Synthesis, spectral and electrochemical characterization of (dithiocarbamato)(arylazoimidazole)Palladium(II) perchlorates
TL;DR: The ternary complexes [Pd(RaaiX)(SS)ClO4] as discussed by the authors, where RaaiX is a N(1)-alkyl-2-(arylazo)imidazole (p-RC6H4N =NC3H2NN(1) X; X = Me, or Et, and R = H, Me or Cl) and SS = N,N-diethyldithiocarbamate or morpholinedithiamato (II) in solution.
Abstract: The ternary complexes [Pd(RaaiX)(SS)ClO4) where RaaiX is a N(1)-alkyl-2-(arylazo)imidazole (p-RC6H4N =NC3H2NN(1) X; X = Me, or Et, and R = H, Me or Cl) and SS = N,N-diethyldithiocarbamate or morpholinedithiocarbamate have been prepared and characterized by elemental analysis, i.r., u.v.-vis. and 1H-n.m.r. data. Electrochemical studies show azo reduction. The complexes are thermally unstable and decompose to bis(dithiocarbamato)palladium(II) in solution.
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TL;DR: In this paper, single-crystal X-ray structure of dichloro-{2-(phenylazo)pyrimidine}zinc(II)·methanol suggests that the complex is a distorted trigonal bipyramidal symmetric around Zn(II), and Cl(1), Cl(2), N(4) (N (azo)) make the trigonal plane.
36 citations
TL;DR: In this paper, the literature dealing with nuclear magnetic resonance (NMR) spectra of azo dyes measured in solution and focusing on azo compounds is discussed. And the 13 C and 15 N CP/magic-angle spinning (MAS) NMR spectra are discussed.
Abstract: Publisher Summary This chapter covers the literature dealing with nuclear magnetic resonance (NMR) spectra of azo dyes measured in solution and focuses on azo compounds. Hydrazo compounds have been included when prepared by diazonium salt coupling reactions or when they are important for azo-hydrazone tautomerism description. The chapter discusses the 13 C and 15 N CP/magic-angle spinning (MAS) NMR spectra. It also discusses azo-hydrazone tautomerism, a property that is indivisibly linked to azo dyes and reviews NMR spectra of metal complexes of azo dyes. Metal-dye complexes play a very important role in dyestuff technology and find applications in many other fields, for example in analytical chemistry. Except for copper phthalocyanine, metal-azo compound complexes are the most important and the most widely used as dyes and pigments. The metals commonly used are chromium, cobalt, copper and nickel. More stringent governmental regulations tend to limit their use owing to the toxicological and ecological drawbacks of these colorants. There are tendencies to substitute the above-mentioned metals by less toxic ones such as by aluminium and to prepare environmentally safer dyes.
27 citations
TL;DR: In this paper, a mixture of square-planar and tetrahedral geometries for the tetracoordinate NiII complex and octahedral for the six-coordinate one were presented.
Abstract: Platinum(II), palladium(II) and nickel(II) complexes with N-allyl-N′-pyrimidin-2-ylthiourea were synthesized in 1:1 and 1:2 [metal:ligand] stoichiometric ratios and characterized by elemental analyses, molar conductivities, magnetic susceptibilities and by i.r., u.v.-vis., 1H- and 13C-n.m.r. and mass spectra. The 1H- and 13C- n.m.r. chemical shifts reveal coordination of one pyrimidine-N and sulphur atoms to PtII and PdII. The i.r. spectra indicate that the ligand behaves as a neutral monodentate towards NiII; coordinates via a pyrimidine-N and as a bidendate towards PdII and PtII coordinates via thione-S and a pyrimidine-N. The magnetic moments and electronic spectral data suggest a square-planar geometry for PtII and PdII complexes, a mixture of square-planar and tetrahedral geometries for the tetracoordinate NiII complex and octahedral for the six-coordinate one. The E.I. mass spectra of the complexes showed some isotope ion peaks of [M]+ and fragments containing metals; assignments of fragments containing metal ions were supported by the appearance of their peaks among isotope clusters.
20 citations
07 Mar 2012
TL;DR: Replacement of the chloro ligands by carboxylate groups in carboplatin, cis-diamine(1-1cyclobutanedicarboxylates)platinum(II), is a widely used second-generation platinum anticancer drug showing less side effects than cis-platin.
Abstract: Cisplatin, cis-Diamminedichloroplatinum (II), is one of the most effective anticancer agents (Rosenberg, 1969). It has demonstrated a remarkable chemotherapeutic potential in a large variety of human solid cancers, such as, testicular, ovarian, bladder, lung and stomach carcinomas (Wong and Giandomenico, 1999; Guo and Sadler, 2000). The successful use of platinum (II) complexes as potent anticancer drugs has attracted the interest of many scientists. It was observed that the nature and arrangement of the ligands can affect the mode of action and metabolism of the drug while crossing the cell membrane and inside the cell. Despite the widespread use of cis-platin as an anticancer drug there is still scope for improvement, with respect to: i) reduced toxicity; ii) increased clinical effectiveness; iii) broader spectrum of action; iv) elimination of side effects (e.g., nausea, hearing loss, vomiting, etc); v) increased solubility and vi) ability to use them in combination with other drugs, limited by severe toxicities so far. Replacement of the chloro ligands by carboxylate groups in carboplatin, cis-diamine(1,1cyclobutanedicarboxylate)platinum(II), is a widely used second-generation platinum anticancer drug showing less side effects than cis-platin. The development of several new anticancer platinum drugs including Carboplatin, Nedaplatin, Lobaplatin and Oxaliplatin (Scheme 1) still have draw-backs and offer no more clinical advantages over the existing cisplatin (Gill, 1984; Galanski et al., 2005; Momekov et al., 2005). Furthermore, the development of acquired resistance to cis-platin is frequently observed during chemotherapy (Heim, 1993).
15 citations
TL;DR: In this article, the reaction between Pd(N,N′)Cl2 and picolinic acid (picH) was studied spectrophotometrically at λ = 463 nm in MeCN at 298 K. The product is [Pd(pic)2] which has been verified by the synthesis of the pure compound from Na2[PdCl4] and picH.
Abstract: The reaction between Pd(N,N′)Cl2 [N,N′ ≡ 1-alkyl-2-(arylazo)imidazole (N,N′) and picolinic acid (picH) have been studied spectrophotometrically at λ = 463 nm in MeCN at 298 K. The product is [Pd(pic)2] which has been verified by the synthesis of the pure compound from Na2[PdCl4] and picH. The kinetics of the nucleophilic substitution reaction have been studied under pseudo-first-order conditions. The reaction proceeds in a two-step-consecutive manner (A → B → C); each step follows first order kinetics with respect to each complex and picH where the rate equations are: Rate 1 = {k′0 + k′2[picH]0} × [Pd(N,N′)Cl2] and Rate 2 = {k′′0 + k′′2[picH]0}[Pd(N,O)(monodentate N,N′)Cl2] such that the first step second order rate constant (k′2) is greater than the second step second order rate constant (k′′2). External addition of Cl− (as LiCl) suppresses the rate. Increase in π-acidity of the N,N′ ligand, increases the rate. The reaction has been studied at different temperatures and the activation parameters (Δ‡H° and Δ‡S°) were calculated from the Eyring plot.
10 citations
References
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TL;DR: In this paper, the N N stretch in copper(I) complexes shows a large shift to lower frequency from the free ligand value (ca 1400 cm−1) due to d(Cu) → π* (RaaiR′) back bonding.
80 citations
TL;DR: In this article, a new chelating resin incorporating imidazolyl azo groups into a matrix of polystyrene divinylbenzene has been prepared, and the exchange capacity of the resin for the ions mercury (II), silver(I) and lead(II) as a function of pH has been determined.
Abstract: A new chelating resin incorporating imidazolyl azo groups into a matrix of polystyrene divinylbenzene has been prepared. The exchange capacity of the resin for the ions mercury (II), silver(I) and lead(II) as a function of pH has been determined. The resin exhibits no affinity to alkali, or alkaline earth metals. It is highly selective for only mercury(II) and silver(I). In column operation it has been observed that mercury(II) in trace quantities is very effectively removed from river water spiked with mercury(II) at the usual pH of natural waters.
54 citations
TL;DR: In this paper, the reaction of Na2PdCl4 with 2-(arylazo)pyridines (A) in ethanol affords yellow complexes of composition [PdACl2] in which the PdCl2 fragment has acis configuration [ν(Pd Cl): 350, 365 cm−1].
52 citations
TL;DR: The position of the LLCT band is largely dependent on the substituent type on the catechol frame and is qualitatively assigned as the 3b 1 (cat) → π*(aap) transition as mentioned in this paper.
52 citations