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161.
De Fazio D Aquilanti V Cavalli S Aguilar A Lucas JM 《The Journal of chemical physics》2006,125(13):133109
In this paper we present integral cross sections (in the 5-220 meV collision energy range) and rate constants (in the 100-300 K range of temperature) for the F+HD reaction leading to HF+D and DF+H. The exact quantum reactive scattering calculations were carried out using the hyperquantization algorithm on an improved potential energy surface which incorporates the effects of open shell and fine structure of the fluorine atom in the entrance channel. The results reproduce satisfactorily molecular beam scattering experiments as well as chemical kinetics data for both the HF and DF channels. In particular, the agreement of the rate coefficients and the vibrational branching ratios with experimental measurements is improved with respect to previous studies. At thermal and subthermal energies, the rates are greatly influenced by tunneling through the reaction barrier. Therefore exchange of deuterium is shown to be penalized with respect to exchange of hydrogen, and the isotopic branching exhibits a strong dependence on translational energy. Also, it is found that rotational excitation of the reactant HD molecule enhances the production of HF and decreases the reactivity at the D end, obtaining insight on the reaction stereodynamics. 相似文献
162.
Efficient oxidation of primary alcohols to the corresponding carboxylic acids can be carried out at room temperature and in acetone/water, using trichloroisocyanuric acid (TCCA) in the presence of catalytic TEMPO. The mild conditions of this procedure and the total absence of any transition metal make this reaction suitable for safe laboratory use. A possible mechanism is presented and discussed. 相似文献
163.
Simonetta Orlandi Marinella Caporale Maurizio Benaglia Rita Annunziata 《Tetrahedron: Asymmetry》2003,14(24):3827-3830
Starting from the commercially available enantiopure (1S,2S)-2-amino-1-phenyl-1,3-propanediol novel enantiomerically pure benzimidazoles were prepared; N-alkylation gave chiral benzimidazolium salts, which were tested in asymmetric benzoin condensations. The synthesis of conceptually new, enantiomerically pure, C2 symmetric bis-thiazolium and bis-benzimidazolium salts was also developed. These new chiral heterocycles were employed as catalysts in the asymmetric dimerisation of benzaldehyde to give benzoin with moderate enantioselectivity. 相似文献
164.
165.
A. Ferrari G. Ghislotti S. Balsamo G. Troiano 《Photonics Technology Letters, IEEE》2003,15(8):1041-1043
We have experimentally and theoretically demonstrated that residual power from a fiber Bragg grating-stabilized 980-nm pump laser in a coherence-collapsed state can be used to lock the wavelength of another solitary 980-nm pump. The coherence collapsed operation is transferred to the slave laser. 相似文献
166.
Marco Caterino Antonello Merlino Anna Balsamo Irene Russo Krauss Silvia Parisi Alessandro Vergara 《Journal of solution chemistry》2014,43(1):135-143
Chemical modifications of protein crystals may be achieved via soaking of reactants from their precipitating solution, through the solvent channel, into the protein matrix. We describe a Raman microscopy approach to follow mercury insertion into cysteine pairs within protein single crystals, via soaking in an aqueous Hg2+ solution. The method has been developed using bovine insulin as the model system. Applying an efficient mercuration protocol, consisting of a first step of disulphide bridge TCEP-induced reduction within the crystal, followed by overnight reaction with a HgCl2 solution, we obtained Hg-derivative crystals. Raman spectra collected on these derivative crystals, kept in the mother liquor, reveal a characteristic Raman band at 335 cm?1, which has been assigned to a –S–Hg–S– bridge. The analysis provides Raman-based markers of mercury binding to cysteines, and thus of mercury intoxication. 相似文献
167.
168.
Piero Stoppioni Massimo Di Vaira Maurizio Peruzzini Simonetta Moneti Luigi Sacconi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):295-298
Abstract The compounds obtained by reacting the P4S3, P4Se3 and As4S3 cage molecules with various transition metal-ligand moieties are reported. The transition metal-ligand systems are bound either to the intact molecules or to fragments (hexa- or tri-atomic) originating from the cage molecules. Such compounds provide examples of selective activation of cage molecules by metal moieties. 相似文献
169.
Dr. Antonio Toppino Maria Elena Bova Dr. Simonetta Geninatti Crich Dr. Diego Alberti Prof. Eliano Diana Dr. Alessandro Barge Prof. Silvio Aime Prof. Paolo Venturello Dr. Annamaria Deagostino 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(2):721-728
In this study, the Huisgen reaction has been used to functionalise a carborane cage with a lipophilic moiety and a 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) ligand to obtain a new Gd boron neutron‐capture therapy (BNCT)/magnetic resonance imaging (MRI) agent. The introduction of the triazole units has been accomplished under both heterogeneous conditions, by the use of a Cu‐supported ionic‐liquid catalyst, and homogeneous conditions. The ability of the Gd complex of the synthesised ligand to form stable adducts with low‐density lipoproteins (LDLs) has been evaluated and then MRI has been performed on tumour melanoma cells incubated in the presence of a Gd‐complex/LDL imaging probe. It has been concluded that the high amount of intracellular boron necessary to perform BNCT can be reached even in the presence of a relatively low‐boron‐containing LDL concentration. 相似文献
170.
In situ generated nitro alkenes underwent tandem Michael-Henry and Michael-Michael sequences leading to the ‘one-pot’ formation of 3,4-substituted tetrahydrothiophenes using the commercially available 1,4-dithiane-2,5-diol (the dimer of mercaptoacetaldehyde) or its 4-mercapto-2-butenoates derivatives as suitable bifunctional partners, respectively. 相似文献