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41.
Alessandro D' Aprano Dorina Ines Donato Antonio Carrubba Doctor in Chemistry thesis of A. Carrubba 《Journal of solution chemistry》1983,12(3):209-220
Conductance measurements are reported for LiPi, NaPi, KPi, RbPi, CsPi, Bu4NPi, Bu4NBr, Bu4NClO4, Bu4NNO3, and Bu4NBBu4 at 25°C in -butyrolactone-sulfolane mixtures. In these mixtures of solvents that are practically homomorphous, isodielectic and with comparable dipole moments, the ion pair association and ionic mobilities of large ions conform to the expectations of the primitive model. Electrolytes containing lithium or sodium ions show anomalies indicating that other factors besides shape, dipole moment, and polarizability of the solvent molecules are involved in the association and transport processes of these ions. 相似文献
42.
Pilar Alonso Isabel de Frutos Teresa Gutiérrez Antonio Doadrio López 《Transition Metal Chemistry》1987,12(2):133-136
Summary The synthesis and the dinuclear or mononuclear nature of several molybdenum(VI) and molybdenum(V) oxocomplexes derived from 1,3-diphenyl-1,3-propanedione (HLL) are described. These complexes were identified by i.r. and electronic spectra, magnetic susceptibility and analytical data, and are assigned the following formulae: [MoO2(LL)2], [Mo2O5(LL)2], [Mo2O4(LL)2], [MoOCl(LL)2], [MoCl2(LL)] and [MoO(OH)(LL)2)]. The low magnetic moments of the dinuclear complexes are due, in part, to intramolecular interactions. The i.r. data show that the dionate is bound by two oxygen atoms forming a chelate six-membered ring. 相似文献
43.
44.
Marino Cavazza Gioia Morganti Antonio Guerriero Francesco Pietra 《Tetrahedron letters》1980,21(38):3703-3704
EtO? in DMSO adds to ethylthiopicrate at C-3 to generate an ephemeral -adduct which ends into 1-ethylthio-4-ethoxy-2,5-dinitrobenzene, whilst ethyl picrate gives two adducts of attack of EtS? at C-3 or C-1. 相似文献
45.
46.
Let X be a nonsingular complex projective surface and let D be an ample divisor on X such that the associated invertible sheaf is spanned by its global sections. We prove that D is 2-connected apart from a few cases we explicitly describe. We also provide a corresponding result for the 3-connectedness when D210 and for the 4-connectedness when D217 and D is very ample. 相似文献
47.
Luigi Antonio Rosati 《Geometriae Dedicata》1987,24(3):261-267
Summary Let G be a sharply 3-transitive permutation set on a finite set E of even cardinality and let 1 be in G. The following theorems are proved.
G is one of the known examples if and only if there exists a non-identity normal subgroup N of G and an element of E such that NG
G.G is a group if and only if G for every G and for every G and for every G
.By using the classification of finite single groups a result concerning sharply k-transitive permutation sets k>3 is also proved.
Dedicato a Guido Zappa in occasione del suo 70° compleanno
Lavoro eseguito nell'ambito dei progetti finanziati dal Ministero della Pubblica Istruzione. 相似文献
Dedicato a Guido Zappa in occasione del suo 70° compleanno
Lavoro eseguito nell'ambito dei progetti finanziati dal Ministero della Pubblica Istruzione. 相似文献
48.
Interactions of dendrimers with selected amino acids and proteins studied by continuous wave EPR and Fourier transform EPR 总被引:1,自引:0,他引:1
Ottaviani MF Jockusch S Turro NJ Tomalia DA Barbon A 《Langmuir : the ACS journal of surfaces and colloids》2004,20(23):10238-10245
Interactions of polyamidoamine dendrimers, termed Gn, where n indicates the generation (=number of amidoamine layers), at different protonation levels with selected amino acids and proteins have been investigated by means of continuous wave electron paramagnetic resonance (cw-EPR) and pulsed-EPR (electron spin-echo = ESE) analyses. A low-generation dendrimer (G2) and a high-generation one (G6) were labeled with nitroxides for the EPR measurements. Gly, Glu, Arg, and Leu were selected as representative of neutral(zwitterionic)-polar, acidic, basic, and low-polar amino acids, respectively. The water-soluble proteins alpha-chymotrypsin and albumin were selected on the basis of a basic and an acidic isoelectric point, respectively. The cw-EPR spectra were analyzed by computing the line shapes to extract information about the dendrimer-biomolecule interactions. In general, dendrimers at a high protonation level interact stronger with amino acids than those at a low level of protonation. However, even for highly protonated dendrimers, a synergistic effect between hydrophilic and hydrophobic interactions promoted the formation of stable Gn-amino acid adducts, as demonstrated by the enhanced interactions with Leu. As expected from acid-base interactions, stable adducts were formed between Arg and highly protonated dendrimers and between Glu and low level protonated dendrimers. The relatively strong dendrimer interactions with the protein chymotrypsin and the poor interactions of dendrimers with albumin demonstrated that the protonated amino groups of the dendrimers are predominantly involved in the interactions with these proteins and indicated a significant role in the interactions with the dendrimers of the hydrophobic external residues of chymotrypsin. Computer-aided analysis of the ESE experiments was consistent with the cw-EPR results and supported the conclusion of a partial complexation of the nitroxides of the dendrimer with Leu and alpha-chymotrypsin. 相似文献
49.
Maurizio Lanfranchi Antonio Tiripicchio Giuliano Giuliano Mauro Ghedini 《Transition Metal Chemistry》1980,5(1):21-25
Summary The structure of [Ir(NCMe)3(NO)(PPh3)2][PF6]2 has been ] determined by x-ray methods. Crystals are orthorhombic, space groupPca 21 , witha = 21.753(14),b = 11.678(10),c = 18.474(12) Å and Z = 4. The structure has been solved from diffractometer data and refined by full-matrix leastsquares to R = 0.076 for 2776 observed reflections. The cation is a hexacoordinate and not a pentacoordinate species as expected. The extra acetonitrile molecule,trans to the nitrosyl ligand, is much more weakly bound to the metal atom [Ir-N 2.360(26) against 1.965(20) and 1.912(14) Å for the other two acetonitriles]. The nitrosyl is bent [Ir-N-O 111(1)° Å] and acts as the formally one-electron donor NO–. 相似文献
50.
Rüdiger O Abad JM Hatchikian EC Fernandez VM De Lacey AL 《Journal of the American Chemical Society》2005,127(46):16008-16009
The orientation of hydrogenase bound covalently to a pyrolytic graphite edge electrode modified with a 4-aminophenyl monolayer can be modulated via electrostatic interactions during the immobilization step. At low ionic strength and when the amino groups of the electrode surface are mostly protonated, the hydrogenase is immobilized with the negatively charged region that surrounds its 4Fe4S cluster nearer to the protein surface facing the electrode. This allows direct electron transfer between the immobilized hydrogenase and the electrode, which is observed by the strong catalytic currents measured in the presence of the H2 substrate. Therefore, a very stable enzymatic electrode is produced that catalyzes nonmediated H2 oxidation. 相似文献