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Purpose: The purpose of this phenomenological study was to describe and interpret the experiences of graduate students in communication sciences and disorders who experienced forms of incivility in the clinical practicum setting. There is precedent for identifying and handling incivility, such as bullying, harassment, and intimidation, in the nursing education, psychology education, medical education, and physical therapy literature. A literature search for incivilities such as bullying, harassment, and intimidation in graduate student education in communication sciences and disorders did not yield any systematic studies. Method: Nineteen participants who were interested in participating contacted the researcher; of those, nine participants were ultimately interviewed. A thematic analysis of videotaped semistructured interviews was used to measure outcomes based on the five questions posed to the participants. The participants responded to the five questions designed to understand the lived experience of incivility for graduate students in speech-language pathology practicum settings. Conclusions: This study fills a gap in the clinical education literature in speech-language pathology. It was a qualitative study using a phenomenological approach that described and interpreted speech-language pathology graduate students' experiences of bullying, harassment, and/or intimidation during clinical practicums across practice settings. Data analysis yielded five themes based on the participants' responses during the interview. The themes were communication, physical and/or psychological effects, interpersonal dynamics, clinical instruction, and lingering physical and psychological effects of the experience. The authors make recommendations to reduce the probability that incivility, bullying, and/or intimidation will occur during a student's clinical practicum experience.

Anthony M Mancinelli,1 Jonathan M Vichich,1 Alexandra D Zinnen,1 Anna Marie Hugon,2 Viktoriya Bondarenko,1 Jeanette M Metzger,1 Heather A Simmons,1 Thaddeus G Golos,1,3,4 Marina E Emborg1,5 1Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI, USA; 2Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA; 3Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; 4Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI, USA; 5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USACorrespondence: Marina E Emborg Email emborg@primate.wisc.eduIntroduction: Gastrointestinal (GI) inflammation elicited by environmental factors is proposed to trigger Parkinson’s disease (PD) by stimulating accumulation of pathological α-synuclein (α-syn) in the enteric nervous system (ENS), which then propagates to the central nervous system via the vagus nerve. The goal of this study was to model, in nonhuman primates, an acute exposure to a common food-borne pathogen in order to assess whether the related acute GI inflammation could initiate persistent α-syn pathology in the ENS, ultimately leading to PD.Methods: Adult female cynomolgus macaques were inoculated by oral gavage with 1× 108 colony-forming units (CFUs) Listeria monocytogenes (LM, n=10) or vehicle (mock, n=3) and euthanized 2 weeks later. Evaluations included clinical monitoring, blood and fecal shedding of LM, and postmortem pathological analysis of colonic and cecal tissues.Results: LM inoculation of healthy adult cynomolgus macaques induced minimal to mild clinical signs of infection; LM shedding in feces was not seen in any of the animals nor was bacteremia detected. Colitis varied from none to moderate in LM-treated subjects and none to minimal in mock-treated subjects. Expression of inflammatory markers (HLA-DR, CD3, CD20), oxidative stress (8-OHDG), α-syn, and phosphorylated-α-syn in the enteric ganglia was not significantly different between treatment groups.Discussion: Our results demonstrate that cynomolgus macaques orally inoculated with LM present with a clinical response that resembles human LM exposure. They also suggest that acute exposure to food-borne pathogens is not sufficient to induce significant and persistent α-syn changes in healthy adult female subjects. Based on the results of this limited experimental setting, we propose that, if LM has a role in PD pathology, other underlying factors or conditions, such as male sex, inflammatory bowel disease, exposure to toxins, dysbiosis, and/or aging, are needed to be present.Keywords: Parkinson’s disease, alpha synuclein, nonhuman primate, listeria, inflammation, enteric nervous system

Purpose The author presents a descriptive sociological framework for the communicative interaction between an adult who stutters (AWS) and other communication partners. The author shows that the communicative interaction between an AWS and another interactant is a sociological object that can be evaluated by both parties in real-time, and is impacted by settings, participants, identity, stigmatization, and the type of talk. These elements are consistent with Hymes' SPEAKING model, which was developed to describe speech communication in a social context and can lay the foundation for the development of an ethnography of stuttering. The clinical applications and implications of a sociological framework are discussed and future directions for research are suggested. Method This work is a refinement and enhancement of Mancinelli (2018) and Mancinelli (2019) and the research associated with that work. This is a tutorial with a clinical focus designed to introduce the readership to a sociological perspective on communicative interactions in AWS. Conclusions Stuttering is an emergent phenomenon embedded within a social interaction, necessitating a deeper understanding of the processes at work during those interactions. A sociological framework can provide a more comprehensive description of the communicative interactions as well as the sociocommunicative lives of people who stutter. The information obtained can inform the formulation of realistic, functional goals based on the daily life of the client. Implications for the development of an ethnography of stuttering are discussed.

Purpose The purpose of this study was to investigate the effects of self-disclosure on the self-perception of stuttering severity, comfort, cognitive effort, and anxiety in a structured conversational interaction with a normally fluent speaker. The benefit of self-disclosure from the perspective of the person who stutters in a self-disclosed and in a non-disclosed condition was also studied. The total syllables produced and percent syllables stuttered were measured in both experimental conditions in order to evaluate the effects on the amount of speech produced and verbal fluency. Methods Twenty-five adults who stutter were recruited in Philadelphia and New Jersey, through social media, university clinics, and National Stuttering Association (NSA) self-help groups. The participants engaged in a conversational task with a normally fluent speaker (NFS). The cognitive-affective variables (self-perception of stuttering severity, comfort, cognitive effort, anxiety and benefit) were measured using self-report questionnaires completed after each condition. The percent syllables stuttered and total syllables in each condition were also transcribed and analyzed. Results Frequency distributions of Likert Scale ratings indicated a slight preference for self-disclosure over non-disclosure, but there was a non-significant difference on the benefit variable for the disclosed and non-disclosed conditions. There were correlations between total syllables produced and percent syllables stuttered and comfort, in the non-disclosed state only. Other findings included non-significant differences for the cognitive-affective variables across conditions. Conclusion From the perspective of the person who stutters, self-disclosure at the outset of the communicative interaction did not have a decisive impact on the cognitive-affective or speech variables.

A large portion of the cow's ration is composed of forages that can vary greatly in mineral concentrations, which may affect animal performance and health. Current methods for mineral analysis require sample destruction either through wet or dry ashing and complex analytical techniques for individual minerals. Energy dispersive X-ray fluorescence (EDXRF) is a nondestructive, multi-mineral, spectroscopy technique, which makes mineral quantification simple, direct, and affordable. The study objective was to evaluate the prediction performance of EDXRF of Na, Mg, P, S, Cl, Ca, K, Mn, Fe, Cu, and Zn concentrations in forages. Twelve certified plant samples with a wide range in mineral concentrations were used to develop calibrations, and 35 forages (18 alfalfa hays, 10 grass hays, 7 corn silages) with measured mineral concentrations, which were collected over several years from 3 proficiency programs, were used as an independent validation set. All the samples were previously dried and finely ground and were prepared by compressing them into a round dense pellet, 40 mm in diameter, using a 40-ton pneumatic laboratory press. Samples were scanned using an EDXRF instrument enhanced for lighter minerals like Na and Mg. Samples were scanned at 20 keV and at 40 KeV associated with an Al filter, for a total analysis time of approximately 6 min. Calibrations were developed with Bruker SpectraEDX (Bruker, Hamburg, Germany) software and optimized to minimize the standard error of calibration. All of the minerals had acceptable calibration performance with coefficient of determination ranging from 0.93 (P) and 0.99 (Cl, Ca, and Mn) and coefficients of variation within 5 to 14%, which are similar to the coefficients of variation of the reference analysis. The coefficients of variation for Na was an exception, with a coefficients of variation of 29%. The validation set obtained similar statistical results as that observed in calibration. The root mean square error of prediction corrected for bias was similar to the standard error of calibration, indicating that it is possible to build a robust calibrations that performed well across different type of forages by using 12 reference samples with a sufficient range in mineral concentrations that were determined accurately. A bias correction was necessary to improve prediction accuracy only for K (−0.23% dry matter) and Ca (−0.16% dry matter). Energy dispersive X-ray fluorescence demonstrated the ability to be an accurate, direct, and simple technique for forage mineral analysis.

Advances in proteomic technology have enabled contaminant proteins to be identified from complex protein mixtures. The purity of two purified urinary gonadotrophin products, human menopausal gonadotrophin (u-HMG) and human FSH (u-hFSH), was compared with a preparation of recombinant human FSH (r-hFSH). After separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), western blot analysis showed that the recombinant preparation contained only FSH, whereas the urine-derived preparations exhibited several non-FSH or LH-related bands. These urinary components were further investigated by a proteomic approach using two-dimensional SDS-PAGE followed by mass spectrometric identification. The proteomic approach detected a total of 23 non-gonadotrophin-related proteins, at variable levels in different batches of the urine-derived preparations. Of these, 16 co-purified proteins have not been previously reported to be present in urine-derived gonadotrophins. These results indicate that the process used to purify urinary gonadotrophins may not remove all non-gonadotrophin proteins. By using a comprehensive proteomic approach, it has been shown that the recombinant FSH preparation has greater purity than either of the urine-derived preparations.

ALS is a neurodegenerative disease that affects nerve cells in the brain and spinal cord that control voluntary skeletal muscle. The muscle weakness that results from ALS is relentlessly progressive and rehabilitative attempts to strengthen affected muscles usually fail. When managing swallowing and communication disorders in individuals with ALS, the goals are to maximize function and safety through the use of compensatory strategies, energy conservation, and patient and caregiver education and counseling. This paper will review the current methods of assessment and treatment used with this population in the outpatient setting.

The revolutionary development of biotechnology-derived therapeutic proteins has provided the expected improvements in quality, purity and consistency, as demonstrated in recombinant human FSH (rhFSH). However, the development of urine-derived gonadotrophins has not always shown comparable improvements. More recently, highly purified urine-derived FSH (uFSH-HP) products have become widely available. The relative purity, level of urine-derived contaminants, and consistency of one such highly purified human uFSH (uhFSH) (urofollitropin) has been assessed and directly compared with rhFSH (follitropin alpha). It has been demonstrated that the highly purified urofollitropin contains variable levels of urine-derived contaminant proteins and demonstrates a variable level of FSH purity, FSH isoforms, and delivered dose. These variable factors may contribute to the control of ovarian stimulation. The relative purity, variable consistency and the presence of contaminants indicates that the urofollitropin is, at best, a partially purified uFSH that is not able to meet the quality attributes of follitropin alpha (rhFSH).

Friction measurements have been made between pairs of Pd(100) surfaces prepared in vacuum with adsorbed n-octane films ranging in thickness from 0 to 20 monolayers on each surface. These measurements have been made at lattice misorientation angles of 0° and 45°. Both sets of measurements reveal friction anisotropy at all except the highest n-octane coverages. The friction coefficient drops with increasing n-octane coverage until it reaches a limiting value of μs ≈ 0.4. The static friction coefficient reveals a different dependence on n-octane coverage than has been observed for alcohols. The friction coefficient decreases more slowly with increasing n-octane coverage than for increasing alcohol coverage.

Friction anisotropy was studied between two Pd(100) single-crystal surfaces sliding in an ultrahigh vacuum environment. Friction measurements were made using Pd(100)/Pd(100) interfaces modified by adsorption of octane at coverages ranging from 4 to 40 molecular monolayers (ML). The relative crystallographic orientation of the two Pd(100) surfaces was systematically varied and friction measurements were made at each orientation as a function of octane coverage. These measurements have revealed that friction is anisotropic with respect to Pd(100) lattice orientation. When the surfaces were aligned, forming a commensurate interface, and sheared along the 〈110〉 direction with 4 ML of octane at the interface, the static friction coefficient was μs > 8.0 ± 2.0. A minimum in the static friction coefficient was obtained when the two Pd(100) surfaces with 4 ML of octane at the interface were misoriented by θ = 45°. Under these conditions, the static friction coefficient for sliding along the 〈110〉 direction of the...

A Si microstrip detector coupled to a Gd converter has been designed for operation as linear position-sensitive detector of thermal neutrons. Test measurements have been carried out on a first prototype. The measured space resolution is reported and discussed in comparison with the results of a Monte Carlo simulation. The space resolution of the Si microstrip detector, given by the response of the sensor to an ideal narrow incoming beam, has been also modeled by the Monte Carlo simulation program.

A 3.3V 8Gb NAND flash memory with a synchronous double-data-rate (DDR) interface is designed and fabricated using 3M 50nm technology to meet the requirements of the markets. This paper achieves a NAND flash program throughput of 100 MB/s with quad-plane operation, which is 5x previously reported. I/O read/write throughput of 200MB/s is achieved using a newly developed DDR interface and data path. The chip features a dual interface, supporting both the newly developed synchronous DDR interface as well as the standard, asynchronous NAND flash interface.

ALS is a neurodegenerative disease that affects nerve cells in the brain and spinal cord that control voluntary skeletal muscle. The muscle weakness that results from ALS is relentlessly progressive and rehabilitative attempts to strengthen affected muscles usually fail. When managing swallowing and communication disorders in individuals with ALS, the goals are to maximize function and safety through the use of compensatory strategies, energy conservation, and patient and caregiver education and counseling. This paper will review the current methods of assessment and treatment used with this population in the outpatient setting.

A commercial preparation of recombinant human chorionic gonadotrophin (r-hCG, Ovitrelle) was launched in 2001. Generally, hCG is available in two formats: human chorionic gonadotrophin (u-hCG), derived from the urine of pregnant females, and r-hCG produced by DNA based biotechnology.The analytical characteristics of a highly purified u-hCG (Gonasi HP) were assessed and compared, for the first time, with the recombinant derived r-hCG (Ovitrelle). Gonasi HP is produced by extracting and purifying hCG from urine to obtain a specific bioactivity of 5000 IU/mg protein. Ovitrelle is produced via a recombinant derived mammalian cell line and purified to obtain a specific activity of 26 000 IU/mg.It has been documented that commercially available u-hCG preparations can contain a number of urine derived protein contaminants as well as hCG related metabolites. This is also the case for Gonasi HP, where hCG related molecules and other proteins were found to be present, including epidermal growth factor (EGF) and eosinophil derived neurotoxin (EDN). It was also demonstrated that this preparation contained high levels of oxidised hCG. r-hCG was confirmed to be essentially intact hCG, free from contaminant proteins and with very low levels of oxidised hCG.

The origins of the tribological properties and corrosion resistance of amorphous and quasicrystalline approximant alloys have been studied by comparing their properties in thin Al-Cu-Fe alloy films with compositions lying near the quasicrystalline region of the ternary compositional phase diagram. Six sputtered thin films of an Al-Cu-Fe alloy were studied using X-ray diffraction, X-ray photoemission spectroscopy (XPS), and an in situ ultrahigh vacuum (UHV) tribometer. The films were annealed in UHV to induce the formation of orthorhombic, rhombohedral, and amorphous bulk structures. The properties of these thin films were then determined in the same UHV apparatus without exposing the films to air. The rates of surface oxidation by H2O and O2 were measured using XPS. Although the oxidation rates and oxide thicknesses were dependent on the oxidant, they were not sensitive to the structures of the films. Friction was measured between identical samples in sliding contact. The friction coefficients (micros = 0.36 +/- 0.11 to 0.56 +/- 0.08) were comparable to those observed in other experiments using quasicrystals and approximants in UHV; however, there was no strong correlation between the friction coefficients and either the film structure or the degree of surface oxidation. These results suggest that the tribological and corrosion resistance properties of these quasicrystalline approximant alloys are not directly connected to crystalline structure.

Ruby is widely used as an in siru pressure gauge for optically transparent pressure cells up to the megabar range. Usually ruby chips cut from bulk crystals are used which are ill-characterized and inconvenient to handle and to identify visually. Here we present a systematic study on corundum samples doped with Cr3+ ions with concentration from 60 to 23500 ppm to determine the optimal conditions for the use as an accurate pressure marker. The influence of the excitation wavelength on the luminescence spectra was investigated. These studies led to the synthesis of small (1–50 micrometer) ruby spheres with 3000 ppm chromium concentration. After annealing and a heat treatment to avoid internal strains we find reproducible values of the position and the width of the fluorescence lines. These ruby spheres are not only well suited for a reliable and accurate pressure determination in experiments using diamond anvil cells, but can also be used as an in sihr micro-thermometer in high pressure-low tempera...

xThe synthesis of architecturally complex polycyclic fused indolines is achieved in a chemo-, regio-, and stereodefined manner, via an enantioselective gold-catalyzed cascade hydroindolination/iminium trapping synthetic sequence. Highly functionalized tetracyclic fused furoindolines (2) and dihydropyranylindolines (4) are synthesized in moderate to good yields and enantiomeric excesses of up to 87%.

The first enantioselective direct aldol addition of N-Boc-oxindoles to polymeric ethyl glyoxylate is presented. The reaction is performed by using as low as 0.1 mol% (DHQ)2PHAL and gives access to a-hydroxycarboxylate derivatives bearing adjacent secondary alcohol and quaternary stereocenters with high levels of diastereo- and enantiocontrol. The use of ethyl glyoxylate in its polymeric form represents an important advantage for synthetic applications and allows us to directly install a C2 unit ready to be converted in useful building blocks. A further one-pot protection/deprotection sequence catalyzed by ZnACHTUNGTRENUNG(ClO4)2·6H2O preserved the a-hydroxycarboxylates from racemization by means of a parasitic alcohol-catalyzed retroaldol reaction.

Anthraquinone substituted by 2-methyl-1-naphthyl groups in positions 1,8 yields syn (meso) and anti (racemic) isomers (red and yellow colored, respectively) that interconvert with a barrier of 35.4 kcal mol(-1) in solution. Their structures were identified by NOE experiments in solution and X-ray diffraction in the solids. The racemic anti form (C(2) point group) entails two atropisomers that were separated by enantioselective HPLC: the absolute configuration was assigned by TD-DFT simulation of the ECD spectrum. Two atropisomers were also separated and assigned in the case of anthraquinone bearing a single 2-methyl-1-naphthyl substituent in position 1.

By making use of low-temperature dynamic NMR spectroscopy, the rotation barriers about the sp3-sp2 bond have been determined in a number of hindered benzyl alcohols symmetrically substituted in the ortho positions, the substituents being F, Cl, Br, and Me. The free energies of activation covered the range 4.6-10.1 kcal mol-1. Ab initio computations matched satisfactorily the trend of these values and predicted the conformation adopted by these compounds. In one case, this result could be also confirmed by the X-ray diffraction structure. In the case of the corresponding methyl ethers two barriers could be measured, corresponding to the passage across two distinguishable transition states: the higher barriers covered the range 5.0-8.1 kcal mol-1 and the lower ones the range 4.7-6.2 kcal mol-1.

4-Aryl-3-bromo-N-benzylmaleimides and 3,4-biaryl-N-benzylmaleimides have been synthesized by a modified Suzuki cross-coupling reaction from 3,4-dibromo-N-benzylmaleimide. The conformational studies by dynamic NMR and DFT calculations showed that the interconversion barrier between the two available skewed conformations is under steric control. When the aryl group was a 2-methylnaphthyl, thermally stable atropisomers were isolated by enantioselective HPLC and their absolute configurations were assigned by TD-DFT simulations of the ECD spectra.

Simple model systems based on the 2,11-dithia-[3,3]-metaparacyclo-phane skeleton were designed and synthesized to study the effect of substituents on the intramolecular aromatic-aromatic interactions between benzene rings. X-Rays structures established that in their more stable conformation these metaparacyclophanes feature partially overlapped aromatic rings (interplanar distance of about 3.5 Å) with the planes of the aromatic systems arranged in a slightly tilted disposition (interplanar angles ranging from 5 to 19°). Calculations showed that these derivatives underwent topomerization by flipping of the meta-substituted ring over the para-substituted one, a process in which the two rings adopted a continuum of edge-to-face dispositions, including also an orthogonal one, which were less stable than the starting face-to-face arrangement. The energy barriers to the isomerization process were experimentally determined by variable temperature NMR spectroscopy, using an internal temperature standard to safely assess even minor differences in energy (estimated experimental error ± 0.1 kJ mol-1). The variation of the barriers as a function of the different substitution on the interacting ring was small and apparently not related to the effect of the substituents on the polarity of the -systems. An explanation based on the charge penetration effect seemed more suitable to rationalize the observed trends in the barriers.

N-Heterocyclic Carbene Rhodium Complexes: Conformational Analysis and Catalytic Studies G. Solinasa, M. A. Bruckaa, M. C. Cassania, C. Femonia, R. Mazzonia, M. Mancinellib, A. Mazzantib aDipartimento di Chimica Fisica ed Inorganica, Università di Bologna, viale Risorgimento, 4, Bologna bDipartimento di Chimica Organica “A. Mangini”, Università di Bologna, viale Risorgimento, 4 Bologna gavino.solinas2@unibo.it N-Heterocyclic carbenes (NHCs) have attracted considerable attention as a new class of ligands over the past decade1 and recently our research in this field has been dealing with the syntheses of rhodium(I) complexes presenting axial chirality and catalitically active in the hydrosilylation of terminal alkynes and in the addition of arylaldehydes with phenylboronic acid.2 We now present the synthesis, characterization (X-ray, VT NMR, DFT calculation) and catalysis of the new NHC-Rh(I) complexes shown below. Preliminary studies on NHC-Fe(II) complexes will be also presented and discussed. References 1. Mercs, L.; Albrecht, M. Chem. Soc. Rev. 2010, 39, 1903. (b) Diez-Gonzalez, S.; Marion, N.; Nolan, S. P. Chem. Rev. 2009, 109, 3612. 2, Busetto L.; Cassani, M.C.; Femoni, C.; Mancinelli, M.; Mazzanti, A.; Mazzoni, R.; Solinas, G. Organometallics 2011, 30, 5258.

The free energies of activation for the aryl-aryl rotation of 17 biphenyl derivatives, bearing a heavy heteroatom (S, Se, Te, P, Si, Sn) as ortho substituent, have been measured by variable temperature NMR. These numbers, so called B values, represent a meaningful measure of the steric hindrance exerted by the selected substituents. DFT computations match quite satisfactorily the experimental barriers and the ground state geometries as well (determined, in two cases, by X-ray diffraction). The present values extend the available list of B values and thus provide an enlarged basis for the compilation of the space requirements of standard substituents, based solely on experimental determinations.

The barrier for the interconversion of the conformational atropisomers of an aryl fluorenylidene derivative was determined by variable-temperature NMR technique. In the case of a more hindered compound the two atropisomers were isolated and the structure determined by X-ray diffraction. The absolute configuration was assigned by theoretical interpretation of the Electronic Circular Dichroism spectrum (ECD).

We describe herein the investigation of the stereodynamic processes occurring in a series of 1-aryl-2,2-dimethylindanols, by dynamic NMR. When the aryl moiety is a mesityl or a 2-methyl-1-naphthyl, the rotational barrier exceeds the 25 kcal/mol, so that stable atropisomers are observed. In two cases, all the chiral-atropisomeric species have been separated by enantioselective HPLC, and the comparison between theoretical and experimental electronic circular dichroism spectra allowed the absolute configuration assignment of all the isolated species to be obtained. Chirality, 2011. © 2011 Wiley-Liss, Inc.

The amide-functionalized imidazolium salts [BocNHCH2CH2ImR]X (R = Me, X = I, 1a; R = benzyl, X = Br, 1b; R = trityl, X = Cl, 1c) bearing increasingly bulky N-alkyl substituents were prepared in high yields by direct alkylation of the (2-imidazol-1-yl-ethyl)carbamic acid tert-butyl ester; 1c is a crystalline solid also characterized by X-ray diffraction. These salts are precursors for the synthesis of rhodium(I) complexes [Rh(NBD)X(NHC)] (NHC = 1-(2-NHBoc-ethyl)-3-R-imidazolin-2-ylidene; X = Cl, R = Me (3a), R = benzyl (3b), R = trityl (3c); X = I, R = Me (4a)). All the complexes display restricted rotation about the metalcarbene bond; however, while the rotation barriers calculated for 3a,b and 4a matched the experimental values, unexpectedly this was not true in the case of 3c, where the experimental value was equal to that obtained for compound 3b (58.6 kJ mol1) and much smaller with respect to the calculated one (100.0 kJ mol1). The catalytic activity of the neutral rhodium(I) complexes 3ac in the hydrosilylation of terminal alkynes with HSiMe2Ph has been investigated with PhCtCH, TolCtCH, nBuCtCH, Et3SiCtCH, and (CPh2OH)CtCH as substrates. The steric hindrance on the N-heterocyclic ligand and on the alkyne substrates affects conversion and selectivity: for the former the best results were achieved employing the less encumbered 3a catalyst with TolCtCH, whereas by employing hindered alkynes such as Et3SiCtCH or (CPh2OH)CtCH the hydrosilylation leads only to the formation of the β-(E)-vinylsilane and α-bis(silyl)alkene isomers. The complexes 3a,b have also been employed in the addition of arylaldehydes with phenylboronic acid, and like in the hydrosylylation case, the best results were obtained using 3a in the presence of aldehydes bearing electron-withdrawing groups, such as 4-cyanobenzaldehyde and 4-acetylbenzaldehyde as substrates.

Imidazolium salts incorporating functional groups represent a class of compounds having great versatility due to their wide range of applications as task specific ionic liquids (ILs)1 or N-heterocyclic carbene precursors (NHCs)2. Recently our research in this field has been dealing with the high-purity synthesis of t-butyloxylcarbonyl (Boc)-protected and deprotected amino-functionalized imidazolium cation [NHR1CH2CH2ImR2]+ ([1]+, R1 = Boc, H; R2 = Me, Bz, Allyl) and related NHC-Ag(I) silver complexes have been obtained by reacting [1]+ with Ag2O.3 Here we report the synthesis of new NHC-Rh(I) (2) complexes that contain an axis of chirality. The enantiomerical inversion has been investigated by variable-temperature NMR spectroscopy, DFT calculation and X-ray diffraction. The catalytic behaviour of 2 in the 1,2 addition reaction of aryl aldehydes with boronic acid will be also presented and discussed.

Anti and syn conformers, due to restricted sp(2)-sp(2) bond rotation, were detected in hindered 1,8-diarylbiphenylenes, the aryl moieties being phenyl groups bearing 0micron-alkyl substituents such as Me, Et, i-Pr, and t-Bu. By means of low-temperature NOE experiments, the corresponding structures were assigned and were found to be in agreement with the results of single-crystal X-ray diffraction. The interconversion barriers of these conformers were determined by line-shape simulation of the variable-temperature NMR spectra and the experimental values were reproduced satisfactorily by DFT calculations. In the case of the bulkiest aryl substituent investigated (i.e., 2-methylnaphthalene), the syn and anti atropisomers were stable enough as to be separated at ambient temperature. The two enantiomers (M,M and P,P) of the isomer anti were also isolated by enantioselective HPLC, and the theoretical interpretation of the corresponding CD spectrum allowed the absolute configuration to be assigned.

Syn and anti conformers in similar proportions were observed at ambient temperature for the title compounds. The conformational assignment of the two anthrones was obtained by the observation of different multiplicity of the methylene NMR signals, whereas that of the anthraquinone derivative was determined by NOE experiments. The anti-to-syn interconversion barriers were obtained by line-shape simulation of the temperature-dependent NMR spectra, and by saturation transfer experiments. In one case the X-ray diffraction indicated that the syn is the only structure observed in the crystals.

The rotation barriers of two 1,8-ditolylanthracene derivatives have been measured by accurate line-shape simulation of their variable-temperature NMR spectra. Both values were found to be more than twice as large as those previously reported in the literature.

NMR spectra of biphenyl derivatives bearing a single CR2OH substituent in the ortho position indicate that they exist as sp (more stable) and ap (less stable) conformers, due to the restricted rotation about the Ar-CR2OH bond. When R = Et (compound 2) the corresponding rotation barrier was determined (7.5 kcal mol-1) by line shape simulation of the low-temperature NMR spectra. Introduction of the prochiral i-Pr group in the position 3' of a biphenyl with the CMe2OH substituent in the position 2 (4) allowed the determination of the enantiomerization barrier (due to the Ar-Ar bond rotation) for the stereolabile axially chiral atropisomers (13.95 kcal mol(-1)). DFT computations of these barriers were all in agreement with the experiments. Biphenyls bearing two CR2OH groups in the 2,2' positions were found to exist as configurationally stable atropisomers: when R = Me (7) they were separated by enantioselective HPLC and the absolute configuration assigned on the basis of the corresponding CD spectra. In solution, compounds 6 (R = H) and 7 (R = Me) were found to originate a dimer, due to H-bond interactions between two enantiomers. In the case of 7, the free energy of activation (9.5 kcal mol-1) for the exchange of the monomer with the dimer could be measured, for the first time, by dynamic NMR. The conformational preferences, predicted by computations for the biphenyls with two CR2OH substituents in the 2,2' positions, were confirmed by X-ray diffraction in the case of R = H (6), R = Me (7), and R = i-Pr (9).

Dynamic NMR spectroscopy allowed, for the first time, the determination of the pi-barriers responsible for the enantiomerisation processes in derivatives bearing two aryl substituents bonded to a planar framework: this could be achieved in the case of 1,8-di-m-tolylbiphenylene (1) and 1,8-di-m-xylylbiphenylene (2). In derivative 1 the three possible conformers predicted by DFT computations (anti-in, syn and anti-out) were detected and, in addition, the steric barrier responsible for their interconversion could be measured. The barriers predicted by DFT calculations were found in satisfactory agreement with the experimental data.