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The chemical physics of halomethanes is an important and challenging topic in several areas of chemistry in particular in the chemistry of the atmosphere. Among the class of halomethanes, the diiodomethane molecule has attracted some interest in the last years, but despite this, the information on its radical cation [CH2I2]·+ is still limited. In this work, we measured and calculated the appearance energy (AE) of the ionic fragments I2·+ and CH2·+ and correlated the different fragmentation channels to the electronic states of the cation via photoelectron-photoion coincidence (PEPICO) experiments. In the case of the CH2/I2·+ channel, the experimentally determined AE is in excellent agreement with the adiabatic theoretical value while a discrepancy is observed for the CH2·+/I2 channel. This discrepancy can be understood accounting for a fragmentation involving the formation of two I atoms (CH2·+/2I channel), which, as explained by time dependent density functional theory (TD-DFT) calculations, occurs when [CH2I2]·+ excited states are involved. [ABSTRACT FROM AUTHOR]

We report the first coherent excitation of intramolecular vibrational modes via the nonlinear interaction of a TeraHertz (THz) light field with molecular liquids. A terahertz-terahertz-Raman pulse sequence prepares the coherences with a broadband, high-energy, (sub)picosecond terahertz pulse, that are then measured in a terahertz Kerr effect spectrometer via phase-sensitive, heterodyne detection with an optical pulse. The spectrometer reported here has broader terahertz frequency coverage, and an increased sensitivity relative to previously reported terahertz Kerr effect experiments. Vibrational coherences are observed in liquid diiodomethane at 3.66 THz (122 cm-1), and in carbon tetrachloride at 6.50 THz (217 cm-1), in exact agreement with literature values of those intramolecular modes. This work opens the door to 2D spectroscopies, nonlinear in terahertz field, that can study the dynamics of condensed-phase molecular systems, as well as coherent control at terahertz frequencies. [ABSTRACT FROM AUTHOR]

Surface energy is widely used in the industry to predict behavior of spray droplets on solid surfaces. The targets of pesticide applications which are used extensively in agricultural production are mainly plant leaf surfaces. Digitization of leaf surfaces to estimate the spread and adhesion of a pesticide application is an important approach in providing descriptive information. In this regards, from intensive agricultural products Triticum aestivum L., Citrus sinensis, Fragaria ananassa, Vitis vinifera L., Cucumis sativus, Capsicum annuum L. culture plants, Elymus repens and Sinapis arvensis from weeds were used to determine surface energy. The leaf surface energies were determined by evaluating the contact angles of the drips while obtained from surface tension and its components from known liquids pure water, diiodomethane and formamide liquids on the surface of the leaves according to five different methods. Wu and Equation of State methods have been found to give more accurate results than other methods. Elymus repens and Triticum aestivum L. plants among the statistically three significant grouped leaves were reduce the spreading and sticking of droplets applied on the leaves by providing a more spherical droplet formation. The Fragaria ananassa leaves have encouraged the higher surface energy that they have the spread of the drips on the leaf surface.

The electronic absorption spectrum of diiodomethane in the 30 000-95 000 cm-1 region is investigated using synchrotron radiation, the spectrum in the 50 000-66 500 cm-1 region is reported for the first time. The absorption bands in the 30 000-50 000 cm-1 region are attributed to valence transitions, while the vacuum ultraviolet (VUV) spectrum (50 000-95 000 cm-1) is dominated by several Rydberg series converging to the first four ionization potentials of CH2I2 at 9.46, 9.76, 10.21, and 10.56 eV corresponding to the removal of an electron from the outermost 3b2, 2b1, 1a2 , and 4a1 non-bonding orbitals, respectively. Rydberg series of ns, np, and nd type converging to each of the four ionization potentials are assigned based on a quantum defect analysis. Time dependent density functional theory calculations of excited states support the analysis and help in interpretation of the Rydberg and valence nature of observed transitions. Density functional theory calculations of the neutral and ionic ground state geometries and vibrational frequencies are used to assign the observed vibronic structure. Vibronic features accompanying the Rydberg series are mainly due to excitation of the C-I symmetric stretch (v3) and CH2 wag (v8) modes, with smaller contributions from the C-H symmetric stretch (v1). UV absorption bands are assigned to low lying valence states 11B2, 11B1, 21A1, 31A1, 21B1, and 21B2 and the unusually high underlying intensity in parts of the VUV spectrum is attributed to valence states with high oscillator strength. This is the first report of a comprehensive Rydberg series and vibronic analysis of the VUV absorption spectrum of CH2I2 in the 50 000-85 000 cm-1 region. The VUV absorption spectrum of CD212 which serves to verify and consolidate spectral assignments is also reported here for the first time. [ABSTRACT FROM AUTHOR]

An efficient and easy template-free method for the preparation of hierarchical porous carbons (HPCs) has been developed using low-priced coal tar pitch (CP) as the starting material. Application of the diketone (-COCO-) radical provides a carbonyl methylene group for polycyclic aromatic hydrocarbons by condensation and produces an effective micro-mesoporous network with a high specific surface area. With the help of controlled Friedel-Crafts reaction and oxidation, carboxyl-functionalized CP is obtained as the stratified porous CP precursor, and the high-temperature decarboxylation (>230°C) helped in generating well-developed micro-mesoporous carbon. The total pore volume of porous carbon of 1277.3 and 1.45 cm³g-1 the maximum BET surface area suggests that the rapid electrolyte ion exchange and charge transportability would be better for the electrochemical capacitor. [ABSTRACT FROM AUTHOR]

Surface or interfacial phenomena, including wetting, adsorption, adhesion, and dissolution, are of significant interest for daily life as well as for industrial and engineering applications. Surface tension and the Hansen solubility parameter (HSP) both represent similar physical characteristics related to these phenomena. It is therefore interesting to study the relation between them, and in the present work, reported empirical relations between surface tension and HSP are critically investigated. There exists an approximately proportional relation between total surface tension and HSP, although the coefficient obtained in the present work is much smaller than the commonly reported ones. The result is supported by an estimation of the coefficient using a simple physical model. On the other hand, finding correlations between the partial components of surface tension and HSP appears to be difficult as they are measured differently. The uses of databases from which measurements are taken must also be taken into question. As an example, the surface tension components of diiodomethane are investigated, and the validity of the reported values are called into question. [Display omitted] [ABSTRACT FROM AUTHOR]

THe Ugi reaction of β‐amino acids with aromatic aldehydes affords β‐lactams which may be used as starting materials in a second β‐lactam formation following a base triggered diiodomethane addition. The sequence may be conducted in a one‐pot fashion affording a straightforward access to bis‐β‐lactams. [ABSTRACT FROM AUTHOR]

Surface energy is widely used in the industry to predict behavior of spray droplets on solid surfaces. The targets of pesticide applications which are used extensively in agricultural production are mainly plant leaf surfaces. Digitization of leaf surfaces to estimate the spread and adhesion of a pesticide application is an important approach in providing descriptive information. In this regards, from intensive agricultural products Triticum aestivum L., Citrus sinensis, Fragaria ananassa, Vitis vinifera L., Cucumis sativus, Capsicum annuum L. culture plants, Elymus repens and Sinapis arvensis from weeds were used to determine surface energy. The leaf surface energies were determined by evaluating the contact angles of the drips while obtained from surface tension and its components from known liquids pure water, diiodomethane and formamide liquids on the surface of the leaves according to five different methods. Wu and Equation of State methods have been found to give more accurate results than other methods. Elymus repens and Triticum aestivum L. plants among the statistically three significant grouped leaves were reduce the spreading and sticking of droplets applied on the leaves by providing a more spherical droplet formation. The Fragaria ananassa leaves have encouraged the higher surface energy that they have the spread of the drips on the leaf surface. [ABSTRACT FROM AUTHOR]

Surface and dynamic viscoelastic properties of the reproduction cork from Quercus variabilis were studied in detail. There were 16 chemical elements in the Q. variabilis cork determined by the energy dispersive spectrometric (EDS) spectrum, and the contents of C and O were the highest. The mean colorimetric parameters L*, a*, and b* were 60.8, 14.0, and 30.6, respectively. The surface contact angles of Quercus variabilis cork were measured using an automatic contact angle meter. Three different types of liquid media (distilled water, formamide, and diiodomethane) were respectively dropped on the surface of corks using a microsyringe. The initial contact angles of water, formamide, and diiodomethane on the cork surface were 112.0°, 85.1°, and 75.2°, and the corresponding values decreased to 102.1°, 30.7°, and 72.1° when the liquids permeated the cork surface for 10 s. The moisture content values were 4.3%, 6.0%, and 9.0% when the dry cork samples were placed in the relative humidity conditions of 45%, 65%, and 85%, respectively, for 30 days. FT-IR spectra indicated the content of suberin in the sclereids and lenticels was much less than the content found in the pure corks. In the dynamic mechanical analysis (DMA) spectrum, three obvious relaxation processes could be observed in the tan δ curve. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A superamphiphobic Cu surface with enhanced corrosion resistance is fabricated. • A coating mechanism of reaction between FTS and OH on Cu surfaces is proposed. • Intergranular corrosion on Cu micro-cones leads to a hierarchical structured surface. Abstract A simple and robust method for fabrication of superamphiphobic surfaces by template-free chemical deposition of Cu micro-cone arrays, followed by air plasma activation and room-temperature treatment in tridecafluoro-1,1,2,2-tetrahydrooctyl trichlorosilane (FTS) is reported in this paper. After only treatment with 15 min of FTS, a water contact angle of 166.1° and an oil (diiodomethane, CH 2 I 2) contact angle of 160.5° are reached on the Cu surfaces. The highest oil contact angle of 168.1° is achieved after 1 h treatment with FTS. Such surfaces also display enhanced corrosion resistance due to the combination of the FTS layer and air pockets which prevent ion diffusion to the internal copper. [ABSTRACT FROM AUTHOR]

A new N,N′‐bridged corrole derivative has been prepared for the first time via the reaction of diiodomethane with 5,10,15‐tris(pentafluorophenyl)corrole. The new macrocycle has been thoroughly characterized by various spectroscopic techniques including single‐crystal X‐ray diffraction analysis. A simple, facile and high yielding synthetic procedure of a highly stable N21,N22‐methylene‐bridged corrole derivative was established starting from its free base corrole analogue. The resulting methylene‐bridged corrole is highly distorted; however, it retains its fluorescence and has the potential to be an ideal platform to synthesize various sitting‐atop metal complexes. [ABSTRACT FROM AUTHOR]

Abstract Here, we present the construction and calibration of a low-cost goniometer to measure contact angles by the sessile drop method. Besides, we propose a simple and fast method to calculate the uncertainty in the determination of the surface free energy (SFE) and its polar and dispersive components through the Owens-Wendt model and tested it by using two testing liquids. The goniometer performance and the SFE uncertainty were determined on two polymers: polytetrafluorethylene (PTFE) and polyoxymethylene (POM), by using water and methylene iodide. The values of contact angle measured were used to calculate the SFE and its components with their errors. The SFE values obtained for PTFE were 17.57–17.91 mJ/m2, with a relative error lower than 5.5%, whereas those for POM were 42.80–43.23 mJ/m2, with a relative error lower than 4.3%. Both the SFE values and the errors were in the range of those previously reported. Based on the mathematical analysis of the uncertainty propagation in the determination of SFE, we concluded that the uncertainty is minimized when the testing liquids are an apolar liquid and water. [ABSTRACT FROM AUTHOR]

Abstract By adding K+, one-dimensional (1D) chain structure (1) can be converted into three-dimensional (3D) porous structure (BIPT-2). Two coordination polymers were characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Thermogravimetric analyses, IR spectroscopy and fluorescence spectroscopy. Owing to its porosity, BIPT-2 shows excellent selectivity and sensitivity to diiodomethane than 1 through a strong fluorescence quenching. Graphical abstract By adding K+, one-dimensional (1D) chain structure (1) can be converted into three-dimensional (3D) porous structure (BIPT-2). Owing to the porous of BIPT-2 , it shows excellent selectivity and sensitivity to diiodomethane than 1 through a strong fluorescence quenching. fx1 Highlights • By adding K+ ions, one-dimensional chain structure (1) can be converted into three-dimensional porous structure (BIPT-2). • BIPT-2 possess 1D quadrangular channel with 3-interpenetration dia network. • Owing to the porous of BIPT-2 , it shows excellent selectivity and sensitivity to diiodomethane than 1 through a strong fluorescence quenching. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Flower-like nanostructure of NiAl-LDH was synthesized on micro-patterned polymer. • The hierarchical structure showed good amphiphobicity after fluorination. • The amphiphobic surface possessed excellent self-cleaning performance. • The amphiphobic surface exhibited good mechanical and chemical robustness. • The coating can be used in anti-contaminant, self-cleaning, and biomedical device. Abstract Many superhydrophobic surfaces lose their repellency to water owing to the contamination of organic liquids or mechanical damage. Though amphiphobic coatings can repel both water and organic liquids, the poor mechanical and chemical stabilities significantly restrict their practical applications. Herein, we demonstrated a hydrothermal method to synthesize micro-patterned substrates bearing NiAl layered double hydroxide with flower-like nanostructures, which resemble the surface morphology of a lotus leaf. The surface was further modified by a low-surface-energy material of perfluorooctanoic acid through a solution immersion method. The binder-free coating formed in-situ on the substrate showed a good adhesion quality of 5B (ASTM D-3359). The coating possessed high repellency to different liquid droplets, including water, diiodomethane, ethylene glycol, soybean oil, etc., with surface tensions ranging from 72.7 to 22.4 mN m−1. Due to the excellent self-cleaning property, the contaminant on the surface was easily cleaned as the water droplet rolled off. Moreover, the coating exhibited good mechanical and chemical robustness in some extreme conditions, such as gas blowing, sea sand abrasion, and chemical immersion tests. These good performances made the coating possible to be applied widely in various practical applications. [ABSTRACT FROM AUTHOR]

European oak wood (W) was thermo-mechanically modified (TM) via densifying at 100 and 150°C and the surface properties of the TMW were investigated. The contact angle (CA) of the wood with the reference liquids water and diiodomethane was determined using the sessile drop method. The surface free energy of the TMW on tangential sections within the first 60 s after applying a drop was analyzed. The roughness parameters Ra and Rz parallel (‖) and perpendicular (⊥) to the grain were investigated. The wettability analysis showed that densified wood had a higher CA and lower work of adhesion and surface free energy than non-densified wood. An X-ray photoelectron spectroscopy [XPS or electron spectroscopy for chemical analysis (ESCA)] analysis showed that the oxygen to carbon atoms ratio (O/C ratio) of densified wood surface was lower than that of non-densified wood. The carbon C1-C2 atoms ratio (C1/C2 ratio) increased with increasing TM temperature. The results were interpreted as being that extractives migrate to the surface and amorphous and glassy polymers, i.e. lignin and hemicelluloses, in wood are rearranged. Increasing densification temperature makes TMW surfaces more hydrophobic. [ABSTRACT FROM AUTHOR]

Abstract: In the current study, we evaluated the solubility of a number of organometallic species and showed that it is noticeably improved in diiodomethane when compared to other haloalkane solvents. The better solvation properties of CH2I2 were associated with the substantially better σ‐hole‐donating ability of this solvent, which results in the formation of uniquely strong solvent–(metal complex) halogen bonding. The strength of the halogen bonding is attenuated by the introduction of additional halogen atoms in the organometallic species owing to the competitive formation of more favourable intermolecular complex–complex halogen bonding. The exceptional solvation properties of diiodomethane and its inertness towards organometallic species make this solvent a good candidate for NMR studies, in particular, for the acquisition of spectra of insensitive spins. [ABSTRACT FROM AUTHOR]

Cellulose nanofibrils (CNFs) have the potential to be applied to paper or plastics to produce a good gas barrier layer. Past work has used CNF at low solids content because high viscosity at higher consistencies is problematic. Efficient coating processes are needed to apply CNF at higher solids and significant coat weights to reduce drying requirement and decrease water-paper interactions. A cylindrical laboratory coater (CLC) is used to coat two different forms of CNF at different solids content in double layers. CNF suspension is applied at moderate solids content and a high coat weight (>10 g/m 2 ) is possible to be obtained using the blade coater. While others have reported the application of CNF at low solids and moderate speeds, this work shows that it is possible to apply CNF at high speeds (10 m/s) and moderate solids. SEM images reveal that a full surface coverage is obtained even at higher solids content especially when carboxymethyl cellulose (CMC) is added to the coating formulation. The results indicate that an increase around 10–20% for tensile index and about 15% for bending stiffness is obtained. A superior grease barrier property is observed in paperboards with a kit number of 12. An increase of over 300% is found for Hercules sizing results. Air resistance of CNF-coated paperboards increases by a significant amount. Additionally, picking resistance of coated sample is improved with increasing the solids content of CNF coating. The contact angle for water droplets decreases for CNF-coated samples over the uncoated paperboards, however for diiodo-methane (a non-polar liquid) an increase in contact angle is observed. [ABSTRACT FROM AUTHOR]

The effects of molecular weight, MW, on the liquid adsorption, surface free energy and rheological properties of dextran were systemically studied. Results showed that the dextran can adsorb both the polar and non-polar liquids, while the non-polar diiodomethane was greatly adsorbed and the non-polar hexane was small adsorbed. This is because of the total surface free energy of dextran dominated by the non-polar Lifshitz-van der Waals interaction component, LW. Dextran is strongly in the Lewis base and weakly in the Lewis acid and the former was increased with the MW increase and the latter was varied on the contrary. Two intrinsic rheological parameters, e.g. [n] and [k], were deduced from the normal flow behavior index, n, and the consistency index, k, correspondingly and found to reduce with the increase of all the surface free energy components except the Lewis base component for dextran. The [n] and [k] can describe the rheological properties as the normal n and k, however, unlike the normal parameters due to ignoring the variety of concentration. [ABSTRACT FROM AUTHOR]

Background/Aims: Both 3,5-diiodo-L-thyronine (3,5-T2) and 3,5,3’-triiodo-L-tyronine (T3) affect energy metabolism having mitochondria as a major target. However, the underlying mechanisms are poorly understood. Here, using a model of chemically induced hypothyroidism in male Wistar rats, we investigated the effect of administration of either 3,5-T2 or T3 on liver oxidative capacity through their influence on mitochondrial processes including: proton-leak across the mitochondrial inner membrane; complex I-, complex II- and glycerol-3-phosphate-linked respiratory pathways; respiratory complex abundance and activities as well as individual complex aggregation into supercomplexes. Methods: Hypothyroidism was induced by propylthiouracil and iopanoic acid; 3,5-T2 and T3 were intraperitoneally administered at 25 and 15 µg/100 g BW for 1 week, respectively. Resulting alterations in mitochondrial function were studied by combining respirometry, Blue Native-PAGE followed by in-gel activity, and Western blot analyses. Results: Administration of 3,5-T2 and T3 to hypothyroid (hypo) rats enhanced mitochondrial respiration rate with only T3 effectively stimulating proton-leak (450% vs. Hypo). T3 significantly enhanced complex I (+145% vs. Hypo), complex II (+66% vs. Hypo), and glycerol-3 phosphate dehydrogenase (G3PDH)-linked oxygen consumptions (about 6- fold those obtained in Hypo), while 3,5-T2 administration selectively restored Euthyroid values of complex II- and increased G3PDH- linked respiratory pathways (+165% vs. Hypo). The mitochondrial abundance of all respiratory complexes and of G3PDH was increased by T3 administration whereas 3,5-T2 only increased complex V and G3PDH abundance. 3,5-T2 enhanced complex I and complex II in gel activities with less intensity than did T3, and T3 also enhanced the activity of all other respiratory complexes tested. In addition, only T3 enhanced individual respiratory component complex assembly into supercomplexes. Conclusions: The reported data highlight novel molecular mechanisms underlying the effect elicited by iodothyronine administration to hypothyroid rats on mitochondrial processes related to alteration in oxidative capacity in the liver. The differential effects elicited by the two iodothyronines indicate that 3,5-T2, by influencing the kinetic properties of specific mitochondrial respiratory pathways, would promote a rapid response of the organelle, while T3, by enhancing the abundance of respiratory chain component and favoring the organization of respiratory chain complex in supercomplexes, would induce a slower and prolonged response of the organelle. [ABSTRACT FROM AUTHOR]

The present study evaluates two different methods for selection of probe liquids to determine the surface free energy (SFE) of asphalt binders: (i) Condition Number (CN) of probe liquids, and (ii) plot between cosine of total SFE ( ϒ L Cosθ) and total SFE of probe liquids ( ϒ L ) . Five different probe liquids, i.e. Water (W), Formamide (F), Ethylene Glycol (E), Diiodomethane (D), and Glycerol (G) were selected. Overall, ten different combinations of probe liquid triplets (W-G-F, W-G-E, W-G-D, W-F-E, W-F-D, W-D-E, G-F-E, G-F-D, F-E-D, and D-E-G) were formed to examine CN and plot of ϒ L Cosθ versus ϒ L . Three asphalt binders, namely unmodified (VG30), SBS polymer modified binder (PMB40) and crumb rubber modified (CRMB60) binders were selected for the present study. The contact angle of asphalt binders was measured using sessile drop method, and SFE of each of the selected asphalt binders was determined for all ten combinations of probe liquids. Thereafter, CN of probe liquid triplets was determined using Singular Value Decomposition (SVD) method. In addition, ϒ L Cosθ versus ϒ L plot was made for triplets using the measured contact angles of probe liquids. The CN approach and ϒ L Cosθ versus ϒ L plot were compared based on binder’s total SFE to identify a better approach for selecting appropriate probe liquid triplets. CN approach was observed to be superior compared to the plot of ϒ L Cosθ versus ϒ L . In fact, it was observed that the plot approach may not be valid for asphalt binders. [ABSTRACT FROM AUTHOR]

Self-assembly of ZnBr2 with 2,7-bis(isonicotinoyloxy)naphthalene (L) yields one-dimensional (1D) zigzag chains of [ZnBr2L] composition. This 1D chain ensemble forms unique suprachannels of 4.0 × 4.2 Å2 size via weak C-H···π and π···π interactions. A 350 nm ultraviolet irradiation affects host-guest conversion. Diiodomethane molecules within the suprachannel structure of CHCl3·CH2I2@[ZnBr2L] were transformed into an unprecedented triiodide-iodine channel skeleton, HL+@[I3·I2]-. Specifically, two clear, quasi-reversible redox peaks were observed at +0.33 and +0.70 V versus Ag/AgCl in the anodic scan and at +0.19 and +0.62 V in the cathodic scan in acetonitrile for HL+@[I3·I2]-. [ABSTRACT FROM AUTHOR]

Among the great number of methods for measuring the surface free energy of solids, all originate in contact angle measurements, which are carried out using various probe liquids, and employ certain relationships and assumptions. Contact angle measurement can be distorted by a number of factors that occur during the measurement and distort obtained values, and therefore must be accounted for. The present work describes the application of the van Oss-Chaudhury-Good approach in determining the surface free energy of aluminium sheets with the use of three probe liquids: water, diiodomethane and glycerol, with assumed values of the surface free energy components. The study employed direct measurement of the contact angle with the goniometer. Subsequently, measurement uncertainty with the van Oss-Chaudhury-Good method was evaluated, which revealed that the major source of uncertainty is the discrepancy between constant values describing properties of probe liquids. [ABSTRACT FROM AUTHOR]

Reactions of the simplest Criegee intermediate (CH2OO) with a series of alcohols have been studied in a flash photolysis flow reactor. Laser photolysis of diiodomethane at 355 nm in the presence of molecular oxygen was used to produce CH2OO, and the absolute number densities were determined as a function of delay time from analysis of broadband transient absorption spectra obtained using a pulsed LED. The kinetics for the reactions of CH2OO with methanol, ethanol, and 2-propanol were measured under pseudo-first-order conditions at 295 K, yielding rate constants of (1.4 ± 0.4) × 10-13 cm³ s-1, (2.3 ± 0.6) × 10-13 cm³ s-1, and (1.9 ± 0.5) × 10-13 cm³ s-1, respectively. Complementary ab initio calculations were performed at the CCSD(T)/aug-cc-pVTZ//CCSD/cc-pVDZ level of theory to characterize stationary points on the reaction enthalpy and free energy surfaces and to elucidate the thermochemistry and mechanisms. The reactions proceed over free energy barriers of ~8 kcal mol-1 to form geminal alkoxymethyl hydroperoxides: methoxymethyl hydroperoxide (MMHP), ethoxymethyl hydroperoxide (EMHP), and isopropoxymethyl hydroperoxide (PMHP). The experimental and theoretical results are compared to reactions of CH2OO with other hydroxylic compounds, such as water and carboxylic acids, and trends in reactivity are discussed. [ABSTRACT FROM AUTHOR]

In this paper, the wettability of chitosan/phospholipid (1,2-dipalmitoylsn-glycero-3-phosphocholine - DPPC), chitosan/lipid (cholesterol - Choi) and chitosan/protein (cyclosporine A - CsA) films on air plasma activated polyetheretherketone (PEEK) plates was studied. The layers were prepared using the solution spreading technique and their surface wetting properties were determined based on the measurements of the advancing and receding contact angles of water, formamide and diiodomethane. Moreover, based on the contact angle hysteresis model of Chibowski, values of total surface free energy were estimated. Significant changes in PEEK polarity were observed after plasma activation and modifications with Ch/DPPC, Ch/Chol and Ch/CsA layers. These molecules modulate the chitosan film surface by changing the type and magnitude of interactions, which is revealed in the values of surface free energy'. These results may be important for the development and implementation of highly biocompatible bone substitution polymers coated with chitosan film with antifungal and anti-bactericidal properties. Those systems based on chitosan may also carry and release biologically active substances which could be relevant in the new generation of drug delivery systems. [ABSTRACT FROM AUTHOR]

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We present a novel route for the quick and easy synthesis of a broad range of β-lactams. The synthesis involves a [3+1] cyclization of amide dianions with diiodomethane. In contrast to the seminal work of Hirai et al. from 1979, the reaction proved to be a general and efficient approach towards azetidinones. The ease of the process was confirmed by DFT calculations and its power demonstrated by a diversity-oriented synthesis of β-lactams with four points of diversity determined by the choice of Ugi adducts as starting materials. [ABSTRACT FROM AUTHOR]

The X-ray structures of the first co-crystals where the three oxygen lone pairs in N-oxides are fully utilized for tridentate C–I…O−–N+ halogen bonding with 1,̉-diiodoperfluoroalkanes are reported, studied computationally, and compared with the corresponding silver(i) N-oxide complexes. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) extrusion coating was performed on paperboard pre-coated with water-borne barrier coatings based on starch-poly(vinyl) (PVOH)-plasticizer blends in order to investigate that how the addition of a plasticizer to the pre-coating affects the oxygen-barrier properties of the board after PE extrusion coating. The plasticizers used were glycerol, polyethylene glycol (PEG) and citric acid (CA). Photomicrographs showed that the barrier coating layers were rather smooth, but defects were observed in the starch-PVOH layers when a plasticizer was added. Starch-PVOH layers had oxygen-barrier properties similar to those of pure PVOH without plasticizers. When a sufficient number of layers (four layers) were applied to cover defects, the starch-PVOH layers containing CA showed oxygen transmission rate (OTR) values similar to those of starch-PVOH layers without plasticizer. The adhesion of PE to pre-coated paperboard decreased when a plasticizer was added to the pre-coating recipes. PE extrusion coating resulted in a reduction in the OTR in the case of pre-coating formulations containing plasticizers. A lower OTR after polyethylene extrusion was observed with PEG as plasticizer than with CA as plasticizer. This could be explained by the increase in brittleness due to cross-linking under the high temperature load during the extrusion process. Dynamic mechanical analysis of the films showed a substantial increase in storage modulus between 100°C and 200°C for CA-containing starch-PVOH films. The contact angle of diiodomethane on the pre-coating layer decreased when a plasticizer was added to the coating recipe indicating an increase in wetting of the PE melt. Addition of PEG to the pre-coating led to a greater wetting than the addition of CA, and this may have sealed some defects in the pre-coating leading to lower OTR values. [ABSTRACT FROM AUTHOR]

Self-assembly of a series of ZnX2 (X− = Cl−, Br−, and I−) with 2,3-bis(4′-nicotinamidephenoxy)naphthalene (L) as a new hemi-circular bidentate ligand yields systematic 46-membered metallacyclodimeric species of [ZnX2L]2. These metallacyclodimers constitute, via inter-digitated π…π interactions, a characteristically staggered molecular array containing both channels and cages. The slightly different features between the channel and cage have been investigated by 1H NMR and TGA. The crystals with such vacant volumes effectively stabilize the unstable CH2I2 molecule and are monitored by UV spectroscopy. Furthermore, the photoluminescence intensity via the chromophore naphthyl moiety of [ZnCl2L]2 gradually decreases with the addition of CH2I2. [ABSTRACT FROM AUTHOR]

The measurements of water, formamide and diiodomethane contact angle ( θ ) on polytetrafluoroethylene (PTFE), polyethylene (PE), polymethyl methacrylate (PMMA), nylon 6, quartz and silica were performed. Based on the θ values of these liquids obtained on PTFE, the Lifshitz-van der Waals and acid-base and/or dispersion and polar components of their surface tension (ST) were determined. In turn, the θ values for water, formamide and diiodomethane on PMMA were applied to calculate the electron-acceptor and electron-donor parameters of the Lewis acid-base component of the formamide ST. For this calculation the same values of the electron-acceptor and electron-donor parameters for water ST were used. Taking into account the values of components and parameters of water, formamide and diiodomethane ST obtained by us, van Oss et al. and from the water(formamide)- n -alkane and water-diiodomethane interface tension, the components and parameters of studied solids ST were calculated. To this end different approaches to the interface tension were considered. The obtained values were compared with those in the literature. It was concluded that for determination of solid ST components and parameters, those of water, formamide and diiodomethane ST obtained from the θ measurements on the model solids should be used. [ABSTRACT FROM AUTHOR]

Self-assembly of Zn(ClO4)2 with 1,3,5-tris(dimethyl(pyridin-3-yl)silyl)benzene (L) as a new C3-symmetric tridentate N-donor gives rise to a discrete sandwich-shaped M3L2 architecture, [Zn3(μ-OH)3L2](ClO4)3·4CH3CN·2H2O. Its blue photoluminescence is significantly quenched only by CH2I2 among the various small molecules, CH2Cl2, CH2Br2, CHCl3, 1,2-dichloroethane, EtOH, CH3CN, benzene, toluene, and phenol. [ABSTRACT FROM AUTHOR]

A 1,3,5,7,9-pentaazanona-1,3,6,8-tetraenate (PANT) chloride platinum(ii) complex (1) was obtained via the metal-mediated double coupling of 2,3-diphenylmaleimidine with both nitrile ligands in trans-[PtCl2(NCtBu)2]. Compound 1 was then co-crystallized with diiodomethane forming solvate 1·½CH2I2. The XRD experiment reveals that this solvate displays the halogen bonds H2C(I)–I…Cl–Pt and hydrogen bonds I2C(H)–H…Cl–Pt, which join two complex and one CH2I2 molecules in a heterotrimeric supramolecular cluster. Inspection of the CCDC database reveals only one example of the halogen bond H2C(I)–I…I–Pt between the CH2I2 molecule and metal-coordinated halide in the structure of VEMWOA. In VEMWOA, CH2I2 serves solely as a halogen bond donor with no hydrogen bond contribution. Results of the Hirshfeld surface analysis and DFT calculations (M06/DZP-DKH level of theory) followed by topological analysis of the electron density distribution within the formalism of Bader's theory (QTAIM method) for both 1·½CH2I2 and VEMWOA confirmed the formation of these weak interactions. The evaluated energies of halogen bonds involving CH2I2 are in the 2.2–2.8 kcal mol−1 range. [ABSTRACT FROM AUTHOR]

The aim of this study was to synthesize hydrophobic cellulose nanofibers (CNFs) using different chemical treatments including polymer and molecular grafting. For polymer grafting, immobilizing poly (butyl acrylate) (PBA) and poly (methyl methacrylate) (PMMA) on CNFs were implemented by the free radical method. Also, acetyl groups were introduced directly onto the CNFs surface by acetic anhydride for molecular grafting. The gravimetric and X-ray photoelectron spectroscopy analysis showed the high grafting density of PMMA on the surface of CNFs. AFM results revealed that molecular grafting created non-uniformity on the CNFs surface, as compared to polymer brushes. In addition, thermodynamic work of adhesion and work of cohesion for the modified CNFs were reduced in water and diiodomethane solvents. Dispersion factor was studied to indicate the dispersibility of CNFs in polar and non-polar media. Dispersion energy was reduced after modification as a result of decreasing interfacial tension and the dispersibility of modified CNFs was improved in diiodomethane. [ABSTRACT FROM AUTHOR]

A new protocol for the catalytic cyclopropanation of α,β-unsaturated carbonyl compounds with diiodomethane by means of photoredox catalysis has been successfully developed. The transformation is characterized by its mild conditions, functional-group compatibility, and excellent selectivity profile. [ABSTRACT FROM AUTHOR]

A simple method, involving twice electric machining by HS-WEDM and chemical etching, is used to fabricate super-amphiphobic (both super-hydrophobic and super-oleophobic) surfaces on aluminium alloy. The surface morphology of the samples was investigated using scanning electron microscopy and laser scanning confocal microscope. The evaluations of surface oleophobicity were carried out using the contact angles of ethylene glycol, diiodomethane and dodecane. Finally, the experimental result indicated that after the twice electric machining and chemical etching, the micro/nanometre-scale binary rough structure was presented on the sample surfaces, and the resulting sample surfaces produced in this method had super-hydrophobic and lipophilic properties (water contact angle of 155.74°). More importantly, after surface fluorination, the sample surfaces turned to super-amphiphobic surfaces and the biggest contact angles of water and oil were 156.24° and 157.34°, respectively. Therefore, it can be considered that the acquirement of the micro/nanometre-scale rough structures and the reduction of the surface energy are essential requirements to fabricate super-amphiphobic surfaces. The advantages of the present method over the other methods are that the used wire electrical discharge machining can machine most metals, and the processes of surface forming and microstructure fabrication were combined, which saves processing time greatly. [ABSTRACT FROM AUTHOR]

The first stereoconvergent cyclopropanation reaction by means of photoredox catalysis using diiodomethane as the methylene source is described. This transformation exhibits broad functional group tolerance and it is characterized by an excellent stereocontrol en route to trans-cyclopropanes regardless of whether E- or Z-styrene substrates were utilized. [ABSTRACT FROM AUTHOR]

Titanium (Ti) and its alloys are the most often used implants material in dental treatment and orthopedics. Topography and wettability of its surface play important role in film formation, protein adhesion, following osseointegration and even duration of inserted implant. In this paper, we prepared Ti-6Al-4V alloy samples using different smoothing and polishing materials as well the air plasma treatment, on which contact angles of water, formamide and diiodomethane were measured. Then the apparent surface free energy was calculated using four different approaches (CAH, LWAB, O-W and Neumann's Equation of State). From LWAB approach the components of surface free energy were obtained, which shed more light on the wetting properties of samples surface. The surface roughness of the prepared samples was investigated with the help of optical profilometer and AFM. It was interesting whether the surface roughness affects the apparent surface free energy. It was found that both polar interactions the electron donor parameter of the energy and the work of water adhesion increased with decreasing roughness of the surfaces. Moreover, short time plasma treatment (1 min) caused decrease in the surface hydrophilic character, while longer time (10 min) treatment caused significant increase in the polar interactions and the work of water adhesion. Although Ti-6Al-4V alloy has been investigated many times, to our knowledge, so far no paper has been published in which surface roughness and changes in the surface free energy of the alloy were compared in the quantitative way in such large extent. This novel approach deliver better knowledge about the surface properties of differently smoothed and polished samples which may be helpful to facilitate cell adhesion, proliferation and mineralization. Therefore the results obtained present also potentially practical meaning. [ABSTRACT FROM AUTHOR]

In this study the effect of dry grinding on hydrophobicity, surface free energy (SFE), particle size distribution, surface area, porosity, oil absorption, and whiteness of talc was investigated. The dry grinding was performed in a vibrating ball mill at various grinding times (5-150 min) by keeping the grinding parameters constant such as the number of ball, ball size, the amount of talc, vibration frequency and amplitude. Then, the contact angle measurements were performed on disc-shaped samples produced under a hydraulic press by using a sessile drop method with different liquids (water, formamide, diiodomethane, and ethylene glycol), and surface free energies (mJ/m2) were calculated according to OCG-AB (van Oss-Chaudhury-Good Acid-Base) method by using the obtained contact angle values. In addition, the physicochemical analyses given above were carried out for each ground sample. According to the obtained results, the water contact angle and SFE of the original sample were 63.800 and 48.70 mJ/m2, respectively. The lowest and highest contact angle values for the samples were obtained as 59.300 and 70.77° at grinding times for 5 and 15 min, respectively. It was also determined that the grinding time over 30 min showed no significant effect on the contact angle and SFE values of the samples. Similarly, the grinding time vs. SFE, and the grinding time vs. contact angle curves showed a similar trend. Parallel to the increase in the surface area upon the grinding, a small increase in the oil absorption and whiteness of talc was also determined. [ABSTRACT FROM AUTHOR]

A superamphiphobic coating on a biobased material shows extreme liquid repellency with static contact angles (CA) greater than 150° and roll-off angles less than 10° against water, ethylene glycol, diiodomethane and olive oil, and a CA for hexadecane greater than 130°. The coating consisting of titania nanoparticles deposited by liquid flame spray (LFS) and hydrophobized using plasma-polymerized perfluorohexane was applied to a birch hardwood. Scanning electron microscopy (SEM) imaging after sample preparation by UV laser ablation of coated areas revealed that capped structures were formed and this, together with the geometrically homogeneous wood structure, fulfilled the criteria for overhang structures to occur. The coating showed high hydrophobic durability by still being non-wetted after 500 000 water drop impacts, and this is discussed in relation to geometrical factors and wetting forces. The coating was semi-transparent with no significant coloration. A self-cleaning effect was demonstrated with both water and oil droplets. A self-cleanable, durable and highly transparent superamphiphobic coating based on a capped overhang structure has a great potential for commercial feasibility in a variety of applications, here exemplified for a biobased material. [ABSTRACT FROM AUTHOR]