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61.
62.
Henri Patin Gerard Mignani Christian Mahe Jean-Yves Le Marouille Alain Benoit Daniel Grandjean 《Journal of organometallic chemistry》1980,193(1):93-103
103Rh Chemical shifts of a variety of mono- and di-nuclear rhodium carbonyl complexes are reported together with the modifications to the probe and decoupler unit of a JEOL PS-100 PFT spectrometer which enable these 103Rh-decoupled 13C NMR measurements to be made. These data are discussed in conjunction with 13C NMR data on other rhodium carbonyls. 相似文献
63.
Chatterton N Gateau C Mazzanti M Pécaut J Borel A Helm L Merbach A 《Dalton transactions (Cambridge, England : 2003)》2005,(6):1129-1135
The ligand N,N'-bis[(6-carboxy-2-pyridylmethyl]ethylenediamine-N,N'-diacetic acid (H(4)bpeda) was synthesised using an improved procedure which requires a reduced number of steps and leads to a higher yield with respect to the published procedure. It was obtained in three steps from diethylpyridine-2,6-dicarboxylate and commercially available ethylenediamine-N,N[prime or minute]-diacetic acid with a total yield of approximately 20%. The crystal structure of the hexa-protonated form of the ligand which was determined by X-ray diffraction shows that the four carboxylates and the two amines are protonated. The crystal structure of the polynuclear complex [Gd(bpeda)(H(2)O)(2)](3)[Gd(H(2)O)(6)](2)Cl(3)(2), isolated by slow evaporation of a 1:1 mixture of GdCl(3) and H(4)bpeda at pH approximately 1, was determined by X-ray diffraction. In complex three [Gd(bpeda)(H(2)O)(2)] units, containing a Gd(III) ion ten-coordinated by the octadentate bpeda and two water molecules, are connected in a pentametallic structure by two hexa-aquo Gd(3+) cations through four carboxylato bridges. The protonation constants (pK(a1)= 2.9(1), pK(a2)= 3.5(1), pK(a3)= 5.2(2), and pK(a4)= 8.5(1)) and the stability constants of the complexes formed between Gd(III) and Ca(II) ions and H(4)bpeda (log beta(GdL)= 15.1(3); log beta(CaL)= 9.4(1)) were determined by potentiometric titration. The unexpected decrease in the stability of the gadolinium complex and of the calcium complex of the octadentate ligand bpeda(4-) with respect to the hexadentate ligand edta(4-) has been interpreted in terms of an overall lower contribution to stability of the metal-nitrogen interactions. The EPR spectra display very broad lines (apparent DeltaH(pp) approximately 800-1200 G at X-band and 90-110 G at Q-band depending on the temperature), indicating a rapid transverse electron spin relaxation. At X-band, Gd(bpeda) is among the fastest relaxing Gd(3+) complexes to date suggesting that the presence of pyridinecarboxylate chelating groups in itself does not lead to slow electron relaxation. 相似文献
64.
Alain Ibanez Jean-Claude Jumas Josette Olivier-Fourcade Etienne Philippot 《Journal of solid state chemistry》1984,55(1):83-91
The crystal structures of Sn2SbX2I3, with X = S or Se, and Sn3SbSe2I5 are characterized by a statistical disorder of part of the [Sb] and [Sb, Sn] sites. All these crystal structures are built up from infinite ribbons (Sn2X4)n of SnX5 pyramids where X = ((S, Se) and I). The ribbons are weakly linked through Sn … I interactions to give infinite sheets. Between sheets are located [Sb] or [Sb, Sn] atoms in twinned sites. 相似文献
65.
Romero I Dubois L Collomb MN Deronzier A Latour JM Pécaut J 《Inorganic chemistry》2002,41(7):1795-1806
Reactions of Mn(II)(PF(6))(2) and Mn(II)(O(2)CCH(3))(2).4H(2)O with the tridentate facially capping ligand N,N-bis(2-pyridylmethyl)ethylamine (bpea) in ethanol solutions afforded the mononuclear [Mn(II)(bpea)](PF(6))(2) (1) and the new binuclear [Mn(2)(II,II)(mu-O(2)CCH(3))(3)(bpea)(2)](PF(6)) (2) manganese(II) compounds, respectively. Both 1 and 2 were characterized by X-ray crystallographic studies. Complex 1 crystallizes in the monoclinic system, space group P2(1)/n, with a = 11.9288(7) A, b = 22.5424(13) A, c =13.0773(7) A, alpha = 90 degrees, beta = 100.5780(10 degrees ), gamma = 90 degrees, and Z = 4. Crystals of complex 2 are orthorhombic, space group C222(1), with a = 12.5686(16) A, b = 14.4059(16) A, c = 22.515(3) A, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, and Z = 4. The three acetates bridge the two Mn(II) centers in a mu(1,3) syn-syn mode, with a Mn-Mn separation of 3.915 A. A detailed study of the electrochemical behavior of 1 and 2 in CH(3)CN medium has been made. Successive controlled potential oxidations at 0.6 and 0.9 V vs Ag/Ag(+) for a 10 mM solution of 2 allowed the selective and nearly quantitative formation of [Mn(III)(2)(mu-O)(mu-O(2)CCH(3))(2)(bpea)(2)](2+) (3) and [Mn(IV)(2)(mu-O)(2)(mu-O(2)CCH(3))(bpea)(2)](3+) (4), respectively. These results have shown that each substitution of an acetate group by an oxo group is induced by a two-electron oxidation of the corresponding dimanganese complexes. Similar transformations have been obtained if 2 is formed in situ either by direct mixing of Mn(2+) cations, bpea ligand, and CH(3)COO(-) anions with a 1:1:3 stoichiometry or by mixing of 1 and CH(3)COO(-) with a 1:1.5 stoichiometry. Associated electrochemical back-transformations were investigated. 2, 3, and the dimanganese [Mn(III)Mn(IV)(mu-O)(2)(mu-O(2)CCH(3))(bpea)(2)](2+) analogue (5) were also studied for their ability to disproportionate hydrogen peroxide. 2 is far more active compared to 3 and 5. The EPR monitoring of the catalase-like activity has shown that the same species are present in the reaction mixture albeit in slightly different proportions. 2 operates probably along a mechanism different from that of 3 and 5, and the formation of 3 competes with the disproportionation reaction catalyzed by 2. Indeed a solution of 2 exhibits the same activity as 3 for the disproportionation reaction of a second batch of H(2)O(2) indicating that 3 is formed in the course of the reaction. 相似文献
66.
Alain Valtz 《Thermochimica Acta》2006,443(2):251-255
Densities of the water + ethylenediamine binary system were measured at atmospheric pressure over the whole range of compositions at temperatures from 288.15 to 353.15 K using an Anton Paar digital vibrating glass tube densimeter. Density increases with water content. The experimental excess molar volume data have been correlated with the Redlich-Kister equation, and partial molar volumes calculated at infinite dilution for each component. 相似文献
67.
Alain Escassut 《Journal of Number Theory》1983,16(3):395-402
Let (K, ∥ · ∥) be a valued transcendence degree 1 extension of p. An element x ∈ K transcendental over p is said to have order ≤a (a > 0) if there exists Cx > 0 such that every polynomial P(X) ∈ p [X] satisfies when ∥ · ∥ is the Gauss norm on p[X]. No x ∈ p can have order ≤α if α < 1 but we construct some x ∈ p with order ≤ 1. Furthermore, we prove order ≤α is stable by algebraic extension. 相似文献
68.
Kanibolotsky A Roquet S Cariou M Leriche P Turrin CO de Bettignies R Caminade AM Majoral JP Khodorkovsky V Gorgues A 《Organic letters》2004,6(13):2109-2112
[structure: see text] In four new dendrimers terminated by 12 electroactive tetrathiafulvalenyl substituents, the tridimensional character of the inter- and intradendrimeric charge and electron transfer, and hence of the electroconductivity, is evidenced by examination of the electronic spectra of their corresponding neutral state and cation radical, dication, and mixed-valence salts, including a closed-shell anion. 相似文献
69.
Max Winter Karl H. Schulte-Elte Alain Velluz Josef Limacher Wilhelm Pickenhagen Günther Ohloff 《Helvetica chimica acta》1979,62(1):131-134
Aroma Constituents of the Purple Passion Fruit. Two New Edulan Derivatives The isolation of (2R*, 4S*, 4aS*, 8aS*)-4,4a-epoxy-4,4a-dihydroedulan ( 1 ), and (2R*, 3S*, 8aS*)-3-hydroxyedulan ( 2 ), two new constituents of the purple passion-fruit (Passiflora edulis SIMS ), is reported. Racemic epoxide 1 was synthesized by oxidation of edulan 6 with peracidic acid, and racemate of alcohol 2 was obtained by reduction of ketone 7 , one of the chromic acid oxidation-products of edulan 6 . 相似文献
70.