrafiltration is known to be efficient for the elimination of micro-organisms (bacteria and viruses). In this study, two pathogens were targeted, a bacterium, Vibrio aestuarianus and a virus, OsHV-1, with the objective to produce high quality water from seawater, in the case of shellfish productions. The retention of those microorganisms by ultrafiltration was evaluated at labscale. In the case of OsHV-1, the protection of oysters was validated by in vivo experiments using oysters spat and larvae, both stages being highly susceptible to the virus. The oysters raised using contaminated seawater which was then subsequently treated by ultrafiltration, had similar mortality to the negative controls. In the case of V. aestuarianus, ultrafiltration allowed a high retention of the bacteria in seawater with concentrations below the detection limits of the 3 analytical methods (flow cytometry, direct seeding and seeding after filtration to 0.22 µm). Thus, the quantity of V. aestuarianus was at least, 400 times inferior to the threshold known to induce mortalities in oysters. Industrial scale experiment on a several months period confirmed the conclusion obtained at lab scale on the Vibrio bacteria retention. Indeed, no bacteria from this genus, potentially harmful for oysters, was detected in permeate and this, whatever the quality of the seawater treated and the bacteria concentration upstream of the membrane. Moreover, the resistance of the process was confirmed with a stability of hydraulic performances over time for two water qualities and even facing an algal bloom. In terms of retention and resistance, ultrafiltration process was validated for the treatment of seawater towards the targeted pathogenic microorganisms, with the aim of biosecuring shellfish productions.

We present a simple way of estimating the entropy cost of solvate formation in crystals. The entropy penalty of making solvates can be as low as 9 kJ mol−1 and is entirely dependent on the nature of the liquid component and the temperature of solvate formation. A link is found between a low entropy cost and a higher likelihood for a solvent to make solvates.

Polycyclic aromatic compounds such as acridine and phenazine are popular molecular partners used in cocrystal synthesis. The intermolecular interactions occurring between coformers and their molecular partners dominate the cocrystal packing energy, but coformer self-interactions might participate with a constant non-negligible contribution to the overall packing energy stabilization. Two new acridine-based cocrystals have been mechanochemically synthesized, then fully characterized via DSC and SCXRD analyses. A statistical analysis in the CSD has been performed to evaluate the recurrent pi-pi stacking orientation of polycyclic coformers in all deposited acridine-based cocrystals, then extended to phenazine-base analogs. Packing energy calculations were performed on a selected cocrystal subset to quantify the contribution of the pi-pi interaction to the overall stabilization energy.

In this contribution, we report novel palladium-catalyzed carbonylative cascade approaches to highly functionalized polyheterocyclic structures. The Pd-catalyzed carbonylative process involves the regioselective insertion of one to three CO molecules and the sequential ordered formation of up to eight new bonds (one C-O, two C-C, five C-N). The exclusive formation of six-membered heterocycles is elucidated by detailed modeling studies.

A bis-pyridyl-bis-amide ligand containing a biphenylene scaffold was combined with four different dicarboxylic acids in the presence of Zn(NO3)2·6H2O under solvothermal conditions, using DMF as solvent. The corresponding coordination frameworks were structurally characterized by single crystal diffraction analysis, the topological and thermal analysis were also conducted. The removing of the included DMF was investigated through solvent assisted activation protocol, the final outcomes being determined by 1HNMR analysis. The dimensionality of the solid networks depends on the type of dicarboxylic acid employed. The use of isophthalic acid and 5-amino-isophthalic acid led to the isolation of 2D-frameworks (PUM20 and PUM32, topological type 3,5L2), while a 1-D polymer was obtained using 2-methoxy-isophthalic acid (PUM30, of topological type SP 1-periodic, ladder-like). Finally, the use of terephthalic acid led to a pillared 2-fold interpenetrated 3D-structure (PUM198, of topological type fet).

The use of Pd(0) mediated C N coupling reaction for the synthesis of large polydentate ligands functionalized with NH groups is described. The protocol has been applied to the synthesis of polycarboxylic ligands and polypyridyl ligands, starting from common aryl halides containing a central phenyl or biphenyl core as electrophiles. Different aromatic amines or isonicotinamide have been used as nucleophiles. In all cases the ligands have been isolated in high yields and purity. The products have been characterized by means of FTIR, 1H NMR, 13C{1H} NMR, EI-MS or CI-MS and elemental analysis. The X-ray structure of N,N′-(biphenyl-4,4′-diyl)diisonicotinamide has also been solved.

We address the problem of stabilizing liquid nicotine in solid forms at ambient conditions by cocrystallization. The design of cocrystals forms of nicotine has been approached by analyzing its molecular electrostatic potential. An intriguing aspect of nicotine lies in the fact that its crystal structure has never been reported in literature and this peculiarity may be ascribed to the liquid-glass transition that occurs when nicotine is supercooled under its melting point (-79°C). Despite nicotine was considered a rigid molecule, its glass forming attitude could be due to a certain extent of conformational variability, which has been assessed by the conformer search of the CCDC software. Based on these considerations, three coformers have been identified and their crystal structure shows that nicotine adapts to the packing features dictated by the coformers. The tool of packing energy frameworks has been used to discuss the stabilization of the cocrystals.

We report design and structural characterization of six new coordination polymers fabricated from PbCl2 and a series of closely related bis-pyridyl ligands LI and HLII–HLVI, namely, [Pb2(LI)Cl4]n, [Pb(HLII)Cl2]n·nMeOH, [Pb(HLIII)Cl2]n·0.5 nMeOH, [Pb2(LIV)Cl3]n, [Pb(HLV)Cl2]n, and [Pb3(LVI)2Cl4]n·nMeOH. The topology of the obtained networks is dictated by the geometry of the organic ligand. The structure of [Pb2(LI)Cl4]n is constructed from the [PbCl2]n two-dimensional (2D) sheets, linked through organic linkers into a three-dimensional framework, which exhibits a unique binodal 4,7-connected three-periodic topology named by us as sda1. Topological analysis of the 2D metal–organic sheet in [Pb(HLII)Cl2]n·nMeOH discloses a binodal 3,4-connected layer topology, regardless of the presence of tetrel bonds. A one-dimensional (1D) coordination polymer [Pb(HLIII)Cl2]n·0.5 nMeOH is considered as a uninodal 2-connected chain. The overall structure of [Pb2(LIV)Cl3]n is constructed from dimeric tetranuclear [Pb4(μ3-L...

Herein, we describe the synthesis and single crystal X-ray diffraction characterization of several Pb(II) complexes using Schiff base hydrazido-based ligands and different counterions (NO3&minus, I&minus, and ClO4). In the three complexes reported in this work, the lead(II) metal exhibits a high coordination number (n &gt, 8) and thus it is apparently not involved in tetrel bonding interactions. Moreover, the aromatic ligands participate in noncovalent interactions that play an important role in the formation of several supramolecular assemblies in the solid state of the three Pb(II) complexes. These assemblies have been analyzed by means of Hirshfeld surface analysis and DFT calculations.

The first organo-catalyzed synthesis of imidazolidin-2-ones and imidazol-2-ones via intramolecular hydroamidation of propargylic ureas is reported. The phosphazene base BEMP turned out to be the most active organo-catalyst compared with guanidine and amidine bases. Excellent chemo- and regioselectivities to five-membered cyclic ureas have been achieved under ambient conditions, with a wide substrate scope and exceptionally short reaction times (down to 1 min). A base-mediated isomerization step to an allenamide intermediate is the most feasible reaction pathway to give imidazol-2-ones, as suggested by DFT studies.

A way to reduce food waste is related to the increase of the shelf-life of food as a result of improving the package type. An innovative active food packaging material based on cocrystallization of microbiologically active compounds present in essential oils i.e. carvacrol, thymol and cinnamaldehyde was developed following the Quality by Design principles. The selected active components were used to produce antimicrobial plastic films with solidified active ingredients on their surface characterized by antimicrobial properties against four bacterial strains involved in fruit and vegetable spoilage. The developed packaging prototypes exhibited good antimicrobial activity in vitro providing inhibition percentage of 69 (±15)% by contact and inhibition diameters of 32 (±6) mm in the gas phase, along with a prolonged release of the active components. Finally, the prolonged shelf-life of grape samples up to 7 days at room temperature was demonstrated.

Two different N-substituted naphthalimide ligands 1 (bearing a phenyl on the imide nitrogen) and 2 (bearing a benzyl on the imide nitrogen) have been synthesized and reacted with the cationic organometallic fragment [Cp*Ru(ACN)3]PF6. Ligand 1 brings to the formation of a sandwich complex (3Naph) where Ru is positioned on the naphthalene platform, while the N-imide phenyl substituent is not involved in coordination. This has been proven by single-crystal X-ray diffraction analysis conducted on crystals of 3Naph, revealing the first sandwich complex structurally characterized containing a naphthaleneimide ligand η6-coordinated to a metal. Ligand 2 shows instead a different behavior, leading to the formation of two isomeric complexes (4Naph and 4Bz), where Ru is placed on the naphthalene platform and on the N-imide benzyl substituent, in a rough 1:1 ratio. Complex 3Naph results very labile in coordinating solvents, such as acetonitrile, where it undergoes a fast and quantitative ligand solvolysis, with formation of free 1 and [Cp*Ru(ACN)3]PF6. In the cases of complexes 4, only complex 4Naph undergoes a fast and quantitative ligand solvolysis once dissolved in acetonitrile, whereas complex 4Bz results more stable.

Most drugs are delivered as crystalline solids, but some widely used pharmaceutical ingredients cannot be crystallized at ambient conditions: propofol, one of the most widely used anesthetic agents in the world is a liquid. Here we stabilize propofol in a crystalline phase by cocrystallization, and we thoroughly characterize the structural and thermodynamic properties of the new materials. Ternary solubility diagrams of a liquid pharmaceutical ingredient cocrystallized with a solid coformer are presented and analyzed for the first time. It is shown that, when equilibrated with the solid cocrsytal, the concentration of propofol in water is kept constant in a wide range of starting compositions.