MULTIDENTATE LIGAND EXCHANGE KINETICS: REACTIONS OF AMINOCARBOXYLATO-FERRATE(Ⅲ) COMPLEXES WITH 4-(2-PYRIDYLAZO) RESORCINOL

The kinetics and mechanism of ligand substitution reactions of nitrilotriacetatoiron(Ⅲ), [Fe(NTA)], and N-(2-hydroxyethyl)-ethylenediaminetfiacetatoiron(Ⅲ), [Fe(HEDTA)], complexes with 4-(2-pyridylazo) resorcinol (Par) has been investigated at pH = 9.0±0.02, I= 0.1mol·1~(-1) (NaClO_4), and temp. = 25 ±0.1℃ and 30±0.1℃ respectively. The reaction has been studied spectrophotometrically at 496 nm. (λ_(max) of Fe(Par)_2). In both reactions the final product was [Fe(Par)_2]~-. The values of second order rate constants for NTA and HEDTA exchange reactions are (10.0±0.8)×10~1·mol~(-1)·s~(-1) and (2.7± 0.1)×10~(-1) 1·mol~(-1)·s~(-1) respectively. The reactions of NTA and HEDTA exchange were studied in the pH range 6-9.5 and 7-10.85 respectively. The rate of reacton of [Fe(NTA)] with HPar~- first increases with pH and then levels off. However, in the case of [Fe(HEDTA)] reaction, the rate increases monotonically with increase of pH in the specified range. The reverse reactions between [Fe(Par)_2     

Chiral Resolution of β-dl-Phenylalanine Using Chiral Macrocyclic Nickel(Ⅱ) Complexes

The reactions of chiral four-coordinated nickel(Ⅱ) complex [Ni(RR-L)](ClO4)2/[Ni(SS- L)](ClO4)2 with β-dl-phenylalanine in acetonitrile/water gave a six-coordinated enantiomer of [Ni(RR-L)(β-d-HPhe)](ClO4)2(1) and [Ni(SS-L)(β-l-HPhe)](ClO4)2(2), respectively(L = 5,5,7, 12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, HPhe = phenylalanine). Single-crystal X-ray diffraction analyses revealed that the nickel(Ⅱ) atom displays a distorted octahedral coordination geometry by coordinating with four nitrogen atoms of L in a folded configuration, and two carboxylate oxygen atoms of β-d/l-HPhe in cis-position in both complexes. The monomers of [Ni(RR-L)(β-d-HPhe)]2+ and [Ni(SS-L)(β-l-HPhe)]2+ are connected through intermolecular hydrogen bonds to generate one-dimensional zigzag chains, respectively. The homochiral natures of 1 and 2 are confirmed by the results of CD spectroscopy.     

Salen型双肟镍(Ⅱ)簇合物的合成与晶体结构

A nickel(Ⅱ) cluster, {[Ni(L)H₂O]₂(OAc)₂Ni}·2EtOH, has been synthesized by the means of the complexation of nickel(Ⅱ) acetate tetrahydrate with a new Salen-type bisoxime ligand (H₂L, 4,4′-dimethoxy-2,2′-[ethylenedioxybis(nitrilo-methylidyne)]diphenol). The crystal structure shows that the hexacoodinated terminal nickel(Ⅱ) ions lie in the N₂O₂ coordination sphere of Salen-type bisoxime ligands, quadruple μ-phenoxo oxygen atoms from two [NiL] chelates coordinated to the central nickel(Ⅱ) ion, and the two acetate anions coordinated to three nickel(Ⅱ) ions through Ni-O-C-O-Ni bridges. Thus, all the three nickel atoms of the cluster have distorted octahedral geometries. CCDC: 736762.     

Rh(Ⅰ)-catalyzed borylation of primary alkyl chlorides

Rhodium-catalyzed cross-coupling reactions of unactivated primary alkyl chlorides with diboron reagents have been developed as practical methods for the synthesis of alkylboronic esters. These reactions expand the concept and utility of Rh(I)-catalyzed cross-coupling of aliphatic electrophiles.     

ELECTROREDUCTION MECHANISM OF Ni(DMG)-2 COMPLEX STUDIED WITH QUANTUM CHEMICAL METHOD

The electronic structures of the species Ni(DMG)_2, (Ni(DMG)_2)~- and (Ni(DMG)_2)_(2-) have been studied by INDO quantum chemical method. The results have clearly shown that in the first stage of the electroreduction of Ni(DMG)_2, one electron interacts with the d orbitals on the nickel atom, while in the further stage the second electron interacts with the p orbitals on the nitrogen atoms. It conforms with our electrochemical experimental studies which showed that not only Ni(Ⅱ) is reduced but also DMG is catalytically reduced during the reduction of Ni(DMG)_2.     

Tf2NH-catalyzed,highly regio-and stereo-selective synthesis of trisubstituted alkenes and indane derivatives from benzylic alcohols and alkenes

A reaction of benzylic alcohols with alkenes has been developed in the presence of bis(trifluoromethane)sulfonimide for the synthesis of trisubstituted alkenes and indane derivatives with high stereoselectivity.In general,benzylic alcohols react with 1,1-diaryl alkenes to afford trisubstituted alkenes,and the reaction with 1,2-disubstituted and trisubstituted alkenes affords indane derivatives through a [3 + 2] annulation reaction.     

V(HSO_4)_3 promoted oxidation of alcohols and trimethylsilyl,tetrahyropyranyl and methoxymethyl ethers with Cu(NO_3)_2·3H_2O in the absence of solvent

V(HSO_4)_3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu(NO_3)_2·3H_2O in the absence of solvent.     

非对称N-(亚水杨基)二亚乙基三胺铜(Ⅱ)配合物的合成、结构分析和催化活性评价(英文)

A new copper(Ⅱ) complex of a non‐symmetric Schiff base, [CuII(saldien)(H2O)]+(1), has been synthesized and characterized by elemental analysis and several other spectroscopic methods (Hsaldien = N‐(salicylidene)diethylenetriamine). The crystal structure of 1 has also been determined by X‐ray crystallography. The geometry of the complex cation in 1 was found to be distorted square pyramidal with the mononegative Schiff base coordinating to the copper in a tetradentate mode via the O,N,N’, and N’’‐donor atoms. The remaining coordination site was occupied by the O atom of a H2O molecule in the axial position. The catalytic potential of 1 was tested in the oxidation reactions of cyclooctene and cyclohexene with aqueous 30% H2O2/NaHCO3 in acetonitrile. These reactions proceeded smoothly to give the corresponding epoxides with selectivity levels greater than 99%. This catalytic system also showed high levels of activity and selectivity towards the oxidation of cyclohexane (i.e., cyclohexanol 37% and cyclohexanone 54%) in comparison with most of the other Cu‐based systems reported in the literature.     

Hydrothermal Synthesis,Crystal Structure and Properties of a New Binuclear Nickel(Ⅲ) Complex with 3-(Pyridin-2-yl)-1,2,4-triazole

A new binuclear nickel(II) complex Ni₂(HPT)_4(H₂O)₃ (1) has been hydrothermally synthesized with nickel hydroxide,3,4-pyridine dicarboxylic acid and 3-(pyridin-2-yl)-1,2,4-triazole (HPT) in the mixed solution (the volume ratio of methanol and water is 1:4).It crystallizes in tetragonal space group P4₂/n,with a=20.844(1),b=20.844(1),c=7.2463(7)A,V=3148.2(5)A³,D_c=1.587 g/cm³,Z=4,μ(Mo Ka)=1.257,F(000)=1544,the final GOOF=1.043,R=0.0437 and w R=0.1297.The crystal structure shows that the whole molecule consists of two nickel ions which are bridged by fourμ₂-η¹:η^0-3-(pyridin-2-yl)-1,2,4-triazole anions.The coordination environment of Ni(II) ion is Ni N₆,giving a distorted octahedral geometry.The thermal stability and fluorescent and magnetic properties of the complex were investigated.     

1-Butyl-3-methylimidazolium Hydrogen Sulfate [bmim]HSO4: An Efficient Reusable Acidic Ionic Liquid for the Formylation of Alcohols

1-Butyl-3-methylimidazolium hydrogen sulfate [bmim]HSO4 as an acidic ionic liquid was prepared and used as a catalyst for the formylation of alcohols with ethyl formate at room temperature with good to excellent yields. A good selectivity was observed for the formylation of primary alcohols in the presence of tertiary alcohols.     

Copper methanesulfonate-acetic acid as a novel catalytic system for tetrahydropyranylation of alcohols and phenols

A synergistic catalytic effect between copper methanesulfonate and acetic acid in tetrahydropyranylation of alcohols and phenol at room temperature under solvent free condition has been described. Both alcohols (primary, secondary and tertiary) and phenols reacted with 3,4-dihydro-2H-pyran smoothly to afford the corresponding tetrahydropyranyl ethers in good yields.     

Crystal Structure of Tris(2,2'-bipyridine)nickel (Ⅱ) Tetrachlorozincate

A bimetallic complex Ni[C10H8N2]3[ZnCl4] has been synthesized and its crystal structure determined at room temperature. The complex crystallizes in the trigonal system, space group R3c, with a = 13.343(2), b = 13.343(2), c =58. 932(12) A, V= 9087(3) A 3, Z = 12, NiZnC30N6CI14H24, Mr=734.30, Dc=1.611 g/cm3, μ= 1. 799 mm-1, F(000)=4464. Least-squares refinement of the structure leads to the agreement factors R1=0. 0278 and wR2=0. 0741 for the observable reflections. The complex consists of discrete tris (2, 2'-bipyridine) nickel (Ⅱ)cation, [Ni-(bipy)3]2+, and tetrachlorozincate anion, [ZnCl4]2-. Each nickel (Ⅱ)atom is six coordinated in an octahedron with six nitrogen atoms of three 2,2'-bipyridine ligands. The mean Ni(Ⅱ)-N bond length is 2. 089(2) A. The zinc(Ⅱ) atom is coordinated with four chloride atoms in tetrahedral geometry. The mean Zn (Ⅱ)- Cl bond length is 2. 264(1) A.     

Synthesis and Crystal Structure of [Ni(II)(L)(py)_3]·(py)

1 INTRODUCTION Schiff bases and their metal complexes are useful reagents in organic synthesis[1], and they have exhi- bited some biological activities as anticancer and antitumor drugs[2]. The crystal structures and physi- cal and chemical properties of many Schiff bases and their transition metals complexes have been re- ported[3~5]. Further interest in the coordination che- mistry of nickel(II) arises from the role of these complexes in several catalytic reactions, such as electrocat…     

Synthesis, Crystal Structure and Electrochemical Properties of [Ni(phen)_3]·(m-nitrobenzoic acid)_2·(H_2O)

A new nickel(II) coordination complex [Ni(phen)3]·(m-nitrobenzoic acid)2·(H2O) was synthesized by self-assembly of m-nitrobenzoic acid, 1,10-phenanthroline and nickelous per- chlorate. It crystallizes in the monoclinic system, space group C2/c, with a = 2.4596(6), b = 1.2124(3), c = 1.9824(5) nm, β = 97.088(5)o, V = 5.866(3) nm3, Dc = 1.474 g/cm3, Z = 4, Mr = 1301.82, μ(MoKα) = 0.417 mm-1 F(000) = 2688, R = 0.0493 and wR = 0.1025. Structural deter- mination indicates that the nickel(II) ion is coordinated with six nitrogen atoms from three phens, giving a distorted octahedral coordination geometry. The cyclic voltametric analysis shows that the electron transfer in the electrode reaction is irreversible.     

DETERMINATION AND REFINEMENT OF THE CRYSTAL STRUCTURE OF CHAIDAMUITE

Chaidamuite (ZnFe(SO_4)_2(OH). 4H_2O), which is a new sulphate mineral, belongs to the triclinic system, space group P1, with the cell parameters corrected by the least-squares method: a=7.309(2), b=7.202(2), c=9.691(3), α=89.64(3), β=105.89(3), γ=91.11(2)°, Z=2. The crystal structure has been determined by the Patterson method and Fourier syntheses and refined by the full-matrix least-squares method to an R factor of 0.032, using 2833 independent reflections. In the structure, a zigzag chain consists of [Fe(1)O_5(OH)] and [Fe(2)O_5(OH)] octahedra sharing the OH corners, and an octahedral-tetrahedral chain running parallel to the b axis consists of the zigzag chain of Fe octahedra and (SO_4) tetrahedra sharing four pairs of octahedral corners on either side of the zigzag chains. These chains are cross-linked by the isolated [Zn(1)O_2(H_2O)_4] and [Zn(2)O_2(H_2O)_4] octahedra into corrugated sheets parallel to the (100) plane. Adjacent sheets are hydrogenbonded through water molecules.     

新型五氟苯铵三氟有机催化剂高效合成14-芳基(烷基)-14H-二苯并[a,j]呫吨类化合物和1,8-二氧代氧杂蒽衍生物(英文)

A simple and facile synthesis of 14-aryl and alkyl-14H-dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthene derivatives has been successfully developed by treatment of β-naphthol or dimedone with aldehydes under mild conditions in the presence of a pentafluorophenyl ammonium triflate(PFPAT) organocatalyst.These catalytic condensation reactions represent green chemical processes and the PFPAT organocatalyst is air-stable,cost-effective,easy to handle,and easily removed from the reaction mixtures.     

Dinuclear Nickel(Ⅱ) Chlorides Bearing N,N′-bis(5,6,7-trihydroquinolin-8-ylidene)-[1,1′-biphenyl]-4,4′-diamines: Synthesis and Ethylene Polymerization

5,6,7-Trihydroquinolin-8-one was condensed with the corresponding benzidine to give N,N′-bis(5,6,7-trihydroquinolin-8-ylidene)-[1,1′-biphenyl]-4,4′-diamine derivatives(L1–L3). The ligands were reacted with two equivalents of Ni Cl_2·6H_2O in a mixture of Et OH and CH_2Cl_2 to afford the corresponding dinickel(II) chloride complexes(Ni1-Ni3). The organic compounds were completely characterized, whilst the bi-metallic complexes were characterized by FTIR spectra and elemental analysis. These nickel complexes exhibited high activities towards ethylene polymerization in the presence of either MAO or Me_2AlCl, maintaining a high activity over a prolonged period. The obtained polyethylenes were confirmed as having low molecular weights by GPC analysis.     

Asymmetric Induction of Chiral 1,1''''-Bis(oxazolinyl)ferrocenes as Ligands in Metal-Catalyzed Cyclopropanation and Diels-Alder Reactions

Bis(oxazoline) ligands1 have been successfully used in a variety of metal-catalyzed asymmetric reactions, such as cyclopropanation, allylic oxidation reactions, etc; Chiral ferrocene derivatives2 have also been proved as effective ligands in numerous asymmetric reactions, for example, chiral ferrocenylphosphines exhibited high enantioselectivity for the reduction of olefins, Heck reactions and Aldol reactions of aldehydes. These results stimulated us to study the behaviour the bis(oxazoline) …     

REACTIONS OF 1-ACETOXY ALLYLIC PHOSPHONATES UNDER PALLADIUM(0) CATALYSIS

l-Acetoxy allylic phosphonates rearrange regioselectively to γ-acetoxy α,β-unsaturated phosphonates under the catalysis of Pd(0). l-Acetoxy allylic phosphonates act as the precursors of phosphonatedπ-allylic cations in palladium(0) catalyzed reactions[1]. The reactions of l-acetoxy allylic phosphonates under palladium(0) catalysis with nucleophiles have been reported. 1-4 These reactions are highly regio- and stereoselective. We wish to report here the palladium(0) catalyzed reaction of l-acetoxy allylic phosphonates in the absence of a nucleophile.     

ASSIGNMENT OF ~(13)C NMR SPECTRA OF POLYMER WITH SEMIEMPIRICAL METHOD——SURVEY OF SPECTRUM OF SECONDARY CARBON OF 1, 2-PBD

In chain molecules of 1, 2-PBD, there are two kinds of gauche arrangements, which is the cause of making the spectrum of the secondary carbon in main chain of the polymer split. In such a complex system, the gauche arrangements of the secondary carbon and the tertiary carbon occupy an important position. Hence, the contribution of the tertiary carbon to the chemical shifts of the secondary carbon has a decisive effect on the sequence structure distribution. In comparison the contribution of vinyl groups is much less. The γ values are: γ_1=-6.37～-6.41 ppm represents the effect of the tertiary carbon and γ_2=0.0～-1.56 ppm the contribution of vinyl. The mean square errors are 0.364 and 0.166×10~(-2) ppm~2, respectively in the two cases of considering the effect of vinyl and vice versa. In this paper, we discuss the effects of model chain type, chain length and temperature on the bond probability. Meanwhile, it is pointed out that there exist a few cases, which are not in accord with the usual distrib