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Aqueous electrolyte is one of the most favored choices for various high-energy, low-cost and safe batteries. However, the undesired parasitic hydrogen evolution reaction (HER), especially on high reactive metal anodes, brought by aqueous electrolyte remains the development bottleneck of these batteries. Here, introducing solvents to manipulate the hydrogen-bond network of aqueous electrolyte is proposed to suppress the parasitic HER. Significantly, theoretical simulations and experimental characterizations demonstrate that donor number of the solvents could serve as a descriptor to ability of confining the free water and reducing the water activity. The solvent additive with high donor number exhibits remarkable suppression on the self-discharge and hydrogen evolution of Al anodes in alkaline electrolyte, which endows a flow-based Al-air battery with an outstanding energy density of 3106.04 Wh kg−1. The findings not only provide a guidance on the rational design of aqueous electrolyte but also expand the application of high-donor solvents.

The title compound, C7H7N3S, which has potential biological activity, can be used as a ligand in metal complexation. This compound exists as the thione tautomer in the crystal phase, which is confirmed by the study of its molecular structure. The amino group has pyramidal configuration. In the crystal phase, the two independent molecules in the asymmetric unit form tetramers as a result of N—H...S hydrogen bonds. These tetramers are linked by N—H...N hydrogen bonds, forming chains/tubes in the [010] direction. The Hirshfeld surface analysis showed that the highest contribution to the total surface is provided by H...H interactions as well as S...H/H...S and C...H/H...C contacts associated with X—H...S hydrogen bonds and X—H...C(π) interactions.

In the title molecule, C25H28N2O5S, (alternative name ethyl 2-{[7-acetyl-4-cyano-6-hydroxy-8-(4-methoxyphenyl)-1,6-dimethyl-5,6,7,8-tetrahydroisoquinolin-3-yl]sulfanyl}acetate) the 4-methoxyphenyl group is disposed on one side of the bicyclic core and the oxygen atoms of the hydroxyl and acetyl groups are disposed on the other side. In the crystal, a layered structure parallel to the ac plane is generated by O—H...O and C—H...O hydrogen bonds plus C—H...π(ring) interactions.

Seven cocrystals of pyridone and perfluorinated halocarbons have been prepared. In all cases pairs of pyridone molecules are connected into dimers by two N–H···O hydrogen bonds, forming the characteristic pyridone homosynthon of R22(8) topology. These dimers further act as acceptors of halogen bonds through the two pyridone oxygen atoms, forming two (in six cases) or three (in one case) halogen bonds with the donor molecules. The stoichiometry of the cocrystals obtained and the overall topology of the supramolecular architecture depend primarily on the topicity of the halogen bond donor, with the monotopic donor yielding a cocrystal of 1:1 stoichiometry comprising discrete supramolecular complexes, the ditopic donors cocrystals of 1:2 stoichiometry comprising chains, and the tritopic donor a cocrystal of 1:2 stoichiometry comprising hydrogen- and halogen-bonded layers. The results indicate that the pyridone homosynthon is a robust and reliable supramolecular synthon that is conserved in halogen-bonded cocrystals of pyridone.

The pyridazine ring in the title compound, C20H17ClN2O3, adopts a screw-boat conformation. The whole molecule is flattened, the dihedral angles subtended by the least-squares plane of the central aromatic ring with those of the terminal benzene and pyridazine rings being 15.18 (19) and 11.23 (19)°, respectively. In the crystal, the molecules are linked by pairs of N—H...O bonds into centrosymmetric dimers and by C—H...π contacts into columns. The results of the Hirshfeld surface analysis show that the most prominent interactions are H...H, accounting for 36.5% of overall crystal packing, and H...O/O...H (18.6% contribution) contacts.

A novel imide compound (DH-MC) and polyimides (DH-PIs) that form multiple intramolecular hydrogen bonds (H-bonds) were synthesised from 2,2′-dihydroxybenzophenone-3,3′,4,4′-tetracarboxylic dianhydride (DHBA) to investigate the effects of distinct H-bond structures on the photoluminescence properties of these compounds. The DHBA moiety, which contains two proton donors and three proton acceptors, can form three types of H-bond structures (MC-0, MC-1, and MC-2). DFT calculations have predicted that the most energetically stable conformation is MC-1, forming an asymmetric H-bond structure, which is consistent with the FT-IR spectroscopy and single-crystal XRD analysis results. A colourless toluene solution of DH-MC exhibited orange fluorescence with a large Stokes shift (ν = 11 905 cm−1), and DH-MC and the DH-PIs exhibited yellow fluorescence with a large ν of >10 000 cm−1 in the solid state, with both originating from excited-state intramolecular proton transfer (ESIPT). In addition, these compounds exhibit small-Stokes-shifted fluorescence from the anionic form of the DHBA moiety, resulting in yellow coloration of the DH-PI film and the DH-MC powder. To reduce coloration, a polyimide copolymer (CoPI) film was prepared using DHBA and 4,4′-oxydiphthalic anhydride (ODPA) in which the molar ratio of DHBA was set at 3%. Owing to the dilution effect and efficient energy transfer from the blue-fluorescent ODPA to the DHBA moiety in the excited state, the colourless and transparent CoPI film exhibited prominent yellow fluorescence with a quantum yield of 0.14. The wavelength-converting spectrum demonstrated that the CoPI film absorbs a wide range of UV radiation from a xenon light source and significantly enhances the yellowish light component via ESIPT emission. The CoPI film is a promising candidate for solar spectral conversion applications.

The recently developed reversibly interlocked polymer networks are made from two-pre-formed crosslinked polymers containing reversible covalent bonds via topological rearrangement. Unlike interpenetrating polymer networks, the resultant is rather homogeneous regardless of the miscibility between the parent single networks, and can be repeatedly self-healed and unlocked/re-locked. The present work focuses on revealing the critical role of the hydrogen bonds between the single networks in construction of the interlocked networks, cooperating with dissociation and re-association of the built-in reversible covalent bonds. Based on the systematic investigations of the small molecules, single networks and interlocked networks, the inter-component hydrogen bonds of the interlocked networks are found to be able to be built-up, which are more stable than the intra-molecular hydrogen bonds of the single networks. They help to pull the chains from different single networks together, preventing the occurrence of phase separation during interlocking and implementing the valuable forced miscibility. Besides, the abundant but weak inter-component hydrogen bonds are preferred. The outcomes not only show the hitherto unknown part of the mechanism involved in the formation of the interlocked networks, but also benefit the design of new members of interlocked networks.

Summary Conventional aqueous electrolytes suffer from a narrow voltage window due to water decomposition. Highly concentrated electrolytes expand the voltage window; however, they are limited by high cost and potential toxicity. Here, we develop a hydrogen bond-anchored electrolyte by introducing sulfolane as hydrogen bond acceptor to limit water activity. The designed electrolyte expands the voltage window to 3.4 V (1.3–4.7 V versus Li+/Li) and forms a hierarchical anode-electrolyte interphase to suppress the hydrogen evolution reaction. An aqueous Li4Ti5O12/LiMn2O4 full cell achieved 141 W h kg−1 for 300 cycles at 1 C and 125 W h kg−1 for 1,000 cycles at 5 C with a high Coulombic efficiency of 99.5%–99.9%. On-line electrochemical mass spectroscopy shows negligible hydrogen/oxygen gas evolution upon cycling, further confirming the stability of the designed electrolyte. This work demonstrates a rational and effective approach to suppress the hydrogen evolution reaction and achieve stable high-voltage aqueous batteries.

The present work investigates the effects of cis and trans butenedioic acid isomers (maleic acid and fumaric acid) on the crystallinity and pharmaceutical behavior of lumefantrine. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), attenuated total reflectance infrared spectroscopy (ATR-IR), solid-state nuclear magnetic resonance spectroscopy (ss-NMR), and single-crystal X-ray diffraction (SC-XRD) studies were employed. Lumefantrine–fumaric acid crystallized as a salt in the monoclinic space group P21/c. In comparison, DSC and PXRD showed the formation of a co-amorphous solid with maleic acid. Complete proton transfer with a strong ionic interaction led to crystalline salt formation with the trans isomer, whereas weaker/fewer hydrogen bonds with the cis isomer of butenedioic acid led to a co-amorphous salt. The in vitro dissolution of both salts resulted in a similar 2.6–2.7-fold improvement in dissolution rate when compared to that of the crystalline lumefantrine. The crystalline and co-amorphous salts were stable under accelerated stability conditions (40 ± 2 °C and 75 ± 5% RH) for one month.

In this work we report on new heteroleptic coordination compounds [Pb2(LI)2](NO3)2∙2MeOH (1), [Pb2(LII)2](NO3)2 (2), [Pb2(LIII)2](NO3)2∙MeOH∙H2O (3) and [Pb2(LIII)2(H2O)](NCS)2 (4), which were obtained through self-assembling of 2-(amino(pyridin-2-yl)methylene)hydrazine-1-carbothioamide (HLI), 2-(amino(pyrazin-2-yl)methylene)hydrazine-1-carbothioamide (HLII) or 2-(amino(pyridin-2-yl)methylene)-N-methylhydrazine-1-carbothioamide (HLIII) with Pb(NO3)2 or a mixture of Pb(ClO4)2 and KNCS, respectively. In all the obtained complexes the lead(II) cation is N,N',S-chelated by the tridentate pincer type monodeprotonated ligand LI–III. In addition to the thiosemicarbazone chelation, the sulfur atom in each structure acts as bridging to connect two [Pb(LI–III)]+ units to form a dinuclear dimeric species having a centrosymmetric geometry, so that the ligands are directed either at different, in 1 and 2, or the same, in 3 and 4, side of the coplanar Pb2S2 core. In the latter structures two metal centers are additionally linked with each other through the oxygen atom of the bridging water molecule. The dimeric units in 1–4 are further linked through the Pb–N tetrel bonds, yielding 1D supramolecular polymeric chains, which, in turn, are interlinked though a myriad of other intermolecular noncovalent inetaractions, including tetrel bonds, hydrogen bonds and π-stacking. Counterions (NO3– and NCS–) as well as co-crystallized solvent molecules (MeOH and H2O) are also responsible in further stabilization of the overall crystal packing of the obtained complexes as a source of either tetrel and/or hydrogen bonds. The observation of the recurrent tetrel bonds in compounds 1–4 has been rationalized using DFT calculations and molecular electrostatic potential (MEP) surface plots. Moreover, coordination bonds (covalent character) and tetrel bonds (noncovalent character) between the complexes and their conterions (and water moelcule) have been differentiated using the quantum theory of «atoms-in-molecules» (QTAIM) and the noncovalent interaction index (NCI index) computational methods.

The acetonitrile solvate of a Schiff base molecule (HL) with acetonitrile (HL·2CH3CN) and its Cd(II) complex (Cd(HL)2Cl2, 1) were designed and synthesized. The different conformation of HL in HL·2CH3CN is adjusted by the hydrogen bonding O-H···O between HL molecules, together with N-H···N between HL molecules and acetonitrile molecules. While the conformation of HL in complex 1 is adjusted by coordination interactions between Zn ions and atoms O and N, together with hydrogen bonding N-H···Cl. The presence of the triphenylamine group makes HL·2CH3CN and complex 1 loosely packed. Upon grinding, HL·2CH3CN and complex 1 both showed high-contrast mechanochromic luminescence (MCL) change from blue to green and cyan to yellow, respectively. These changes can be eliminated by fumigation with organic vapor. The results of powder X-ray diffraction (PXRD) show that their MCL is due to the phase transformation from crystalline to amorphous state. In addition, HL·2CH3CN and complex 1 also exhibited high-contrast acidochromism upon exposure to HCl and NH3 vapor. X-ray photoelectron spectroscopy (XPS) and PXRD studies show that the protonation of the -NH- group together with a phase transformation from crystalline to amorphous state is attributed to the fluorescence switching. For HL·2CH3CN, the protonation process was accompanied by the departure of acetonitrile molecules. The emission of HL was restored to the amorphous state rather than the original crystalline state emission after further exposure to NH3 vapor, while 1-HCl could restore to the original crystalline state emission. In addition, HL·2CH3CN and complex 1 have been successfully used to produce writable and acid-responsive test papers.

Coordination polymers have received immense attention for proton conduction owing to their highly tunable and designable structures. Herein, based on the flexible ligand 5-(4-pyridine)-methoxyisophthalic acid (H2L), two novel highly chemically stable indium coordination polymers (In-CPs), InL(H2O)Cl·H2O (In–L–Cl) and InL(H2O)(NO3) (In–L–NO3), were synthesized through solvothermal methods. In–L–Cl and In–L–NO3 are isostructural, in which every individual In(III) atom connects to L2− to form a single layer, and coordinated Cl− and NO3− are inserted into the windows of the interlayers. Both of them possess high water and chemical stability. More importantly, the abundant Cl− and NO3− exposed in the interlayer can act as hydrogen bond acceptors to facilitate the formation of a dense hydrogen bonding network, thus improving proton transfer efficiently. Electrochemical impedance spectroscopy shows that In–L–Cl and In–L–NO3 display optimized proton conductivities of 1.88 × 10−3 and 1.00 × 10−3 S cm−1 at 100% relative humidity (RH) and 80 °C, respectively. The difference in proton conductivity of In–L–Cl and In–L–NO3 likely stems from the variations in the hydrogen bonding networks formed by lattice water and the different electronegativities of the coordinated anionic functional sites. This study provides an alternative way to prepare highly proton-conductive CPs.

The structure of (C18H15Sb)3TeO6, contains a [TeO6] octa­hedral unit linked to three trigonal–bipyramidal [SbC3O2] units via pairs of bridging O atoms to form a discrete mol­ecular unit. The packing of the units is dominated by C—H⋯O hydrogen bonding and weak dispersion forces, with a minor contribution from C—H⋯π bonds and π–π stacking inter­actions., In the structure of the title compound [systematic name hexa-μ-oxido-1:2κ4 O:O;1:3κ4 O:O;1:4κ4 O:O-nona­phenyl-2κ3 C,3κ3 C,4κ3 C-tri­anti­mony(V)tel­lur­ium(VI)], [Sb3Te(C6H5)9O6], the hexa­oxidotellurate(VI) ion is coordinated to three SbV ions via pairs of cis-positioned O atoms to form a discrete mol­ecular unit. The TeVI and SbV central ions exhibit distorted octa­hedral [TeO6] and distorted trigonal–bipyramidal [SbC3O2] coordination geometries, respectively. The linking of these polyhedra, by sharing the dioxide edges, results in the Te-based octa­hedron having a mer-configuration. The packing of the mol­ecules is dominated by C—H⋯O hydrogen bonding and weak dispersion forces, with a minor contribution from C—H⋯π bonds and π–π stacking inter­actions. According to the Hirshfeld surface analysis, the contributions of the H⋯H, H⋯C/C⋯H and H⋯O/O⋯H contacts are 58.0, 32.6 and 7.8%, respectively. The title structure provides a model for the bonding of triorgano­anti­mony dications to octa­hedral oxoanions, and the observed doubly bridged motifs, Te(μ-O)2Sb, may find application in the functionalization of polyoxometalate species.

The title complex, systematic name catena-poly[[[acetatochloridozinc(II)]-μ-(5R,6R,7S)-5-(furan-2-yl)-7-phenyl-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidin-6-amine] monohydrate], {[Zn(C2H3O2)Cl(C15H15N5O)]·H2O} n , is the first coordination complex in which the neutral tetrahydrotriazolopyrimidine derivative acts as bridging ligand between two zinc molecules. As a result, polymeric chains of the coordination complex are found. The coordination of the zinc metal atom occurs with the lone pairs of the triazolo nitrogen atom and amino group. The positive charge of the zinc atom is compensated by the chlorine anion and deprotonated acetic acid. The coordination complex exists as a monohydrate in the crystalline phase. The water molecules bind neighbouring polymeric chains by the formation of O—H...O, O—H...Cl and N—H...O hydrogen bonds.

In the title compound, ring conformations in the tetra­cyclic system are twist, chair, half-chair and boat-chair forms. In the crystal, the inter­molecular O—H⋯O hydrogen bonds connect the mol­ecules into a helical chain, and the inter­molecular C—H⋯O inter­actions link the chains into a three-dimensional architecture., In the fused tetra­cyclic system of the title compound, C29H36O9, the five-membered dioxolane ring adopts a twist conformation; the two adjacent C atoms deviate alternately from the mean plane of the other three atoms by −0.252 (6) and 0.340 (6) Å. The cyclo­hexane, cyclo­hexene and central cyclo­octane rings show chair, half-chair and boat-chair forms, respectively. There are three intra­molecular C—H⋯O inter­actions supporting the mol­ecular conformation, with one S(6) and two S(7) graph-set motifs. In the crystal, inter­molecular O—H⋯O hydrogen bonds connect the mol­ecules into a helical chain running along the c-axis direction, generating a C(7) graph-set motif. The chains are further linked by inter­molecular C—H⋯O inter­actions to construct a three-dimensional network. There is no valid C—H⋯π inter­action.

In the title compound, [Ag(CF3SO3)(C10H6F2N2)2], the AgI centre adopts a highly distorted trigonal–planar coordination environment resulting from its coordination by one O atom of the trifluoromethanesulfonate anion and the pyridine N atoms of two crystallographically independent 2′,6′-difluoro-2,3′-bipyridine ligands, which display very similar conformations to one another. Pairwise Ag...O–SO2CF3 − [Ag...O = 2.8314 (14) Å] interactions and intermolecular C—H...O interactions between inversion-related units lead to the formation of an eight-membered cyclic dimer in which the silver atoms are separated by 6.2152 (3) Å. In the crystal, the dimers are linked through C—H...O hydrogen bonds, halogen...π and weak π–π stacking interactions, resulting in the formation of a three-dimensional supramolecular network. The title compound exhibits a strong and broad emission band from 400 nm to 550 nm in solution and its photoluminescence quantum efficiency is estimated to be ca 0.2, indicating that the title compound could have applications as an emitting material in organic light-emitting diodes (OLEDs).

In the crystal, mol­ecules of 4,6-di­bromo­indole­nine are linked by C—Br⋯π halogen bonds, forming zigzag chains propagating in the [001] direction. The mol­ecules of the salt form layers parallel to the (010) plane where they are linked by C—H⋯Br hydrogen bonds C—Br⋯Br and C—Br⋯I halogen bonds., 4,6-Di­bromo-2,3,3-trimethyl-3H-indole, C11H11Br2N, exists as a neutral mol­ecule in the asymmetric unit. The asymmetric unit of 4,6-di­bromo-2,3,3-trimethyl-3H-indol-1-ium iodide, C12H14Br2N+·I−, contains one organic cation and one iodine anion. The positive charge is localized on the quaternized nitro­gen atom. In the crystal, mol­ecules of 4,6-di­bromo­indole­nine are linked by C—Br⋯π halogen bonds, forming zigzag chains propagating in the [001] direction. The mol­ecules of the salt form layers parallel to the (010) plane where they are linked by C—H⋯Br hydrogen bonds, C—Br⋯Br and C—Br⋯I halogen bonds. The Hirshfeld surface analysis and two dimensional fingerprint plots were used to analyse the inter­molecular contacts present in both crystals.

2-{[(E)-(3-Cyclo­butyl-1H-1,2,4-triazol-5-yl)imino]­meth­yl}phenol was synthesized by an eco-friendly microwave-assisted method that is highly selective and efficient. In the crystal, mol­ecules are linked by N—H⋯N and C—H⋯O hydrogen bonds., The title compound, C13H14N4O, was developed using the reaction of salicyl­aldehyde and 3-amino-5-cyclo­butyl-1,2,4-triazole in ethanol under microwave irradiation. This eco-friendly microwave-promoted method proved to be efficient in the synthesis of 2-{[(E)-(3-cyclo­butyl-1H-1,2,4-triazol-5-yl)imino]­meth­yl}phenol in good yields and purity. The title compound is a Schiff base that exists in the phenol–imine tautomeric form and adopts an E configuration. The three independent mol­ecules in the asymmetric unit (A, B and C) are not planar, the cyclo­butyl and the phenol-imine rings are twisted to each other making a dihedral angle of 67.8 (4)° in mol­ecule A, 69.1 (2)° in mol­ecule B and 89.1 (2)° in mol­ecule C. In each mol­ecule an intra­molecular O—H⋯N hydrogen bond is present, forming an S(6) ring motif. A Hirshfeld surface analysis was performed to investigate the contributions of the different inter­molecular contacts within the supra­molecular structure. The major inter­actions are H⋯H (53%), C⋯H (19%) and N⋯H (17%) for mol­ecule A, H⋯H (50%), N⋯H (20%) and C⋯H (20%) for mol­ecule B and H⋯H (57%), C⋯H (14%) and N⋯H (13%) for mol­ecule C.

Deoxynivalenol (DON), which is known as one of the most harmful mycotoxins, has contaminated food and feed and attracted concerns worldwide. However, the effective adsorptive removal of DON to ensure food safety still is a challenge, which is ascribed to the poor planarity and larger steric hindrance of DON molecules. Here, a new Zr(IV)-based metal-organic framework, entitled BUT-16 with one-dimensional channels and N-atom-decorated pore surface, is designed, prepared, and utilized for the adsorptive removal of DON. It exhibits excellent adsorption ability with an adsorption capacity of 46 mg/g higher than all reported adsorbents until now and a rapid adsorption rate of 0.031 g mg-1 min-1. DFT calculation and X-ray photoelectron spectroscopy results of the guest-loaded phase suggest that the record-breaking adsorption could be due to the cooperation of hydrogen bonding and Zr···O interaction between DON molecules and BUT-16 host. Most importantly, BUT-16 can effectively adsorb and remove DON in the simulated gastric fluid, but DON adsorbed on BUT-16 is hardly desorbed in the simulated intestinal fluid. The results demonstrate that BUT-16 has great promising application for the control of DON in foods and feeds.

Hydrogels have attracted widespread attention for breaking the bottlenecks faced during facile drug delivery. To date, the preparation of jelly carriers for hydrophobic drugs remains challenging. In this study, by evaporating ethanol to drive the formation of hydrogen bonds, hydrophilic poly(vinyl alcohol) (PVA) and certain hydrophobic compounds [luteolin (LUT), quercetin (QUE), and myricetin (MYR)] were rapidly prepared into supramolecular hydrogel within 10 min. The gelation performance of these three hydrogels changed regularly with the changing sequence of LUT, QUE, and MYR. An investigation of the gelation pathway of these hybrid gels reveals that the formation of this type of gel follows a simple supramolecular self-assembly process, called "hydrophobe-hydrophile crosslinked gelation". Because the hydrogen bond between PVA and the drug is noncovalent and reversible, the hydrogel has good plasticity and self-healing properties, while the drugs can be controllably released by tuning the output stimuli. Using a rat sidewall-cecum abrasion adhesion model, the as-prepared hydrogel was highly efficient and safe in preventing postsurgical adhesion. This work provides a useful archetypical template for researchers interested in the efficient delivery and controllable release of hydrophobic drugs.

As the high-power density and environmentally friendly energy resources, proton exchange membrane fuel cells (PEMFCs) have a promising future in portable power generation. Herein, the hybrid Nafion membranes of ionic hydrogen-bonded organic frameworks (iHOFs) for PEMFC applications are demonstrated. By adjusting the position of sulfonic groups on naphthalene disulfonic acid compounds, four iHOFs with different types of hydrogen bonds were synthesized successfully based on 1,1'-diamino-4,4'-bipyridylium and naphthalene disulfonic acid. The formation of hydrogen bond interactions between amino and sulfonate groups provides a rich hydrogen bond network, which makes such iHOFs have high conductivity, and the maximum value is 2.76 × 10-3 S·cm-1 at 100 °C and 98% RH. Besides, composite membrane materials were obtained by mixing Nafion and iHOFs, and the maximum proton conductivity values can achieve 1.13 × 10-2 S·cm-1 for 6%-iHOF-3/Nafion and 2.87 × 10-3 S·cm-1 for 6%-iHOF-4/Nafion membranes at 100 °C under 98% RH. Through the H2/O2 fuel cell performance test by using iHOF/Nafion as the solid electrolyte, the maximum power and current density values of hybrid membranes are 0.36 W·cm-2 and 1.10 A·cm-2 for 6%-iHOF-3/Nafion and 0.42 W·cm-2 and 1.20 A·cm-2 for 6%-iHOF-4/Nafion at 80 °C and 100% RH. This work provides a practicable approach for establishing high-performance proton exchange hybrid membranes by doping high proton-conducting iHOFs into the Nafion matrix.

The structural diversity and designability of metal–organic frameworks (MOFs) make these porous materials a strong candidate for NH3 uptake. However, to achieve a high NH3 capture capacity and good...

Hindered rotation about a sp(2) C-N bond is known to occur in arginine (Arg), asparagine (Asn), and glutamine (Gln) side chains of proteins. However, very little is known about the rotational dynamics of Asn and Gln side-chain NH(2) groups. Here, using a unique NMR method, we quantitatively characterized the hindered rotations of protein Asn/Gln side-chain NH(2) groups. This NMR method yields simple NH(2)-selective spectra that allow for accurate determination of the kinetic rate constants for the hindered rotations. Through the NMR measurements at some different temperatures, we investigated the energy barriers that restrict the C-N bond rotations of protein side-chain NH(2) groups. Through comparison of the kinetic data for the free and DNA-bound states of the Antp homeodomain, we also examined the impact of hydrogen-bonding on the hindered rotations of the side-chain NH(2) groups. Our data suggest that the hydrogen-bonding increases the energy barriers by 1–6 kJ/mol.

Continuing the studies of proton sponge-based oligo(arylene-ethynylenes), the protonation of the para-ortho-para-linked trimer (POP-trimer) has been investigated. For the first time, selective mono...

The mol­ecular and crystal structures of the chloro­benzene solvate of fluorenonophane have been studied using X-ray diffraction analysis. The fluorenonophane contains two fluorenone fragments linked by two m-substituted benzene fragments. Some decrease in its macrocyclic cavity leads to a stacking inter­action between the tricyclic fluorenone fragments. In the crystal, the fluorenonophane and chloro­benzene mol­ecules are linked by weak C—H⋯π(ring) inter­actions and C—H⋯Cl hydrogen bonds., The title compound, 19 H,79 H-3,5,9,11-tetra­oxa-1,7(2,7)-difluorena-4,10(1,3)-dibenzena­cyclo­dodeca­phane-19,79-dione (fluorenonophane), exists as a solvate with chloro­benzene, C42H28O6·C6H5Cl. The fluorenonophane contains two fluorenone fragments linked by two m-substituted benzene fragments. Some decrease in its macrocyclic cavity leads to a stacking inter­action between the tricyclic fluorenone fragments. In the crystal, the fluorenonophane and chloro­benzene mol­ecules are linked by weak C—H⋯π(ring) inter­actions and C—H⋯Cl hydrogen bonds. The Cl atom of chloro­benzene does not form a halogen bond. A Hirshfeld surface analysis and two-dimensional fingerprint plots were used to analyse the inter­molecular contacts found in the crystal structure.

Two model substances were used in the study – 2,6-dimethoxybenzoic acid (2,6MeOBA) and 3-hydroxybenzoic acid (3OHBA), each having two polymorphic forms, including a form without carboxylic acid homodimers in their crystal structure. For each polymorph 2-3 largest crystal faces were selected for MD simulations and the crystal was cut along these planes by preparing simulation box with these planes facing towards solution. In the performed study it was determined which additives potentially can influence the crystal morphology (based on the selected planes) and possibly also the obtained polymorph achieved by significantly changing crystal growth rate by adsorbing on the surface. For the study 4-5 additives providing different intermolecular interaction possibilities were selected. Growth of both explored surfaces of 2,6MeOBA form I are best inhibited by urea in 1,4-dioxane, while in methanol all explored additives act almost equally. All the studied surfaces of form II dissolved, indicating the very low stability of this. A different effect of urea and para-aminobenzoic acid (PABA) on the morphology of 3OHBA form I was found. In 1,4-dioxane different sorption results were observed for both additives. The growth of {011} surface could be inhibited by urea, but the {020} surface by PABA. The simulations showed that urea could not play a decisive role in the discrimination of 3OHBA polymorphic forms, as it was well sorbed on surfaces of both forms. Meanwhile the simulations showed that trans-stilbene has the potential to inhibit the formation of {110} surface of 3OHBA form II in methanol due to a strong π-π interactions. It was also observed that solvent has notable effect on the sorption of additives. The sorption of the studied additives was notably different in 1,4-dioxane, but in the methanol sorption of all additives was rather similar. Based on the results 1,4-dioxane is probably a better solvent for inhibition of growth of surfaces where hydrogen bonds are the dominant type of interactions. Among the studied additives urea showed the mot complete sorption and the longest residence time on surfaces for both substances with the exceptions of some specific planes. Meanwhile, complete and irreversible adsorption on crystal could also indicate on the possibility of formation of a mixed phase (co-crystal) in the presence of these additives.

The dissociation of a single water molecule on a ZnO(101̅0) surface has been investigated at the atomic level by low temperature STM manipulation combined with DFT calculations. The positive pulses applied from the tip inject electrons into the system and break the bonding between water and the ZnO surface, thus leading to the hopping of water molecules. Negative pulses inject holes wherein the lower energy ones split the free O-H bond pointing out of the surface whereas the higher energy ones split the second O-H bond that is directed to the surface through hydrogen bonding. Moreover, the yielded proton and hydroxyl species present distinctly charged status through different reaction pathways, manifesting their unique impacts on tailoring the surface properties of the metal oxide.

Reaction of K8{Ta6O19}·16H2O with [Ni(tren)(H2O)Cl]Cl·H2O in different solvents led to the formation of single crystals of the title compound, [Ni4Ta6O19(C6H18N4)4]·19H2O or {[Ni2(κ4-tren)(μ-κ3-tren)]2Ta6O19}·19H2O (tren is N,N-bis(2-aminoethyl)-1,2-ethanediamine, C6H18N4). In its crystal structure, one Lindqvist-type anion {Ta6O19}8– (point group symmetry \overline{1}) is connected to two NiII cations, with both of them coordinated by one tren ligand into discrete units. Both NiII cations are sixfold coordinated by O atoms of the anion and N atoms of the organic ligand, resulting in slightly distorted [NiON5] octahedra for one and [NiO3N3] octahedra for the other cation. These clusters are linked by intermolecular O—H...O and N—H...O hydrogen bonding involving water molecules into layers parallel to the bc plane. Some of these water molecules are positionally disordered and were refined using a split model. Powder X-ray diffraction revealed that a pure crystalline phase was obtained but that on storage at room-temperature this compound decomposed because of the loss of crystal water molecules.

The molecular bis-chelate complex (2-{[(2-hydroxyethyl-κO)amino-κN]methyl}-6-methoxyphenolato-κO)(2-{[(2-hydroxyethyl)imino-κN]methyl}-6-methoxyphenolato-κO)copper(II), [Cu(C10H14NO3)(C10H12NO3)] or [Cu(HL im)(HL am); HL im = C10H14NO3; HL am = C10H12NO3, represents the first compound containing a salicylidene-2-ethanolamine type ligand in both imino HL im (Schiff base) and amino HL am (reduced Schiff base) forms that has been structurally characterized on the basis of X-ray data. Two molecules of the monodeprotonated ligands coordinate the CuII ion in an (N,O phen)-bidentate and an (N,O phen,O alc)-tridentate fashion in the case of the imino and amino forms, respectively. The shape of the CuN2O3 coordination polyhedron is a distorted square-pyramid (geometry index τ5 = 0.26). Intermolecular N—H...O and O—H...O hydrogen bonds, involving H atoms of the amino and hydroxyethyl groups, create a two-dimensional supramolecular array extending parallel to (010).

Two structurally different metal–organic frameworks based on Sr2+ ions and 1,2,4,5-tetrakis(4-carboxyphenyl)benzene linkers have been synthesized solvothermally in different solvent systems and studied with single-crystal X-ray diffraction technique. These are poly[[μ12-4,4′,4′′,4′′′-(benzene-1,2,4,5-tetrayl)tetrabenzoato](dimethylformamide)distrontium(II)], [Sr2(C34H18O8)(C3H7NO)2] n , and poly[tetraaqua{μ2-4,4′-[4,5-bis(4-carboxyphenyl)benzene-1,2-diyl]dibenzoato}tristrontium(II)], [Sr3(C34H20O8)2(H2O)4]. The differences are noted between the crystal structures and coordination modes of these two MOFs, which are responsible for their semiconductor properties, where structural control over the bandgap is desirable. Hydrogen bonding is present in only one of the compounds, suggesting it has a slightly higher structural stability.

It is generally accepted that while efficient suppression of molecular vibration is inevitable for purely organic phosphors due to their long emission lifetime in the regime of 1 ms or longer, fluorophores having a lifetime in the nanoseconds regime are not sensitive to collisional quenching. Here, however, we demonstrate that a fluorophore, 2,5-bis(hexyloxy)terephthaldehyde (BHTA), capable of having hydrogen bonding (H bonding) via its two aldehyde groups can have a largely enhanced (450%) fluorescence quantum yield (QY) in amorphous poly(acrylic acid) (PAA) matrix compared to its crystalline powder. We ascribe this enhanced QY to the efficient suppression of molecular vibrations via intermolecular H bonding. We confirm this feasibility by conducting temperature-dependent fluorescence emission intensity measurement. As gaseous phenol can intervene with the H bonding between BHTA and PAA, interestingly, BHTA embedded in PAA can selectively detect gaseous phenol by a sharp fluorescence emission intensity drop that is visibly recognizable by the naked eye. The results provide an insightful molecular design strategy for a fluorophore and fluorometric sensory system design for enhanced photoluminescence QY and convenient detection of various volatile organic compounds.

The ability of 4-[(benzyl­amino)­carbon­yl]-1-methyl­pyridinium to form iodide salts with cation:iodine ratio different from equimolar was studied and a Hirshfeld surface analysis was performed to investigate the inter­molecular inter­actions., The two iodide salts, 4-[(benzyl­amino)­carbon­yl]-1-methyl­pyridinium iodide–iodine (2/1), C14H15N2O+·I−·0.5I2, I, and 4-[(benzyl­amino)­carbon­yl]-1-methyl­pyridinium triiodide, C14H15N2O+·I3 −, II, with different cation:iodine atoms ratios were studied. Salt I contains one cation, one iodide anion and half of the neutral I2 mol­ecule in the asymmetric unit (cation:iodine atoms ratio is 1:2). Salt II contains two cations, one triiodide anion (I 3 −) and two half triiodide anions (cation:iodine atoms ratio is 1:3). The NH group forms N—H⋯I hydrogen bonds with the I− anion in the crystal of I or N—H⋯O hydrogen bonds in II where only triiodide anions are present.

9-Amino­acridinium chloride N,N-di­methyl­formamide monosolvate was found to crystallize in the monoclinic space group P21/c. The crystal structure of this compound is stabilized by N—H⋯O and N—H⋯Cl hydrogen bonds, as well as π–π stacking., 9-Amino­acridinium chloride N,N-di­methyl­formamide monosolvate, C13H11N2 +Cl−·C3H7NO, crystallizes in the monoclinic space group P21/c. The salt was crystallized from N,N-di­methyl­formamide. The asymmetric unit consists of two C13H11N2 +Cl− formula units. The 9-amino­acridinium (9-AA) mol­ecules are protonated with the proton on the N atom of the central ring. This N atom is connected to an N,N-di­methyl­formamide mol­ecule by a hydrogen bond. The H atoms of the amino groups create short contacts with two chloride ions. The 9-AA cations in adjacent layers are oriented in an anti­parallel manner. The mol­ecules are linked via a network of multidirectional π–π inter­actions between the 9-AA rings, and the whole lattice is additionally stabilized by electrostatic inter­actions between ions.

The coordination polyhedra of the nickel(II) ions of the title compound in the complex cation and the anion, viz., trans-NiN4O2 and trans-NiO4N2, are distorted octa­hedra. In the crystal, the donor groups of the tetra­amine and the coordinated water mol­ecules and the carboxyl­ate groups of the pyridine-2,6-di­carboxyl­ate anions are involved in numerous N—H⋯O and O—H⋯O hydrogen bonds, thereby forming sheets of ions lying parallel to the (001) plane., The asymmetric unit of the title compound, trans-di­aqua­(1,4,8,11-tetra­aza­undecane-κ4 N 1,N 4,N 8,N 11)nickel(II) bis­(pyridine-2,6-di­carboxyl­ato-κ3 O 2,N,O 6)nickel(II) {[Ni(L)(H2O)2][Ni(pdc)2] where L = 1,4,8,11-tetra­aza­undecane (C7H20N4) and pdc = the dianion of pyridine-2,6-di­carb­oxy­lic acid (C7H3NO4 2−)} consists of an [Ni(L)(H2O)2]2+ complex cation and a [Ni(pdc)2]2– anion. The metal ion in the cation is coordinated by the four N atoms of the tetra­amine ligand and the mutually trans O atoms of the water mol­ecules in a tetra­gonally elongated octa­hedral geometry with the average equatorial Ni—N bond length slightly shorter than the average axial Ni—O bond [2.087 (4) versus 2.128 (4) Å]. The ligand L adopts its energetically favored conformation with five-membered and six-membered chelate rings in gauche and chair conformations, respectively. In the complex anion, the NiII ion is coordinated by the two tridentate pdc2– ligands via their carboxyl­ate and nitro­gen atom donors in a distorted octa­hedral trans-NiO4N2 geometry with nearly orthogonal orientation of the planes defining the carboxyl­ate rings and the average Ni—N bond length [1.965 (4) Å] shorter than the average Ni—O bond distance [2.113 (7) Å]. In the crystal, the NH donor groups of the tetra­amine, the carb­oxy­lic groups of the pdc2– anion and the coordinated water mol­ecules are involved in numerous N—H⋯O and O—H⋯O hydrogen bonds, leading to electroneutral sheets oriented parallel to the (001) plane.

The synthesis and crystal structure of the racemic title compound C26H24N2O2S2 with two stereocenters is reported., In the racemic title compound, C26H24N2O2S2, one of the thia­zine rings shows a twisted boat conformation (Q = 0.743 Å, θ = 92.1°) and the other a half-chair puckering (Q = 0.669 Å, θ = 54.3°). The terminal phenyl rings are almost parallel to each other [dihedral angle 21.71 (10)°]. Both of these rings are orthogonal to the central phenyl ring, subtending a dihedral angle of about 78° in each case. The extended structure is consolidated by C—H⋯O and C—H⋯S hydrogen bonds as well as aromatic ring inter­actions of parallel-displaced and T-type. The mol­ecule has approximate C2 local symmetry but this is not carried over to its three-dimensional structure or the inter­molecular inter­actions.

A hydrogen sulfate salt, C15H18NSe+·HSO4 −·H2O or [BnSeCH2CH(Ph)NH3 +](HSO4 −), of a chiral selenated amine (R)-2-(benzylselanyl)-1-phenylethanamine (BnSeCH2CH(Ph)NH2) has been synthesized and characterized by elemental analysis,1H and 13C{1H} NMR, FT–IR analysis, and single-crystal X-ray diffraction studies. The title salt crystallizes in the monohydrate form in the non-centrosymmetric monoclinic P21 space group. The cation is somewhat W shaped with the dihedral angle between the two aromatic rings being 60.9 (4)°. The carbon atom attached to the amine nitrogen atom is chiral and in the R configuration, and, the –C—C– bond of the –CH2—CH– fragment has a staggered conformation. In the crystal structure, two HSO4 − anions and two water molecules form an R 4 4(12) tetrameric type of assembly comprised of alternating HSO4 − anions and water molecules via discrete D(2) O—H...O hydrogen bonds. This tetrameric assembly aggregates along the b-axis direction as an infinite one-dimensional tape. Adjacent tapes are interconnected via discrete D(2) N—H...O hydrogen bonds between the three amino hydrogen atoms of the cation sandwiched between the two tapes and the three HSO4 − anions of the nearest asymmetric units, resulting in a complex two-dimensional sheet along the ab plane. The pendant arrangement of the cations is stabilized by C—H...π interactions between adjacent cations running as chains down the [010] axis. Secondary Se...O [3.1474 (4) Å] interactions are also observed in the crystal structure. A Hirshfeld surface analysis, including d norm, shape-index and fingerprint plots of the cation, anion and solvent molecule, was carried out to confirm the presence of various interactions in the crystal structure.

The reaction of a nickel precursor with an enanti­omerically pure amino-oxime issued from (R)-limonene led to the formation of bis­[κ3 N,N,N-(amino­oxime)-μ-chlorido]­dichloro­dinickel as a new dinuclear nickel complex., A dinuclear nickel complex with (S)-limonene based amino­oxime ligand has been isolated and its crystal structure determined. The resolved structure of dichloridobis­{(2S,5R)-2-methyl-5-(prop-1-en-2-yl)-2-[(pyridin-2-yl)methyl­amino]­cyclo­hexan-1-one oxime}dinickel(II), [Ni2Cl2(C16H23ClN3O)2], at 100 K has monoclinic (P21) symmetry. The two NiII ions in the dinuclear complex are each coordinated in a distorted octa­hedral environment by three nitro­gen atoms, a terminal chloride and two μ bridging chlorides. Each oxime ligand is coordinated to nickel(II) by the three nitro­gen atoms, leading to two five-membered chelate rings, each displaying an envelope conformation. In the crystal, numerous inter­molecular and intra­molecular hydrogen bonds lead to the formation of a three-dimensional network structure.

The asymmetric unit of the first title compound iodido(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)zinc(II) iodide, [ZnI(C10H24N4)]I, I, consists of the zinc–cyclam macrocyclic cation with one iodide anion coordinated to the metal ion [Zn—I = 2.6619 (5) Å] and the second present as a counter-ion. The asymmetric unit of the second title compound iodido(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)zinc(II) triiodide, [ZnI(C10H24N4)]I3, II, consists of half of the centrosymmetric macrocyclic cation, in which the ZnII ion coordinated to an iodide anion [Zn—I = 2.766 (2) Å] is disordered over two positions [Zn...Zn = 0.810 (3) Å], and of the two halves of the crystallographically non-equivalent, non-coordinated, centrosymmetric triiodide anions. In both compounds, the N,N,N,N-tetradentate macrocyclic ligand is present in the most energetically favored trans-III conformation. In the crystals of I, the [Zn(C10H24N4)I]+ cations and the non-coordinated iodide anions are linked by N—H...I and bifurcated N—H...(I,I) hydrogen bonds, resulting in the formation of two-dimensional networks lying parallel to the (001) and (101) planes. In contrast, the crystals of II are built up from infinite chains of the five-coordinate macrocyclic units arranged along the b-axis direction and perpendicular sheets formed of the triiodide counter-ions without significant hydrogen bonding between them.

The crystal structures of ethyl 1-[N-(4-methyl­phen­yl)-N-(methyl­sulfon­yl)alan­yl]piperidine-4-carboxyl­ate and 1-[N-(4-methyl­phen­yl)-N-(methyl­sulfon­yl)alan­yl]piperidine-4-carb­oxy­lic acid, two analogues studied as potentiators of Ubiquitin C-terminal hydro­lase-L1 (UCH-L1), have been determined. Despite being analogues, different crystal packings are observed. A polymorph risk assessment was carried out to study inter­actions in the second compound., The structure of ethyl 1-[N-(4-methyl­phen­yl)-N-(methyl­sulfon­yl)alan­yl]piperidine-4-carboxyl­ate, C19H28N2O5S, I, a compound of inter­est as activator of Ubiquitin C-terminal Hydro­lase-L1 (UCH-L1), was determined by single-crystal X-ray diffraction (SCXRD) analysis. In order to find new activators, a derivative of compound I, namely, 1-[N-(4-methyl­phen­yl)-N-(methyl­sulfon­yl)alan­yl]piperidine-4-carb­oxy­lic acid, C17H24N2O5S, II, was studied. The synthesis and crystal structure are also reported. Despite being analogues, different crystal packings are observed. Compound II bears a carb­oxy­lic group, which favors a strong hydrogen bond. A polymorph risk assessment was carried out to study inter­actions in compound II.

In the xanthene moiety of the title compound, the central ring adopts a flattened-boat conformation whereas the cyclo­hexenone rings adopt envelope conformations. In the crystal, mol­ecules are linked by pairs of O—H⋯O hydrogen bonds, forming inversion dimers with an (20) ring motif., In the fused ring system of the title compound, C24H27BrO5, the mean plane and maximum deviations of the central pyran ring are 0.0384 (2) and 0.0733 (2) Å, respectively. The cyclo­hexenone rings both adopt envelope conformations with the tetra-substituted C atoms as flap atoms, whereas the central pyran ring adopts a flattened boat conformation. The central pyran and phenyl substituent rings are almost perpendicular to each other, making a dihedral angle of 89.71 (2)°. In the crystal, pairs of mol­ecules are linked via O—H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(20) ring motif. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (50.6%), O⋯H/H⋯O (22.9%) and C⋯H/H⋯C (11.1%) contacts. Quantum chemical calculations for the frontier mol­ecular orbitals were undertaken to determine the chemical reactivity of the title compound.

The mol­ecular and crystal structures of the title compound, C37H41ClN4O8, which has potential biological activity have been studied. This compound exists in the crystal phase as a methanol solvate., The title compound, C36H37ClN4O7·CH3OH, which crystallizes as a methanol solvate, may possess biological activity, which is inherent for a natural peptide or protein. In the crystal, mol­ecules of the title compound form hydrogen-bonded tetra­mers with the solvate mol­ecules acting as bridges as a result of the O—H⋯O and N—H⋯O inter­molecular hydrogen bonds. Hirshfeld surface analysis was used to study the different types of inter­molecular inter­actions whose contributions are: H⋯H = 53.8%, O⋯H/H⋯O = 19.0%, C⋯H/H⋯C = 14.8%, Cl⋯H/H⋯Cl = 5.3%, N⋯H/H⋯N = 3.2%.

Please provide a synopsis (of no more than two sentences) for inclusion in the Contents listing of the journal., The title compounds, di-μ-chlorido-bis­({2-[(η-2,3)-(prop-2-en-1-yl)sulfan­yl]pyridine-κN}copper(I)), [Cu2Cl2(C8H9NS)2], and di-μ-bromido-bis­({2-[(η-2,3)-(prop-2-en-1-yl)sulfan­yl]pyridine-κN}copper(I)), [Cu2Br2(C8H9NS)2], were obtained by alternating-current electrochemical synthesis starting from an ethano­lic solution of 2-[(prop-2-en-1-yl)sulfan­yl]pyridine (Psup) and the copper(II) halide. The isostructural crystals are built up from centrosymmetric [Cu2 Hal 2(Psup)2] dimers, which are formed due to the π,σ-chelating behavior of the organic ligand. In the crystals, the dimers are linked by C—H⋯Hal hydrogen bonds as well as by aromatic π–π stacking inter­actions into a three-dimensional network.

The metal ion of the title salt hydrate shows a 4 + 2 (N4O2) tetra­gonally elongated coordination geometry defined by four macrocyclic-N atoms and two weakly associated acetate-O atoms; the crystal features conventional hydrogen-bonding inter­actions., The title CuII macrocyclic complex salt tetra­hydrate, [Cu(C22H46N6O2)](C2H3O2)2·4H2O, sees the metal atom located on a centre of inversion and coordinated within a 4 + 2 (N4O2) tetra­gonally distorted coordination geometry; the N atoms are derived from the macrocycle and the O atoms from weakly associated [3.2048 (15) Å] acetate anions. Further stability to the three-ion aggregate is provided by intra­molecular amine-N—H⋯O(carboxyl­ate) hydrogen bonds. Hydrogen bonding is also prominent in the mol­ecular packing with amide-N—H⋯O(amide) inter­actions, leading to eight-membered {⋯HNCO}2 synthons, amide-N—H⋯O(water), water-O—H⋯O(carboxyl­ate) and water-O—H⋯O(water) hydrogen bonds featuring within the three-dimensional architecture. The calculated Hirshfeld surfaces for the individual components of the asymmetric unit differentiate the water mol­ecules owing to their distinctive supra­molecular association. For each of the anion and cation, H⋯H contacts predominate (50.7 and 65.2%, respectively) followed by H⋯O/O⋯H contacts (44.5 and 29.9%, respectively).

With a view to establishing molecular recognition rules, the host p-tert-butyl­calix[6]arene was crystallized with different guest molecules. The ratio between the apolar surface area and the volume was used to predict the formation of inclusion versus exclusion complexes, with inclusion complexes observed at ratios, Calixarenes are host molecules that can form complexes with one or more guest molecules, and molecular recognition in calixarenes can be affected by many factors. With a view to establishing molecular recognition rules, the host p-tert-butyl­calix[6]arene (TBC6) was crystallized with different guest molecules (cyclo­hexane, anisole, heptane, toluene, benzene, methyl acetate, ethyl acetate, di­chloro­methane, tetra­hydro­furan and pyridine) and the obtained structures were characterized by X-ray diffraction. With most solvents, 1:1 and/or 1:3 host–guest complexes were formed, although other stoichiometries were also observed with small guest molecules, and crystallization from ethyl acetate produced the unsolvated form. The calculated fill percentage of the TBC6 cavity was ∼55% for apolar guests and significantly lower for polar solvents, indicating that polar molecules can bind to apolar cavities with significantly lower packing coefficients. The most stable crystals were formed by 1:1 host–guest inclusion complexes. The ratio between the apolar surface area and the volume was used to predict the formation of inclusion versus exclusion complexes, with inclusion complexes observed at ratios

In this paper, three different methods (secondary growth method, in situ hydrothermal method and hot pressing with silane method) for synthesizing silicalite-1 molecular sieve anti-corrosive film on open-cell aluminum foam surface were studied, and the silane coupling agent was used as a connecting layer to enhance the bonding force. The surface morphology was observed by scanning electron microscopy, the phase composition was analyzed by x-ray diffraction, and the corrosion resistance was predicted by electrochemical test results. It was shown that the silicalite-1 anti-corrosion film prepared by the secondary growth method has the best surface, crystallinity (more than 98%), anti-corrosion performance, and good hydrophobicity. Finally, through Raman Microscopy test, the film formation mechanism of the secondary growth method was analyzed. The results show that the initial hydrogen bonds between the hydroxyl groups of the molecular sieve particle and the hydroxyl groups of the silane coupling agent change to covalent bonds due to the dehydration condensation reaction, and other free hydroxyl groups react in the same way with the hydroxyl groups on the aluminum foam surface.

A bio relevant organo sulfur compound, 3-(sec-butylthio)-4-hydroxy-2H-chromen-2-one (mf. C13H14O3S) has been synthesized following a visible light-induced green protocol in the atmosphere of oxygen...

As part of our ongoing investigation on the chemical and biological properties of piperazinium salts, we synthesized three novel compounds: 1-ethyl­piperazinium 3,5-di­nitro­benzoate (I), 1-methyl­piperazinium 3,5-di­nitro­benzoate (II) and 1-methyl­piperazinium 4-iodo­benzoate (III). The crystal structures of these compounds are built up of organic layers formed by the strong connection between the mol­ecules by hydrogen bonds of type N—H...O. These layers are linked through N—H...O hydrogen bonds and C—H...O inter­actions or C—I...N halogen bonding, leading to the formation of a three-dimensional network., Funding for this research was provided by: Spanish Ministerio de Ciencia e Innovacion (grant No. PID2020-113558RB-C41 to Santiago Garcia-Granda); Gobierno del Principado de Asturias (grant No. GRUPIN-ID2018-170 to Santiago GarciaGranda); University of Mysore (grant to Sriramapura D. Archana); Darmstadt University of Technology (studentship to Hemmige S. Yathirajan).

The organic-inorganic hybrid material bis(azepanium) hexachlorostannate(IV) (BAHCS) has been synthesized from azepanium chloride at room temperature. The hybrid was characterized by IR, TG-DTA, UV-...

The asymmetric unit of the title compound, catena-poly[[[(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ-cyanido-κ2 N:C-[bis(cyanido-κC)nickel(II)]-μ-cyanido-κ2 C:N] dihydrate], {[Ni2(CN)4(C10H24N4)]·2H2O] n or [{[Ni(C10H24N4)][Ni(CN)4]}·2H2O] n , consists of a pair of crystallographically non-equivalent macrocyclic cations and anions. The nickel(II) ions (all with site symmetry \overline{1}) are coordinated by the four secondary N atoms of the macrocyclic ligands, which adopt the most energetically stable trans-III conformation, and the mutually trans N atoms of the tetracyanonickelate anion in a slightly tetragonally distorted NiN6 octahedral coordination geometry. The [Ni(CN)4)]2– anion exhibits a bridging function, resulting in the formation of parallel polymeric chains running along the [1\overline{1}0] direction. The water molecules of crystallization play a pivotal role in the three-dimensional supramolecular organization of the crystal. Acting as acceptors, they form N—H...Ow (w = water) hydrogen bonds with the secondary amino groups of the macrocycles, forming layers oriented parallel to the (001) plane. At the same time, as donors, they interact with the non-coordinated cyano groups of the anion via Ow—H...Nc (c = cyanide) hydrogen bonds, giving two-dimensional layers oriented parallel to the (100) plane and thus generating a three-dimensional network.

Two-dimensional (2D) graphitic carbon nitrides (g-C3N4) have sparked much interest as photocatalysts. However, they suffer from high activation energy and a low separation rate of photoexcited charge carriers. Here we report a viable strategy to craft one-dimensional carbon nitrides denoted as polymelem (PM). Our PM possesses NH-bridged and the N-bridged tautomers, both of which are π-conjugated polymers based on aromatic tri-s-triazine units, as revealed by solid-state nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and Raman techniques. A 2D 1H double-quantum-single-quantum (DQ-SQ) NMR spectrum illustrates that the 2D architecture of PM is constructed by the formation of interchain N-H···N hydrogen bonds between different 1D PM chains. PM exhibits largely improved photocatalytic efficiency compared to g-C3N4. This can be attributed to the conjugated structures of PM, which are conducive to the decrease in activation energy and separation rate of photogenerated charge carriers.