Synthesis and Characterization of Some Novel Dialkyldithiophosphate Derivatives of Macrocyclic Complexes of Pb(II) Having N2 S2 Potential Donors in 14- to 20-Membered Rings

Dialkyldithiophosphate derivatives of macrocyclic complexes of Pb(II), having N₂S₂ potential donors, of the general formula, [Pb(L)S₂P(OR)₂] (where L = macrocyclic ligands L¹, L², L³, L⁴ & L⁵ and R = CH₃-, C₃H₇ ⁿ- & C₃H₇ ⁱ-) have been Synthesized from the reactions of [Pb(L)X₂] (where X = Cl, NO₃, or CH₃COO) with sodium dialkyl dithiophosphates in 1:2 molar ratios in THF. Fifteen new derivatives have been synthesized by the combination of five macrocyclic complexes of 14–20 member rings with three different types of dialkyldithiophosphate. These compounds have been characterized by elemental analysis, molar conductance, molecular weight determination, IR, ¹H NMR, ¹³C, and ³¹P NMR. Molecular weight determinations of these complexes indicate their monomeric nature. An octahedral structure is proposed.     

Dinuclear Nickel(II) and Zinc(II) Complexes of 2,6-[N,N′-bis(2-hydroxyphenylmethyl)-N,N′-bis(2-pyridylmethyl)aminomethyl]-4-methylphenol

Abstract

The symmetric 'end-off' compartmental proligand 2,6-[N,N′-bis(2-hydroxy-phenylmethyl)-N,N′-bis(2-pyridylmethyl)aminomethyl]-4-methylphenol (H₃L) has been used to generate homodinuclear nickel(II) and zinc(II) complexes. The crystal structures of the complexes reveal that the di-nickel(II) complex is donor asymmetric and the di-zinc(II) complex is coordination number asymmetric. In both complexes non-coordinated acetic acid molecules are tightly hydrogen-bonded to the pendant phenols of the ligand generating a double acid salt of the type[CH₃COO…H…L…H…OOCCH₃]^3? in the dinickel complex and a single acid salt of the type [CH₃COO…H…L]^3? in the dizinc complex. In both cases the ligand periphery has been extended to provide a supraligand in which the donor potential of the original ligand has been enhanced.     

Cycloolefin Copolymers by Early and Late Transition Metal Catalysts

The complex [Pd(κ²‐P,O‐{2‐(2‐MeOC₆H₄)₂P}C₆H₄SO₃)Me(dmso)] ( 1 ) is investigated for the copolymerization of (E) with norbornene (N) and functionalized N derivatives affording P(E‐co‐N) in excellent yields. Copolymer molar masses are higher than those of PE and increase with N concentration. In addition, the complex [Ti(κ²‐N,O‐{2,6‐F₂C₆H₃N = C(Me)C(H) = C(CF₃)O})₂Cl₂] ( 2 ) is evaluated as catalyst for living E‐co‐N copolymerization upon activation with dried methylaluminoxane between 25 and 90 °C. Copolymerization at different [N]/[E] feed ratios affords stereoirregular alternating high molar mass P(E‐co‐N) with narrow molar mass distribution. P(E‐co‐N) living copolymerization is demonstrated by kinetics at 50 °C. Block copolymers are synthesized and fully characterized.

     

New Cyclization Route to the Skeletons of Lennoxamine and Chilenine

A new cyclization route, triggered by epoxide opening, has been performed to provide the key intermediates for isoindolobenzapine alkaloids, lennoxamine and chilenine. The epoxide was prepared by the Stille reaction using vinyltributylstannane and the following dioxirane treatment. Cyclization under the treatment of BF₃ · OEt₂ provided an azepine moiety, and the oxidative cyclization toward the known precursor for the alkaloids has been achieved by reaction with a stoichiometric amount of Pd(OAc)₂. This formal synthesis suggests a new route to the alkaloids.     

Efficient and Convenient Method for the Synthesis of N‐Arylhydrazones using a Palladium‐Catalyzed Bond‐Forming Reaction

A highly effective, convenient, and reproducible industrial process for palladium‐catalyzed carbon–nitrogen cross coupling has been developed and applied on a large scale. Thus various functionalized N‐arylhydrazones have been easily prepared and well characterized by conventional spectroscopic methods.     

Bromamine-B/PdCl2 is an Efficient System for the Synthesis of Anthranilic Acids from Indoles and Indigos

A convenient method has been developed for the conversion of indoles and indigos into anthranilic acids in good to excellent yields using a bromamine-B/PdCl₂ system. The general process utilizes our efficient method for the oxidation of indoles and indigos in alkaline (pH 12) acetonitrile/water (1:1) at 60 °C.     

Palladium-catalyzed asymmetric 1,6-addition of diphenylphosphine to (4-aryl-1,3-butadienylidene)bis(phosphonates) for the synthesis of chiral phosphines

An asymmetric 1,6-addition of diphenylphosphine to (4-aryl-1,3-butadienylidene)bis(phosphonates) catalyzed by a PCP pincer–Pd complex has been developed for the synthesis of chiral allylic phosphines with up to 91% ee under mild conditions.     

Synthesis,spectroscopy, electrochemistry,and methylation reaction of the dithiolate-based cobalt(II) complex derived from tert-butyl N-(2-mercaptoethyl)carbamate

A dithiolate-containing a carbamate mononuclear cobalt(II) complex namely, [Co(Boc-S)₂] (1), was obtained by the reaction of a methanolic solution of cobalt(II) nitrate hexahydrate with two equimolar amounts of the deprotonated form of tert-butyl N-(2-mercaptoethyl)carbamate (Boc-SH). The cobalt(II) complex (1) was characterized in the solid state and in solution by using FT–IR, Raman, UV–visible, and EI–mass spectroscopies, as well as thermal and X-ray diffraction studies. Spectral data showed that the carbamate (Boc-SH) acts as a mono-anionic bidentate ligand coordinating the cobalt(II) ion through two imine nitrogen and two deprotonated thiolate sulfur donor atoms in a distorted tetrahedral geometry. The thermoanalytical data evidence that the complex is stable up to 165 °C and undergoes complete decomposition, resulting in CoO. TEM imaging of the oxide residue shows its nano size clusters, suggesting that the complex (1) may be used as a precursor for nano-oxides. X-ray powder diffraction patterns evidence an isomorphism among the complex. The redox behavior of the cobalt(II) complex was also investigated by cyclic voltammetry. The reaction of the dithiolate cobalt(II) complex (1) with methyl iodide appears to occur intramolecularly with the cobalt-bound dithiolate, forming the cobalt(II)-bound dithioether complex [Co(Boc–SCH₃)₂]I₂ (2), as a dication complex with a clean second-order reaction of 13.24 × 10⁻² M⁻¹·s⁻¹.     

An innovative SiO2-pyrazole nanocomposite for Zn(II) and Cr(III) ions effective adsorption and anti-sulfate-reducing bacteria from the produced oilfield water

Novel SiO₂-pyrazole (SiO₂-PYZ) nanocomposite was introduced for the elimination of Zn(II) and Cr(III) from oil reservoir water. Characterization analysis of prepared SiO₂-PYZ nanocomposite was investigated using SEM, FTIR, TGA, XRD, TEM, and BET. Studying the effects and optimization of the parameters such as retention time, pH, initial Cr(III) and Zn(II) ions concentrations, adsorbent dosage, and temperature were examined. For kinetics investigation, the pseudo-second-order (PSO) model matches the adsorption process effectively under different operating conditions. After applying two other isotherm models (Langmuir and Freundlich), the experimental data was adequately equipped with Langmuir, R² = 1. The thermodynamic results pointed that the adsorption of Zn(II) and Cr(III) ions was spontaneous, endothermic, and physisorption reaction. At pH 12, the influence of more than one ion, such as Ca(II) and Na(I), was checked, and the results revealed that this conjugate substance was highly selective to Cr(III). After washing with water in multiple cycles, the adsorbed material was regenerated with 0.1 M HCl and subsequently reused without deterioration in its case cavities. Interestingly, SiO₂-PYZ was highly effective against sulfate-reducing bacteria (SRB) in the petroleum field.