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Herein, we report the facile growth of three-dimensional CsPbBr3 perovskite supercrystals (PSCs) self-assembled from individual CsPbBr3 perovskite quantum dots (PQDs). By varying the carbon chain length of a surface-bound ligand molecule, 1-alkynyl acid, different morphologies of PSCs were obtained accompanied by an over 1000-fold photoluminescence improvement compared with that of PQDs. Systematic analyses have shown, for the first time, that under UV irradiation, CsBr, the byproduct formed during PQDs synthesis, could effectively catalyze the homocoupling reaction between two alkynyl groups, which further worked as a driving force to push forward the self-assembly of PQDs.

Quantum chemical calculations were used to study the reaction of carboxylic acids with isonitriles inside a resorcinarene-based self-assembled capsule. Experimentally, it has been shown that the reactions between p-tolylacetic acid and n-butyl isonitrile or isopropyl isonitrile behave differently in the presence of the capsule compared both with each other and also with their solution counterparts. Herein, the reasons for these divergent behaviors are addressed by comparing the detailed energy profiles for the reactions of the two isonitriles inside and outside the capsule. An energy decomposition analysis was conducted to quantify the different factors affecting the reactivity. The calculations reproduce the experimental findings very well. Thus, encapsulation leads to lowering of the energy barrier for the first step of the reaction, the concerted α-addition and proton transfer, which in solution is rate-determining, and this explains the rate acceleration observed in the presence of the capsule. The barrier for the final step of the reaction, the 1,3 O→N acyl transfer, is calculated to be higher with the isopropyl substituent inside the capsule compared with n-butyl. With the isopropyl substituent, the transition state and the product of this step are significantly shorter than the preceding intermediate, and this results in energetically unfavorable empty spaces inside the capsule, which cause a higher barrier. With the n-butyl substituent, on the other hand, the carbon chain can untwine and hence uphold an appropriate guest length.

Allenes (carbodicarbenes) and [3]cumulenes are linear carbon chains that can be bent when the terminal group has a strong carbene nature. This bending can be quite pronounced in allenes but not in [3]cumulenes. In this study, how N-heterocyclic or cyclic (alkyl)(amino) carbene (NHC and CAAC, respectively) terminal groups can modify the linear structure of [n]cumulenes has been analyzed. A low π acidity of the terminal carbene affects the linearity of [2n]cumulenes. Indeed, it has been found that the NHC [4]cumulene is extremely bent, contrary to classical [4]cumulenes. The predicted NHC [4]cumulene or tricarbodicarbene has two lone pairs and the π electrons are delocalized over the whole molecule. More significantly, DFT calculations have shown that this bent [4]cumulene is very stable, considerably more so than the corresponding [3]cumulene, which has been elusive to synthesize. Remarkably, calculations have shown that all the NHC [2n]cumulenes are more than 25 kcal mol-1 more stable than the [2n-1]cumulenes.

Synthetic routes to dimetallated Cx carbon wires in which two metals are separated by a linear carbon chain involving terminal metal-carbon triple bonds are described for the complexes [(Tp*)(CO)2 W≡C-(C≡C)n -C≡W(CO)2 (Tp*)] (Tp*=hydrotris(dimethylpyrazolyl)borate) where n=1, 3 or 4, joining the previously known examples with n=0, 1 and 2 to complete the series as models for linear carbyne C∞ .

Isomerizing olefin metathesis is currently undergoing a transformation from laboratory curiosity to powerful synthetic concept at the heart of orthogonal tandem catalysis. In this process, an isomerization catalyst continuously moves double bonds along carbon chains, while a metathesis catalyst scrambles the residues at the C-C double bonds. This cooperative action of two catalysts can be used to access single, defined products from a complex mixture of compounds. Alternatively, it enables the transformation of uniform starting materials into complex product blends with defined, tunable properties. This concept article highlights recent developments and potential applications of this fascinating reaction concept.

Current therapeutic drugs for Alzheimer's disease (AD) can only offer limited symptomatic benefits and do not halt disease progression. Multitargeted directed ligands (MTDLs) have been considered to be a feasible way to treat AD due to the multiple neuropathological processes in AD. Previous studies proposed that compounds containing two aromatic groups connected by a carbon chain should act as effective amyloid β (Aβ) aggregation inhibitors although the optimal length of the carbon chain has not been explored. In the current study, a series of naphthalimide analogs were designed and synthesized based on the proposed structure and multiple bioactivities beneficial to the AD treatment were reported. In vitro studies showed that compound 8, which has two aromatic groups connected by a two-carbon chain, exhibited significant inhibition of Aβ aggregation through the prevention of elongation and association of Aβ fibril growth. Furthermore, this compound also displayed antioxidative activities and neuroprotection from Aβ monomer induced toxicity in primary cortical neurons. The results of the present study highlight a novel naphthalimide-based compound 8 as a promising MTDL against AD. Its structural elements can be further explored for enhanced therapeutic capabilities.

Shifting from petroleum-based resources to inedible biomass for the production of valuable chemicals and fuels is one of the significant aspects in sustainable chemistry for realizing the sustainable development of our society. Various renowned biobased platform molecules, such as 5-hydroxymethylfurfural, furfural, levulinic acid, and lactic acid, are successfully accessible from the transformation of biobased sugars. To achieve the specific reaction routes, heterogeneous nanoporous acidic materials have served as promising catalysts for the conversion of bio-sugars in the past decade. This Review summarizes advances in various nanoporous acidic materials for bio-sugar conversion, in which the number of carbon atoms is variable and controllable with the assistance of the switchable structure of nanoporous materials. The major focus of this Review is on possible reaction pathways/mechanisms and the relationships between catalyst structure and catalytic performance. Moreover, representative examples of catalytic upgrading of biobased platform molecules to biochemicals and fuels through selective C-C cleavage and coupling strategies over nanoporous acidic materials are also discussed.

A highly stereoselective synthesis of hitherto less accessible chiral α-tertiary amines with multiple structurally similar linear carbon chains was achieved through chiral auxiliary mediated addition of organolithium reagents to the geometrically well-controlled alkynyl Z-ketimines. This stereoselective nucleophilic addition offers a general approach to the asymmetric synthesis of nitrogen-containing chiral materials.

This study pertains to the dynamic evolution of the Belousov–Zhabotinsky (BZ) chemical oscillator upon the addition of different aliphatic alcohols (methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, iso-butanol, and tert-butanol) at 30°C in a stirred batch reactor. The oscillations are monitored potentiometrically. The experimental findings reveal that the course of the BZ reaction is significantly altered depending on the concentration of the alcohol and the type of the carbon chain present. The mechanism of the alcohol perturbation has been interpreted on account of the experimental results. Besides the qualitative study, a new approach for monitoring the analytical concentration of these alcohols using the BZ oscillatory regime has been explored and it has been found that the alcohol perturbation is directly related to the concentration of the alcohol added, which in turn depends on the inhibition time for the rebirth of oscillatory regime.

A convergent synthetic approach towards all carbon chain frame work of cyclicdepsipeptides acremolides A–D is described. The two key fragments, acyclic chain with four chiral centers and a dipeptide with two chiral centers were coupled together through an amide bond formation. Sharpless asymmetric epoxidation and Evans syn aldol reaction are the other key reactions involved in generating chiral centers.in the aliphatic side chain fragment.

Microbial polyhydroxyalkanoates (PHA) containing short- and medium/long-chain-length monomers, abbreviated as SCL-co-MCL/LCL PHAs, generate suitable thermal and mechanical properties. However, SCL-co-MCL/LCL PHAs with carbon chain longer than nine are difficult to synthesize due to the low specificity of PHA synthase PhaC and the lack of either SCL- or MCL/LCL monomer precursor fluxes. This study succeeds in reprogramming a β-oxidation weakened Pseudomonas entomophila containing synthesis pathways of SCL 3-hydroxybutyryl-CoA (3HB) from glucose and MCL/LCL 3-hydroxyalkanoyl-CoA from fatty acids with carbon chain lengths from 9 to 18, respectively, that are polymerized under a low specificity PhaC61-3 to form P(3HB-co-MCL/LCL 3HA) copolymers. Through rational flux-tuning approaches, the optimized recombinant P. entomophila accumulates 55 wt% poly-3-hydroxybutyrate in 8.4 g L-1 cell dry weight. Combined with weakened β-oxidation, a series of novel P(3HB-co-MCL/LCL 3HA) copolymers with over 60 wt% PHA in 9 g L-1 cell dry weight have been synthesized for the first time. P. entomophila has become a high-performing platform to generate tailor-made new SCL-co-MCL/LCL PHAs.

Three new quinone-containing Hoveyda-type complexes have been synthesised and fully characterised. Their ability to suppress undesired double-bond migration along the carbon chain during metathesis reactions was examined. It was proved that these catalysts decrease the amounts of undesired side-products with a shifted double bond in the reaction mixture.

The role of milk in the transfer of perfluoroalkyl substances (PFASs) to offspring is not well known in wildlife. Eight PFASs were quantified in plasma and milk in mother–pup pairs of hooded seals (Cystophora cristata) during the nursing period, and the role of milk in the transfer process was analyzed. Hooded seal was chosen because of its short lactation period (3–4 d), during which the pup feeds only on milk. Placental or lactation transfer would thus be the only source of PFAS in the pup. Of the 8 PFASs analyzed (Σ8PFAS), 7 were found in all samples; therefore, milk is a source to PFASs in pups. Perfluorooctane sulfonate was the dominant PFAS in all samples. Mean Σ8PFAS concentrations were 6.0 ng/g protein (36 ng/g wet wt) in maternal plasma, 0.77 ng/g protein (3.2 ng/g wet wt) in milk, and 12 ng/g protein (66 ng/g wet wt) in pup plasma. Measured concentrations in plasma were within ranges previously reported from other seal species, below known toxicity thresholds for experimental rodents. Individual PFASs differed in transfer efficiency from mother to pup, depending on carbon chain lengths, with the lowest relative transfer for the intermediate-chained PFASs (C9–C10). The results show maternal transfer of PFASs via both milk and the placenta, of which placental transfer is the dominant pathway. Environ Toxicol Chem 2017;36:763–770. © 2016 SETAC

A photo-induced substitutive introduction of an aldoxime functional group to carbon chains was achieved using photo-excited 4-benzoylpyridine as a C(sp(3) )-H bond cleaving agent and arylsulfonyl oxime as an aldoxime precursor. The non-acidic C-H bonds in various substances, including cycloalkanes, ethers, azacycles, and cyclic sulfides, were chemoselectively converted at ambient temperature under neutral conditions. The present transformation is a formal formylation of non-acidic C(sp(3) )-H bonds in a single step.

Sodium 4,6-(2-(N,N-bis-ethylhexylamino)-1,3,5-triazine-4,6-yl-amino) ethane sulfonate (IXC8), Sodium 4,6-(2-(N,N-bis-octylamino)-1,3,5-Triazine-4,6-yl-amino) ethane sulfonate (XC8) and 2,2′-(6,6′-(ethane-1,2-diylbis(azanediyl) bis(4-(octylamino)-1,3,5-triazine-6,2-diyl)) bis(azanediyl))diethane sulfonate (C8-2-C8) were synthesized from cyanuric chloride. The surface activity and application properties of these surfactants (XC8, IXC8 and C8-2-C8) were discussed. The values of CMC, γ CMC, pC20, Γmax, and Amin calculated from surface tension measurement at 30 °C indicate that the surface activity of IXC8, which has two branched hydrophobic carbon chains, has lower γ CMC (26.8 mN m−1) than the other investigated surfactants and excellent wetting ability.

Insects are of growing significance in veterinary medicine and human healthcare; therefore, an understanding of their biology is very important. The cuticular and internal fatty acid compositions of Chorthippus brunneus males and females have been studied for the first time. The lipids of males and females were separated into classes of compounds using high-performance liquid chromatography with a laser light scattering detector. The free fatty acid (FFA) fractions obtained by HPLC were silylated and then analyzed by GC-MS. The cuticular lipids of males contained 15 saturated, four unsaturated with even-numbered and two unsaturated with odd-numbered carbon chains, FFAs ranging from C8 to C25. The major free fatty acids in males were C16 (20.8%), C18:2 (8.5%), C18:1 (32.9%) and C18 (24.4%). The cuticular lipids of females contained 17 saturated, four monounsaturated and two diunsaturated free fatty acids ranging from C8 to C30. The major cuticular fatty acids in females were C16 (25.1%), C18:2 (6.2%), C18:1 (23.7%) and C18:0 (33.2%). The internal FFAs of males consisted of 20 compounds ranging from C8 to C26. Four of these compounds were detected as major compounds: C16 (14.1%), C18:2 (21.6%), C18:1 (38.0%) and C18 (22.5%). Among 18 internal free fatty acids of females, C16 (22.3%), C18:2 (10.9%), C18:1 (40.2%) and C18 (20.5%) were the most abundant compounds. The following cuticular fatty acids present in the lipids of females were absent in the lipids of males: C26, C27 and C30. On the other hand, only C24 was absent from the cuticular lipids of females. Only C10 and C24 internal fatty acids present in the lipids of males were absent in the lipids of females. Copyright © 2016 John Wiley & Sons, Ltd.

The atomic-thin 2D semiconductors have emerged as plausible candidates for future optoelectronics with higher performance in terms of the scaling process. However, currently reported 2D photodetectors still have huge shortcomings in ultraviolet and especially visible-blind wavelengths. Here, a simple and nontoxic surfactant-assisted synthesis strategy is reported for the controllable growth of atomically thin (1.5 to 4 nm) ZnO nanosheets with size ranging from 3 to 30 µm. Benefit from the short carbon chains and the water-soluble ability of sodium dodecyl sulfate (SDS), the synthesized ZnO nanosheets possess high crystal quality and clean surface, leading to good compatibility with traditional micromanufacturing technology and high sensitivity to UV light. The photodetectors constructed with ZnO demonstrate the highest responsivity (up to 2.0 × 104 A W-1 ) and detectivity (D* = 6.83 × 1014 Jones) at a visible-blind wavelength of 254 nm, and the photoresponse speed is optimized by the 400 °C annealing treatment (τR = 3.97 s, τD = 5.32 s), thus the 2D ZnO can serve as a promising material to fill in the gap for deep-UV photodetection. The method developed here opens a new avenue to controllably synthesize 2D nonlayered materials and accelerates their applications in high-performance optoelectronic devices.

Exponentially localized Wannier functions of cumulene are calculated from the Bloch functions obtained through a tight-binding approach. Numerical results and discussions are given for the and bands. In the latter case, the single-band Wannier functions are similar to the orbitals of a diatomic molecule, while the two-band Wannier functions resemble hybrid atomic orbitals. Contour plot of an sp-like Wannier function of cumulene.

The synthesis of a unique series of long, asymmetric 1-iodopolyynes (1-Cn I and 2-Cn I) with the sp-hybridized carbon chain up to a decapentayne is reported. These compounds were then used as substrates in reactions with Pd(PPh3 )4 leading to another series of palladium end-capped polyynes, which were unstable in solution. Organometallic octatetraynes 1-C8 [Pd]I, 2-C8 [Pd]I, and decapentayne 1-C10 [Pd]I are palladium end-capped polyyne compounds with the longest carbon chains reported so far. All the complexes as well as their organic precursors were fully characterized by NMR, HRMS(ESI), IR, TGA-DTA, and UV/Vis techniques, and the X-ray crystal structures of two silyl-protected precursors and one palladium complex are presented. The synthetic approach for palladium species is envisioned as a general route for the synthesis of labile organometallic polyynes.

Analytical methods for determining perfluoroalkyl acids (PFAAs) in leaves were developed to quantify a suite of analytes in both coniferous and deciduous broad-leaved trees. Sodium hydroxide-methanol and solid-phase extraction was selected as the extracting and cleanup strategy for PFAA analysis. Ten perfluorocarboxylic acids (PFCAs) and 4 perfluorosulfonic acids (PFSAs) were monitored in 7 kinds of leaves grown in the urban areas of Dalian, China. The results show that coniferous tree leaves take up more PFAAs than broad-leaved tree leaves, with the highest amount of 150 ng/g in pine needles. Leaf PFCA levels were much higher than PFSAs level. Short carbon-chain PFCAs with 3 to 6 perfluorinated carbons account for approximately 40% to 80% of the total leaf PFAAs, where uptake decreased with increasing carbon chain length. Temporal observation of leaf PFAAs revealed no significant variation of concentrations in the leaves over a weekly interval and the absence of significant seasonal change in pine needles and sophora. The present study provides some evidence for the accumulation of PFAAs in leaves, which is valuable for understanding their environmental behavior and the development of alternative bioindicator.

In this study, we evaluated the efficacy of a novel minipig strain, the Microminipig (MMPig), as an animal model for studying the pharmacokinetics of a mixture of 10 perfluoroalkyl acids (PFAAs). After a single oral dose was given, we found that the blood depuration of PFAAs (blood t1/2), which we calculated using first-order elimination curves, ranged from 1.6 to 86.6 days. Among the five body compartments analyzed, the liver was the greatest site of accumulation of perfluorooctanesulfonate and longer chain perfluorinated carboxylates such as perfluorodecanoic acid, perfluoroundecanoic acid and perfluorododecanoic acid. We observed an increasing accumulation trend of perfluorinated carboxylates in the organs associated with the fluorinated carbon chain length. The perfluorononanoic acid burden was the highest among the treated compounds 21 days after a single exposure, as 29% of the given perfluorononanoic acid dose was accumulated in the tissues. The persistence of PFAAs in edible pig tissues even after 21 days post-exposure raises concerns about the safety of swine products. This was the first study to use MMPigs to elucidate the pharmacokinetics of a group of environmental pollutants. We found that MMPigs could be excellent experimental animals for toxicological studies due to their easy handling, cost efficacy for target compounds and ease of waste treatment. Copyright © 2015 John Wiley & Sons, Ltd.

The olive (Olea europaea) is one of the most important crops in the Mediterranean region for economic and culinary reasons. Cuticular waxes coat olives and olive leaves and play a significant role in plant physiology and resistance against environmental stresses. The present study describes n-alkane profiles in cuticular waxes of olives and leaves of three Italian varieties (Frantoio, Leccino and Maraiolo) during different stages of olive development. Additionally, the study investigates the differences between n-alkane profiles of extra virgin olive oils with low and high leaf content. Olive leaves are characterised by the predominance of n-alkanes with longer carbon chains (n-C29-C33) compared with olives (n-C25-C29). During all stages of olive ripening period, n-alkane average chain length (ACL) values of olive leaves are significantly higher compared with those of olives. Extra virgin olive oils with admixture of leaves have significantly different n-alkane profiles than those free from leaf material. Practical applications: The results of this study will contribute significantly to the currently very limited information on n-alkane data from olive tree varieties used for oil production. The presence of leaves increases the concentrations of long chain n-alkanes (n-C31-C35) in extra virgin olive oils, therefore studying the differences between n-alkane profiles of olives and olive leaves could help establishing the presence of leaf material in produced extra virgin olive oils. Information about the relative and absolute concentrations of n-alkanes in olives, olive leaves and olive oil will also be useful for biochemical and metabolic studies of the olive tree.

Compounds (2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L1), 2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L2), and 2-(3,5-diphenyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L3) were prepared using the synthetic routes reported in literature. These compounds were reacted with [NiCl2(DME)2] or [NiBr2(DME)2] under appropriate reaction conditions to afford six new nickel(II) compounds ([NiCl2(L1)] (1), [NiCl2(L2)] (2), [NiCl2(L3)] (3), [NiBr2(L1)] (4), [NiBr2(L2)] (5) and [NiBr2(L3)] (6)). The new nickel(II) pre-catalysts catalyze the oligomerization of ethylene, in the presence of ethylaluminium dichloride as co-catalyst, to produce butenes, hexenes, octenes and higher carbon chain ethylene oligomers with very little Friedel-Crafts alkylation products when the reactions were run in toluene.

Allylic pinacol boronic esters are stable toward 1,3-borotropic rearrangement. We developed a Pd(II)-mediated isomerization process that gives di- or trisubstituted allylic boronic esters with high E selectivity. The combination of this method with lithiation-borylation enables the synthesis of carbon chains that bear 1,5-stereogenic centers. The utility of this method has been demonstrated in a formal synthesis of (+)-jasplakinolide.

A question of both fundamental as well as practical importance is the nature of one-dimensional carbon, in particular whether a one-dimensional carbon allotrope is polyynic or cumulenic, that is, whether bond-length alternation occurs or not. By combining the concept of aromaticity and antiaromaticity with the rule of Peierls distortion, the occurrence and magnitude of bond-length alternation in carbon chains with periodic boundary conditions and corresponding carbon rings as a function of the chain or ring length can be explained. The electronic properties of one-dimensional carbon depend crucially on the bond-length alternation. Whereas it is generally accepted that carbon chains in the limit of infinite length have a polyynic structure at the minimum of the potential energy surface with bond-length alternation, we show here that zero-point vibrations lead to an effective equalization of all carbon-carbon bond lengths and thus to a cumulenic structure.

Mechanofluorochromic materials have great potential for a wide variety of applications such as sensors, memory devices, motion systems, security systems, and so forth. However, only few design principles have been disclosed, which greatly impedes the growth of mechanofluorochromic dyes. Here, a strategy of molecular design for mechanochromic luminescence is reported, based on the cation–anion interaction-directed switching of molecular stacking. On the basis of this strategy, a series of common N-heteroaromatic onium fluorophores such as imidazolium, 1,2,4-triazolium, triazolopyridinium, benzoimidazolium, γ-carbolinium, and pyridinium salts have been designed and proved to have striking reversible mechanofluorochromic behaviors. The simple attachment of a non-fluorescent imidazolium unit to the pyrene scaffold through a flexible carbon chain can even trigger the mechanofluorochromic phenomenon, which gives a consummate interpretation that the cation–anion interaction can be considered as an important general tool to design organic mechanochromic luminescent materials.

The donor–acceptor molecule is the only molecule that features a real intrinsic rectifi cation. However, all investigations in the last decades showed that rectifi cation behaviors of such molecules are not promising since their rectifi cation ratio is only on the order of 10. Use of carbon chains C n to serve as spacers is reported, along with attempts to modulate electrical behavior of the donor–acceptor molecule. Calculations using the fi rst-principles method show that electrical behavior is indeed altered substantively, and a particular regularity can be clearly observed, i.e., a dramatic odd–even oscillation for electronic behavior with increasing carbon-chain length n. For models with even- n carbon chains, the rectifi cation ratio is small (30), and no negative differential resistance (NDR) behavior is detected, but the rectifying performance of models with odd- n carbon chains is tremendously improved and rectifi cation ratios on the order of 50 to 400 can be achieved, alongside a large NDR. This study thus suggests that using a suitable spacer might be an effective way to signifi cantly boost electrical characteristics, including rectifying performance, of the donor–acceptor molecule.

This chapter focuses on the stereo-controlled homologation of chiral boronic esters with chiral lithium carbenoid (lithiation–borylation) as a powerful method for the asymmetric synthesis of many complex molecules. It is highlighted that the potential methodology to create multiple contiguous stereogenic centers on “growing” carbon chains.

The rearrangement of 4-oxobutane-1,1,2,2-tetracarbonitriles to give the penta-1,3-diene-1,1,3-tricarbonitrile moiety, accompanied by elongation of the carbon chain via introduction of the cyano group carbon atom to the carbon skeleton, is described. The rearrangement in acetic acid in the presence of ammonium acetate allows the synthesis of 2-(3-cyano-7a-hydroxy-5,6,7,7a-tetrahydro-1H-indol-2(4H)-ylidene)malononitriles, which are structural analogs of practically significant tricyanofuran (TCF) and tricyanopyrrole (TCP) acceptors for donor–acceptor chromophores.

A photo-induced substitutive introduction of an aldoxime functional group to carbon chains was achieved using photo-excited 4-benzoylpyridine as a C(sp(3) )-H bond cleaving agent and arylsulfonyl oxime as an aldoxime precursor. The non-acidic C-H bonds in various substances, including cycloalkanes, ethers, azacycles, and cyclic sulfides, were chemoselectively converted at ambient temperature under neutral conditions. The present transformation is a formal formylation of non-acidic C(sp(3) )-H bonds in a single step.

A simple iron-catalyzed aerobic oxidative C–C σ-bond cleavage of ketones has been developed. Readily available and environmentally benign air is used as the oxidant. This reaction avoids the use of noble metal catalysts or specialized oxidants, chemoselectively yielding carbon chain-shortened aldehydes, ketones and 1,2-dicarbonyl compounds without overoxidation.

Long carbon chains: Self-assembly of monomeric carbon intermediates into long-chain hydrocarbons on catalytically reactive surface was studied when full reversibility of the chain growth is included in the kinetic model. Using Brønsted-Evans-Polanyi relations, the maximum chain growth as a function of the surface reactivity is predicted.

Environmental contaminants are usually encountered as mixtures, and many of these mixtures yield synergistic or antagonistic effects attributable to an intracellular chemical reaction that pose a potential threat on ecological systems. However, how atomic charges of individual chemicals determine their intracellular chemical reactions, and then determine the joint effects for mixtures containing reactive toxicants, is not well understood. To address this issue, the joint effects between cyanogenic toxicants and aldehydes on Photobacterium phosphoreum were observed in the present study. Their toxicological joint effects differed from one another. This difference is inherently related to the two atomic charges of the individual chemicals: the oxygen charge of -CHO (O(aldehyde toxicant)) in aldehyde toxicants and the carbon-atom charge of a carbon chain in the cyanogenic toxicant (C(cyanogenic toxicant)). Based on these two atomic charges, the following QSAR (quantitative structure-activity relationship) model was proposed: When (O(aldehyde toxicant) -C(cyanogenic toxicant) )-0.125, the joint effect of equitoxic binary mixtures at median inhibition (TU, the sum of toxic units) can be calculated as TU = 1.00 ± 0.20; when (O(aldehyde toxicant) -C(cyanogenic toxicant) ) ≤ -0.125, the joint effect can be calculated using TU = - 27.6 x O (aldehyde toxicant) - 5.22 x C (cyanogenic toxicant) - 6.97 (n = 40, r = 0.887, SE = 0.195, F = 140, p0.001, q(2) (Loo) = 0.748; SE is the standard error of the regression, F is the F test statistic). The result provides insight into the relationship between the atomic charges and the joint effects for mixtures containing cyanogenic toxicants and aldehydes. This demonstrates that the essence of the joint effects resulting from intracellular chemical reactions depends on the atomic charges of individual chemicals. The present study provides a possible approach for the development of a QSAR model for mixtures containing reactive toxicants based on the atomic charges.

International audience; A first preliminary interlaboratory trial was planned to prepare ISO/DIS 12010: Water quality - determination of short chain polychlorinated alkanes (SCCP) in water - method using GC/MS and electron capture negative ionisation (ECNI). The task was to determine the sum of short chain polychlorinated n-alkanes with carbon chain lengths of C10-C13 and a chlorine content between 49 and 67% in water by GC-ECNI-MS and quantification by multiple linear regression described in ISO/DIS 12010 as the compulsory method. Distributed samples were obtained from a real water extract spiked with a target concentration of 0.4 micro g/mL sum of SCCP, i.e. the environmental quality target level according to the Water Framework Directive. The interlaboratory trial included the calibration, a column chromatographic clean up, a concentration step and an integration of chromatographic unresolved humps as well as the quantification with multiple linear regression. Reproducibility standard deviations between 21.5 and 22.9% were achieved by 17 participating laboratories from four countries. The method outlined no significant difference of the results between the standard solution and a real water matrix extract. On the basis of this succeeded preliminary interlaboratory trial the final interlaboratory trial for validation of ISO 12010 was prepared in autumn 2010.

Carbon Chain Growth by Formyl Insertion on Rhodium and Cobalt Catalysts in Syngas Conversion

The method of Whitmore and of Cramer and Mulligan, for preparing alkenes by the thermal decomposition of the acetates of alcohols has been applied to some alcohols with straight and branched carbon chains. The acetates of pentanol-3 and heptanol-l respectively afford pentene-2 and heptene-1. The acetate of 2: 4-dimethylpentanol-3 affords 2: 4-dimethylpentene-2 and the acetate of 2: 4: 4′-trimethylpentanol-3 affords 2:4: 4-trimethylpentene-2. In these reactions no migration of the double bond occurs and no modification of the carbon skeleton is involved.

It has been shown that with a special type of silica as adsorbent all unbranched saturated fatty acids are adsorbed to the same amount from non-polar solvents, independent of the length of the carbon chain. Branched fatty acids are adsorbed less and unsaturated more. The same rules are valid for the methyl esters of the fatty acids. It has also been shown that this phenomenon can be utilized for analytical purposes both by means of frontal analysis and displacement development. By the latter method it is possible to make a quantitative separation of a mixture of fatty acids into groups containing branched, normal and unsaturated compounds, respectively, which thereafter can be analysed for compounds with differing lengths of the carbon chain, with activated carbon as adsorbent. The adsorption of some other compounds have also been investigated using silica as adsorbent.

A simple method has been developed for the preparation of 1-monoalkyl- and 1,2-dialkyl-cyclopropenes from cyclopropene and alkyl halides which is in many instances superior to those reported in the literature. High product yields are obtained with primary β-unsubstituted halides and moderate yields when primary β-monosubstituted halides are employed. The method is not applicable to primary β-disubstituted, secondary and tertiary halides. In principle it can also be used for the synthesis of alkylcyclopropenes that bear functional groups in the carbon chain. The strain-releasing migration of the double bond in the cyclopropene product from the endocyclic to the exocyclic position can, in most cases, be successfully prevented by choosing proper reaction conditions.

The series of the normal saturated fatty acids and their methyl esters with 5 to 20 carbon chain atoms was synthesized and careful purified, mainly by fractional distillation of the methyl esters in columns with up to 58 theoretical plates. The purity was checked with the aid of melting curves determined in a microcalorimeter and proved to be 96.6% or better. Refractive indices were determined and can be represented by with an accuracy of 5 units in the fifth decimal place (c = number of carbon chain atoms). Densities, accurate to 1 unit in the fourth decimal place, can be represented by Boiling points can be given by b.pt. 20 mm for the methyl esters (c> 5), accurate to 0.1 °. From our data, combined with literature values, the molecular refractivity of the CH2 group in an aliphatic chain calculated according to Lorentz-Lorenz. was determined at 4.64 at room temperature. In addition, melting and transition points, and heats of fusion and transition were determined.

Vegetable oils are potential substitutes for petroleum-based lubricants because they are environmentally friendly, renewable, less toxic and readily biodegradable. The addition of free fatty acids has been shown to increase the lubrication performance of vegetable oils at elevated temperatures. The purpose of this study was to evaluate the relationship between the length of the carbon chain in the fatty acid and its effectiveness as an additive for a range of elevated temperatures. Stearic, arachidic and behenic fatty acid additives were added to commercial sunflower oil. All fatty acid additives were shown to be effective in lowering the wear rate and coefficient of friction in ball-on-disc tribological tests. The overall carbon chain length was not observed to have a consistent influence on the effectiveness of the additive. All additives were less effective at temperatures above 100°C. Copyright © 2010 John Wiley & Sons, Ltd.

Marine huge polyol and polyether compounds are remarkable molecules owing to their extraordinary structures and significant biological activities. Currently, palytoxin and maitotoxin are believed to have the longest carbon chains in nature (more than 100 A in length), except for biopolymers. The structural properties of such marine huge molecules are highlighted, especially with regard to the length and shape of their carbon chains.