2-氯吡啶和2,6-二氯吡啶

2-氯吡啶和2,6-二氯吡啶是重要的医药、农药、日化用品和染料等的原料,文章 介绍了2-氯吡啶和2,6-二氯吡啶的合成技术,应用,市场与发展。     

INFLUENCE OF THE AMINE NATURE ON THE COMPOSITION OF PALLADIUM COMPLEXES IN SOLVENT EXTRACTION SYSTEMS

ABSTRACT

The extraction of palladium chloro complexes by di-n-octylamine and diamines of various structure as function of the composition of the aqueous and organic phases has been studied. The compositions of the extracted species are indicated and the mechanisms of their distribution are described. It was shown that from 1 to 3 M HC1 solutions. complexes such as (R₂NH₂)₂PdCl₄ solvated by molecules of dioctvlamine chloride are extracted. With increasing the initial concentrations of palladium or decreasing acidity of the aqueous phase, a direct coordination takes place, first of one and then two molecules of amine to atom of palladium with the formation of extracted compounds such as HC1 solutions by salts of amines, diamines and QAB ionic associates such as (AmH)₂PdCl₄, (AmH)₂)PdCl₄ and (R₄N)₂PdCl₄, respectively, are recovered into the organic phase. In systems containing trioctylamine, tetraoctylalkylenediamines (n = 4, 6) and QAB. ionic associates containing the dimeric complex anion, Pd₂Cl₆ ^2-, are also formed. When primary (n-octylaniline - OA) and secondary amines are used as extractants the formation of dimeric species in the organic phase is not observed.

The extraction of palladium from weakly acidic and neutral solutions can proceed through a combination of anion-exchange and coordination mechanisms with the formation of (AmH)[Pd(Am)Cl₃] in systems with primary and secondary amines, and through a coordination mechanism with the formation of complexes such as Pd(Am)₂Cl₂ in systems with primary, secondary and tertiary amines. When palladium is extracted by diamines with a short hydrocarbon chain (n=2) the formation of coordination compounds also takes place.     

Syntheses,characterizations, antitumor activities and cell apoptosis induction of Cu(II), Zn(II) and Cd(II) complexes with hydrazone Schiff base derived from isonicotinohydrazide

Three novel complexes, [Cu₄(L)₄Cl₄]·H₂O (1), Zn(L)₂ (2) and Cd(L)₂ (3), based on HL (where HL = 2-acetylpyridine isonicotinohydrazone) were synthesized and characterized by X-ray diffraction analyses. In the tetranuclear complex 1, each copper(II) ion with a distorted square-planar coordination geometry is five-coordinated by one chloride anion, one ON₂ donor set and one 4-pyridine nitrogen atom from another adjacent actylhydrazone ligand. However, the central ions in complexes 2 and 3 possess distorted octahedral coordination geometry, surrounded by two ON₂ donor sets. In addition, all the complexes have excellent antitumor activity towards human lung cancer (A549) and human gastric cancer (SGC7901 and BGC823) cell lines. Furthermore, cell apoptosis induced by complex 1 was detected through TUNEL and Annexin V/PI staining with flow cytometric analysis and western blotting analysis.     

Structural and Dynamic Aspects of Palladium(II)‐Based Self‐Assembled Binuclear Coordination Complexes

Self‐assembled binuclear complexes of Pd₂L′₂L₂ and Pd₂L₄ type formulations have been achieved by combining the cis‐protected palladium(II) component i. e., [PdL′]²⁺ (where L′ stands for tmeda) and naked palladium(II) separately with a 3‐pyridyl appended non‐chelating bidentate ligand, L under suitable conditions. Supramolecular fusion of the Pd₂L₄ and PdL′₂ type complexes have been demonstrated that provided the corresponding Pd₂L′₂L₂ type complex. One pot synthesis of the binuclear Pd₂L′₂L₂ type complex is achieved by combining palladium(II), L′ and L at equimolar ratio, however, along with an unidentified trap. The crystal structure of a Pd₂L₄ type complex confirmed the binuclear architecture of the cage. Intermolecular H‐bonding and π‐π stacking interactions are analyzed from the crystal structure and the extended intermolecular interactions apparently generated a grid pattern.     

The first carbamoyl–carboxylate complex of transition metals: Synthesis and structure of {(OC4H8NH)[OC4H8NC(O)]Pd}2(μ-CMe3CO2)2

Reactions of palladium(I) carbonyl carboxylate complexes [Pd(μ-CO)(μ-RCO₂)]_n with secondary amines on the example of morpholine were studied. It was found that intramolecular carbonylation of amine in coordination sphere of polynuclear palladium species proceeds and binuclear palladium carbamoyl complex {(OC₄H₈NH)[OC₄H₈NC(O)]Pd}₂(μ-RCO₂)₂ forms as a result. This is the first structurally characterized carbamoyl–carboxylate complex of transition metals. Also it was shown that morpholine itself and carboxylate-anions act as proton acceptors in the reaction of carbonylation of morpholine by coordinated CO.     

Synthesis of palladium clusters with surface initiator for polymerization of 2-methyl-2-oxazoline

Summary Palladium clusters were synthesized by reduction of palladium(II) acetate in the presence of a bipyridyl ligand (1) with an initiator for polymerization of 2-methyl-2-oxazoline. The 1-protected palladium clusters were soluble in CHCl₃ and CH₂Cl₂. The 1-protected palladium clusters were combined with 2-methyl-2-oxazoline in chloroform. After polymerization, the reacted bipyridyl ligand was removed from the palladium cluster by suspending the obtained palladium clusters with pyridine. The ¹H NMR measurement indicated that the reacted bipyridyl ligand was formed via surface polymerization of 2-methyl-2-oxazoline. Received: 19 April 2001/Accepted: 2 May 2001     

SOLVENT EXTRACTION OF PALLADIUM FROM CHLORIDE SOLUTIONS BY ALKYLAMMONIUM DI(2-ETHYLHEXYL)DITHIOPHOSPHATES

ABSTRACT

The extraction of palladium (II) from chloride solutions (over a wide region of aqueous acidity) by di(2-ethylhexyl)dithiophosphates of tetraoctylammonium, tri-n-octylammonium and di-n-octylammonium in toluene at the constant chloride concentration has been studied. A synergistic effect was shown to be observed in these systems and it is explained by the formation of unusual complexes with mixed ligands. It has been established the palladium complexes, such as (R₃NH)[PdCl₂A], (R₃NH)[PdCl₂A] and (R₂NH₂)[PdCl₂A], involving both alkylammonium cation and dialkyldithiophosphate anion are extracted under conditions of the loaded organic phase using distribution methods depending on a composition of aqueous and organic phase. At the excess of R₃NHA or R₂NH·HA, PdA₂ is extracted into the organic phase. Table 8 reports the results obtained and indicates the domains of existence of the various species of palladium (II) extracted into the organic phase in the binary ex-tractant systems in comparison with the initial systems     

Palladium(II) complexes with polyphosphazene

An allylphenoxy-substituted polyphosphazene has been modified via inorganic chemical concepts. The transition metal salt is bis(acetonitrile)dichloropalladium(II). The coordination complexes have been characterized using acid-base solution chemistry, sol-gel phase transitions, thermomechanical property measurements and infrared spectroscopy. Solid complexes of polyphosphazene and PdCl₂ cannot be dissolved in the original solvent (i.e., tetrahydrofuran) used during sample preparation. These polymeric palladium complexes also cannot be disrupted by a stronger base, like triphenylphosphine. There is a monotonic increase in the glass transition temperature at higher concentrations of palladium chloride. T_g of the pure polymer increases by 21°C in the presence of 10 mol% palladium chloride. The increase in high-strain mechanical properties cannot be explained solely by a “filler effect.” At higher PdCl₂ concentrations, there is a direct correlation between the enhancement in T_g, higher mechanical fracture stress, and increased infrared absorbance @ 1092 cm^?1 because of the formation of a palladium-π-complex with allylic substituents in the phenoxy sidegroup. Palladium chloride relinquishes its acetonitrile ligands after dissolution in THF, and the vacant sites in the first-shell coordination sphere of the transition metal are occupied by these allylic substituents in the sidegroup. This produces interchain coordination crosslinks, which modify the thermomechanical properties of polyphosphazene/ PdCl₂ complexes.     

Preparation of novel lanthanide complexes with hindered amine via solid‐state reaction and preliminary evaluation of their efficiency as light stabilizers

In this research, a series of lanthanide complexes with a low molecular weight hindered amine have been synthesized for the first time from lanthanide chloride and bis‐(2,2,6,6‐tetramethyl‐4‐piperidinyl)‐decanedioicacid (L) by simply using a solvent‐free solid‐state reaction. Elemental and thermo analysis suggest that the component of the complexes is LnLCl₃ 2H₂O (Ln = Y, La, Nd, Sm, Eu, Gd, Dy, Er). Infrared spectra indicate that the lanthanide ions are coordinated with oxygen atoms of the carbonyl group in ligand. Polypropylene films containing the ligand and complexes were prepared by melt blending and compression molding, and were exposed to UV irradiation before and after ethanol extraction. The measurements of carbonyl index, thermal decomposition temperature, and tensile elongation at break reveal that these complexes have comparable photostabilizing efficiency and improved extraction resistance compared to the ligand alone. This study suggests that hindered‐amine lanthanide complexes can provide novel approach to the cheap and efficient light stabilizers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Ring-opening copolymerization of CHO and MA catalyzed by the asymmetrical Cr(III)-bis-Schiff-base complex

Using an asymmetrical Cr(III)-bis-Schiff-base complex [Cr(L)Cl] (1; H₂L obtained from condensation of 5-bromo-salicylaldehyde and HL⁰ ((Z)-4-((2-aminophenylimino)(phenyl)methyl)-3-methyl-1H-pyrazol-5(4H)-one) as the catalyst, bulk solvent-free ring-opening copolymerization of CHO (cyclohexene oxide) and MA (maleic anhydride) in the presence of cocatalyst DMAP (4-(dimethylamino)-pyridine) was effectively realized, in which, on the condition of low 1/DMAP concentration for a controllable polymerization, perfectly alternating polyester while not poly(ester-co-ether) could be obtained.     

CuII Pyrazolyl-Benzimidazole Dinuclear Complexes with Remarkable Antioxidant Activity

Three dinuclear coordination complexes generated from 1-n-butyl-2-((5-methyl-1H-pyrazole-3-yl)methyl)-1H-benzimidazole ( L ), have been synthesized and characterized spectroscopically and structurally by single crystal X-ray diffraction analysis. Reaction with iron(II) chloride and then copper(II) nitrate led to a co-crystal containing 78 % of [Cu(NO₃)(μ-Cl)( L’ )]₂ ( C₁ ) and 22 % of [Cu(NO₃)(μ-NO₃)( L’ )]₂ ( C₂ ), where L was oxidized to a new ligand L^’ . A mechanism is provided. Reaction with copper chloride led to the dinuclear complex [Cu(Cl)(μ-Cl)( L) ]₂ ( C₃ ). The presence of N−H⋅⋅⋅O and C−H⋅⋅⋅O intermolecular interactions in the crystal structure of C₁ and C₂ , and C−H⋅⋅⋅N and C−H⋅⋅⋅Cl hydrogen bonding in the crystal structure of C₃ led to supramolecular structures that were confirmed by Hirshfeld surface analysis. The ligands and their complexes were tested for free radical scavenging activity and ferric reducing antioxidant power. The complex C₁ / C₂ shows remarkable antioxidant activities as compared to the ligand L and reference compounds.     

On the topology of highly branched polyethylenes prepared by amine−imine nickel and palladium complexes: the effect of ortho‐aryl substituents

Series of nickel and palladium complexes bearing amine?imine ligands in various ortho‐aryl and backbone positions were prepared and investigated in ethene polymerization. Ethene polymerization initiated by symmetrically ortho‐substituted nickel and palladium amine?imine catalysts is controlled. Mono‐substitution in the ortho‐aryl positions of nickel complexes is not as efficient in protecting centers from chain transfer as di‐substitution. Both the central metal and the size of the ortho‐aryl substituent have a significant effect on the polyethylene (PE) topology. Based on detailed characterization by high temperature SEC‐IR‐η, SEC with multi‐angle laser light scattering and ¹³C NMR data, PEs prepared by nickel amine?imine complexes have a linear rather than dendritic topology. In contrast, palladium amine?imine complexes with small ortho‐aryl substituents at low ethene pressure were shown for the first time to form dendritic PEs with topology comparable to PEs formed by α‐diimine palladium catalyst. © 2018 Society of Chemical Industry     

Some Parametric Studies on Separation of Palladium from Perchloric Acid Medium by Radiolytic Reduction

Abstract

The radiolytic reduction of palladium ions to palladium metal in perchloric acid solutions has been studied with the aim of separating palladium from aqueous acidic waste. Fraction of Pd separated out as precipitate has been studied as a function of initial Pd concentration and strength of HClO₄. Addition of t‐butanol to the system has been found to cause substantial enhancement in the amount of Pd precipitated as compared to that in its absence. At a given absorbed dose, the extent of Pd separated is found to increase with the concentration of HClO₄ in presence of t‐butanol. However, the converse is true for the radiolysis in absence of t‐butanol. The decrease in the extent of reduction of Pd(II) to Pd(0) has been found to be due to increasing formation of chloride ions that tend to form reduction resistant cholorocomplexes of Pd. This is supported by the red‐shifting in the absorption bands of Pd(ClO₄)₂ observed for the spectra of gamma radiolysed solutions of Pd(II) at higher HClO₄ concentrations. External addition of chloride ions to aqueous Pd(II)/HClO₄ system even in presence of t‐butanol has been found to cause substantial inhibition to the radiolytic reduction of Pd(II) owing to formation of reduction‐resistant complexes. Correspondingly, the addition of nitrate ions to Pd(II)/HClO₄/t‐butanol system showed inhibition effect at much greater stoichiometric amount of nitrate.     

SOLVENT EXTRACTION OF PALLADIUM(II) WITH A SULFUR-CONTAINING CARBOXYLIC ACID

The mechanism of solvent extraction of palladium (II) from aqueous ammonium chloride solution with α-butylthiolauric acid( α-BTLA = S) in toluene was investigated in terms of extraction equilibrium and kinetics at 303 K. From the results of extraction equilibrium, it was found that α-BTLA behaves as a solvating extractant for palladium(II) and that the extracted species is a 1:2 metal:reagent complex, PdCl₂S₂ The extraction rate of palladium(II) was measured in a batch-type vigorously stirred cell. The effects of the concentrations of palladium(I I), hydrogen ion, chloride ion and extractant on the extraction rate were quantitatively interpreted by a reaction mechanism where the parallel reactions of α-BTLA with PdCl₃(H₂0)- and PdCl₄ ^2- are the rate-determining steps.     

Synthesis and structural characterisation of new binuclear Pd(II) complexes with both bridging and terminal pyrazolate ligands

Dinuclear pyrazolato-bridged Pd(II) complexes Pd₂L₄⁰ and Pd₂L₄¹ have been prepared by reacting Pd(Ac)₂ and one equivalent of HL⁰ (3-phenyl-5-(2-pyridyl)pyrazole) or HL¹ (3-phenyl-5-(6-methyl-(2-pyridyl))pyrazole. The new complexes have been characterised by elemental analyses, IR, ¹H NMR and in the case of PdL¹₄ by single crystal X-ray diffraction methods. This structure shows two palladium atoms bridged by two L¹ ligands. The square-planar geometry of each Pd atom is completed by a bidentate chelating L¹ ligand. The six-membered dipalladacycle formed by the two Pd atoms and the two bridging pyrazolato ligands adopts a distorted boat-like conformation.     

Synthesis of Pd(II) coordination complexes of (S)-4-isobutyl-2-methyl-2-oxazoline and (S)-2-(2,2-dimethylpropyl)-4-isopropyl-2-oxazoline

(S)-4-Isobutyl-2-methyl-2-oxazoline (1) was obtained from ethyl acetimidate hydrochloride and l-leucinol in 81% yield. (S)-2-(2,2-Dimethylpropyl)-4-isopropyl-2-oxazoline (2) was synthesized from 3,3-dimethylbutyryl chloride and l-valinol in two steps in a total yield of 44%. Reactions of oxazolines 1 and 2 with Pd(OAc)₂ in AcOH or MeCN at different temperatures followed by treatment with LiCl resulted in the formation of the corresponding coordination complexes PdCl₂(1)₂ and PdCl₂(2)₂ with no traces of cyclopalladated complexes.     

Effect of Br− on the Adsorption Rate of Palladium(II) Ions onto Condensed-Tannin Gel in Chloride Media

Abstract

In chloride media, chloropalladium(II) species are adsorbed onto tannin gel particles through an inner-sphere redox reaction mechanism containing the intermediate step, formation of a ligand-substituted Pd(II)-tannin complex. In this Pd(II) adsorption process, it was observed that the adsorption rate can be increased by introducing Br^?, a softer ligand than Cl^?, into the aqueous chloride solution. The formation of mixed-ligand palladium(II) complexes accelerates the rate of ligand-substitution reactions with the hydroxyl groups of tannin gel by the trans effect. The adsorption condition can be optimized by controlling the [Br_tot]/[Cl_tot] ratio, in which the predominant Pd(II) species are bromo-chloro palladium(II) complexes, the favorable species for the trans effect.     

New metal catalysts for soybean oil transesterification

We report here the synthesis, characterization, and use of tin (3-hydroxy-2-methyl-4-pyrone)₂(H₂O)₂, lead (3-hydroxy-2-methyl-4-pyrone)₂ (H₂O)₂, mercury (3-hydroxy-2-methyl-4-pyrone)₂-(H₂O)₂, and zinc (3-hydroxy-2-methyl-4-pyrone)₂(H₂O)₂ as catalysts in the transesterification reaction of soybean oil with methanol. All complexes are active in this reaction, with the following decreasing activities: Sn²⁺≫Zn²⁺>Pb²⁺≈Hg²⁺. The catalytic activities of these complexes were also compared with classical alkali and acid transesterification catalysis (with NaOH and H₂SO₄).     

A Spectrophotometric Study of Trivalent Actinide Complexes in Solution. IV. Americium with Chloride Ligands

The light absorption spectra of americium(III) in ethanolic and concentrated aqueous lithium chloride solutions, and in long-chain alkylammonium chloride solutions in aromatic diluents were obtained, as well as those of certain solid double salts and complexes. A strong 5f⁶ → 5f⁵6d¹ transition was observed in the aqueous solutions at 235 nm (42,500 cm^?1), and from the dependence of the intensity of this and the 503 nm (19,880 cm^?1) band, on the effective chloride activity, the stability constants of the inner sphere complexes: AmCl²⁺, logβ₁^* = ?2.21± 0.08, and AmCl₂⁺, log β₂^* = ?4.70 ± 0.08, were determined. The spectrum of the long-chain amine extracts is comparable to that of solids of the composition AmCl₃ · 2N(C₄H₉)₄Cl · × LiCl, and the nature of the extracts and of this and similar solids is discussed.     

Synthesis and structural study of tri- and dinuclear palladium complexes of 2,6-bis(diphenylphosphino)pyridine

The bridging ligand 2,6-bis(diphenylphosphino)pyridine, L, was used to synthesize two palladium complexes: Pd₃Cl₆(μ-L)₃ has a C₂ axis passing through an 18-membered macrocyclic ring, in which two cis- and one trans-coordinated palladium(II) atoms are alternately bridged by three L ligands; [Pd₂(μ-L)₂]²⁺ exhibits a rare coordination mode in which two metal–metal bonded palladium(I) atoms (Pd–Pd = 2.5525(7) Å) are each P, N-chelated by one ligand and connected to the bridging phosphorus atom of the other ligand.