Anionic Chains Research Articles

Effects of anion and alkyl chain length of cation on the thermophysical properties of imidazolium-based ionic liquid

Abstract This study focused on the effects of anions and the alkyl chain length of cations on the thermophysical properties of imidazolium-based ionic liquid (ILs). The data were obtained from references and the NIST database. The studied parameters include the melting temperature (Tm), glass transition temperature (Tg), decomposition temperature (Td), enthalpy of fusion (ΔHm), and thermal conductivity ( λ ). The variations of Tm with the anions in [C16MIM][A] where A = Br, Cl, BF4, PF6, and TFO, generally decreased with increasing anion radius, except for A = PF6, due to strong hydrogen bonds for the sake of an F atom. The values of the critical temperatures (Tm, Tg, and Td) generally show a strong variation with the number of carbon atom or alkyl chain length (the number of n in [CnMIM][A] for A = BF4, NTf2, and PF6). The variation of Tm corresponding to n shows non-monotonous variations. This characteristic is the result of the combination of interaction potentials in the crystalline and liquid phases. The variation of Tg corresponding to n shows even–odd alternation, presumably due to the competition between the electrostatic and van der Waals forces. Many types of ILs have a relatively high Td value, enabling them to remain in the liquid state above 400 °C, they have excellent catalytic activity and dynamic properties. The variation of Td with n appears different to that of Tm. Furthermore, the variation of ΔHm with n seems to follow that of Tm. This behaviour is in accordance with the thermodynamic relation between ΔHm, Tm, and the entropy of the system. The values of λ varied weakly with the alkyl chain length, and strongly depend on the type of anion.

Improving the wettability of structural steels by employing ionic liquids

Surface wetting behavior is tied to different surface phenomena such as lubrication and corrosion resistance of steel surfaces. In this study, the surface wetting behavior of room-temperature ionic liquids (RTILs) treated steel surfaces is investigated. To this end, polished steel surfaces are individually surface-treated using seven imidazolium-based RTILs with varying alkyl chain lengths ([CnMIM], n = 2, 4, 6) and anion groups ([PF6], [NTf2], [Br], [BF4], [AlCl4]) for two different exposure durations (0.5 h and 4 h). The wetting behavior of RTIL-treated steel surfaces is quantified in terms of contact angles and surface energies corresponding to polar (water) and non-polar (diiodomethane) probing liquids. The RTIL surface treatment is observed to improve the surface wetting behavior of steel surfaces for both polar and non-polar probing liquids. The average initial water contact angle of steel surfaces decreased by 24−87% after RTIL surface treatment. Similarly, the average initial non-polar liquid contact angles of RTIL-treated steel surfaces decreased by 25−66% when compared to the untreated steel surface. The water contact angle decreased with an increase in the time elapsed after droplet impingement on the surface, whereas, for the non-polar liquid, the contact angle remained relatively unchanged during the elapsed duration adopted herein. The average surface free energy of RTIL-treated steel specimens increased by 49%−100%, which rendered the RTIL-treated steel surfaces more wettable. The increase in the RTIL treatment time only nominally improved the wetting of steel surfaces for both polar and non-polar probing liquids. The results reported herein can be used to prepare the surfaces of inaccessible structural steel components and bridge bearings for efficient water cleaning and lubrication.

Deciphering the Structure of the Gramicidin A Channel in the Presence of AOT Reverse Micelles in Pentane Using Molecular Dynamics Simulations.

Structural studies of proteins and, in particular, integral membrane proteins (IMPs) using solution NMR spectroscopy approaches are challenging due to not only their inherent structural complexities but also the fact that they need to be solubilized in biomimetic environments (such as micelles), which enhances the slow molecular reorientation. To deal with these difficulties and increase the effective rate of molecular reorientation, the encapsulation of IMPs in the aqueous core of the reverse micelle (RM) dissolved in a low-viscosity solvent has been proven to be a viable approach. However, the effect of the reverse micelle (RM) environment on the IMP structure and function is little known. To gain insight into these aspects, this article presents a series of atomistic unconstrained molecular dynamics (MD) of a model ion channel (gramicidin A, gA) with RMs formed with anionic surfactant diacyl chain bis(2-ethylhexyl) sodium succinate (AOT) in pentane at a water-to-surfactant molar ratio (W0) of 6. The simulations were carried out with different protocols and starting conditions for a total of 2.4 μs and were compared with other MDs used with the gA channel inserted in models of the SDS micelle or the DMPC membrane. We show here that in the presence of AOT RMs the gA dimer did not look like the "dumbbell-like" model anticipated by experiments, where the C-terminal parts of the gA are capped with two RMs and the rest of the dimer is protected from the oil solvent by the AOT acyl chains. In contrast, the MD simulations reveal that the AOT, Na+, and water formed two well-defined and elongated RMs attached to the C-terminal ends of the gA dimer, while the rest is in direct contact with the pentane. The initial β6.3 secondary structure of the gA is well conserved and filled with 6-9 waters, as in SDS micelles or the DMPC membrane. Finally, the water movement inside the gA is strongly affected by the presence of RMs at each extremity, and no passage of water molecules through the gA channel is observed even after a long simulation period, whereas the opposite was found for gA in SDS and DMPC.

The anti-tumor effects of imidazolium salts on oral squamous cell carcinoma.

Imidazolium salts (IS), ionic derivatives of neutral imidazoles, have properties that can be adjusted by structural modifications to their cations and anions, which makes this particular class of compounds a promising option for developing biologically active compounds. The anti-tumor effects of the IS 1-n-butyl-3-methylimidazolium chloride (C4 MImCl), 1-n-decyl-3-methylimidazolium chloride (C10 MImCl), 1-n-hexadecyl-3-methylimidazolium chloride (C16 MImCl), 1-n-hexadecyl-2,3-dimethylimidazolium chloride (C16 M2 ImCl), 1-n-octadecyl-3-methylimidazolium chloride (C18 MImCl), 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16 MImMeS), and 1-n-hexadecyl-2,3- dimethylimidazolium methanesulfonate (C16 M2 ImMeS) on oral squamous cell carcinoma (OSCC) have been studied here. Oral squamous cell carcinoma cells (CAL27) were incubated with increasing IS doses and then submitted to proliferation (2D), cell death (2D) and spheroid assay (3D). The IS anti-tumor effect was dependent on both its N-alkyl chain length and anion, whereby C16 MImCl proved to be more effective in combination for inhibiting cell proliferation and cell-cell adhesion, outperforming the methylated C16 M2 ImCl derivative and, most importantly, the gold standard-cisplatin. In addition, C16 MImCl had little effect on keratinocytes and more pronounced effects on more aggressive tumor cells. It also exhibited similar effects on inducing cell death when compared to Cisplatin. This compound spread to a greater area of the tumor sphere and produced an enhanced number of apoptotic and necrotic cells in the tumor cell line, demonstrating only a small rise in the healthy cells. These data indicate that the effect of C16 MlmCl on OSCC is promising, as it is selective for cancer cells.

Successive Phase Transitions and Dual Dielectric Switching in an Organic-Inorganic Hybrid Perovskite.

Molecular phase transition compounds have become a hot research area in recent years because of their potential as functional materials, such as ferroelectrics, ferroelastics, dielectric switches, etc. However, materials combining switchable dielectric properties and ferroelasticity are still rare. Here, we reported an organic-inorganic hybrid perovskite, [CPtmp][Cd(SCN)3] (1) ([CPtmp]+ is a cyclopentyltrimethylphosphonium cation), with a potential ferroelastic property. This material undergoes three structural phase transitions at 247/226, 335/312, and 349/341 K (upon heating/cooling). The successive phase transitions are mainly caused by the stepwise ordering of [CPtmp]+ cations and the concomitant deformation of [Cd(SCN)3]- anionic chains revealed by structural analyses, which triggers the double-step dielectric switching in 1 as well. These results would inspire further exploration on molecular dielectric switches with ferroelastic properties.

Binding of Gold(III) from Solutions by Tetranuclear Lead(II) Dipropyldithiocarbamate [Pb4{S2CN(C3H7)2}8] and Chemisorption Synthesis of the Double Ionic Polymer Complex ([Au{S2CN(C3H7)2}2][PbCl3] · 0.5CH3–C6H5)n: Heteronuclear ( 13 C, 15 N) CP-MAS NMR, Structural Organization, and Construction Principles of Cationic and Anionic Polymer Chains

Solid-state 13C and 15N CP-MAS NMR data adequately reflected the presence of four nonequivalent PrDtc ligands in the tetranuclear lead(II) N,N-dipropyldithiocarbamate (PrDtc), [Pb4{S2CN(C3H7)2}8] (I); the spin–spin coupling constants 3J(15N–207Pb) for the ligands were estimated. It was shown by 13C MAS NMR that the chemisorption binding of AuCl3 from a solution in 2M HCl using lead(II) dipropyldithiocarbamate is accompanied by complete redistribution of the PrDtc ligands from Pb(II) to Au(III) coordination sphere; this gives the double complex of [Au{S2CN(C3H7)2}2][PbCl3] (II). Upon crystallization from an acetone–toluene mixture (3 : 1), this complex was isolated as the solvated form ([Au{S2CN(C3H7)2}2][PbCl3] ⋅ 1/2CH3C6H5)n (IIa), which was characterized by X-ray diffraction (CIF file CCDC no. 1978947). The cationic part of the complex is represented by non-centrosymmetric gold(III) complex ions, [Au{S2CN(C3H7)2}2]+, which are combined by pairs of nonequivalent Au···S secondary bonds, thus forming supramolecular pseudo-polymer chain ([Au{S2CN(C3H7)2}2]+)n. The 1D polymeric trichloroplumbate(II) anion, {[Pb(μ2-Cl)3]–}n, acts as the counter-ion. The C–H···Cl hydrogen bonds between the anionic and cationic chains lead to formation of channels in the crystal lattice, which are occupied by solvating toluene molecules.

Effect of salt addition on iota-carrageenan solution properties

Polysaccharides are versatile biopolymers available to mankind for multiple uses ranging from achieving desirable food texture to serving as tissue scaffolds. Their complete utility, however, is yet unrealized by the lack of precise knowledge on their structure function relationships. Herein, sodium iota-carrageenan (IC) is selected as a model polysaccharide and its viscoelastic properties, molecular assembly, water mobility, microstructure and melting behavior have been analyzed to understand the salt effect. Results demonstrate that while the storage modulus, gel-sol transition temperature, thermal stability and helical aggregation increase, water mobility decreases, with salt addition; the initial no-salt IC ordered microstructure transforms to an irregular structure composed of larger cavities. These observations are intimately associated with the dynamic interactions persistent at the molecular level between the anionic IC chains and salt ions. Overall, results help to move a step closer to realize the functional behavior of iota-carrageenan and by extrapolation to other polysaccharides as well.

Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br): Halides with Strong Second-Harmonic Generation Response Induced by Acetate Groups.

Nonlinear optical (NLO) crystals are the key component in solid-state lasers. New second-harmonic generation (SHG) effective halides, Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br), have been rationally synthesized by introducing acetate groups into lead halide perovskites under moderate solvothermal conditions. Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br) feature highly oriented anionic chains constructed by distorted [PbX4 O2 ] (X=I, Br) polyhedrons. Both the theoretical studies and the dipole moment calculations uncover that their SHG effects are mainly originated from the distorted [PbX4 O2 ] (X=I, Br) polyhedrons. Remarkably, Cs3 Pb2 (CH3 COO)2 I5 exhibits strong phase-matching SHG response (8×KDP) and large birefringence (0.26@ 1064 nm). Moreover, Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br) also possess high laser damage threshold (LDT) which are almost 27 and 41 times that of AgGaS2 , respectively.

Cs3Pb2(CH3COO)2X5 (X=I, Br): Halides with Strong Second‐Harmonic Generation Response Induced by Acetate Groups

AbstractNonlinear optical (NLO) crystals are the key component in solid‐state lasers. New second‐harmonic generation (SHG) effective halides, Cs3Pb2(CH3COO)2X5 (X=I, Br), have been rationally synthesized by introducing acetate groups into lead halide perovskites under moderate solvothermal conditions. Cs3Pb2(CH3COO)2X5 (X=I, Br) feature highly oriented anionic chains constructed by distorted [PbX4O2] (X=I, Br) polyhedrons. Both the theoretical studies and the dipole moment calculations uncover that their SHG effects are mainly originated from the distorted [PbX4O2] (X=I, Br) polyhedrons. Remarkably, Cs3Pb2(CH3COO)2I5 exhibits strong phase‐matching SHG response (8×KDP) and large birefringence (0.26@ 1064 nm). Moreover, Cs3Pb2(CH3COO)2X5 (X=I, Br) also possess high laser damage threshold (LDT) which are almost 27 and 41 times that of AgGaS2, respectively.

Crystal Chemistry of Alkali–Aluminum–Iron Sulfates from the Burnt Mine Dumps of the Chelyabinsk Coal Basin, South Urals, Russia

Technogenic steklite, KAl(SO4)2, and unnamed mineral phase (K,Na)3Na3(Fe,Al)2(SO4)6 from burnt dumps of the Chelyabinsk Coal Basin have been investigated by single-crystal X-ray diffraction and electron microprobe analysis. Steklite is trigonal, space group P3¯, a = 4.7277(3), c = 7.9871(5) Å, V = 154.60(2) Å3. The crystal structure was refined to R1 = 0.026 (wR2 = 0.068). It is based upon the [Al(SO4)2]− layers formed by corner sharing of SO4 tetrahedra and AlO6 polyhedra. The anionic [Al(SO4)2]− layers are parallel to the (001) plane and linked via interlayer K+ ions. The regular octahedral coordination of Al is observed that distinguishes technogenic steklite from that found in Tolbachik fumaroles. The (K,Na)3Na3(Fe,Al)2(SO4)6 phase is trigonal, space group R3¯, a = 13.932(2), c = 17.992(2) Å, V = 3024.4(7) Å3, R1 = 0.073 (wR2 = 0.108). The crystal structure is based upon the anionic chains [(Fe,Al)(SO4)3]3− running parallel to the c axis and interconnected via K+ and Na+ ions. There are no known minerals or synthetic compounds isotypic to (K,Na)3Na3(Fe,Al)2(SO4)6, due to the presence of separate K and Na sites in its structure.

Anions of Ionic Liquids Are Important Players in the Rescue of DNA Damage.

The non-targeted action of fungicides generates genotoxic effect in vertebrates by perturbing the structure of DNA, which impacts its replication and transcriptional process, leading to several serious gene associated diseases. Hence, finding a suitable medium that can reduce/reverse the structural perturbation of DNA induced by fungicide, viz. dodine, is essential. Spectroscopic as well as molecular dynamics simulation techniques have been implemented to understand the effect of ionic liquids (ILs) having a tetramethylguanidinium cation along with short and long hydrophobic chain anions mixed with fungicide. The addition of ILs possessing anions with long hydrophobic chain blocks the fungicide from binding in the groove region of DNA by forming micelle-like structure and reverses the structural change induced by the fungicide. The hydrophobicity of long hydrocarbon and fluorocarbon chains of anions is a key parameter for reversing the effect of fungicide as small anion based ILs are incapable of annulling the structural change of DNA.

Bifunctional Catalysis Prevents Inhibition in Reversible-Deactivation Ring-Opening Copolymerizations of Epoxides and Cyclic Anhydrides.

Reversible-deactivation chain transfer is a viable strategy to increase the catalytic efficiency of ring-opening polymerizations, such as the alternating copolymerization of epoxides and cyclic anhydrides. In conjunction with the catalyst, protic chain transfer agents (CTAs) initiate polymerization and facilitate rapid proton transfer between active and dormant chains. Functional-group-tolerant Lewis acid catalysts are therefore required to successfully apply protic CTAs in reversible-deactivation ring-opening copolymerizations (RD-ROCOP), yet the predominant binary Lewis acid catalyst/nucleophilic cocatalyst systems suffer lower polymerization rates when used with protic CTAs. New mechanistic insight into the inhibition pathways reveals that the alcohol chain ends compete with epoxide binding to the Lewis acid and hydrogen-bond with anionic chain ends to impede epoxide ring opening. We report that a bifunctional aminocyclopropenium aluminum salen complex maintains excellent activity in the presence of protic functionality, exhibiting resilience against these inhibition pathways, even at high CTA concentrations. We apply reversible-deactivation chain transfer in the bifunctional ROCOP system to demonstrate precise molecular-weight control, CTA functional group scope, and accessible polymer architectures.

Prediction of infinite dilution activity coefficient of alcohol in ionic liquids using group contribution method

Group contribution (GC) method is one of the predictive models used to estimate the thermodynamics properties of a compound. In this work, GC is applied to develop a predictive model to estimate the infinite dilution activity coefficient (IDAC) of ethanol and propanol in ionic liquids (ILs). Developing a GC model is easier compared to other models that require 3 or more parameters. GC method has rarely been used to estimate the chemical potential of alcohol solutes in ILs. Thus, a simple two parameters van't Hoff model using multiple linear regression (MLR) is applied and fitted by generalized reduced gradient (GRG) non-linear algorithm to calculate the IDAC values of alcohol solutes in ILs. The GC model predicted IDAC values that are based on the structure of interacting species is then, compared to the experimental values obtained from literature. The developed model is known to be in best performance if the differences between predicted and experimental IDAC values are at the least. The percentage of difference or deviation between the estimated and experimental IDAC values was determined using the absolute average relative deviation (AARD). 46 ILs with varying anions and cations are used in developing a predictive model at different temperature based on the alcohol solutes. An overall AARD value of 7.49% and 9.91% is obtained from ethanol and propanol solute, respectively, that was formed by the combination of training and validation set. The efficiency of the model with lesser than 10% deviation has been validated by the comparison between predicted and experimental IDAC values based on anion, cation headgroup, and alkyl chain length. Hydrogen bonding basicity of anion and an increase in the alkyl chain of cation headgroup contribute an important role in their interaction with ethanol and propanol as a notable reduction of IDAC values could be observed. The effect of IL's structural characteristics on IDAC is discernible, which aids in designing several ILs that have enhanced interaction with alcohol solutes.

Directed Structure Formation in Tetranuclear Xylaratogermanates(IV) with Complex Phenanthrolinecopper(II) Cations

New xylatogermanates with the same homogermanate complex anion and various phenanthrolinecopper(II) cations, namely, [Cu(Phen)3]2[(OH)2Ge2(µ-HXylar)4Ge2(µ-OH)2] · 8H2O (I), [Cu(H2O)(Phen)2]2[(OH)2Ge2(µ-HXylar)4Ge2(µ-OH)2] · 8H2O (II), and [CuCl(Phen)2]4[(OH)2Ge2(µ-HXylar)4Ge2(µ-OH)2] · 8H2O (III), have been synthesized by the developed method and studied by IR spectroscopy and thermogravimetry. According to X-ray diffraction data, they represent ionic type complexes with the [(OH)2Ge2(μ-HXylar)4Ge2(μ-OH)2]4– tetranuclear germanium-containing complex anion and three complex cations: [Cu(Phen)3]2+ (I), [Cu(H2O)(Phen)2]2+ (II), and [CuCl(Phen)]+ (III). The Ge atoms in the complex anion have two types of coordination: they are five- or six-coordinated. Each Ge atom is linked to the deprotonated carboxylic and hydroxyl groups of two xylaric acid molecules. The five-coordinated Ge atom is additionally linked to one terminal hydroxyl ligand, and the six-coordinated Ge atom is linked to two bridging hydroxyl groups. In crystal structures I and II, cations and anions form alternating layers, which are interchangeably composed of cations and anions. In crystal structure III, cations form “porous” layers, whose cavities accommodate chains of anions. The layers of cations are linked by weak stacking-interactions between the π-systems of Phen.

Repulsive Backbone-Backbone Interactions Modulate Access to Specific and Unspecific Binding Sites on Surface-Bound Mucins.

Mucin glycoproteins are the matrix-forming key components of mucus, the innate protective barrier protecting us from pathogenic attack. However, this barrier is constantly challenged by mucin-degrading enzymes, which tend to target anionic glycan chains such as sulfate groups and sialic acid residues. Here, we demonstrate that the efficiency of both unspecific and specific binding of small molecules to mucins is reduced when sulfate groups are enzymatically removed from mucins; this is unexpected because neither of the specific mucin-binding partners tested here targets these sulfate motifs on the mucin glycoprotein. Based on simulation results obtained from a numerical model of the mucin macromolecule, we propose that anionic motifs along the mucin chain establish intramolecular repulsion forces which maintain an elongated mucin conformation. In the absence of these repulsive forces, the mucin seems to adopt a more compacted structure, in which the accessibility of several binding sites is restricted. Our results contribute to a better understanding on how different glycans contribute to the broad spectrum of functions mucin glycoproteins have.

Low-Valent, Multiply Bonded, Trigonal-Planar Sb Complex: Rational Syntheses, Dual Acidic/Basic Properties, and Unexpected Semiconducting Characteristics.

A 4-center, 6π-conjugated, multiply bonded trigonal-planar complex, [Sb{Cr(CO)5}3]- (1), was synthesized via the hydride abstraction of [HSb{Cr(CO)5}3]2- (1-H) with HBF4·H2O, with the release of high yields of H2. The oxidation state of the Sb atom in [Et4N][1] was well-defined as 0, which was evidenced by X-ray photoelectron spectroscopy and X-ray absorption near-edge structure. The distinct color-structure relationship of this low-valent Sb complex 1 toward a wide range of organic solvents was demonstrated, as interpreted by time-dependent density functional theory calculations, allowing the trigonal-planar 1 and the tetrahedral solvent adducts to be probed, revealing the dual acid/base properties of the Sb center. In addition, 1 showed pronounced electrophilicity toward anionic and neutral nucleophiles, even with solvent molecules, to produce tetrahedral complexes [(Nu)Sb{Cr(CO)5}3]n- [1-Nu; n = 2, Nu = H, F, Cl, Br, I, OH; n = 1, Nu = PEt3, PPh3, N,N-dimethylformamide (DMF), acetonitrile (MeCN)]. On the contrary, the Fe/Cr hydride complex [HSb{Fe(CO)4}{Cr(CO)5}2]2- (2-H) was obtained by treating 1 with [HFe(CO)4]-. Upon hydride abstraction of 2-H with HBF4·H2O or [CPh3][BF4], a multiply bonded Fe/Cr trigonal-planar complex, [Sb{Fe(CO)4}{Cr(CO)5}2]- (2), was produced in which the oxidation coupling Sb2-containing complexes [Sb2Cr4Fe2(CO)28]2- (3-Cr) and [HSb2Cr3Fe2(CO)23]- (3-H) were yielded as final products. Complex 3-Cr exhibited dual Lewis acid/base properties via hydridation and protonation reactions, to form 2-H or 3-H, respectively. Surprisingly, [Et4N][1] possessed a low energy gap of 1.13 eV with an electrical conductivity in the range of (1.10-2.77) × 10-6 S·cm-1, showing that [Et4N][1] was a low-energy-gap semiconductor. The crystal packing, crystal indexing, and density of states results of [Et4N][1] further confirmed the efficient through-space conduction pathway via the intermolecular Sb···O(carbonyl) and O(carbonyl)···O(carbonyl) interactions of the 1D anionic zigzag chain of 1.

Crystal structures of salts of bedaquiline.

Bedaquiline [systematic name: 1-(6-bromo-2-methoxyquinolin-3-yl)-4-(dimethylamino)-2-(naphthalen-1-yl)-1-phenylbutan-2-ol, C32H31BrN2O2] is one of two important new drugs for the treatment of drug-resistant tuberculosis (TB). It is marketed in the US as its fumarate salt {systematic name: [4-(6-bromo-2-methoxyquinolin-3-yl)-3-hydroxy-3-(naphthalen-1-yl)-4-phenylbutyl]dimethylazanium 3-carboxyprop-2-enoate, C32H32BrN2O2+·C4H3O4-}, and about a dozen other salts of bedaquiline have been described in patent literature, but none have so far been structurally described. In a first communication, we present the crystal structure of bedaquilinium fumarate and of two new benzoate salts, as well as that of a degradation product of the reaction of bedaquilinium fumarate with sodium ethoxide, 3-benzyl-6-bromo-2-methoxyquinoline, C17H14BrNO. The fumarate and benzoate salts both feature cations monoprotonated at the dimethylamino group. The much less basic quinoline N atom remains unprotonated. Both salts feature a 1:1 cation-to-anion ratio, with the fumarate being present as monoanionic hydrofumarate. The conformations of the cations are compared to that of free base bedaquiline and with each other. The flexible backbone of the bedaquiline structure leads to a landscape of conformations with little commonalities between the bedaquiline entities in the various structures. The conformations are distinctively different for the two independent molecules of the free base, the two independent molecules of the hydrofumarate salt, and the one unique cation of the benzoate salt. Packing of the salts is dominated by hydrogen bonding. Hydrogen-bonding motifs, as well as the larger hydrogen-bonded entities within the salts, are quite similar for the salts, despite the vastly differing conformations of the cations, and both the hydrofumarate and the benzoate structure feature chains of hydrogen-bonded anions that are surrounded by and hydrogen bonded to the larger bedaquilinium cations, leading to infinite broad ribbons of anions, cations, and (for the benzoate salt) water molecules. The benzoate salt was isolated in two forms: as a 1.17-hydrate (C32H32BrN2O2+·C7H5O2-·1.166H2O), obtained from acetone or propanol solution, with one fully occupied water molecule tightly integrated into the hydrogen-bonding network of anions and cations, and one partially occupied water molecule [refined occupancy 16.6 (7)%], only loosely hydrogen bonded to the quinoline N atom. The second form is an acetonitrile solvate (C32H32BrN2O2+·C7H5O2-·0.742CH3CN·H2O), in which the partially occupied water molecule is replaced by a 74.2 (7)%-occupied acetonitrile molecule. The partial occupancy induces disorder for the benzoate phenyl ring. The acetonitrile solvate is unstable in atmosphere and converts into a form not distinguishable by powder XRD from the 1.17-hydrate.

Mixed micelles of sodium perfluorooctanoate and imidazolium based ionic liquids in aqueous solution: A SANS and Tensiometric study

Micellization and microstructure of mixed micelles from mixtures of an anionic fluorocarbon surfactant sodium perfluorooctanoate (NaPFO) and cationic alkylmethyl-imidazolium based non-amphiphilic and amphiphilic ionic liquids (ILs) with different alkyl chain length (C4, C6, C8, C10 and C12) and anions viz. chloride (Cl−), tetrafluoroborate (BF4−), hexaflurophosphate (PF6−), octylsulphate (C8SO4−) and trifluoromethane-sulphonate (CF3SO3−) were examined extensively by surface tension and small-angle neutron scattering (SANS) measurements. Low critical micelle concentration (CMC) and large negative value of interaction parameter (β) showed synergism in all the mixed systems and it depends on the molecular characteristics of ILs. Thermodynamic parameters for mixed monolayers and mixed micelles were evaluated and discussed. Micellar growth, shape changes and micelle to vesicle transitions obtained from these oppositely charged mixed systems depend on the surface activity of ILs (alkyl chain and counter ions). Influence of ILs which differ in counter ions with similar chain length and similar counter ions with different chain lengths on aggregation patterns of NaPFO micelles have been examined using SANS. The data for size, shape and aggregation number for aggregates formed by these mixed systems evaluated from the fitted SANS data are reported and discussed in terms of their distinct interaction with NaPFO micelles. The present study is a significant addition to existing knowledge on ionic liquid induced morphological changes of sodium perfluorooctanoate micelles.

Self-assembly and photocatalytic property of a new inorganic-organic hybrid material based on 1,4-bis(4-pyridylthio)butane

A new hybrid compound consisting of 1,4-bis(4-pyridylthio)butane ([Bpytb]) ligand, namely {[Bpytb]Ag2I3}n (1), has been prepared and characterized by IR spectroscopy, solid UV-visible diffuse reflectance spectrum, X-ray Powder Diffraction (PXRD) and TG. Compound 1 consists of 1D anion chain structure. Crystal system: Monoclinic, Space group: P2/c, a = 4.5092(3), b = 11.1895(9), c = 21.3893(14), α= 90°, β= 92.907(2)°, γ= 90°, V = 1077.82(13) Å3, Z = 2, Dcalc = 2.693 g cm–3. The photocatalytic property of compound 1 was also studied and it exhibits a better degradation effect on organic dye MB.

From Ag2 Zr(IO3 )6 to LaZr(IO3 )5 F2 : A Case of Constructing Wide-band-gap Birefringent Materials through Chemical Cosubstitution.

Two mixed-metal zirconium iodates were prepared and studied as a case of chemical cosubstitution. The structure of Ag2 Zr(IO3 )6 (P21 /c) features 0D [Zr(IO3 )6 ]2- anion group and 1D [Ag(IO3 )2 ]- anionic chain, with the [Zr(IO3 )6 ]2- anion groups interconnected by Ag+ ions into 3D network; LaZr(IO3 )5 F2 (P21 /n) features 0D [Zr(IO3 )5 F2 ]3- anion group and 2D [La(IO3 )5 ]2- anionic layer, with the [Zr(IO3 )5 F2 ]3- groups interlinked by La3+ ions into 3D structure. Notably, LaZr(IO3 )5 F2 is the first zirconium iodate fluoride reported. Wide optical band gaps of 3.77 and 4.13 eV are given for Ag2 Zr(IO3 )6 and LaZr(IO3 )5 F2 , respectively. Theoretical calculations confirmed that the weak d-d transition of Zr4+ in the band structure leads to a moderate band gap of Ag2 Zr(IO3 )6 , and the introduction of F- into the zirconium iodate compound results in a large band gap of LaZr(IO3 )5 F2 . Both of the compounds are birefringent materials with birefringences of 0.064 @1064 nm and 0.082 @1064 nm, respectively.