X-ray photoelectron spectroscopy of morpholinium ionic liquids: impact of a long alkyl side substituent on the cation-anion interactions.

In this study, X-ray photoelectron spectroscopy is used to analyse nine morpholinium ionic liquids, which are of great interest in green chemistry because of their low toxicity and high recyclability. The effect of the alkyl chain length on the aliphatic C 1s binding energy and the impact of the anion basicity on the cationic N 1s and O 1s binding energies are investigated. It is concluded that by changing the basicity of the anion, there is a more notable change in the electronic environment of the oxygen centre. The impact of a long alkyl side substituent on the cation-anion interactions is also discussed. It is observed that there is an intense charge shielding effect of the alkyl side chain in the cases of octyl and dodecyl substituents, which is reflected in the reduced Br 3d5/2 binding energy.

[Association of MTHFR gene C677T polymorphism with problem behavior and inheritance pattern among children with autism].

OBJECTIVE: To assess the association of C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene with autistic behavior and inheritance pattern of children patients. METHODS: Ninety three autism patients were selected as the study group, whilst 93 healthy children were selected as the control group. The C677T genotype of the MTHFR gene was determined, and the correlation between the genotype and the autistic behavior and inheritance pattern were investigated. RESULTS: MTHFR gene C677T locus revealed three genotypes CC, CT and TT. Compared with the control group, the study group had fewer CC genotype but more TT genotype (P<0.05). Individuals with the three genotypes showed a statistically significant difference in the frequencies of four problem behaviors (P<0.05). Regression analysis showed that at least one T allele encoding the degree of 1 and 2 for the 4 problem behaviors that were statistically different. MTHFR gene C677T genotype was associated with autism under the recessive inheritance model and allelic inheritance model (P<0.05). CONCLUSION: The C677T polymorphism of the MTHFR gene is associated with autistic behaviors. Children with the TT genotype or T allele are at higher risk of developing autism, particularly direct gaze, complex limb movements, self-injurious behavior and hyperactivity 1 and 2 related with the degree of coding.

Ionic Liquid-Directed Nanoporous TiNb2 O7 Anodes with Superior Performance for Fast-Rechargeable Lithium-Ion Batteries.

Nanoporous TiNb2 O7 (NPTNO) material is synthesized by a sol-gel method with an ionic liquid (IL) as the nanoporous structure directing template. NPTNO exhibits a high reversible capacity of 210 mAh g-1 even at the charging rate of 50 C and an excellent cyclability of half-cell capacity retention of 74% for 1000 cycles at 5 C and LiNi0.5 Mn1.5 O4 -coupled full-cell capacity retentions of 81% and 87% for 1000 cycles at 1 C and 2 C, respectively. The studies of the 1000 cycled NPTNO electrode illustrate that the IL-directed mesoporous structure can enhance the cyclability of NPTNO cells due to the alleviation of repetitive mechanical stress and volume fluctuation induced by the repetitive Li+ insertion-extraction processes. The measured Li+ diffusion coefficients from the galvanostatic intermittent titration technique suggest that the IL-templating strategy indeed ensures the fast rechargeability of NPTNO cells based on the fast Li+ diffusion kinetics. Benefitting from the nanoporous structure, NPTNO with unhindered Li+ diffusion pathways achieves a superior rate capability in the titanium-based oxide materials and the best full-cell cyclability in the TNO materials. Therefore, the templating potential of IL is demonstrated, and the superb electrochemical performance establishes the IL-directed NPTNO as a promising anode candidate for fast-rechargeable LIBs.

Probing the impact of the N3-substituted alkyl chain on the electronic environment of the cation and the anion for 1,3-dialkylimidazolium ionic liquids.

In this study, X-ray photoelectron spectroscopy is used to probe the impact of the N3-substituted alkyl group on the electronic environment of the cation and the anion by comparing two types of imidazolium cations, 1-alkyl-3-butylimidazolium and 1-alkyl-3-methylimidazolium. Due to the more intense inductive effect changing from methyl to butyl, the electronic environment of the cationic nitrogen can be significantly affected, which is reflected in a shift of N 1s binding energy. The magnitude of the binding energy shift is found to be more pronounced in the case of the less basic anion and inversely proportional to the basicity of the anion. The increase of the N3-substituted alkyl chain length can also influence the charge-transfer effect from the anion to the cation. This gives rise to a change in the electronic environment of the anion. Such an impact is found to be concentrated on the anion-based component bearing more negative point charges.

X-ray photoelectron spectroscopy of piperidinium ionic liquids: a comparison to the charge delocalised pyridinium analogues.

In this study, nine piperidinium-based ionic liquids are analysed by X-ray photoelectron spectroscopy. The effect of alkyl substituent length and the nature of the anion on the electronic environment of the cation are investigated. The electronic environment of the hetero carbon and the cationic nitrogen is compared between two structurally similar cations, 1-octyl-1-methylpiperidinium ([C8C1Pip]+) versus 1-octylpyridinium ([C8Py]+). Due to the charge delocalisation, the hetero carbon component within [C8Py]+ is more positively charged, which exhibits much higher binding energy; whilst the cationic nitrogen component is in the similar electronic environment. The impact of the charge delocalisation on the electronic environment of the anion is also compared between [C8C1Pip]+ and [C8Py]+. It is found that for the more basic anion, the cation can significantly affect the electronic environment of the anion; for the less basic anion, such an effect concentrates on the component bearing more negative point charges.

The impact of cation acidity and alkyl substituents on the cation-anion interactions of 1-alkyl-2,3-dimethylimidazolium ionic liquids.

In this study, eight 1-alkyl-2,3-dimethylimidazolium ionic liquids are analysed by X-ray photoelectron spectroscopy. The effect of both the anion and the cation on the electronic environment of cationic nitrogen regions is explored. It concludes that the cationic N 1s binding energy shifts to the lower value when the basicity of the anion increases or the acidity of the cation decreases. The impact of the cation acidity on the cation-anion interactions is demonstrated systematically by carefully comparing the binding energies of anion-based components for each anion. It is found that for more basic anions, the charge-transfer effect between counterions can be effectively shielded; for less basic anions, such an effect is negligible. The charge shielding effect of the alkyl substituent is also studied by using dodecyl-based ionic liquids, compared to 1-alkyl-3-methylimidazolium analogues. It suggests that long alkyl substituents can have a significant electron donating effect to the cation headgroup and thus effectively shield the charge-transfer effect between cations and anions.

X-ray Photoelectron Spectroscopy of Pyridinium-Based Ionic Liquids: Comparison to Imidazolium- and Pyrrolidinium-Based Analogues.

We investigate eight 1-alkylpyridinium-based ionic liquids of the form [Cn Py][A] by using X-ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake-up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic-liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8 Py][A] and analogues including 1-octyl-1-methylpyrrolidinium- ([C8 C1 Pyrr][A]), and 1-octyl-3-methylimidazolium- ([C8 C1 Im][A]) based samples, where X is common to all ionic liquids.

Chlorostannate(II) ionic liquids: speciation, Lewis acidity, and oxidative stability.

The anionic speciation of chlorostannate(II) ionic liquids, prepared by mixing 1-alkyl-3-methylimidazolium chloride and tin(II) chloride in various molar ratios, χ(SnCl2), was investigated in both solid and liquid states. The room temperature ionic liquids were investigated by (119)Sn NMR spectroscopy, X-ray photoelectron spectroscopy, and viscometry. Crystalline samples were studied using Raman spectroscopy, single-crystal X-ray crystallography, and differential scanning calorimetry. Both liquid and solid systems (crystallized from the melt) contained [SnCl(3)](-) in equilibrium with Cl(-) when χ(SnCl(2)) < 0.50, [SnCl(3)](-) in equilibrium with [Sn(2)Cl(5)](-) when χ(SnCl(2)) > 0.50, and only [SnCl(3)](-) when χ(SnCl(2)) = 0.50. Tin(II) chloride was found to precipitate when χ(SnCl(2)) > 0.63. No evidence was detected for the existence of [SnCl(4)](2-) across the entire range of χ(SnCl(2)), although such anions have been reported in the literature for chlorostannate(II) organic salts crystallized from organic solvents. Furthermore, the Lewis acidity of the chlorostannate(II)-based systems, expressed by their Gutmann acceptor number, has been determined as a function of the composition, χ(SnCl(2)), to reveal Lewis acidity for χ(SnCl(2)) > 0.50 samples comparable to the analogous systems based on zinc(II). A change of the Lewis basicity of the anion was estimated using (1)H NMR spectroscopy, by comparison of the measured chemical shifts of the C-2 hydrogen in the imidazolium ring. Finally, compositions containing free chloride anions (χ(SnCl(2)) < 0.50) were found to oxidize slowly in air to form a chlorostannate(IV) ionic liquid containing the [SnCl(6)](2-) anion.

Microcrystalline cellulose grafted hyperbranched polyester with roll comb structure for synergistic toughening and strengthening of microbial PHBV/bio-based polyester elastomer composites.

The brittle feature of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is the major challenge that strongly restricts its application at present. Successfully synthesized bio-based engineering polyester elastomers (BEPE) were combined with PHBV to create entirely bio-composites with the intention of toughening PHBV. Herein, the 2,2-Bis(hydroxymethyl)-propionic acid (DMPA) was grafted onto microcrystalline cellulose (MCC) and then further transformed into hyperbranched polyester structure via polycondensation. The modified MCC, named MCHBP, had plenty of terminal hydroxyl groups, which get dispersed between PHBV and BEPE. Besides, a large number of terminal hydroxyl groups of MCHBP can interact with the carbonyl groups of PHBV or BEPE in a wide range of hydrogen bonds, and subsequently increase the adhesion and stress transfer between the PHBV and BEPE. The tensile toughness and the elongation at break of the PHBV/BEPE composites with 0.5phr MCHBP were improved by 559.7 % and 221.8 % in comparison to those of PHBV/BEPE composites. Results also showed that MCHBP can play a heterogeneous nucleation effect on the crystallization of PHBV. Therefore, this research can address the current issue of biopolymers' weak mechanical qualities and may have uses in food packaging.

Does the influence of substituents impact upon the surface composition of pyrrolidinium-based ionic liquids? An angle resolved XPS study.

The surface chemistry of a series of four pyrrolidinium based ionic liquids, [C(n)C(1)Pyrr][Tf(2)N] where n = 4-10, is investigated by angle resolved X-ray photoelectron spectroscopy (ARXPS). The importance of sample purity is demonstrated and the stability of the ionic liquids under X-ray irradiation investigated. It is apparent that the surface chemistry and orientation is broadly analogous to that of similar imidazolium-based systems.

Tailoring compatibility and toughness of microbial poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/bio-based polyester elastomer blends by epoxy-terminated hyperbranched polyester.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a type of promising bio-based thermoplastic for food packaging but find restricted industrial applications due to its brittleness and poor processability that is caused by its large spherulite sizes. In this study, for the purpose of toughening PHBV, bio-based engineering polyester elastomers (BEPE) were synthesized and blended with PHBV to prepare fully bio-based blends. In order to improve the compatibility and toughness of the BEPE/PHBV blends, epoxy-terminated hyperbranched polyesters (EHBP) were synthesized, which could be homogeneously dispersed into the PHBV/BEPE blends and improve the compatibility between the two phases of the matrix. The results showed that compared to those of the PHBV/BEPE blends, the elongation at break, impact strength and tensile toughness of the PHBV/BEPE blends with 3.0phr EHBP were enhanced by 134.2 %, 76.8 %, and 123.5 %, respectively. The crystallization study demonstrated the crystallization rate of PHBV/BEPE blends decreased due to the addition of EHBP. The reasons lied in that the addition of EHBP leads to chemical cross-linking between PHBV and BEPE. Meanwhile, the formation of hydrogen bonding, co-crystallization and chain entanglement increased the adhesion between PHBV and BEΡE, which generated the superior toughness of the blends.

X-ray photoelectron spectroscopy of pyrrolidinium-based ionic liquids: cation-anion interactions and a comparison to imidazolium-based analogues.

We investigate seven 1-alkyl-1-methylpyrrolidinium-based ionic liquids, [C(n)C(1)Pyrr][X], using X-ray photoelectron spectroscopy (XPS). The electronic environment for each element is analysed and a robust fitting model is developed for the C 1s region that applies to each of the ionic liquids studied. This model allows accurate charge correction and the determination of reliable and reproducible binding energies for each ionic liquid studied. The electronic interaction between the cation and anion is investigated for ionic liquids with one and also two anions. i.e., mixtures. Comparisons are made to imidazolium-based ionic liquids; in particular, a detailed comparison is made between [C(8)C(1)Pyrr][X] and [C(8)C(1)Im][X](-), where X(¬) is common to both ionic liquids.

On the diffusion of ferrocenemethanol in room-temperature ionic liquids: an electrochemical study.

The electrochemical behaviour of ferrocenemethanol (FcMeOH) has been studied in a range of room-temperature ionic liquids (RTILs) using cyclic voltammetry, chronoamperomery and scanning electrochemical microscopy (SECM). The diffusion coefficient of FcMeOH, measured using chronoamperometry, decreased with increasing RTIL viscosity. Analysis of the mass transport properties of the RTILs revealed that the Stokes-Einstein equation did not apply to our data. The "correlation length" was estimated from diffusion coefficient data and corresponded well to the average size of holes (voids) in the liquid, suggesting that a model in which the diffusing species jumps between holes in the liquid is appropriate in these liquids. Cyclic voltammetry at ultramicroelectrodes demonstrated that the ability to record steady-state voltammograms during ferrocenemethanol oxidation depended on the voltammetric scan rate, the electrode dimensions and the RTIL viscosity. Similarly, the ability to record steady-state SECM feedback approach curves depended on the RTIL viscosity, the SECM tip radius and the tip approach speed. Using 1.3 µm Pt SECM tips, steady-state SECM feedback approach curves were obtained in RTILs, provided that the tip approach speed was low enough to maintain steady-state diffusion at the SECM tip. In the case where tip-induced convection contributed significantly to the SECM tip current, this effect could be accounted for theoretically using mass transport equations that include diffusive and convective terms. Finally, the rate of heterogeneous electron transfer across the electrode/RTIL interface during ferrocenemethanol oxidation was estimated using SECM, and k(0) was at least 0.1 cm s(-1) in one of the least viscous RTILs studied.

An ultra high vacuum-spectroelectrochemical study of the dissolution of copper in the ionic liquid (N-methylacetate)-4-picolinium bis(trifluoromethylsulfonyl)imide.

Ultra high vacuum-spectroelectrochemistry was used to investigate the electrochemically generated Cu species in the ionic liquid (N-methylacetate)-4-picolinium bis(trisfluoromethylsulfonyl)imide, [MAP][Tf(2)N]. The diffusion of Cu(+) across the surface of the ionic liquid was monitored in situ by X-ray photoelectron spectroscopy (XPS). A numerical procedure was developed to simulate the surface process from which, the apparent diffusion coefficient of Cu(+) across the surface is estimated to be 3.5 x 10(-5) cm(2) s(-1). Bulk diffusion process of Cu(+) in [MAP][Tf(2)N] was investigated ex situ for comparison with the surface process.

Tuning the Cation-Anion Interactions by Methylation of the Pyridinium Cation: An X-ray Photoelectron Spectroscopy Study of Picolinium Ionic Liquids.

X-ray photoelectron spectroscopy is used to investigate the impact of methylation on the electronic environment of pyridinium cations. Because of the electron-donating effect of the methyl group, there is a significant increase in electron density on the cationic nitrogen. The shift of the N 1s binding energy is inversely proportional to the anion basicity. The methylation position on the electronic environment of the cationic nitrogen is investigated. The N 1s binding energy follows the trend: 1-octylpyridinium > 1-octyl-3-picolinium > 1-octyl-4-picolinium > 1-octyl-2-picolinium, which is in good agreement with the cation acidity. The increase in the inductive effect subsequently weakens the cation-anion interactions through charge transfer from the anion to the cation, causing a subtle change in the electronic environment of the anion. Such an effect is noticeably reflected in the Br 3d binding energy. It shows that the Br 3d5/2 binding energy of 1-octyl-2-picolinium bromide is 0.2 eV lower than that of 1-octylpyridinium bromide.

Highly Porous NiCoSe4 Microspheres as High-Performance Anode Materials for Sodium-Ion Batteries.

Binary transition metal selenides have been more promising than single transition metal selenides as anode materials for sodium-ion batteries (SIBs). However, the controlled synthesis of transition metal selenides, especially those derived from metal-organic-frameworks with well-controlled structure and morphology is still challenging. In this paper, highly porous NiCoSe4 @NC composite microspheres were synthesized by simultaneous carbonization and selenization of a Ni-Co-based metal-organic framework (NiCo-MOF) and characterized by scanning electron microscopy, transition electron microscopy, X-Ray diffraction, X-Ray photoelectron spectroscopy and electrochemical techniques. The rationally engineered NiCoSe4 @NC composite exhibits a capacity of 325 mAh g-1 at a current density of 1 A g-1 , and 277.8 mAh g-1 at 10 A g-1 . Most importantly, the NiCoSe4 @NC retains a capacity of 293 mAh g-1 at 1 A g-1 after 1500 cycles, with a capacity decay rate of 0.025 % per cycle.

CoSe2 Nanoparticles Encapsulated by N-Doped Carbon Framework Intertwined with Carbon Nanotubes: High-Performance Dual-Role Anode Materials for Both Li- and Na-Ion Batteries.

It is of fundamental and technological significance to develop dual-role anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) with high performance. Here, a composite material based on CoSe2 nanoparticles encapsulated in N-doped carbon framework intertwined with carbon nanotubes (CoSe2@N-CF/CNTs) is prepared successfully from cobalt-based zeolitic imidazolate framework (ZIF-67). As anode materials for LIBs, CoSe2@N-CF/CNTs composites deliver a reversible capacity of 428 mAh g-1 even after 500 cycles at a current density of 1 A g-1 with almost 100% Coulombic efficiency. The charge and discharge mechanisms of CoSe2 are characterized using ex situ X-ray diffraction and Raman analysis, from which the lithiation products of CoSe2 are found to be Li x CoSe2 and Li2Se, which are further converted to CoSe2 upon delithiation. The CoSe2@N-CF/CNTs composites also demonstrate excellent electrochemical performance as anode materials for SIBs with a carbonate-based electrolyte, with specific capacities of 606 and 501 mAh g-1 at 0.1 and 1 A g-1 in the 100th cycle. The electrochemical performance of the anode materials is further studied by pseudocapacitance and galvanostatic intermittent titration technique (GITT) measurements. This work may be exploited for the rational design and development of dual-role anode materials for both Li- and Na-ion batteries.