bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine‐Tuning Dual Emission and Aggregation‐Induced Emission Switching in NPI–BODIPY Dyads
Authors: Mukherjee Sanjoy , Thilagar Pakkirisamy 
Published: June 2014

AbstractThree new NPI–BODIPY dyads 1–3 (NPI=1,8‐naphthalimide, BODIPY=boron‐dipyrromethene) were synthesized, characterized, and studied. The NPI and BODIPY moieties in these dyads are electronically separated by oxoaryl bridges, and the compounds only differ structurally with respect to methyl substituents on the BODIPY fluorophore. The NPI and BODIPY moieties retain their optical features in molecular dyads 1–3. Dyads 1–3 show dual emission in solution originating from the two separate fluorescent units. The variations of the dual emission in these compounds are controlled by the structural flexibilities of the systems. Dyads 1–3, depending on their molecular flexibilities, show considerably different spectral shapes and dissimilar intensity ratios of the two emission bands. The dyads also show significant aggregation‐induced emission switching (AIES) on formation of nano‐aggregates in THF/H2O with changes in emission color from green to red. Whereas the flexible and aggregation‐prone compound 1 shows AIES, rigid systems with less favorable intermolecular interactions (i.e., 2 and 3) show aggregation‐induced quenching of emission. Correlations of the emission intensity and structural flexibility were found to be reversed in solution and aggregated states. Photophysical and structural investigations suggested that intermolecular interactions (e.g., π–π stacking) play a major role in controlling the emission of these compounds in the aggregated state.
Tuning the Halogen/Hydrogen Bond Competition: A Spectroscopic and Conceptual DFT Study of Some Model Complexes Involving CHF2I
Authors: Nagels Nick , Geboes Yannick , Pinter Balazs , De Proft Frank , Herrebout Wouter A. 
Published: June 2014

AbstractInsight into the key factors driving the competition of halogen and hydrogen bonds is obtained by studying the affinity of the Lewis bases trimethylamine (TMA), dimethyl ether (DME), and methyl fluoride (MF) towards difluoroiodomethane (CHF2I). Analysis of the infrared and Raman spectra of solutions in liquid krypton containing mixtures of TMA and CHF2I and of DME and CHF2I reveals that for these Lewis bases hydrogen and halogen‐bonded complexes appear simultaneously. In contrast, only a hydrogen‐bonded complex is formed for the mixtures of CHF2I and MF. The complexation enthalpies for the CH⋅⋅⋅Y hydrogen‐bonded complexes with TMA, DME, and MF are determined to be −14.7(2), −10.5(5) and −5.1(6) kJ mol−1, respectively. The values for the CI⋅⋅⋅Y halogen‐bonded isomers are −19.0(3) kJ mol−1 for TMA and −9.9(8) kJ mol−1 for DME. Generalization of the observed trends suggests that, at least for the bases studied here, softer Lewis bases such as TMA favor halogen bonding, whereas harder bases such as MF show a substantial preference for hydrogen bonding.
Hydride‐Rhodium(III)‐N‐Heterocyclic Carbene Catalysts for Vinyl‐Selective H/D Exchange: A Structure–Activity Study
Authors: Di Giuseppe Andrea , Castarlenas Ricardo , Pérez‐Torrente Jesús J. , Lahoz Fernando J. , Oro Luis A. 
Published: June 2014

AbstractA series of neutral and cationic RhIII‐hydride and RhIII‐ethyl complexes bearing a NHC ligand has been synthesized and evaluated as catalyst precursors for H/D exchange of styrene using CD3OD as a deuterium source. Various ligands have been examined in order to understand how the stereoelectronic properties can modulate the catalytic activity. Most of these complexes proved to be very active and selective in the vinylic H/D exchange, without deuteration at the aromatic positions, displaying very high selectivity toward the β‐positions. In particular, the cationic complex [RhClH(CH3CN)3(IPr)]CF3SO3 showed excellent catalytic activity, reaching the maximum attainable degree of β‐vinylic deuteration in only 20 min. By modulation of the catalyst structure, we obtained improved α/β selectivity. Thus, the catalyst [RhClH(κ2‐O,N‐C9H6NO)(SIPr)], bearing an 8‐quinolinolate ligand and a bulky and strongly electron‐donating SIPr as the NHC, showed total selectivity for the β‐vinylic positions. This systematic study has shown that increased electron density and steric demand at the metal center can improve both the catalytic activity and selectivity. Complexes bearing ligands with very high steric hindrance, however, proved to be inactive.
Bis‐ and Tris(pyrazolyl)borate/Methane‐Stabilized PIII‐Centered Cations
Authors: Gu Lianghu , Gopakumar Gopinadhanpillai , Gualco Pauline , Thiel Walter , Alcarazo Manuel 
Published: June 2014

AbstractWe report the synthesis of [H2B(pz)2PR]+, [H2C(pz)2PR]+2, [HB(pz)3P]+2, and [HC(pz)3P]+3 (H2B(pz)2=bis(pyrazolyl)borate; H2C(pz)2=bis(pyrazolyl)methane; HB(pz)3=tris(pyrazolyl)borate; HC(pz)3=tris(pyrazolyl) methane; R=Ph, Cy or Et2N) by reaction of the corresponding neutral or anionic ligands with chlorophosphines in the presence of TMSOTf. The structures of these compounds were determined by X‐ray crystallographic analysis and the nature of their bonding was examined using density functional theory.
Hydroalumination of a Chlorotrialkynylsilane: Spontaneous Stepwise 1,3‐Dyotropic Rearrangement via an Intermediate Silyl Cation
Authors: Uhl Werner , Bohnemann Jörg , Layh Marcus , Würthwein Ernst‐Ulrich 
Published: June 2014

AbstractA new functionalised alkynylsilane, Cl‐Si(CC‐CMe3)3 (3), was obtained by a facile multistep synthesis. Treatment of 3 with equimolar quantities of the hydrides H‐M(CMe3)2 (M=Al, Ga) gave the mixed alkenyl‐di(alkynyl)silanes, in which the chlorine atom adopts a bridging position between the aluminium and silicon atoms. Dual hydrogallation of 3 resulted in the formation of a di(alkenyl)‐alkynylsilane containing two gallium atoms, one of which is coordinated to the chlorine atom, and the second is bonded to the α‐carbon atom of the remaining alkynyl group. A tert‐butylsilane was unexpectedly formed by a unique 1,3‐dyotropic chlorine–tert‐butyl exchange for the corresponding dialuminium compound. One aluminium atom is bonded to a tert‐butyl group, a terminal chlorine atom and the α‐carbon atom of the ethynyl moiety; the second is coordinatively unsaturated, with two terminal tert‐butyl substituents. High‐level quantum‐chemical calculations favour a stepwise dyotropic rearrangement with an intermediate cationic silicon species over a simultaneous tert‐butyl–chlorine migration via a five‐coordinate silicon atom in the transition state.
The Mixed Gold–Palladium Polyoxo‐Noble‐Metalate [NaAuIII4PdII8O8(AsO4)8]11−
Authors: Izarova Natalya V. , Kondinski Aleksandar , Vankova Nina , Heine Thomas , Jäger Patrick , Schinle Florian , Hampe Oliver , Kortz Ulrich 
Published: June 2014

AbstractThe first fully inorganic, discrete gold–palladium–oxo complex [NaAuIII4PdII8O8(AsO4)8]11− has been synthesized in aqueous medium. The combination of single‐crystal XRD, elemental analysis, mass spectrometry, and DFT calculations allowed establishing the structure and composition of the novel polyanion, and UV/Vis studies suggest that it is stable in neutral aqueous media.
Primary Malignancies of the Heart and Pericardium
Authors: Burazor Ivana , Aviel‐Ronen Sarit , Imazio Massimo , Markel Gal , Grossman Yoni , Yosepovich Ady , Adler Yehuda 
Published: June 2014

ABSTRACTPrimary malignancies of the heart and pericardium are rare. All the available data come from autopsy studies, case reports, and, in recent years, from large, specialized, single‐center studies. Nevertheless, if primary malignancy is present, it may have a devastating implication for patients. Malignancies may affect heart function, also causing left‐sided or right‐sided heart failure. In addition, they can be responsible for embolic events or arrhythmias. Today, with the widespread use of noninvasive imaging modalities, heart tumors become evident, even as an incidental finding. A multimodality imaging approach is usually required to establish the final diagnosis. Despite the increased awareness and improved diagnostic techniques, clinical manifestations of primary malignancy of the heart and pericardium are so variable that their occurrence may still come as a surprise during surgery or autopsy. No randomized clinical trials have been carried out to determine the optimal therapy for these primary malignancies. Surgery is performed for small tumors. Chemotherapy and radiation therapy can be of help. Partial resection of large neoplasms is performed to relieve mechanical effects, such as cardiac compression or hemodynamic obstruction. Most patients present with marginally resectable or technically nonresectable disease at the time of diagnosis. It seems that orthotopic cardiac transplantation with subsequent immunosuppressive therapy may represent an option for very carefully selected patients. Early diagnosis and radical exeresis are of great importance for long‐term survival of a primary cardiac malignancy. This can rarely be accomplished, and overall results are very disappointing.
Synthesis, σ Receptor Affinity, and Pharmacological Evaluation of 5‐Phenylsulfanyl‐ and 5‐Benzyl‐Substituted Tetrahydro‐2‐benzazepines
Authors: Hasebein Peer , Frehland Bastian , Schepmann Dirk , Wünsch Bernhard 
Published: June 2014

AbstractIn accordance with a novel strategy for generating the 2‐benzazepine scaffold by connecting C6–C1 and C3–N building blocks, a set of 5‐phenylsulfanyl‐ and 5‐benzyl‐substituted tetrahydro‐2‐benzazepines was synthesized and pharmacologically evaluated. Key steps of the synthesis were the Heck reaction, the Stetter reaction, a reductive cyclization, and the introduction of diverse N substituents at the end of the synthesis. High σ1 affinity was achieved for 2‐benzazepines with linear or branched alk(en)yl residues containing at least an n‐butyl substructure. The butyl‐ and 4‐fluorobenzyl‐substituted derivatives, (±)‐5‐benzyl‐2‐butyl‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine (19 b) and (±)‐5‐benzyl‐2‐(4‐fluorobenzyl)‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine (19 m), show high selectivity over more than 50 other relevant targets, including the σ2 subtype and various binding sites of the N‐methyl‐D‐aspartate (NMDA) receptor. In the Irwin screen, 19 b and 19 m showed clean profiles without inducing considerable side effects. Compounds 19 b and 19 m did not reveal significant analgesic and cognition‐enhancing activity. Compound 19 m did not have any antidepressant‐like effects in mice.
Management of the lymph node‐positive neck in the patient with human papillomavirus‐associated oropharyngeal cancer
Authors: Garden Adam S. , Gunn Gary B. , Hessel Amy , Beadle Beth M. , Ahmed Salmaan , El‐Naggar Adel K. , Fuller Clifton D. , Byers Lauren A. , Phan Jack , Frank Steven J. , Morrison William H. , Kies Merill S. , Rosenthal David I. , Sturgis Erich M. 
Published: June 2014

BACKGROUNDThe goal of the current study was to assess the rates of recurrence in the neck for patients with lymph node‐positive human papillomavirus‐associated cancer of the oropharynx who were treated with definitive radiotherapy (with or without chemotherapy).METHODSThis is a single‐institution retrospective study. Methodology included database search, and statistical testing including frequency analysis, Kaplan‐Meier tests, and comparative tests including chi‐square, logistic regression, and log‐rank.RESULTSThe cohort consisted of 401 patients with lymph node‐positive disease who underwent radiotherapy between January 2006 and June 2012. A total of 388 patients had computed tomography restaging, and 251 had positron emission tomography and/or ultrasound as a component of their postradiation staging. Eighty patients (20%) underwent neck dissection, and 21 patients (26%) had a positive specimen. The rate of neck dissection increased with increasing lymph node stage, and was lower in patients who had positron emission tomography scans or ultrasound in addition to computed tomography restaging. The median follow‐up was 30 months. The 2‐year actuarial neck recurrence rate was 7% and 5%, respectively, in all patients and those with local control. Lymph node recurrence rates were greater in current smokers (P = .008). There was no difference in lymph node recurrence rates noted between patients who did and those who did not undergo a neck dissection (P = .4)CONCLUSIONSA treatment strategy of (chemo)radiation with neck dissection performed based on response resulted in high rates of regional disease control in patients with human papillomavirus‐associated oropharyngeal cancer. Cancer 2014;120:3082–3088. © 2014 American Cancer Society.
Fluorescence Microscopy with 6 nm Resolution on DNA Origami
Authors: Raab Mario , Schmied Jürgen J. , Jusuk Ija , Forthmann Carsten , Tinnefeld Philip 
Published: June 2014

AbstractResolution of emerging superresolution microscopy is commonly characterized by the width of a point‐spread‐function or by the localization accuracy of single molecules. In contrast, resolution is defined as the ability to separate two objects. Recently, DNA origamis have been proven as valuable scaffold for self‐assembled nanorulers in superresolution microscopy. Here, we use DNA origami nanorulers to overcome the discrepancy of localizing single objects and separating two objects by resolving two docking sites at distances of 18, 12, and 6 nm by using the superresolution technique DNA PAINT(point accumulation for imaging in nanoscale topography). For the smallest distances, we reveal the influence of localization noise on the yield of resolvable structures that we rationalize by Monte Carlo simulations.
Structures and Magnetic Properties of Group 13 Metal Tris‐O‐benzosemiquinonato Complexes
Authors: Piskunov Alexandr V. , Meshcheryakova Irina N. , Maleeva Arina V. , Bogomyakov Artyem S. , Fukin Georgy K. , Cherkasov Vladimir K. , Abakumov Gleb A. 
Published: June 2014

AbstractNew tris‐o‐benzosemiquinonato complexes of Al, Ga, and In based on the sterically hindered o‐benzoquinone 5,8‐di‐tert‐butyl‐2,3‐dihydro‐1,4‐ethanoquinoxaline‐6,7‐dione (NN‐3,6‐Q) were synthesized. The structures of the hexacoordinate metal compounds were investigated by X‐ray diffraction. The magnetic properties of the complexes obtained were found to be strongly dependent on their molecular geometry. The octahedral Al and Ga derivatives demonstrate ferromagnetic exchange between the magnetic centers, whereas the trigonal‐prismatic In complex shows an antiferromagnetic coupling.
Photosensitizing Properties of Alkynylrhenium(I) Complexes [Re(–C≡C–R)­(CO)3(N∩N)] (N∩N = 2,2′‐bipy, phen) for H2 Production
Authors: Oberholzer Miriam , Probst Benjamin , Bernasconi Dominik , Spingler Bernhard , Alberto Roger 
Published: June 2014

AbstractA series of complexes of the type [fac‐Re(X)(CO)3(N∩N)] (X = –C≡C–R, N∩N = 2,2′‐bipy, 2,2′‐phen) were synthesized and fully characterized. Their photophysical characteristics make them very convenient photosensitizers (PSs). Upon light irradiation, H2 formation was observed for all alkynyl complexes in the presence of a water‐reducing catalyst (WRC) and a sacrificial electron donor. Relative rates of H2 production indicate a dependency upon the diimine ligands rather than upon the nature of the σ‐bonded alkynyl derivatives. The coordinated acetylene group induces a redshift of the λmax of the MLCT band in UV/Vis spectroscopy as compared to those of the corresponding halides, nitriles, or cationic ReI complexes, such as [fac‐ReX(CO)3(N∩N)] (X = pyridine, H2O, N∩N = bipy, phen).
Metallo‐β‐lactamases and Their Biomimetic Complexes
Authors: Daumann Lena J. , Schenk Gerhard , Gahan Lawrence R. 
Published: June 2014

AbstractIn order to treat bacterial infections successfully in the future, the mechanism of action of metallo‐β‐lactamases (MβLs) needs to be fully understood so that clinically useful inhibitors and new therapeutic approaches can be developed. This microreview describes recent developments and the achievements towards the design of MβL biomimetics to aid in the mechanistic and structural understanding of these enzyme systems. We highlight the known inhibitors and substrates employed in these studies, the different ligands and complexes employed, and the experimental and computational studies undertaken to explore the possible mechanisms of action of the MβLs.
Organotantalum Phosphaketene and Phosphaazaallene Complexes
Authors: Grundmann Anne , Sárosi Menyhárt B. , Lönnecke Peter , Hey‐Hawkins Evamarie 
Published: June 2014

AbstractThe first tantalum phosphaketene and phosphaazaallene complexes [Cp*Ta{1,2‐(NSiMe3)2C6H4}{P(R)CX}] {Cp* = C5Me5; X = O; R = cyclohexyl (Cy, 3), iPr (4); X = NCy, R = Cy (5), iPr (6)} were obtained by insertion of carbon monoxide or cyclohexyl isocyanide into the Ta–P bond of cyclohexyl‐ and (isopropylphosphanylidene)tantalum(V) complexes, [Cp*Ta{1,2‐(NSiMe3)2C6H4}(PR)] {R = Cy (1), iPr (2)}. Phosphaazaallene complexes 5 and 6 occur as E and Z isomers. These isomers have different electronic structures according to NMR spectroscopic studies and DFT calculation. Both isomers of the cyclohexylphosphanyl derivative (i.e., 5a and 5b) and one isomer of the isopropylphosphanyl derivative (i.e., 6b) could be structurally characterized by X‐ray crystallography.
Vanadium Complexes as Prospective Therapeutics: Structural Characterization of a VIV Lysozyme Adduct
Authors: Santos Marino F. A. , Correia Isabel , Oliveira Ana R. , Garribba Eugenio , Pessoa João Costa , Santos‐Silva Teresa 
Published: June 2014

AbstractThe biological activity of vanadium complexes, namely, as insulin enhancers, is well known. We report a combined X‐ray crystallography, electron paramagnetic resonance, and density functional theory study of the interaction of vanadium picolinate complexes with hen egg white lysozyme (HEWL). We show that the VIVO(pic)2 complex covalently binds to the COO– group of the side chain of Asp52 of HEWL. The long VIV=O bond obtained in the X‐ray study is explained to be due to reduction of VIV to VIII during exposure of the crystals to the intense X‐ray beam.
Synthesis and Evaluation of Polyunsaturated Fatty Acid–Phenol Conjugates as Anti‐Carbonyl‐Stress Lipophenols
Authors: Crauste Céline , Vigor Claire , Brabet Philippe , Picq Madeleine , Lagarde Michel , Hamel Christian , Durand Thierry , Vercauteren Joseph 
Published: June 2014

AbstractCarbonyl and oxidative stress play a substantial role in various neurodegenerative diseases such as Alzheimer's Disease, Parkinsonism, and Age‐related Macular Degeneration (AMD). In retinal pathologies, both mechanisms are involved in the transformation of all‐trans‐retinal (AtR, reactive aldehyde) into bis‐retinoid A2E. Since an accumulation of AtR and A2E contributes to photoreceptor apoptosis, we designed and synthesized a series of O‐alkylated resorcinol derivatives featuring enhanced anti‐carbonyl‐stress properties. Additionally, these phenolic structures are linked to a polyunsaturated fatty acid such as docosahexaenoic acid (C22:6 n‐3; DHA) or to a lysophosphatidylcholine–DHA conjugate, in order to specifically increase their bioavailability, and thus, to target the retina. Selective syntheses of phloroglucinol–DHA, resveratrol–DHA, and phloroglucinol–DHA–PC (PC = phosphatidylcholine) conjugates using silyl protecting group strategies are presented, along with results of testing that demonstrate their ability to lower AtR toxicity in ARPE‐19 cell lines.
On the biogeochemical response of a glacierized High Arctic watershed to climate change: revealing patterns, processes and heterogeneity among micro‐catchments
Authors: Nowak Aga , Hodson Andy 
Published: June 2014

AbstractOur novel study examines landscape biogeochemical evolution following deglaciation and permafrost change in Svalbard by looking at the productivity of various micro‐catchments existing within one watershed. It also sheds light on how moraine, talus and soil environments contribute to solute export from the entire watershed into the downstream marine ecosystem.We find that solute dynamics in different micro‐catchments are sensitive to abiotic factors such as runoff volume, water temperature, geology, geomorphological controls upon hydrological flowpaths and landscape evolution following sea level and glacial changes. Biotic factors influence the anionic composition of runoff because of the importance of microbial SO42− and NO3− production. The legacy of glaciation and its impact upon sea level changes is shown to influence local hydrochemistry, allowing Cl− to be used as a tracer of thawing permafrost that has marine origins. However, we show that a ‘glacial signal’ dominates solute export from the watershed. Therefore, although climatically driven change in the proglacial area has an influence on local ecosystems, the biogeochemical response of the entire watershed is dominated by glacially derived products of rapid chemical weathering. Consequently, only the study of micro‐catchments existing within watersheds can uncover the landscape response to contemporary climate change. Copyright © 2014 John Wiley & Sons, Ltd.
Effects of Neonatal Enzyme Replacement Therapy and Simvastatin Treatment on Cervical Spine Disease in Mucopolysaccharidosis I Dogs
Authors: Chiaro Joseph A , O'Donnell Patricia , Shore Eileen M , Malhotra Neil R , Ponder Katherine P , Haskins Mark E , Smith Lachlan J 
Published: June 2014

ABSTRACT

Mucopolysaccharidosis I (MPS I) is a lysosomal storage disease characterized by deficient α-L-iduronidase activity, leading to the accumulation of poorly degraded glycosaminoglycans (GAGs). Children with MPS I exhibit high incidence of spine disease, including accelerated disc degeneration and vertebral dysplasia, which in turn lead to spinal cord compression and kyphoscoliosis. In this study we investigated the efficacy of neonatal enzyme replacement therapy (ERT), alone or in combination with oral simvastatin (ERT + SIM) for attenuating cervical spine disease progression in MPS I, using a canine model. Four groups were studied: normal controls; MPS I untreated; MPS I ERT-treated; and MPS I ERT + SIM–treated. Animals were euthanized at age 1 year. Intervertebral disc condition and spinal cord compression were evaluated from magnetic resonance imaging (MRI) images and plain radiographs, vertebral bone condition and odontoid hypoplasia were evaluated using micro–computed tomography (µCT), and epiphyseal cartilage to bone conversion was evaluated histologically. Untreated MPS I animals exhibited more advanced disc degeneration and more severe spinal cord compression than normal animals. Both treatment groups resulted in partial preservation of disc condition and cord compression, with ERT + SIM not significantly better than ERT alone. Untreated MPS I animals had significantly lower vertebral trabecular bone volume and mineral density, whereas ERT treatment resulted in partial preservation of these properties. ERT + SIM treatment demonstrated similar, but not greater, efficacy. Both treatment groups partially normalized endochondral ossification in the vertebral epiphyses (as indicated by absence of persistent growth plate cartilage), and odontoid process size and morphology. These results indicate that ERT begun from a very early age attenuates the severity of cervical spine disease in MPS I, particularly for the vertebral bone and odontoid process, and that additional treatment with simvastatin does not provide a significant additional benefit over ERT alone. © 2014 American Society for Bone and Mineral Research.