Coordination Compounds Of Palladium Research Articles

Coordination Compounds of Palladium(II) and 4‐Amino‐1,2,4‐triazole

Mononuclear coordination compounds of the type [Pd(NH2trz)4]2+ with the counterions chloride, nitrate, trifluoromethanesulfonate, and methanesulfonate were synthesized and their structures identified with single‐crystal X‐ray diffraction. In case of the synthesis with methanesulfonate as the counterion the dominant product was of the generic formula [Pd2(NH2trz)3](CH3SO3)4, and the complex [Pd(NH2trz)4](CH3SO3)2 only emerged as a byproduct. While the structure of the byproduct could be analyzed by single‐crystal X‐ray diffraction, suitable crystals of the main product [Pd2(NH2trz)3](CH3SO3)4 could not be obtained. However, stoichiometry implies a polynuclear nature with NH2trz present in the rare μ3‐η1:η1:η1 coordination type, i.e. with NH2trz molecules coordinating to three palladium atoms. Accordingly, identification of solids by single‐crystal analysis alone can be misleading in particular with NH2trz as a ligand due to its versatile coordination behavior. Finally, analysis by differential scanning calorimetry (DSC) revealed that the complexes were thermally stable (the onset of decomposition well above 100 °C), with [Pd2(NH2trz)3](CH3SO3)4 being the most stable compound (onset of decomposition at 204 °C).

Synthesis and coordination chemistry of enantiopure t-BuMeP(O)H.

Both enantiomers of the optically pure Secondary Phosphine Oxide (SPO) t-BuMeP(O)H (1) have been obtained by deboronation of phosphinous acid-borane t-BuMeP(O)H·BH3 (3) with HBF4 followed by hydrolysis of the intermediate adduct t-BuMeP(O)H·BF3 (1·BF3), which has been isolated and crystallographically characterised. Complexes [MCl(COD)(κP-(R)-1)] (M = Ir, Rh; 4 and 7 respectively) have been detected in solution but could not be isolated while trans-[RhCl(CO)(κP-(S)-1)2] (9) has been successfully obtained in good yield. Gold complex [AuCl(κP-(S)-1)] (10) has been prepared and its crystal structure shows the presence of aurophilic interactions. Three new ruthenium complexes ([RuCl2(η6-p-cymene)(κP-(R)-1)], 12), ([RuCl2(CO)3(κO-(S)-1)], 13) and trans-([RuCl2(CO)2(κP-(S)-1)2], 14) have been synthesised and fully characterised, including the crystal structure of 12. Four palladium coordination compounds have been prepared: trans-[PdCl2(κP-(S)-1)2] (trans-15), [Pd(μ-Cl)(κP-(S)-1)2]2 (16·OH and 16·BF2) and [Pd(μ-OAc)(κP-(S)-1)2] (17) and the crystal structure of complex 16·OH proves the pseudobidentate coordination of the two molecules of 1. Three organometallic allylpalladium complexes have been prepared namely [Pd(η3-Ph2C2H3)Cl(κP-(S)-1)] (18) and [Pd(η3-Ph2C2H3)(κP-(S)-1)2] (19·OH and 19·BF2). The crystal structure of 19·BF2 constitutes the first allylpalladium-SPO complex reported to date.

Synthesis, Structural, and Antimicrobial Studies of Some New Coordination Compounds of Palladium(II) with Azomethines Derived from Amino Acids

Some new coordination compounds of palladium(II) have been synthesized by the reaction of palladium(II) acetate with azomethines in a 1 : 2 molar ratio using acetonitrile as a reaction medium. Azomethines used in these studies have been prepared by the condensation of 2‐acetyl fluorene and 4‐acetyl biphenyl with glycine, alanine, valine, and leucine in methanol. An attempt has been made to probe their bonding and structures on the basis of elemental analyses and IR, 1H, and 13C NMR spectral studies. Pd(II) compounds have been found to be more active than their uncomplexed ligands as both of them were screened for antibacterial, antifungal, and insecticidal activities.

Sulfur-Bonded Coordination Compounds of Palladium(II) and Platinum(II) and Their Antimicrobial Activity

The synthetic, spectroscopic, and biological studies of some new palladium(II) and platinum(II) complexes derived from biologically active sulfur donor ligands 1H-indol-2,3-dione benzothiazoline (Bzt 1 H) and 5-nitro-1H-indol-2,3-dione benzothiazoline (Bzt 2 H) have been described. The reactions were carried out in 1:2 molar ratios. The authenticity of the benzothiazolines and their complexes has been established on the basis of elemental analyses; molecular weight determinations; and IR, 1 H NMR, 13 C NMR, and UV spectral studies. Based on IR and 1 H NMR spectral studies, a square-planar structure has been assigned to these complexes. Studies were conducted to assess the comparative growth inhibiting potential of the synthesized complexes against the benzothiazolines for a variety of fungal and bacterial strains. The studies demonstrate that the ligands and complexes possess antimicrobial properties. Further, it was noted that the growth-inhibiting potential of the complexes is greater than the parent benzothiazolines.

Search of structure and ligands exchange for palladium(II) complexes with N-allylimidazole; X-ray and solid-state/solution NMR studies

Two coordination compounds of palladium(II) with N-allylimidazole ( l) of the general formula [PdL 4]Cl 2 · 3H 2O ( 1) and trans-[PdL 2Cl 2] ( 2) have been synthesized. The crystal and molecular structure of complexes 1 and 2 was established by single-crystal X-ray diffraction analysis. The X-ray structural data were supplemented by solid-state 13C NMR measurements (CP MAS and PASS 2D). The 1D and 2D NMR studies in solution reveal that complex 1 is unstable at room temperature and undergoes reversible decomposition to 2. The method for how to preserve a complex with four allyl-imidazole ligands in solution is shown.

Antiandrogen and Antimicrobial Aspects of Coordination Compounds of Palladium(II), Platinum(II) and Lead(II)

Synthesis, characterization and antimicrobial activities of an interesting class of biologically potent macrocyclic complexes have been carried out. All the complexes have been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria. The testicular sperm density, testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trails and biochemical parameters of reproductive organs have been examined and discussed. The resulting biologically active [M(MaLn)(R2)]Cl2 and [Pb(MaLn)(R2)X2] (where, M = PdII or PtII and X = Cl or NO3) type of complexes have been synthesized by the reactions of macrocyclic ligands (MaLn) with metal salts and different diamines in 1:1:1 molar ratio in methanol. Initially the complexes were characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding was established on the basis of IR, 1H NMR, 13C NMR, 195Pt NMR, 207Pb NMR, XRD and electronic spectral studies. The macrocyclic ligand coordinates through the four azomethine nitrogen atoms which are bridged by benzil moieties. IR spectra suggest that the pyridine nitrogen is not coordinating. The palladium and platinum complexes exhibit tetracoordinated square-planar geometry, whereas a hexacoordinated octahedral geometry is suggested for lead complexes.

Coordination compounds of palladium(II) and platinum(II) with benzotriazoles

The nitrogen-donor ligands 1-methylbenzotriazole (1Mebta), 5-methylbenzotriazole (5MebtaH), 5-chlorobenzotriazole (5ClbtaH) and 5-nitrobenzotriazole (5NO2btaH) react with palladium(II) and platinum(II) to give cis-[PdL2Cl2], cis-[PtL2Cl2] (L = 1Mebta, 5MebtaH, 5ClbtaH or 5NO2btaH), [Pt(5ClbtaH)4]Cl2, [Pd-(5MebtaH)Cl2]2, [Pd(5ClbtaH)Cl2]2 and [Pd(5NO2btaH)-Cl2]2. The complexes were characterized by physicochemical and spectroscopic methods. The benzotriazoles act as monodentate ligands binding through N(3). Monomeric square planar structures are assigned for the 1∶2 complexes and [Pt(5ClbtaH)4]Cl2 in the solid state. Centrosymmetric, chloro-bridged, dinuclear square planar structures of C2h symmetry are proposed for the 1∶1 palladium(II) compounds.

THE CRYSTAL STRUCTURE OF DIBROMO (PHENYL-2-PYRIDYL DIMETHYLHYDRAZONE)PALLADIUM(II)

Abstract Nitrogen-containing heterocyclic compounds play an important role in several biological processes. Furthermore, their biological activity seems often to depend upon interaction with a metal ion. Interest in the study of hydrazones and their metal complexes has been growing because of their physiological activity, coordination capability and application in analytical chemistry.1,2 Many hydrazones and their metallic derivatives show very interesting biological activity, e.g., as antitumour or anticonvulsant agents, and behave as cytotoxic compounds toward tumour cells.3 During the past few years, in addition to platinum compounds, coordination compounds of palladium(II) and (IV) seem to be promising in cancer chemotherapy.4 Due to the biological activity of heterocyclic hydrazones and in continuing our systematic investigations of the platinum group metals with hydrazones and generally with heterocyclic nitrogen donor ligands,5–10 we report here the crystal structure of dibromo(phenyl-2-pyridyldime...

Thermal stability and non-isothermal kinetic study of the decomposition of two coordination compounds of palladium and platinum with ligands derived from thiobenzamide and acetylacetone

The results concerning the thermal behaviour of two coordination compounds synthesised by template condensation are presented. The values of the non-isothermal kinetic parameters have been determined for some of the decomposition steps.

Complexation of palladium(II) and copper(II) halides with the stable 4-methyliminomethyl-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl radical and the addition of alcohols

1. Coordination compounds of palladium(II) and copper(II) halides with 4-methyliminomethyl-2,2,5,5-tetramethyl-3-imidazolin-1-oxyl have been synthesized. 2. When copper(II) halide reacts with 4-methyliminomethyl-2,2,5,5-tetramethyl-3-imidazolin-1-oxyl in anhydrous alcohols, a molecule of alcohol adds at the C=N bond of the aliphatic segment of the starting ligand. The coordination compounds that form by this reaction of the coordinated ligand were isolated.

New coordination compounds of palladium(II) with iminodiacetic acid

Iminodiacetic acid (IDA) forms 1:1 or 1:2 complexes with Pdll at room temperature and pH 6.0. The solid compounds have been characterized by elemental analysis, titrimetry, magnetic measurements, i.r. spectroscopy and thermal studies. The far i.r. spectra show peaks that can be assigned to Pd-Cl, Pd-N and Pd-O vibrations. On the basis of these studies tentative structures for the isolated substances are proposed.