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111.
Tommaso R. I. Cataldi Giampaolo Ricciardi Giuliana Bianco Daniela Pietrangeli Salvatore Abate 《Rapid communications in mass spectrometry : RCM》2009,23(13):1927-1933
Some newly synthesized 10B nido‐carborane derivatives, i.e., 7,8‐dicarba‐nido‐undecaborane monoanions ([7‐Me‐8‐R‐C2B9H10]‐K+, R = H, butyl, hexyl, octyl and decyl), have been fully characterised and examined by electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry with liquid chromatographic separation (LC/ESI‐FTICR‐MS). These boron‐containing compounds exhibit abundant molecular ions ([M]?) at m/z 140.22631 [CB9H14]?, m/z 196.28883 [CB9H22]?, m/z 224.32032 [CB9H26]?, m/z 252.35133 [CB9H30]? and m/z 280.38354 [CB9H34]? at the normal tube lens voltage setting of ?90 V, which was an instrumental parameter value selected in the tuning operation. Additional [M–nH2]? (n = 1?4) ions were observed in the mass spectra when higher tube lens voltages were applied, i.e., ?140 V. High‐resolution FTICR‐MS data revealed the accurate masses of fragment ions, bearing either an even or an odd number of electrons. Collision‐induced dissociation of the [M–nH2]? ions (n = 0–4) in the quadrupole linear ion trap (LTQ) analyzer confirmed the loss of hydrogen molecules from the molecular ions. It is suggested that the loss of H2 molecules from the alkyl chain is a consequence of the stabilization effect of the nido‐carborane charged polyhedral skeleton. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
112.
Buonsante P Giampaolo SM Illuminati F Penna V Vezzani A 《Physical review letters》2008,100(24):240402
We investigate the properties of strongly interacting heteronuclear boson-boson mixtures loaded in realistic optical lattices, with particular emphasis on the physics of interfaces. In particular, we numerically reproduce the recent experimental observation that the addition of a small fraction of 41K induces a significant loss of coherence in 87Rb, providing a simple explanation. We then investigate the robustness against the inhomogeneity typical of realistic experimental realizations of the glassy quantum emulsions recently predicted to occur in strongly interacting boson-boson mixtures on ideal homogeneous lattices. 相似文献
113.
Giampaolo E. D’Errico 《Accreditation and quality assurance》2014,19(1):1-10
Scrutiny of hypotheses by means of statistical tests is a common practice in experimental research. However, valid inference drawn from data analysis needs scientific grounds, whereas conclusions based on significance tests or hypothesis testing may be problematic, especially when dealing with a multiplicity of tested hypotheses, as in experiments performed on bio-molecules. The problem of false discovery rate is focused in the present paper, aiming at eliciting application of sound criteria for rejection/acceptance of hypotheses, with a view of addressing related methods for uncertainty characterization. 相似文献
114.
David Buceta Natalia Busto Giampaolo Barone Jos M. Leal Fernando Domínguez Lisandro J. Giovanetti Flix G. Requejo Begoa García M. Arturo Lpez‐Quintela 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(26):7722-7726
Subnanometric samples, containing exclusively Ag2 and Ag3 clusters, were synthesized for the first time by kinetic control using an electrochemical technique without the use of surfactants or capping agents. By combination of thermodynamic and kinetic measurements and theoretical calculations, we show herein that Ag3 clusters interact with DNA through intercalation, inducing significant structural distortion to the DNA. The lifetime of Ag3 clusters in the intercalated position is two to three orders of magnitude longer than for classical organic intercalators, such as ethidium bromide or proflavine. 相似文献
115.
A number of the title compounds have been prepared through a three step reaction sequence based on the cyclization of Δ-acetal amides. 相似文献
116.
117.
Luciano Lardicci Anna M. Caporusso Giampaolo Giacomelli 《Journal of organometallic chemistry》1974,70(3):333-338
The reaction between triisobutylaluminum and aliphatic 1-alkynes having alkyl groups of different structure on the 3-carbon atom has been investigated. At room temperature and in the absence of solvents, products which correspond to metallation, reduction and carbalumination processes, are isolated after hydrolysis. The extent of such reactions, and in particular the regiospecificity of the carbalumination is dependent on the experimental conditions adopted and on steric factors associated with the structure of the 1-alkyne used. On the basis of these results and the complete stereospecificity of the reaction when (+)(S-3,4-dimethyl-1-pentyne is used, possible mechanisms are discussed. 相似文献
118.
Mauro Biliotti Vikram Jha Norman L. Johnson Giampaolo Menichetti 《Geometriae Dedicata》1989,29(1):7-43
This paper is devoted to the study of translation planes of order q
2 and kernel GF(q) that admit a collineation group of order q
2 in the linear translation complement. We give a representation of this group by a suitable set of matrices depending on some functions over GF(q). Using this representation we obtain several results concerning the existence and the collineation group of the plane. 相似文献
119.
Gunaratne TC Gusev AV Peng X Rosa A Ricciardi G Baerends EJ Rizzoli C Kenney ME Rodgers MA 《The journal of physical chemistry. A》2005,109(10):2078-2089
Reported herein is a combination of experimental and DFT/TDDFT theoretical investigations of the ground and excited states of 1,4,8,11,15,18,22,25-Octabutoxyphthalocyaninato-nickel(II), NiPc(BuO)(8), and the dynamics of its deactivation after excitation into the S(1)(pi,pi) state in toluene solution. According to X-ray crystallographic analysis NiPc(BuO)(8) has a highly saddled structure in the solid state. However, DFT studies suggest that in solution the complex is likely to flap from one D(2)(d)-saddled conformation to the opposite one through a D(4)(h)-planar structure. The spectral and kinetic changes for the complex in toluene are understood in terms of the 730 nm excitation light generating a primarily excited S(1) (pi,pi) state that transforms initially into a vibrationally hot (3)(d(z)2,d(x)2(-)(y)2) state. Cooling to the zeroth state is complete after ca. 8 ps. The cold (d,d) state converted to its daughter state, the (3)LMCT (pi,d(x)2(-)(y)2), which itself decays to the ground state with a lifetime of 640 ps. The proposed deactivation mechanism applies to the D(2)(d)-saddled and the D(4)(h)-planar structure as well. The results presented here for NiPc(BuO)(8) suggest that in nickel phthalocyanines the (1,3)LMCT (pi,d(x)2(-)(y)2) states may provide effective routes for radiationless deactivation of the (1,3)(pi,pi) states. 相似文献
120.
A resin capture and release strategy for making a combinatorial array of 2,4,5-trisubstituted pyrimidines is demonstrated by capturing beta-ketoesters and beta-ketoamides on a solid-supported piperazine. Through a cyclocondensation reaction, the solid-supported enaminone is reacted with several guanidines under heating or microwave irradiation affording the corresponding pyrimidines in good yield and chemical purity directly on solution. After this final step, the support can be effectively recycled. 相似文献