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671.
Dr. Simona Rizzo Prof. Tiziana Benincori Dr. Valentina Bonometti Dr. Roberto Cirilli Prof. Patrizia R. Mussini Prof. Marco Pierini Dr. Tullio Pilati Prof. Francesco Sannicolò 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):182-194
A series of tris‐aryl phosphanes, structurally designed to exist as residual enantiomers or diastereoisomers, bearing substituents differing in size and electronic properties on the aryl rings, were synthesized and characterized. Their electronic properties were evaluated on the basis of their electrochemical oxidation potential determined by voltammetry. The configurational stability of residual phosphanes, evaluated by dynamic HPLC on a chiral stationary phase or/and by dynamic 1H and 31P NMR spectroscopy, was found to be rather modest (barriers of about 18–20 kcal mol?1), much lower than that shown by the corresponding phosphane oxides (barriers of about 25–29 kcal mol?1). For the first time, the residual antipodes of a tris‐aryl phosphane were isolated in enantiopure state and the absolute configuration assigned to them by single‐crystal anomalous X‐ray diffraction analysis. In this case, the racemization barrier could be calculated also by CD signal decay kinetics. A detailed computational investigation was carried out to clarify the helix reversal mechanism. Calculations indicated that the low configurational stability of tris‐aryl phosphanes can be attributed to an unexpectedly easy phosphorus pyramidal inversion which, depending upon the substituents present on the blades, can occur even on the most stable of the four conformers constituting a single residual stereoisomer. 相似文献
672.
Caracciolo G Pozzi D Capriotti AL Cavaliere C Foglia P Amenitsch H Laganà A 《Langmuir : the ACS journal of surfaces and colloids》2011,27(24):15048-15053
The concept that the effective unit of interest in the cell-nanomaterial interaction is the particle and its corona of associated proteins is emerging. Here we investigate the compositional evolution of the protein corona of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) cationic liposomes (CLs) and DOTAP/DNA lipoplexes over a wide range of plasma concentrations (2.5-80%). The composition of the hard corona of lipoplexes is quite stable, but that of CLs does evolve considerably. We show that the protein corona of CLs is made of both low-affinity and competitive-binding proteins whose relative abundance changes with the plasma concentration. This result may have deep biological implications for the application of lipid-based gene vectors both in vitro and in vivo. 相似文献
673.
Daniela Cupelli Fiore P. Nicoletta Giovanni De Filpo Patrizia Formoso Giuseppe Chidichimo 《Journal of Polymer Science.Polymer Physics》2011,49(4):257-262
The development of electrically activated chromogenic materials is important for their potential applications in smart windows. Several previous works have reported on reverse mode operation polymer dispersed liquid crystals (PDLCs) based on negative dielectric anisotropy liquid crystals. They have a transparent OFF state, which turns opaque after the application of a suitable external electric field. Nevertheless, these devices have some limitations such as the use of large amount of expensive liquid crystals with peculiar physical‐chemical properties. In addition, a good matching between the refractive index of liquid crystal and the polymer matrix one is required. The main result of this work is the achievement of reverse mode operation devices prepared with a positive dielectric anisotropy liquid crystal and characterized by a high OFF state transmittance obtained by the onset of high intensity built‐in DC electric fields in a direct mode operation PDLC, which allows the OFF state homeotropic alignment of liquid crystal directors. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
674.
Patrizia Diana Antonina StagnoPaola Barraja Alessandra MontalbanoAnna Carbone Barbara ParrinoGirolamo Cirrincione 《Tetrahedron》2011,67(19):3374-3379
Derivatives of the new ring system pyrrolizino[2,3-b]indol-4(5H)-one were prepared in four steps starting from substituted benzonitriles bearing a functionalized amino group in the adjacent position. The unsubstituted- and the dimethoxy-pyrrolizinoindolones 5a and 5b exhibited modest activity against the HL-60(TB) human leukemia cell line, whereas the N-methylated dimethoxy-pyrrolizinoindolone 6b showed to be selective against MOLT-4 leukemia, A549/ATCC, HOP-92, and NCI-H460 non-small cell lung cancer, and CAKI-1 renal cancer cell lines. 相似文献
675.
Patrizia Diana Annamaria MartoranaPaola Barraja Alessandra MontalbanoAnna Carbone Girolamo Cirrincione 《Tetrahedron》2011,67(11):2072-2080
A novel synthetic approach to the synthesis of 3-substituted isoindoles through nucleophilic substitution of 3-halo derivatives by charged carbon, and neutral nitrogen, oxygen, and sulfur nucleophiles, assisted by a 1-acyl group, is reported. Aryl-thio-isoindoles, obtained through a direct nucleophilic substitution with sulfur nucleophiles, showed cytotoxic activity, with GI50 values from micromolar to sub-micromolar concentrations, against the total number of cell lines investigated. 相似文献
676.
Köster AM Calaminici P Orgaz E Roy DR Reveles JU Khanna SN 《Journal of the American Chemical Society》2011,133(31):12192-12196
First-principles electronic structure calculations within a gradient corrected density functional formalism have been carried out to investigate the electronic structure and magnetic properties of Pd(13) clusters. It is shown that a bilayer ground-state structure that can be regarded as a relaxed bulk fragment is most compatible with the experimental results from Stern-Gerlach measurements. An icosahedral structure, considered to be the ground state in numerous previous studies, is shown to be around 0.14 eV above the ground state. A detailed analysis of the molecular orbitals reveals the near degeneracy of the bilayer or icosahedral structures is rooted in the stabilization by p- or d-like cluster orbitals. The importance of low-lying spin states in controlling the electronic and magnetic properties of the cluster is highlighted. 相似文献
677.
Matteo Piccolini Farzam Nosrati Giuseppe Compagno Patrizia Livreri Roberto Morandotti Rosario Lo Franco 《Entropy (Basel, Switzerland)》2021,23(6)
We address the problem of entanglement protection against surrounding noise by a procedure suitably exploiting spatial indistinguishability of identical subsystems. To this purpose, we take two initially separated and entangled identical qubits interacting with two independent noisy environments. Three typical models of environments are considered: amplitude damping channel, phase damping channel and depolarizing channel. After the interaction, we deform the wave functions of the two qubits to make them spatially overlap before performing spatially localized operations and classical communication (sLOCC) and eventually computing the entanglement of the resulting state. This way, we show that spatial indistinguishability of identical qubits can be utilized within the sLOCC operational framework to partially recover the quantum correlations spoiled by the environment. A general behavior emerges: the higher the spatial indistinguishability achieved via deformation, the larger the amount of recovered entanglement. 相似文献
678.
Gloria Zanotti Patrizia Imperatori Anna Maria Paoletti Giovanna Pennesi 《Molecules (Basel, Switzerland)》2021,26(6)
This work aims to investigate more sustainable reaction conditions for the synthesis of metallophthalocyanines. Anisole, glycerol and their mixtures have been investigated as reaction media for the tetramerization of phthalonitriles. Acetates of three divalent first-transition metal cations, Co(II), Cu(II) and Zn(II), were used and several bases were tested, depending on the chosen substrates and reaction conditions, with a view to making the whole process more sustainable while ensuring its scalability. Unsubstituted phthalocyanines were synthesized to analyze the behavior of the different metal ions in terms of reactivity in the new reaction media, resulting in a general Cu > Co > Zn trend, while the nonpolar tetra-tert-butyl substitution was investigated to evaluate the synthesis of soluble derivatives in the new conditions. Furthermore, the potassium hydroxide (KOH)-aided statistical synthesis of the unsymmetrical 9(10), 16(17), 23(24)-tri-tert-butyl-2-iodophthalocyaninato zinc(II), starting from 4-tert-butylphthalonitrile and 4-iodophthalonitrile in a glycerol/anisole mixture, proceeded with a satisfactory 26% yield. Our results provide insights into the investigation of new reaction environments and the understanding of their strengths and weaknesses, with a view to further increasing the sustainability of the synthesis of metallomacrocycles with high added value while lowering their production cost. 相似文献
679.
Dr. Khohinur Hossain Luca Florean Dr. Anna Del Tedesco Prof. Dr. Elti Cattaruzza Prof. Dr. Marco Geppi Dr. Silvia Borsacchi Prof. Dr. Patrizia Canton Prof. Dr. Alvise Benedetti Prof. Dr. Pietro Riello Prof. Dr. Alessandro Scarso 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(71):17941-17951
The use of readily prepared bisphosphonic acids obtained in few steps through a thio-Michael addition of commercially available thiols on tetraethyl vinylidenebisphosphonate enables the straightforward surface modification of amorphous mesoporous zirconia nanoparticles. Simple stirring of the zirconia nanoparticles in a buffered aqueous solution of the proper bisphosphonic acid leads to the surface functionalization of the nanoparticles with different kinds of functional groups, charge and hydrophobic properties. Formation of both chemisorbed and physisorbed layers of the bisphosphonic acid take place, observing after extensive washing a grafting density of 1.1 molecules/nm2 with negligible release in neutral or acidic pH conditions, demonstrating stronger loading compared to monophosphonate derivatives. The modified nanoparticles were characterized by IR, XPS, ζ-potential analysis to investigate the loading of the bisphosphonic acid, FE-SEM to investigate the size and morphologies of the nanoparticles and 31P and 1H MAS NMR to investigate the coordination motif of the phosphonate units on the surface. All these analytical techniques demonstrated the strong affinity of the bisphosphonic moiety for the Zr(IV) metal centers. The functionalization with bisphosphonic acids represents a straightforward covalent approach for tailoring the superficial properties of zirconia nanoparticles, much straightforward compared the classic use of trisalkoxysilane or trichlorosilane reagents typically employed for the functionalization of silica and metal oxide nanoparticles. Extension of the use of bisphosphonates to other metal oxide nanoparticles is advisable. 相似文献
680.
We analyze the efficiency as thermoelectric energy converter of a silicon–germanium alloy with composition and temperature dependent heat conductivity. The dependency on composition is determined by a non-linear regression method (NLRM), while the dependency on temperature is approximated by a first-order expansion in the neighborhood of three reference temperatures. The differences with respect to the case of thermal conductivity depending on composition only are pointed out. The efficiency of the system is analyzed under the assumption that the optimal energy conversion corresponds to the minimum rate of energy dissipated. The values of composition and temperature which minimize such a rate are calculated as well. 相似文献