UO2、UC2和UCO分子的结构和热力学性质

用密度泛函B3LYP方法,计算了UO2、UC2和UCO分子的结构和热力学函数,计算了固体U的振动内能Ev、振动和电子熵Sev,以及U在不同气氛（O2、C2、CO）中形成UO2、UC2和UCO晶体的ΔHfΘ、ΔSfΘ和ΔGfΘ.结果表明,UO2晶体最稳定.     

Infrared spectra and quantum chemical calculations of the uranium-carbon molecules UC, CUC, UCH, and U(CC)2

Laser evaporation of carbon rich uranium/carbon alloy targets into condensing argon or neon matrix samples gives weak infrared absorptions that increase on annealing, which can be assigned to new uranium carbon bearing species. New bands at 827.6 cm(-1) in solid argon or 871.7 cm(-1) in neon become doublets with mixed carbon 12 and 13 isotopes and exhibit the 1.0381 carbon isotopic frequency ratio for the UC diatomic molecule. Another new band at 891.4 cm(-1) in argon gives a three-band mixed isotopic spectrum with the 1.0366 carbon isotopic frequency ratio, which is characteristic of the anti-symmetric stretching vibration of a linear CUC molecule. No evidence was found for the lower energy cyclic U(CC) isomer. Other bands at 798.6 and 544.0 cm(-1) are identified as UCH, which has a uranium-carbon triple bond similar to that in UC. Evidence is found for bicyclic U(CC)(2) and tricyclic U(CC)(3). This work shows that U and C atoms react spontaneously to form the uranium carbide U≡C and C≡U≡C molecules with uranium-carbon triple bonds.     

Die Teilsysteme von HfC mit TiC,ZrC, VC,NbC, TaC,Cr3C2, Mo2C (MoC), WC und UC

Zusammenfassung In Übereinstimmung mit der Volumregel sind die isotypen Monokarbide von Ti, Zr, Nb und Ta mit HfC lückenlos mischbar. HfC und Cr₃C₂ zeigen keinerlei gegenseitige Löslichkeit, dagegen löst HfC in sehr starkem Maße Mo₂C bzw. MoC (über 80 Mol%). WC wird von HfC unter den gewählten Bedingungen bis gegen 40 Mol% aufgenommen. HfC und UC lösen sich weitgehend, entgegen der Erwartung jedoch nicht lückenlos. Ein vollkommener Übergang dürfte erst bei hohen Temperaturen (etwa 2500°C) bestehen, aber es genügen 10 Mol% ZrC, um die bei tiefen Temperaturen bestehende Mischungslücke zu schließen.Mit 6 Abbildungen     

Charakterisierung von Energiebändern in Termen relativistischer lokaler Festkörpermodelle. Anwendung auf VC,NbC und UC

Ohne Zusammenfassung     

Charakterisierung von Energieb?ndern in Termen relativistischer lokaler Festk?rpermodelle. Anwendung auf VC, NbC und UC

Ohne Zusammenfassung     

Theoretical study of the structure and bonding in ThC2 and UC2

The electronic structure and various molecular properties of the actinide (An) dicarbides ThC(2) and UC(2) were investigated by relativistic quantum chemical calculations. We probe five possible geometrical arrangements: two triangular structures including an acetylide (C(2)) moiety, as well as the linear AnCC, CAnC, and bent CAnC geometries. Our calculations at various levels of theory indicate that the triangular species are energetically more favorable, while the latter three arrangements proved to be higher-energy structures. Our SO-CASPT2 calculations give the ground-state molecular geometry for both ThC(2) and UC(2) as the symmetric (C(2v)) triangular structure. The similar and, also very close in energy, asymmetric (C(s)) triangular geometry belongs to a different electronic state. DFT and single-determinant ab initio methods failed to distinguish between these two similar electronic states demonstrating the power of multiconfiguration ab initio methods to deal with such subtle and delicate problems. We report detailed data on the electronic structure and bonding properties of the most relevant structures.     

基态UC2分子的结构和势能函数

采用密度泛函理论(DFT)的B3LYP方法和相对论有效原子实势理论模型(RECP),对UC2分子可能的结构进行优化计算,得到UC2分子稳定构型为角形C-U-C(C2v);由微观可逆性原理,判断了UC2分子的离解极限;并且导出了基态UC2分子(X 5B1)的多体项展式势能函数,其势能面等值图展现了C-U-C(C2v)稳定结构;根据势能面等值图,讨论了C+UC(X 3П)反应和U+C2(X 1∑+g)反应的势能面静态特征.     

AMIDO- AND AMINO-ALKYLATION OF SULFIMIDES,SULFOXIMIDES, AND SULFODIIMIDES

Abstract

Sulfimides, Sulfoximides and Sulfodiimides are polyfunctional compounds with nucleophilic/basic nitrogen and acidic hydrogen adjacent to sulfur. From these Mannich-type-reaction products 1 were prepared. For example, amidomethylation on nitrogen was achieved either directly via three-component condensation (pathway (a) or, after conversion of the S-Imide into the sodium salt by treatment with N-chloromethyl-amides (pathway (b)). With highly reactive methylene-iminium halides pathway (b) provided N-aminomethylated sulfoximides, the stability of which mainly depends on the substituents on sulfur. Surprisingly stable, however, are their monoquaternary salts. These are of pharmaceutical interest with respect to anticholinergic and antihistamine activity, which was found in this series and will briefly be discussed. Of similar interest but spasmolytically less active are C-Mannich-bases of type 2 as well as N-aminoalkylated sulfodiimides 3, which were synthesized by different reaction routes.     

NEMATICIDAL,INSECTICIDAL, ANTIFERTILITY,ANTIFUNGAL AND ANTIBACTERIAL ACTIVITIES OF SALICYLANILIDE SULPHATHIAZOLE AND ITS MANGANESE,SILICON AND TIN COMPLEXES

A facile synthesis and studies on the stereochemistry and biochemical aspects of some organosilicon(IV), organotin(IV), and manganese(II) complexes derived from imine having N^∪N^∪O donor system is reported. The imine was prepared by the condensation of salicylanilide with sulphathiazole. This imine reacts with organosilicon(IV)chloride, organotin(IV)chloride, and hydrated manganese(II) chloride to yield compounds having M─O and M←N bonds. The structures of the compounds have been elucidated by physicochemical and spectral (IR, ¹H NMR, ¹³C NMR, ²⁹Si NMR, ¹¹⁹Sn NMR, and ESR) studies, which clearly point to a trigonal bipyramidal geometry around silicon(IV) and tin(IV), and tetrahedral geometry around manganese(II), as the active lone pair of the nitrogen is also included in the coordination sphere. In the search for better fungicides and bactericides, studies were conducted to assess the growth-inhibiting potential of the synthesized complexes against various pathogenic fungal and bacterial strains. These complexes are highly active against nematode (Meloidogyneincognita) and insect (Trogodermagranarium). The activity will be increased with increasing concentration. These studies demonstrate that the concentrations reached levels that are sufficient to inhibit and kill the pathogens. All compounds have also been found to act as sterilizing agents by reducing the production of sperm in male mice.     

POLYHEDRAL METALLOPHOSPHONATES AND -SILICATES: SYNTHESIS,FUNCTIONALIZATION, AND TRANSFORMATIONS

We synthesized molecular cyclic and polyhedral precursors to aluminophosphate and silicate materials and studied their substitution and nonhydrolytic sol-gel reactions.     

Capillary electrophoresis determination of nitrate and nitrite in high-salt perchlorate solutions for the UC dissolution study

The capillary electrophoresis method with direct UV detection is proposed for the determination of nitrite and nitrate in high-salt perchlorate solutions issued from uranium carbide dissolution. The isotachophoretic sample stacking was used to compensate for the perchlorate matrix interference. Simple electrolyte composed of 120 mM formiate buffer, pH 3.8 enabled the nitrate and nitrite determination in the presence of up to 1000-fold excess of perchlorate with 2 μM and 4 μM detection limits for nitrate and nitrite, respectively. The proposed method was applied to the determination of nitrate and nitrite in high-salt non-irradiated uranium carbide dissolution samples.     

四苯氧基酞菁镁、锰、铝和锌的合成和性质

合成了新的酞菁配合物４，４，４，４－四苯氧基酞菁镁［ＴＰｈＯＰｃＭｇ（Ⅱ）］，锰［ＴＰｈＯＰｃＭｎ（Ⅱ）Ａｃ］，铝［ＴＰｈＯＰｃＡｌ（Ⅲ）Ｃｌ］，锌［ＴＰｈＯＰｃＺｎ（Ⅱ）］测定了它们的ＩＲ，ＵＶ－Ｖｉｓ光谱，在ＤＭＦ中的氧化还原半波电势（Ｅ１／２），电子转移速度常数，在乙腈中的荧光性质及锰的配合物在不同电位下的光谱变化情况。     

CHEMOSELECTIVE ACETYLATION OF ALCOHOLS,AMINES, AND THIOLS WITHOUT CATALYST AND SOLVENT

Microwave induced rapid and selective acetylation of alcohols, amines and thiols with acetic anhydride was carried out under non-catalytic and solvent free conditions.     

SOME NEW S-, S,S- AND N,S-SUBSTITUTED 2-NITRODIENES AND BUTADIENYL-SUBSTITUTED PIPERAZINES

Nitrodiene 1 reacted with 2a, b and gave the novel compounds 3a, b, 4a, b, and 5a. Monosubstituted diene compound 3a gave the compounds 9a with morpholine, 11a with piperidine, and 13a with homopiperazine. Compound 3a gives the thioether compound 15 by the reaction with the dithiol (HS─(CH₂)₂─O─(CH₂)₂─SH) in ethanol containing sodium hydroxide.     

COMPLEX FORMATION BETWEEN PYRENE AND THE NUCLEOTIDES GMP, CMP, TMP AND AMP

Pyrene has been found to form ground and excited electronic state complexes of 1:1 stoichi-ometry with GMP, CMP, TMP and AMP. The values of their ground state association constants are 45 M^-1, 13M^-1, 14 M^-1, and 52 M^-1 respectively. The fluorescence of pyrene is strongly quenched by GMP, CMP, and TMP but only slightly by AMP. Fluorescence quenching analysis has yielded the values 87M^-1, 73 M^-1, and 154 M^-1 for the excited state association constants with GMP, CMP, and TMP, respectively. The corresponding values for the excited state second-order rate constant for complex formation are: 3.3 times 10⁹M^-1 s^-1 4.1 times 10⁹M^-1 s^-1, and 4.0 times 10⁹M^-1 s^-1. The probabilities of complex formation per collision between an excited pyrene molecule and a nucleotide are: 0.52, 0.64, and 0.63. The values for the excited state rate constant for dissociation of the complex are: 3.8 times 10⁷s^-1 5.6 times 10⁷s^-1, and 2.6 times 10⁷s^-1. The possibility is discussed that partial transfer of charge from pyrene to nucleotide may be playing a role in the complex formation process.     

COACERVATION,COMPLEX-COACERVATION AND FLOCCULATION

The mechanism of coacervation is reexamined in the light of recent studies on the polar (i.e., hydrogen-bonding) components of interfacial Interactions in aqueous media. The differences and similarities between coacervation, complex coacervation and flocculation are outlined and illustrated with a number of examples.     

COMPARATIVE STUDIES ON THE LETHAL, MUTAGENIC, AND RECOMBINOGENIC EFFECTS OF ULTRAVIOLET-A,-B,-C, AND VISIBLE LIGHT WITH AND WITHOUT 8-METHOXYPSORALEN IN Saccharomyces cerevisiae

Genetic effects of UV-A, UV-B, UV-C, and the combination of 8-methoxypsoralen (8-MOP) with UV-A or visible light were studied in the haploid strain XV185-14C and diploid strain D5 of Saccharomyces cerevisiae. The induction of his+, lys+, and hom+ reverse mutations was measured in strain XV185-14C. In strain D5 we measured the induction of genetically altered colonies, particularly twin spot colonies arising from a mitotic crossing-over. UV-C and UV-B induced point mutations at the three loci in the haploid strain and mitotic crossing-over and other genetic alterations in the diploid strain. UV-C was more mutagenic and recombinogenic than UV-B. UV-A or visible light alone did not induce genotoxic effects at the doses tested. However, UV-A plus 8-MOP produced lethal and mutagenic effects in the haploid strain XV185-14C, although mutagenic activity was less than that of UV-B. Visible light plus 8-MOP also induced genotoxic effects in strain XV185-14C. In the diploid strain D5, UV-A plus 8-MOP induced a higher frequency of genetic alterations than UV-B at comparative doses. Visible light plus 8-MOP was also genetically active in strain D5. The haploid strain was more sensitive to the lethal effects of UV-C, UV-B, UV-A, and impure visible light plus 8-MOP than the diploid strain.