Search

This work investigates the relationship between the structure and physicochemical properties of three different starches in starch/polyvinyl alcohol aqueous solutions. For this purpose, accurate nuclear magnetic resonance (NMR) analyses were performed to determine the role that the starch structure plays in the formation of binder solutions. Moreover, a dynamic shear rheometer (DSR) was used to investigate the mechanical properties of the solutions and correlate them with the structure of each starch. Complete characterization of the analysed starches and the starch/PVOH solutions was also carried out through light scattering measurements. Furthermore, by crossing the data coming from NMR and light scattering with those coming from rheology, the best solution was identified. Finally, to confirm the interaction mechanism between starch and PVOH, thermogravimetric analysis and an NMR study, using 1H and 13C NMR spectra, were carried out on the film obtained from the best solution. The analyses carried out showed that PVOH has a stabilizing effect on starch/PVOH solutions, and the starch with the greatest branching degree is the one that forms a more structured network. [ABSTRACT FROM AUTHOR]

Structural concrete aggregate can be substituted with sustainable alternatives from construction and demolition waste, such as reclaimed asphalt pavement (RAP). This contribution assesses the RAP aggregate production chain and aims to investigate the economic aspect of RAP aggregate, evaluating the costs associated with its production and comparing them with the ones necessary to produce NA and recycled concrete aggregate (RCA). This analysis aims to provide additional information on the possible advantages of RAP aggregate use in order to promote sustainable construction. The evaluation was developed using a four-step methodology consisting of (i) determining the RAP aggregate production procedure; (ii) selecting a case study; (iii) defining the mix design; and (iv) performing a cost evaluation and comparing it to the cost of NA and RCA production. The results of the cost analysis of three concretes containing different RAP percentages (0%, 30%, and 45%) demonstrated that RAP's presence led to more expensive admixtures, with the RAP unit cost being higher than NA (+155.39%). Some strategies were proposed to diminish RAP's cost, resulting in a reduction of −39.64% with respect to NA's cost and ranging from 45.13% to 67.30% when compared to RCA's cost. [ABSTRACT FROM AUTHOR]

Protection of amine groups by amide formation is still among the preferred strategies for multifunctional molecular synthesis despite its waste production, especially the enormous quantities of organic solvents used. In this study, we present a fast, cheap and eco-friendly method for amine group protection involving amide bond formation using choline chloride as a hydrogen bond acceptor and the starting amine as a hydrogen bond donor through the generation of "in situ" amine-based deep eutectic solvents. This novel approach avoids the use of toxic solvents, both during reaction and the work-up phase, thus representing a sustainable alternative to classic amine protection procedures. [ABSTRACT FROM AUTHOR]

In recent years, the food industry has become increasingly involved in researching vegetable fats and oils with appropriate mechanical properties (ease of transport, processing, and storage) and a specific lipidic composition to ensure healthy products for consumers. The chemical–physical behavior of these matrices depends on their composition in terms of single fatty acids (FA). However, as we demonstrate in this work, these properties, as well as the absorption, digestion and uptake in humans of specific FAs, are also largely determined by their regiosomerism within the TriAcylGlycerols (TAG) moieties (sn-1,2,3 positions). The goal of this work is to study for the first time vegetable fats obtained directly from a sample of natural cocoa butter (CB) through a process that manipulates the distribution of FAs but not their nature. Even if the initial percentage of each FA in the mixture remains the same, CB derivatives seem to show improved chemical–physical features. In order to understand which factors account for their physical and chemical characteristics, and to check whether or not the obtained new matrices could be considered as valid alternatives to other vegetable fats (e.g., palm oil (PO)), we carried out an experimental investigation at both the macroscopic and molecular level including: (i) Differential Scanning Calorimetry (DSC) analyses to examine thermal features; (ii) rheological testing to explore mechanical properties; (iii) powder X-ray diffraction (PXRD) to evaluate the solid-state phases of the obtained fats; and (iv) 1H and 13C Nuclear Magnetic Resonance (NMR, 1D and 2D) spectroscopy to rapidly analyze fatty acid composition including regioisomeric distribution on the glycerol backbone. These last results open up the possibility of using NMR spectroscopy as an alternative to the chromatographic techniques routinely employed for the investigation of similar matrices. [ABSTRACT FROM AUTHOR]

Tacle is a citrus variety which recently gained further interest due to its antioxidant and biological properties. This study suggests using Nuclear Magnetic Resonance (NMR) imaging to characterize Tacle juice's metabolic composition as it is intimately linked to its quality. First, polar and apolar solvent systems were used to identify a significant fraction of the Tacle metabolome. Furthermore, the antioxidant capacity and the total content of flavonoids, polyphenols and β-carotene in the juice were investigated with UV—Visible spectroscopy. Tacle juice was clarified and fractionated by ultrafiltration (UF) and nanofiltration (NF) membranes in order to recover and purify its bioactive principles. Finally, the second part of this work sheds light on the spectrophotometric assays and 1H-NMR spectra of fractions coming from membrane operations coupled with a multivariate data analysis technique, PCA, to explore the impact of UF and NF processes on the metabolic profile of the juice. [ABSTRACT FROM AUTHOR]

The structural characterization of a new flavonoid from bergamot fruit (Citrus bergamia Risso) carrying the 3-hydroxy-3-methyl glutaryl (HMG) ester moiety has been accomplished, and its antioxidant ability was tested from a chemical point of view. The peculiarity of the new molecule, named peripolin, relies on the presence of the HMG chemical group linked to the sugar portion of neoeriocitrin; the structure was elucidated using both high-resolution mass spectrometry and nuclear magnetic resonance experiments performed on the purified molecule extracted from the fruit. The antioxidant ability of the new molecule was tested by classical chemical approaches, such as DPPH, ABTS and FRAP assays, and from a theoretical point of view. 1H and 13C NMR experiments and HR-ESI-MS/MS experiments show unequivocally that the HMG moiety is linked to the primary position of the glucose unit of neohesperidose, while the chemical tests and the computational results show that peripolin possesses strong antioxidant behavior, similar to that of neoeriocitrin and remarkably higher respect to the other flavonoids present in the fruit. Furthermore, the quantitative assays carried out by UPLC-MS/MS showed that its amount in the fruit is similar to that of the other main flavonoids. Furthermore, molecular dynamics simulations allowed us to investigate the possible conformations adopted by the antioxidants in the presence of water molecules. In particular, the switch of open-closed conformations of HMG-containing species was evidenced. As far as the reaction with DPPH, the calculation of ΔGrea supported the experimental outcomes regarding the peripolin and neoeriocitrin activity. In conclusion, bergamot fruit, already known for its potential to lower the level of blood cholesterol, has been proven to contain molecules such as neoeriocitrin and the newly characterized peripolin, which could have important in-vivo antioxidant characteristics. [ABSTRACT FROM AUTHOR]

Cannabis sativa is a herbaceous multiple-use species commonly employed to produce fiber, oil, and medicine. It is now becoming popular for the high nutritional properties of its seed oil and for the pharmacological activity of its cannabinoid fraction in inflorescences. The present study aims to apply nuclear magnetic resonance (NMR) spectroscopy to provide useful qualitative and quantitative information on the chemical composition of seed and flower Cannabis extracts obtained by ultra-sound-assisted extraction, and to evaluate NMR as an alternative to the official procedure for the quantification of cannabinoids. The estimation of the optimal ω-6/ω-3 ratio from the 1H NMR spectrum for the seed extracts of the Futura 75 variety and the quantitative results from the 1H and 13C NMR spectra for the inflorescence extracts of the Tiborszallasi and Kompolti varieties demonstrate that NMR technology represents a good alternative to classical chromatography, supplying sufficiently precise, sensitive, rapid, and informative data without any sample pre-treatment. In addition, different extraction procedures were tested and evaluated to compare the elaboration of spectral data with the principal component analysis (PCA) statistical method and the quantitative NMR results: the extracts obtained with higher polarity solvents (acetone or ethanol) were poor in psychotropic agents (THC < LOD) but had an appreciable percentage of both cannabinoids and triacylgliceroles (TAGs). These bioactive-rich extracts could be used in the food and pharmaceutical industries, opening new pathways for the production of functional foods and supplements. [ABSTRACT FROM AUTHOR]

Aqueous solutions of F127 pluronic systems exhibit an interesting thermal gelation above a certain concentration. This phenomenon concerns the transition from a liquid-like behavior at low temperatures to a solid-like behavior at high temperatures, and it is due to different temperature responses from the different polymer segments, polypropylene oxide (PPO) and polyethylene oxide (PEO). Such property leads to a structural change in the self assembled macromolecule upon heating, from an isotropic micellar structure to an ordered cubic structure. These two types of assembly are clearly distinct with respect to their rheological behavior. This contribution emphasizes the rheological properties of the pluronic system in micellar and cubic phase, in combination with NMR, Dynamic Light Scattering and DSC information. The results emphasize the gelation process upon heating and a cubic phase characterized by higher storage modulus and higher A and z Weak Gel Model exponents than the micellar phase. Micellar growth upon heating was found within micellar phase. The presented data support the hypothesis that each polymer segment actively participates in the formation of the different phases: while PPO is responsible for micelle formation, PEO plays a dominating role in cubic phase formation. Finally, different stiffness between the core and the corona of the aggregates in the two phases is observed.

Recycled materials from construction and demolition waste, such as recycled concrete aggregate, recycled brick aggregate, or recycled asphalt coming from the milling of road/motorway surfaces, are the key for a sustainable production of concrete. This paper reviews in particular the use of recycled asphalt pavement (RAP) aggregates in the production of concrete for structural uses. An overview is initially presented to describe the different areas of use of RAP, its definition and the limitations imposed by codes and standards. Relatively to the experimental data provided by the literature, a comparison with the Italian minimum requirements is also provided. Lastly, the influence of RAP on the characteristics of concrete such as compressive strength, flexural strength, Young's Modulus and a study of durability are presented to define the possible applications of RAP in structural concrete in relation to the current allowable percentage of substitution. [ABSTRACT FROM AUTHOR]

Polymer-Dispersed Liquid Crystal, PDLC, are composite materials formed by liquid crystal droplets embedded in a polymer matrix. They allow to simultaneously exploit the electro-optical properties of liquid crystals and the mechanical properties of polymers, giving rise to interesting electro-optical devices such as smart windows. In this work monomer/LC mixtures in different weight ratios were polymerised in the presence of an external magnetic field to obtain PDLCs, whose director was aligned along the field direction. The time behaviour of LC order parameter was followed by 2H-NMR and the final morphology of PDLCs was investigated by SEM. Then, the electro-optical properties of PDLCs prepared in the absence of any magnetic field were investigated and correlated to the order parameter measurements, confirming the strong correlation between large order parameters and optimal electro-optical properties. [ABSTRACT FROM AUTHOR]

The use of high-resolution magic angle spinning (HR-MAS) 13C NMR spectroscopy is proposed here as an innovative and non-destructive approach to investigate the chemical composition of the organic fraction of municipal solid waste (OFMSW) and for monitoring the evolution of their composition during the oxidative iron-based Fenton treatment to which the initial matrix is subjected. The high quality and the good resolution of the 13C HR-MAS NMR spectra allowed an accurate assignment and quantification of the various types of carbon present in the analyzed organic matrix. Moreover, the HR-MAS has also shown its effectiveness in monitoring the different oxidative processes to which the same initially organic matrix has been subjected. The results obtained from the HR-MAS spectra on the collected samples during the different oxidative experiments, indicate that Fenton treatment is able to modify the percentage of the different types of carbons as a function of the concentrations of both Fenton reactants, H2O2 and Fe2+ salt, and of the oxidative process time. [ABSTRACT FROM AUTHOR]

Introduction: Renal dysfunction is a frequent complication in patients suffering from β-thalassemia major (β-TM). The aim of this study was to analyze the renal function and urine metabolomic profile of β-TM patients undergoing transfusions and deferasirox (DFX) therapy, in order to better characterize and shed light on the pathogenesis of renal disease in this setting. Methods and Subjects: 40 patients affected by β-TM treated with DFX and 35 age- and gender-matched healthy controls were enrolled in the study. Renal function was assessed. Glomerular filtration rate (GFR) was estimated with CKD-EPI and Schwartz formula for adults and children, respectively. Renal tubular function and maximal urine concentration ability were tested. Urine specimens were analyzed by nuclear magnetic resonance spectroscopy to identify the urinary metabolite profiles. Results: The study of renal function in β-TM patients revealed normal estimated (e)GFR mean values and the albumin-to-creatinine ratio was <30 mg/g. The analysis of tubular function showed normal basal plasma electrolyte levels; 60% of patients presented hypercalciuria and many subjects showed defective urine concentration. Several amino acids, N-methyl compounds, and organic acids were overexcreted in the urine of thalassemic patients compared with controls. Discussion: The major finding of this work is that β-TM patients and controls exhibit different concentrations of some metabolites in the urine. Early recognition of urinary abnormalities may be useful to detect and prevent kidney damage. [ABSTRACT FROM AUTHOR]

In liquid crystals, while the second and fourth rank orientational order parameters characterizing a nematic phase can be experimentally determined via several techniques, there is no straightforward experiment rendering the positional order parameters characterizing a smectic A phase. This work illustrates a novel method to estimate the positional order parameters of a smectogenic liquid crystal solvent from knowledge of the orientational order parameters of a number of solutes dissolved therein. The latter order parameters can be experimentally determined via liquid crystal NMR spectroscopy. These data can be then analyzed with a statistical-thermodynamic density functional theory, whose basic ingredient is a model for solute-solvent intermolecular interactions. Its parametrization and the subsequent fitting procedure eventually permit one to obtain the positional order parameters of the solvent besides the positional-orientational distribution function of the solutes. The method is applied to the smectogen 4,4′-di-n-heptyl-azoxybenzene, in which the solutes 1,4-dichlorobenzene and naphthalene have been dissolved. With the help of this exploratory practical example, pros and cons of the method are pointed out and further developments prospected. [ABSTRACT FROM AUTHOR]

The proton NMR spectra of two 13C-labeled isotopomers of styrene dissolved in two liquid crystalline solvents have been obtained and analyzed to yield four sets each of 24 dipolar couplings. These couplings were then used to investigate the structure of the ring and the ene fragments of the molecule, and the position of the maximum, [lowercase_phi_synonym]0, in the ring–ene bond rotational probability distribution. To do this, the effect on the dipolar couplings of small-amplitude vibrational motion was taken into account using vibrational wave functions calculated by molecular orbital and density functional methods. It is concluded that the NMR data are consistent with the ring fragment, averaged over the ring–ene rotation, planar, while the ene fragment is not. The value of [lowercase_phi_synonym]0 is found to be 18.0°±0.2° for the two solutions, compared with a value of 27° calculated by the molecular method MP2/6-31G*. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A model carried out the ordering of apolar molecules dissolved in uniaxial mesophases where the interactions between the solute and the local medium were described on a molecular scale. The proposed model proved to be highly reliable and very effective tool for the description of orientational order when short-range interactions totally control the solute ordering.

The photochromic compound 2,6-bis(2-hydroxybenzilidene)cyclohexanone (PC) has been dissolved in some selected liquid amphiphiles: dibutyl, tributyl, bis-2-ethylhexyl, tris-2-ethylhexyl phosphate and bis-2-ethylhexyl amine. The aim was to explore its photophysical properties when embedded in the novel chemical environment provided by the amphiphilic solvents. UV-Vis spectra revealed different features depending on the solvent thus highlighting specific solvent-solute interactions and different chemical environments. All the alkylphosphate-based systems were found to be unstable; slow (days) changes in the absorption features due to the slow change in populations of the various species present in solution. Interestingly, the dissolution of PC into bis-2-ethylhexyl amine leads to stable solutions most probably due to the basic character of the solvent stabilising as major specie chalcone forms. Fluorescence spectra suggested the equilibrium between two species with different absorption and fluorescence properties. [ABSTRACT FROM AUTHOR]

The three-dimensional structure and conformational equilibrium of flexible bioactive molecules in solution are of considerable importance in clarifying their role in chemical and biological activity, since their action takes place in a liquid medium. The use of residual dipolar couplings (RDCs) recently emerged as a promising and effective method to address this kind of investigation. In this brief review, the conformational analysis of several flexible non-steroidal anti-inflammatory drugs, belonging to the class of salicylates and a-arylpropionic acids (profens), is described using the RDCs measured in weakly aligning poly-γ-benzyl-L-glutamate solutions. By combining these experimental parameters, extracted by using different mono- and bi-dimensional nuclear magnetic resonance experiments, with the theoretical additive potential-direct probability description approach, accurate descriptions of the probability distributions have been obtained for all the drug molecules selected. [ABSTRACT FROM AUTHOR]

Bitumen has unique chemo-mechanical properties, and for this reason, it is today one of the main constituents of many industrial products beside its common use in highway pavements construction. While the excellent rheological properties of bitumens have been investigated by means of different techniques, much remains to be known about the intrinsic properties of this complex material. It is therefore important to investigate its structure and properties from a closer point of view, towards possible useful modifications of the neat material. The present research developed a technique to investigate the composition of bitumens using Thin Layer Chromatography (TLC) to separate the different fractions, and Nuclear Magnetic Resonance (NMR) spectroscopy to assess and quantify the aliphatic hydrogen part with respect to the aromatic part. To achieve a comprehensive understanding of the chemical composition of the materials, Proton Nuclear Magnetic Resonance (¹H-NMR) analysis was conducted in solution, using CCl4 as solvent, on three different neat bitumens and on their asphaltene and maltene fractions. The combined application of TLC and ¹H-NMR spectroscopy enables the advanced characterization of bitumens supplied from different sources or obtained from different processes. This further allows addressing the use of specific modifications according to the bitumen final applications. [ABSTRACT FROM AUTHOR]

Naproxen and flurbiprofen are among the most popular and widely used drugs for treating pain and inflammation and new different therapeutic uses are still being proposed. Their pharmacological activity comes from the specific binding to target proteins and is evidently driven by the spatial arrangement they adopt at the active sites. A detailed conformational elucidation analysis in solution able to probe equilibria between more possible conformers is then crucial for understanding and rationalizing their biological role and possibly for designing improved analogues. Here we combine NMR data obtained in weakly ordered media and suitable theoretical models to look for the energetically admissible conformers of these two anti-inflammatory drugs in a liquid medium. This approach leads to rather complex probability distributions characterized for both molecules by an equilibrium of different global and local minimum energy structures. [ABSTRACT FROM AUTHOR]

A weakly ordering organic-based lyotropic phase and a strongly ordering nematic liquid crystal have been used as NMR media for a parallel study of the conformation and orientational order of the same solute, trans-stilbene. A careful comparison allows to figure out some interesting conclusions on accessibility and precision of the experimental data and reliability and accuracy of the conformational descriptions into these two kinds of mesophases. [ABSTRACT FROM PUBLISHER]

Heterogeneous bifuctional catalysts are multifunctional synthetic catalysts enabling efficient organic transformations by exploiting two opposite functionalities without mutual destruction. In this paper we report the first Er(III)-based metallorganic heterogeneous catalyst, synthesized by post-calcination MW-assisted grafting and modification of the natural aminoacid L-cysteine. The natural acid-base distance between sites was maintained to assure the cooperation. The applicability of this new bifunctional heterogeneous catalyst to C-C bond formation and the supposed mechanisms of action are discussed as well. [ABSTRACT FROM AUTHOR]

The correct estimation of building energy consumptions is assuming an always increasing importance, and a detailed reproduction of building structures, with all the single components involved, is necessary to achieve this aim. In addition, the current ecological development tries to limit the use of natural raw materials as building components, in favor of alternative (waste) materials, which ensure significant advantages from the economic, energetic and environmental point of views. In this work, dynamic heat and vapor transport in a typical three-dimensional (3D) building structure, involving different types of environmental-friendly concrete mixtures, have been simulated by using finite elements. In particular, the authors propose to substitute part of the aggregates with plastic waste and to use a fly ash based geopolymeric binder for the production of low conductivity concrete, to be employed in eco-efficient buildings. Concrete produced with natural limestone aggregates has been considered as the reference benchmark. The whole characterization of the different types of concrete tested in the present work has been obtained through laboratory experiments. The structure taken into account in the simulations is a 3D thermal bridge, typical of building envelopes. The thermal and hygrometric transient behavior of this structure, employing plastic waste in different percentages and geopolymer concrete, has been analyzed by the authors. [ABSTRACT FROM AUTHOR]

The first example of spontaneous self‐assembly of ionic octahedral Ir(III) complexes containing carboxylates counterions into luminescent ordered aqueous gel phases is reported. The gel phases formed at 2.5% w/w (“Ir‐Ci”:H20) are investigated by POM, 1H and 2H NMR and UV–vis spectroscopies, whereas a detailed structural analysis by WAXS, SAXS, and SANS experiments is performed for the acetate complex, in both anisotropic gel and isotropic phases. This comprehensive investigation shows that the complex with the shortest carboxylate self‐assembles into double string polyelectrolyte‐type supramolecular columns surrounded by the counterions, at low concentrations in the isotropic solution (1.0% w/w). Upon increasing concentration, these supramolecular columns grow one‐dimensionally, and eventually gelation occurs and birefringent textures begin to be observed by POM, resembling the textures developed by chromonic systems. The gelation occurs with the close packing of the supramolecular columns sheathed in their solvation shell into a 2D rectangular lattice. Furthermore, a significant enhancement of the luminescence quantum yield is observed for all the complexes in the gel phases with respect to the isolated molecule. [ABSTRACT FROM AUTHOR]

In the present paper, the peculiar orientational behavior, studied by liquid crystal NMR (LXNMR) spectroscopy, of the D2dsymmetry quasi-spherical molecule of tetramethylallene (TMA) dissolved in the nematic solvent I52 is exploited to attempt a quantitative experimental assessment of the correlation between molecular vibrations and overall rotations in weakly oriented molecules. The analysis of the very small DHHand 1D13C–Hdipolar couplings, available from the natural abundance LXNMR spectra of TMA at different temperatures, allows for a derivation leading (by making a few approximations) to the quantification of the vibration–reorientation (also called nonrigid) contribution affecting the observed direct 1D13C–Hdipolar coupling. The obtained results show that, under the particular conditions of the studied system (very weak orientational ordering of a highly symmetric molecule), this contribution is particularly important, in order to reproduce the whole value of the “observed” dipolar coupling. This issue is discussed and commented on at length in the work, also, by making reference to the analogy with perfectly symmetric molecules (such as methane and analogues) dissolved in liquid crystalline phases. [ABSTRACT FROM AUTHOR]

A novel, simple synthetic strategy for the preparation of crosslinked polymers with significant antioxidant properties is proposed. Ferulic acid (FA), a well‐known antioxidant compound, due to its reactivity toward free radical process, was inserted into a polymeric network with methacrylic acid (MAA) and ethylene glycole dimethacrylate acting as comonomer and crosslinker, respectively. All the reactants were simultaneously mixed in the polymerization feed and one‐pot radical reaction was carried out. Irregular microparticles were prepared by bulk polymerization and microspheres by precipitation polymerization. The materials were characterized by nuclear magnetic resonance–magic angle spinning (NMR‐MAS) studies, to verify effective FA insertion into polymeric networks, and by morphological, dimensional analyses, and water absorption measurement to study their superficial and swelling properties, respectively. Antioxidant properties of materials were evaluated by linoleic acid emulsion system–thiocyanate assay, determination of scavenging activity on DPPH radicals, determination of available phenolic groups in polymeric matrices, and determination of total antioxidant capacity. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The origins of asthma might be traced back to events occurring during fetal life. Reduced lung development has been shown to be a risk factor both for viral induced wheeze and allergic asthma. The evidence for a causal relationship between exposure to environmental tobacco smoke, chemical domestic products for cleaning, outdoor pollutants, and reduction in lung function is quite strong. Reduced maternal intake of vitamin E, vitamin D, and zinc, or increased use of paracetamol during pregnancy is associated with increased wheezing outcomes in children. The odds ratio for asthma onset is also increased in infants born from mothers with oligohydramnios, chorioamnionitis, hypertension, preeclampsia, diabetes and exposed to stressful events. The risk of developing allergic asthma is increased if the child is exposed in the first months of life to synthetic bedding and is enhanced by allergen exposure and an inadequate barrier function of the skin. In conclusion, several lines of evidence support the concept of fetal programming and very early life events in the development of the different phenotypes of asthma. Since some environmental triggers can be easily avoided and some protective factors can be easily implemented all efforts should be made to prevent intrauterine insults and early sensitization. [ABSTRACT FROM AUTHOR]

A two-dimensional Fluorine Detected Local Field (FDLF) NMR experiment is demonstrated on a sample of perfluoropropyl iodide dissolved in the nematic solvent ZLI1132. In analogy to the proton detected local field (PDLF) technique, for each resolved site of the carbon spectrum, a simple map of the heteronuclear coupling network is obtained in the indirect dimension. A full analysis of the FDLF spectrum was achieved with the aid of two-dimensional 19F–13C HETCOR and 13C, D-resolved spectra (with Drepresenting the anisotropic spin–spin coupling). A one-dimensional 19F spectrum was recorded on the same sample at intermediate resolution, and values of the residual spin–spin couplings TCFand TFFobtained from both experiments were combined and used to provide starting parameters for the analysis of a very high resolution 19F spectrum, including the weak satellite lines from single-13C isotopomers. The high-precision, residual, anisotropic couplings were used to explore whether they have an appreciable contribution from the anisotropic electron-mediated spin–spin couplings. [ABSTRACT FROM AUTHOR]