One and Two-dimensional Structures of a New Oxamido Copper(II) Complex with Phthalato Bridged

1 INTRODUCTION Coordination polymers are a family of materials composed of 1D chains, 2D sheets, and 3D networks of metal-organic building blocks connected via co- valent and hydrogen bonds. Recently, they have re- ceived increasing attention for their fascinating struc- tures and topological features[1～4]. The complex as ligands approach is one of the best strategies to de- sign and synthesize polynuclear species, and a good example of ‘complex ligand’ is represented by mono- nuclear…     

Synthesis and structure of a novel three-dimensional metal selenite containing multidirectional intersecting double helical chains: [Fe2(H2O)4(SeO3)2]

A novel three-dimensional metal selenite [Fe₂(H₂O)₄(SeO₃)₂] (1) has been hydrothermally synthesized and characterized by the elemental analyses, IR spectrum, TG analysis and the single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P21/n, with a=6.5283(13) Å, b=8.8754(18) Å, c=7.6798(15) Å, (=98.82(3)β, V=439.71(15) Å3, and Z=2. Compounds 1 exhibits interesting three-dimensional structure constructed from {FeO₆} octahedra and {SeO₃} pyramids linked via the corner- and/or edge-sharing mode. The most interesting structural feature of compound 1 is that the existence of multidirectional intersecting double helical chains in one compound.     

The electron microscope characterization of the fine structure of nylon 6: II. On the rearrangement of the structure during cold-drawing

The transmission electron microscope (TEM) visualization of the supermolecular structure of cold-drawn, oriented nylon 6 bulk material (bristles) by stained ultra-thin sections is reported. For evaluating the electron micrographs optical diffraction (OD) has been applied in comparison with small angle X-ray scattering (SAXS). The deformation of the spherulites was followed by polarization microscopy. In addition, investigations were carried out on commercial nylon 6 fibres. As the main result a transverse structure was revealed within the drawn samples at draw ratios between =4 and 4.5, consisting of mosaic crystals which show some lateral alignment. The structure is described by a modified layer lattice model. While the long period may increase slightly during drawing, the crystallite thickness remains almost constant. Fibres with =3.4 show a similarly oriented structure though the lateral alignment of the crystals is not so pronounced.     

The reactions of 2-benzoylpyridine with [RuHCl(CO)(PPh3)3] and [(C6H6)RuCl2]2

The reactions of [RuHCl(CO)(PPh₃)₃] and [(C₆H₆)RuCl₂]₂ with 2-benzoylpyridine have been examined, and two novel ruthenium(II) complexes – [RuCl(CO)(PPh₃)₂(C₅H₄NCOO)] and [RuCl₂(C₁₂H₉NO)₂] – have been obtained. The compounds have been studied by IR and UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagrams of the complexes have been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of the compounds have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the compounds have been discussed on this basis.     

The synthesis and electronic structure of a novel [NiS4Fe2(CO)6] radical cluster: implications for the active site of the [NiFe] hydrogenases

A novel [NiS4Fe2(CO)6]cluster (1: 'S(4)'=(CH(3)C(6)H(3)S(2))(2)(CH(2))(3)) has been synthesised, structurally characterised and has been shown to undergo a chemically reversible reduction process at -1.31 V versus Fc(+)/Fc to generate the EPR-active monoanion 1(-). Multifrequency Q-, X- and S-band EPR spectra of (61)Ni-enriched 1(-) show a well-resolved quartet hyperfine splitting in the low-field region due to the interaction with a single (61)Ni (I=3/2) nucleus. Simulations of the EPR spectra require the introduction of a single angle of non-coincidence between g(1) and A(1), and g(3) and A(3) to reproduce all of the features in the S- and X-band spectra. This behaviour provides a rare example of the detection and measurement of non-coincidence effects from frozen-solution EPR spectra without the need for single-crystal measurements, and in which the S-band experiment is sensitive to the non-coincidence. An analysis of the EPR spectra of 1(-) reveals a 24 % Ni contribution to the SOMO in 1(-), supporting a delocalisation of the spin-density across the NiFe(2) cluster. This observation is supported by IR spectroscopic results which show that the CO stretching frequencies, nu(CO), shift to lower frequency by about 70 cm(-1) when 1 is reduced to 1(-). Density functional calculations provide a framework for the interpretation of the spectroscopic properties of 1(-) and suggest that the SOMO is delocalised over the whole cluster, but with little S-centre participation. This electronic structure contrasts with that of the Ni-A, -B, -C and -L forms of [NiFe] hydrogenase in which there is considerable S participation in the SOMO.     

丙醛的等离子体聚合以及聚合物的结构与性质初探

应用外部电容耦合式等离子体聚合方法,制得了丙醛聚合物,研究了不同的等离子体条件对丙醛的聚合行为的影响。通过元素分析、红外光谱分析、色谱-质谱联合分析、X-射线衍射、润湿性测定等手段研完发现,聚合物为无定形交联结构,表面能为41—45达因/厘米。     

Secondary structural changes of chymotrypsinogen A,alpha-chymotrypsin,and the isolated polypeptides Cys1-Leu13, Ile16-Tyr146, and Ala149-Asn245 in sodium dodecyl sulfate,urea and guanidine hydrochloride

Secondary structural changes of chymotrypsinogen A,-chymotrypsin, and their isolated polypeptides Cys¹-Leu¹³, Ile¹⁶-Tyr¹⁴⁶, and Ala¹⁴⁹-Asn²⁴⁵were examined in aqueous solutions of sodium dodecyl sulfate (SDS), urea, and guanidine hydrochloride (residue numbers from chymotrypsinogen). After the fragmentation by the cleavage of disulfide bridges in-chymotrypsin, the helical structure was formed in the isolated polypeptide 16–146 where the helical segments do not exist in the protein state. The polypeptide 149–245, where the helical segments of the parent protein are originally located, contained no helices. The polypeptide 1–13 was almost disordered. The three polypeptides, chymotrypsinogen,-chymotrypsin and the polypeptide 16–146, clearly showed differences in the stabilities of helical structures in solutions of urea and guanidine hydrochloride. The addition of SDS accelerated the formation of helical structures in each polypeptide except for 1–13.     

苯硫酚等离子体聚会及其结构与性能

应用外部电容耦合式等离子体聚合装置．研究了苯硫酚等离子体聚合规律，找到了最佳聚合条件，通过热失重、红外光谱、X－射线衍射、电子衍射、GC－MS和接触角测定等研究了聚合物结构与性能。电导率测定表明等离子体聚苯硫酚具有半导体性质。     

Multianvil high-pressure/high-temperature preparation, crystal structure, and properties of the new oxoborates Dy4B6O14(OH)2 and Ho4B6O14(OH)2

This paper reports about two new hydrogen-containing rare-earth oxoborates RE₄B₆O₁₄(OH)₂ (RE=Dy, Ho) synthesized under high-pressure/high-temperature conditions from the corresponding rare-earth oxides, boron oxide, and water using a Walker-type multianvil equipment at 8 GPa and 880 °C. The single crystal structure determination of Dy₄B₆O₁₄(OH)₂ showed: Pbcn, a=1292.7(2), b=437.1(2), , Z=2, R1=0.0190, and wR2=0.0349 (all data). The isotypic holmium species revealed: Pbcn, a=1292.8(2), b=436.2(2), , Z=2, R1=0.0206, and wR2=0.0406 (all data). The compounds exhibit a new type of structure, which is built up from layers of condensed BO₄-tetrahedra. Between the layers, the rare-earth cations are coordinated by 7+2 oxygen atoms. Furthermore, we report about temperature-resolved in situ powder diffraction measurements, DTA/TG, and IR-spectroscopic investigations into RE₄B₆O₁₄(OH)₂ (RE=Dy, Ho).     

Trinuclear Schiff base complexes with uranium(V) and copper(II) or zinc(II) ions

Treatment of the uranium(IV) complexes [{ML¹(py)}₂U^IV] (M = Cu, Zn; L¹ = N,N′-bis(3-hydroxysalicylidene)-1,3-propanediamine) with silver nitrate in pyridine led to the formation of the corresponding cationic uranium(V) species which were found to be thermally unstable and were converted back into the parent U^IV complexes; no electron transfer was observed in solution between the U^IV and U^V compounds. In the crystals of [{ML¹(py)}₂U^IV][{ML¹(py)}₂U^V][NO₃], the neutral U^IV and cationic U^V species are clearly identified by the distinct U–O distances. Similar reaction of [{ZnL²(py)}₂U^IV] [L² = N,N′-bis(3-hydroxysalicylidene)-1,4-butanediamine] with AgNO₃ gave crystals of [{ZnL²(py)}U^V{ZnL²(py)₂}][NO₃] but the copper counterpart was not isolated. Crystals of [{ZnL¹(py)}₂U^V][OTf] · THF (OTf = OSO₂CF₃) were obtained fortuitously from the reaction of [Zn(H₂L¹)] and U(OTf)₃.