Complexes of nickel(II) and palladium(II) with thiobenzamide

Summary The electronic and vibrational spectra of Ni^II and Pd^II complexes with thiobenzamide, L, are discussed. L acts as a sulphur donor ligand. The Pd^II compounds and (NiL₄)(ClO₄)₂ are square planar. PdL₂Cl₂ has acis-structure, while PdL₂X₂ (X=Br or I) istrans; NiL₄Cl₂ istrans-octahedral. The i.r. bands due to(M.S) and(MX) have been assigned. The influence of the anions on the properties of the complexes, both in solution and in the solid state, is discussed.     

Complexes of substituted dipyridylpyridazines with palladium(II) and platinum(II)

Reactions of 3,6-bis(2′-pyridyl)pyridazine derivatives (n-dppn)¶ ¶For the n-dppn ligands, n stands for the size of the cyclic aliphatic ring on positions 4 and 5 of the pyridazine ring, n?=?5, 6, 8, and 12. with MX₂(PhCN)₂ (M?=?Pd, Pt; X?=?Cl,?Br) have been investigated. The new complexes cis-[PdCl₂(n-dppn)] (n?=?5,?6,?8,?12), cis-[PtCl₂(n-dppn)]?·?H₂O (n?=?5,?6), cis-[PtCl₂(8-dppn)] and cis-[PtBr₂(5-dppn)] have been characterized by elemental analyses, conductivity measurements, infrared, electronic and ¹H-NMR spectra.     

Complexes of aminobenzylamines. part II. Complexes ofo-aminobenzylamine with palladium(II) and platinum(II)

Summary The reactions of K₂[MX₄] (M = Pd^II or Pt^II and X = Cl or Br) witho-aminobenzylamine (o-aba) have been studied in neutral aqueous solutions. Two types of complexes were isolated from these studies: [MLX₂] and [ML₂]X₂. Elemental analyses, conductivity measurements, i.r. and visible spectra suggest polymeric structures for [MLX₂] with the ligand,o-aba = L, acting as a bridge, and/or mononuclear structures for [ML₂]X₂.     

Complexes of palladium(II) and platinum(II) with 2-hydrazinopyridine and 8-hydrazinoquinoline

The square planar complexes cis-[MCl₂(hypy)], cis-[MCl₂(hyqu)], [Pt(hypy)₂] [PtCl₄], [Pd(hypy)₂][ClO₄]₂ and [Pd(hyqu)₂][ClO₄]₂ (M = Pd or Pt, hypy = 2-hydrazinopyridine, hyqu = 8-hydrazinoquinoline), in which hypy and hyqu act as bidentate chelating ligands, have been prepared and characterized. Complexes containing hyqu do not appear to have been isolated previously.     

Synthesis and spectroscopic and catalytic properties of a complex of palladium(II) with alizarin complexone

A 11 complex of Pd(II) with alizarin complexone was synthesized and characterized. This complex displays high catalytic activity in the hydrogenation of nitrobenzene and 1-hexene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 741–743, March, 1991.     

Synthesis of trans-Mono(silyl)palladium(II) Bromide Complexes

The stoichiometric reaction of cis-[Pd(ITMe)₂(SiR₃)₂], where (SiR₃ = SiMe₃ and SiMe₂Ph and ITMe = 1,3,4,5-tetramethylimidazol-2-ylidene) with allyl bromide affords the corresponding allylsilanes along with complexes of the type trans-[Pd(ITMe)₂(SiR₃)(Br)]. The structure of trans-[Pd(ITMe)₂(SiMe₂Ph)Br] 2b has been determined in the solid state and displays a slightly distorted square-planar geometry with the two N-heterocyclic carbene ligands in a trans-configuration.     

Complexes of palladium (II) with L-proline. Mixed L-prolinato nucleoside complexes of Palladium (II)

The reaction of Palladium (II) chloride and L-proline (ProH) in aqueous solution gave the dimeric complex, Pd(Pro)Cl₂, which was characterized by elemental analysis, molecular weight, conductivity measurements and IR and NMR spectra. The complex, reacted further with the purine nucleosides inosine or guanosine (Nucl) and the complexes Pd(Pro)(Nucl-H⁺) were isolated from aqueous solution. The insolubility of these complexes suggested a rather polymeric structure in which the nucleoside bridges two adjacent palladium atoms through its N(7) and the exocyclic O(6) atoms. Reaction in dmso gave the complex Pd(Pro)(Nucl)Cl in which the nucleoside act as monodentate ligands with their N(7) atom as ligation site. In aqueous solutions these complexes are quantitatively transformed to the polymeric analogues with the liberation of HCl. The nucleoside adenosine (Ado) reacted in a different way giving only the dimeric complex [Cl(Pro)PdAdoPd(Pro)Cl] in which adenosine bridges two palladium atoms through its N(1) and N(7) atoms. Finally with the pyrimidine nucleoside cytidine (Cyd) the monomer Pd(Pro)(Cyd)Cl was isolated.     

Complexes of platinum(II) and palladium(II) involving thiohydantoin as a bidentate ligand

Summary K₂PtCl₄ and K₂PdCl₄ react with thiohydantoin (2 moles) to give new types of bidentate chelate complexes PtL₂ · 2H₂O and PdL₂ · 2H₂O, where L is the deprotonated ligand. With palladium the rate of reaction is very fast, whereas in the platinum case reaction occurs stepwise allowing isolation and characterization, by elemental analysis, n.m.r. and by i.r. spectroscopy, of intermediate species.     

The coordination chemistry of simple phospholes: Complexes of nickel(II), palladium(II) and platinum(II)

The reactions between four very simply substituted phospholes and the chlorides of Ni(II), Pd(II) and Pt(II) are described. The phospholes 1-phenylphosphole, 3-methyl-1-phenyl-phosphole and 3,4dimethyl-1-phenylphosphole all readily form bis-complexes of formula L₂MCl₂ [L = phosphole ligand and M = Ni(II), Pd(II) or Pt(II)] or tris-complexes of formula L₃MCI₂. 1-n-Butyl-3,4-dimethylphosphole appears to form stable complexes only with Ni(II). Evidence is put forward which indicates that the L₂MCl₂ complexes exist in a four-coordinate, square-planar monomeric/five coordinate equilibrium while the L₃MCl₂ complexes are primarily the ionic species [L₃MCl]⁺ Cl^? in solution. Comparisons are made with the behaviour of other simple phospholes which do not form Ni(II) complexes and the results are discussed briefly in terms of both aromatic and non-aromatic phosphole models.     

N-aminorhodamne complexes of palladium(II), palladium(IV) and platinum(II)

Summary TheN-aminorhodanine (L) complexes: PdLX, (X = Br or I), ML_1.5Cl₂ (M = Pd or Pt), PtL₂X₂ (X = Br, I or ClO₄), PdL₃(ClO₄)₂, PdL_1.5Cl₄ and PdL₃(ClO₄)₄ have been prepared and investigated. The ligand is bonded to the metal ion through the aminic nitrogen atom as monodentate or through this atom and the thiocarbonylic sulphur atom when it acts as chelating or bridging ligand. The carbonylic oxygen atom is never coordinated.     

Platinum(II) and palladium(II) complexes with substituted pyrimidines

Summary Platinum(II) and Palladium(II) complexes with 2-mercaptopyrimidine, 2-thiocytosine (4-aminopyrimidine 2-thione), and isocytosine (2-amino-4-hydroxy pyrimidine) were prepared and characterised by elemental analysis, conductivity data, i.r.,¹H n.m.r. and¹³C n.M.r. spectral studies. 2-Mercaptopyrimidine and 2-thiocytosine are coordinated to the metal ion through N(3) and C₂S, thus forming a four-membered chelate ring. Isocytosine acts as a monodentate ligand and coordinates to the metal ion through N(1). All the complexes are non-electrolytes.     

Spectrophotometric study of acidity constants of Alizarine Red S in various water-organic solvent

The acidity constants of Alizarine Red S were determined spectrophotometrically at 25 degrees C and at constant ionic strength 0.1 M (KNO3) in pure water as well as in aqueous media containing variable mole percentages (5-70%) of organic solvents. The organic solvents used were methanol, ethanol, N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile and dioxan. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program was applied for determining of acidity constants and pure spectra of different form of Alizarine Red S. The obtained results indicated that acidity constants decrease as the content of an organic solvent in the medium increases. There are linear relationship between acidity constants and the mole fraction of various organic solvents in the solvent mixtures. Effect of various solvents on acidity constants and pure spectrum of each component are also discussed.     

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

Summary 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 12 complexes and [Pt(5ClbtaH)₄]Cl₂ in the solid state. Centrosymmetric, chloro-bridged, dinuclear square planar structures of C_2h symmetry are proposed for the 11 palladium(II) compounds.     

Mesomorphic behaviour and TSDC measurements of ortho-metallated palladium(II) and platinum(II) complexes with S,O-donor co-ligands

A series of ortho-metallated Pd and Pt complexes containing an imine ligand carrying three alkoxy chains and N-benzoylthiourea derivatives as co-ligands were prepared and their liquid crystalline properties investigated. Their structures were assigned based on elemental analysis, IR and ¹H NMR spectroscopy, whereas thermal properties were investigated by differential scanning calotimetry and polarising optical microscopy. All the compounds exhibit monotropic transitions involving nematic and smectic A phases, with the mesomorphic behaviour strongly related to the type of N-benzoylthiourea as well as the metal centre used. The thermally stimulated depolarisation current technique was employed to determine the conduction mechanism, phase transition temperature and the activation energies for one of the ortho-metallated Pd complexes.     

Synthesis of palladium(II) and nickel(II) complexes with tetrabenzoporphine

Palladium and nickel complexes with tetrabenzoporphine were synthesized by reacting tetrabenzoporphine and cadmium tetrabensoporphine with palladium and nickel chlorides in boiling dimethylformamide and identified.     

Determination of palladium(II) with picramine-epsilon

We found a reaction of palladium(II) with picramine-epsilon to give a colored complex with an absorption maximum at 556 nm and a molar absorption coefficient of (2.01 ± 0.02) × 10⁴. Conditions of spectrophotometric reaction were selected for determining palladium(II) in nitric acid solutions or solutions containing aqua regia without the conversion of initial complexes into other forms. A rapid procedure was developed for the direct spectrophotometric determination of palladium(II) in concentrations down to 0.5 mg/L in various process solutions (including those containing nitric acid and aqua regia) within 15 min.