比光谱导数-零交点法同时测定铜、锌、镍

在ｐＨ＝８的硼砂－ＨＣｌ缓冲溶液中，以乳化剂ＯＰ作增溶剂，Ｃｕ＾２＋，Ｚｎ６２＋，Ｎｉ＾２＋分别与５－Ｂｒ－ＰＡＤＡＰ形成稳定的配合物，用比光谱导数－零交点法同时测定铜，锌，镍，合成试样６次测定的相对标准偏差小于５％，铜，锌，镍的回收率分别为９７．０％－１０３．２％，９６．３５－１０４．８％和９５．２％－１０１．９％。     

Direct carbohydrate to carbocycle conversions via intramolecular allylation with Et2Zn/Pd(0)

Treatment of 5-vinylpyranosides with Et₂Zn and catalytic Pd(0), in the presence of ZnCl₂, results in the formation of 5-membered carbocyclic products. This carbohydrate ring-contraction features an intramolecular allylation of a ring-opened carbohydrate aldehyde by an in situ-generated nucleophilic allylzinc species. The stereoselectivity about vinyl and free hydroxyl groups at the newly created stereogenic centers varies from low to moderate while both its extent and sense are found to depend on particular structural features (e.g. the configuration of the starting carbohydrate).     

Synthesis and Crystal Structure of a Two-dimensional Zinc(II) Coordination Polymer: [Zn_2(DTB)(DMF)_4(H_2O)_2]_n (DTM= 1,4-Dinitro-2,3,5,6-tetracarboxylatebenzene Tetravalent Anion; DMF = Dimethylformamide)

1 INTRODUCTION For a long time much research interest has beenfocused on coordination polymers because they mayafford new materials with useful properties, such ascatalytic activity, microporosity, electrical conduc-tivity, non-linear optical activit…     

Formation of upper rim acylated calix[4]arenes using a sacrificial zinc anode

A straightforward electrosynthetic method is described, which allows upper rim acylation of non-p-halogenated calix[4]arenes. For example, a solution of tetrapropoxycalix[4]arene 4 was electrolysed in the presence of ZnBr₂ in an undivided cell fitted with a sacrificial zinc anode using pure acetonitrile as solvent, yielding an organozinc species, which was then treated with acetyl chloride in the presence of a palladium catalyst to afford 5,11-diacetyl-25,26,27,28-tetrapropoxycalix[4]arene 5 in ca. 35% yield after workup.     

Homoleptische Zinkamide: Der Übergang zu monomeren Molekülen

Homoleptic Zinc Amides: Transition to Monomeric Molecules Zinc chloride reacts with the lithium salts of the bulky secondary amines HN(i-Bu)₂ and HN(t-Bu)₂ to form the corresponding homoleptic zinc compounds {Zn[N(i-Bu)₂]₂}₂ ( 1 ) and Zn[N(t-Bu)₂]₂ ( 2 ). The NMR spectroscopic and mass spectrometric results as well as the molecular weight determinations and X-ray diffraction data are consistent with a dimeric structure of 1 and a monomeric structure of 2 in the gas phase, in solution and in the solid state.     

Sol-Gel Synthesis of Hollow Zinc Ferrite Fibers

Hollow zinc ferrite fibers have been prepared via a facile citrate sol-gel process using Fe(OH)(HCOO)₂ prepared in laboratory and Zn(CH₃COO)₂⋅2H₂O as the original materials. The obtained hollow fibers were flexible and handlable with the outer diameter being 1–4 μm and the wall thickness less than 1 μm, and the fiber wall were made up of nanoparticles about 50 nm. Rheological behaviour of the precursor sol was tracked by Rheometer. The development of the gel fibers to zinc ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM and TEM.     

A novel preparation of methyl ketones through one-carbon homologation of aldehydes

A novel two-step aldehyde homologation procedure for the preparation of methyl ketones has been developed, which involves the use of 1,1-dibromo-1-alkenes as precursors and zinc metal as mediator in near-critical water.     

An insight into a novel class of self-assembled porphyrins: geometric structure, electronic structure, one- and two-photon absorption properties

We have theoretically investigated a series of butadiyne-linked porphyrin derivatives that exhibit large two-photon absorption (TPA) cross sections in the visible-IR range. The electronic structure, one-photon absorption (OPA), and TPA properties have been studied in detail. We found that the introduction of a butadiyne linkage and the increase of the molecular dimensionality from monomer to dimer determine the OPA intensities of Q band and Soret band, respectively. A most important role for the enhancement of the TPA cross section is played by introducing a butadiyne bridge. The complementary coordination and the combination of the terminal free base and the core zinc porphyrin are also two effective factors for the enhancement of the TPA efficiency. The dimer with two porphyrins linked at meso-positions by a butadiyne linkage results in a maximum TPA cross section (79.35 x 10(-48) cm4 s per photon). Our theoretical findings are consistent with the recent experimental observations. This series of porphyrin derivatives as promising TPA materials are the subject of further investigation.     

泡沫塑料柱色谱法纯化可溶性锌（镉）盐

研制出复合泡沫塑料色诸柱，并且将其用于可溶性锌（镉）盐的深度纯化，除去重金属杂质离子Ｆｅ￣（２＋）、Ｃｒ￣（３＋）、Ｍｎ￣（２＋）、Ｐｂ￣（２＋）、Ｃｕ￣（２＋）、Ｃｏ￣（２＋）和Ｎｉ￣（２＋），快速而效果显著。     

Synthesis and Crystal Structure of a Novel Hydrogen-Bonded Three-Dimensional Polymer [Zn(1,4-benzenedicarboxylate)-(pyridine)·H_2O]_n

ＩｎｔｒｏｄｕｃｔｉｏｎＤｅｓｉｇｎａｎｄｓｙｎｔｈｅｓｅｓｏｆｎｏｖｅｌｓｕｐｒａｍｏｌｅｃｕｌａｒｃｏｍ ｐｌｅｘｅｓｗｉｔｈｕｎｕｓｕａｌａｎｄｔａｉｌｏｒａｂｌｅｓｔｒｕｃｔｕｒｅｓａｒｅｆｕｎｄａ ｍｅｎｔａｌｓｔｅｐｓｉｎｄｉｓｃｏｖｅｒｙａｎｄｆａｂｒｉｃａｔｉｏｎｏｆｖａｒｉｏｕｓｔｅｃｈ ｎｏｌｏｇｉｃａｌｌｙｕｓｅｆｕｌｆｕｎｃｔｉｏｎａｌｓｕｐｒａｍｏｌｅｃｕｌａｒｄｅｖｉｃｅｓ .1 3Ｒｅｃｅｎｔｌｙ ,ｃｏｎｓｉｄｅｒａｂｌｅｅｆｆｏｒｔｓｈａｖｅｂｅｅｎｄｅｖｏｔｅｄｔｏｃｒ…