Palladium(II) Complexes of N-(2-Thienylmethylidene)aniline Derivatives

Coordination reactions of N-(2-thienylmethylidene)aniline derivatives, L, with PdCl₂ or [PdCl₄]^2? in ethanol yield stable complexes of the type trans-(L)₂PdCl₂ with the azomethine nitrogen atoms as σ donors. These are not readily convertible to othor-palladated complexes. An X-ray crystallographic study of the complex (L₂)₂PdCl₂ reveals a centrosymmetric geometry. The structure is in the triclinic space group $ {\rm P}\bar 1 $ with a = 8.633(2) Å, b = 12.759(3) Å, c = 8.398(2) Å, α = 96.65(5)°, β = 111.47(5)*, γ= 101.28(6)°, and Z = 1. The final R factor is 0.043 (Rw = 0.044) for 2396 observed reflections. There is no real bonding between a thiophene sulfur atom and a central palladium ion. However, a long distance interaction between S and Pd does exist.     

Studies on Mn(II) and Mn(IV) Complexes of an Unsymmetrical Bidentate Donor,N(4-Chlorophenyl)-Pyridine-2-Aldimine (ClL): Crystal Structure of [Mn(ClL)2(NCS)2]

The synthesis, characterisation and X-ray structure of an Mn(II) compound, [Mn(ClL)₂(NCS)₂], is described. Oxidation of the compound by H₂O₂ leads to a mononuclear Mn(IV) compound [Mn(ClL)(ClL')(NCS)₂]ClO₄·2H₂O where one of the ClL ligands is oxidised to the corresponding amide ClL'. Oxidation of [Mn(ClL)₂(NCS)₂] by Ce(IV), however, leads to a binuclear Mn(IV) compound [Mn₂O(ClL')₃(ClL)(H₂O)₂](NCS)₂ClO₄·2MeCN. Electron transfer behaviour of the compounds was investigated by cyclic voltammetry and differential pulse voltammetry.     

New Palladium(II) Complexes with a Tridentate PNO Ligand

The synthesis of neutral and cationic palladium complexes containing the tridentate monoanionic ligand [2-(2-Ph₂PC₆H₄-CH=N)C₆H₄O]^? is described. Deprotonation of the Schiff base formed by condensation of 2-(diphenylphosphino)benzaldehyde with 2-aminophenol in the presence of the appropriate palladium precursor ([Pd(AcO)₂] or [PdCl₂(PhCN)₂]) form the corresponding neutral complexes [Pd{2-(2-Ph₂PC₆H₄-CH=N)C₆H₄O}(AcO)] (1) or [Pd{2-(2-Ph₂PC₆H₄-CH=N)C₆H₄O}(Cl)] (2) in good yield. The first reacts smoothly with thiols and activated phenols to give complexes of general formula [Pd{2-(2-Ph₂PC₆H₄-CH=N)C₆H₄O}(X)] (X = OC₆F₅ (3), SEt (4), S^tBu (5), SC₆H₅ (6), SC₆H₄-4Me (7), SC₆H₄-4NO₂ (8)). When the chloro complex is treated with silver perchlorate and tertiary phosphines (L) the cationic derivatives [Pd{2-(2-Ph₂PC₆H₄-CH=N)C₆H₄O}(L)][ClO₄] (L = PPh₃ (9), PMePh₂ (10), PMe₂Ph (11), PEt₃ (12)) were obtained. The new complexes were characterized by partial elemental analyses and spectroscopic methods (IR, ¹H, ¹⁹F and ³¹P NMR).     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

Synthesis and Characterization of Novel Trans-Mixed Diamine Platinum(II) and Platinum(IV) Complexes

A series of novel trans-mixed diamine platinum(II) and platinum(IV) complexes of type trans-[Pt^II(R-NH₂)(R'-NH₂)Cl₂] and trans -[Pt^IV(R-NH₂)(R'-NH₂)Cl₄] (where R-NH₂ = ethylamine or butylamine and R'-NH₂ = methylamine, propylamine, isopropylamine, pentylamine, or hexylamine) was synthesized and characterized using elemental analysis and infrared and ¹⁹⁵Pt nuclear magnetic resonance spectroscopic techniques.     

Synthesis,Properties and X-ray Crystal Structures of Nickel(II) Complexes of a Hexaazamacrotetracyclic Ligand

The complexes [N₂(L²)₂(H₂O)₄]Cl₄(1) and [Ni(L²)](ClO₄)₂ [sdot]2H₂O (2) (L = 1,3,10,12,16,19-hexaazatetracyclo [17,3,1,1 ^12.16,0^4.9]tetracosane) have been synthesized and structurally characterized by X-ray crystallography, spectroscopic and cyclic voltammetry. The crystal structure of 1 has a distorted octahedral geometry with two secondary and two tertiary amines of the macrocycle and two water molecules. In 2, the coordination geometry around the nickel atom is square-planar with four nitrogen atoms of the macrocycle. The equilibrium [Ni(L²)]²⁺ + 2H₂O &rlhar2; [Ni(L²)(H₂O)₂]²⁺ has been studied in aqueous solution over a temperature range, yielding Δ H° = -19.0 ± 0.2 kJ mol^-1 and Δ S° = - 56.0 ± 0.4 JK^-1 mol^-1. Cyclic voltammetry of the complexes give two one-electron waves corresponding to Ni(II)/Ni(III) and Ni(II)/Ni(I) processes. The electronic spectra and redox potentials of the complexes are influenced significantly by the geometry.     

Silylierte Phosphanimin-Komplexe von Chrom(II), Palladium(II) und Kupfer(II). Die Kristallstrukturen von [CrCl2(Me3SiNPMe3)2], [PdCl2(Me3SiNPEt3)2] und [CuCl2(Me3SiNPMe3)]2

Silylated Phosphaneimine Complexes of Chromium(II), Palladium(II), and Copper(II). The Crystal Structures of [CrCl₂(Me₃SiNPMe₃)₂], [PdCl₂(Me₃SiNPEt₃)₂], and [CuCl₂(Me₃SiNPMe₃)]₂ The title compounds have been prepared by the reaction of the silylated phosphaneimines Me₃SiNPR₃ (R = CH₃, C₂H₅) with CrCl₂(THF)₂, PdCl₂ and CuCl₂, respectively, in dichloromethane suspensions. All donor-acceptor complexes were characterized by IR spectroscopy and by crystal structure determinations. [ CrCl₂(Me₃SiNPMe₃ )₂]: Space group Pccn, Z = 4, structure determination with 2104 observed unique reflections, R = 0.045. Lattice dimensions at ?70°C: a = 1326.3, b = 1562.5, c = 1171.5 pm. Within the monomeric molecular structure the chromium atom is planarly coordinated within the trans-configuration of the Cl atoms and the N atoms with distances of Cr? Cl = 235.94 pm and Cr? N = 211.7 pm. [ PdCl₂(Me₃SiNPEt₃)₂ ]: Space group P2₁/n, Z = 2, structure determination with 2412 observed unique reflections, R = 0.031. Lattice dimensions at 20°C: a = 917.3, b = 1390.2, c = 1161.7 pm, β = 95.80°. Within the monomeric molecular structure the palladium atom is planarly coordinated within the trans-configuration of the Cl atoms and the N atoms with distances of Pd? Cl = 222.9 pm and Pd? N = 209.5 pm. [ CuCl₂(Me₃SiNPMe₃)₂ ]: Space group Pbca, Z = 4, structure determination with 1861 observed unique reflections, R = 0.067. Lattice dimensions at ?70°C: a = 1440.2, b = 1205.1, c = 1536.5 pm. The compound forms centrosymmetric dimeric molecules, in which the Cu atoms are linked via almost symmetrical chloro-bridges with Cu? Cl distances of 231.4 pm. The distance Cu? N is 196.7 pm.     

Investigation of DNA Binding Interaction of Newly Synthesized Nickel(II) and Palladium(II) Complexes Containing Ferrocenyl Schiff Base Ligand

New complexes of nickel(II) and palladium(II) were synthesized using the ferrocenyl imine ligand, which was formed by the condensation of 2‐aminothiophenol and acetylferrocene. This bidentate Schiff base ligand was coordinated to the metal ions through the NS donor atoms. Monomeric complexes of nickel(II) and palladium(II) were synthesized by the reactions of the Schiff base ligand with nickel(II) and palladium(II) chloride in a 2:1 M ratio. In these complexes, the thiol group was deprotonated and coordinated to the metals. The molar conductivity values of the complexes in DMSO showed the presence of non‐electrolyte species. The fluorescence characteristics of the Schiff base ligand and its complexes were studied in DMSO. The synthesized complexes were characterized by FT‐IR, ¹H NMR, UV–vis spectroscopy, elemental analysis, and conductometry. Furthermore, the binding interactions of the complexes with DNA were investigated by electronic absorption spectroscopy, and the intrinsic binding constant (K _b) was calculated. Moreover, viscosity and melting temperature (T _m) were investigated in order to further explore the nature of interactions between the complexes and DNA.     

Complexing properties of methyl and phenyl glycine derivatives in their compounds with H+, Ni(II), Cu(II), and Zn(II)

The influence of the solvent and the substituents on the complexing properties of methyl and phenyl glycine derivatives is discussed. On the basis of a computer analysis of potentiometric titration results, the composition and the stability constants of the complexes ofN-methylglycine,N,N-dimethylglycine,N-phenylglycine and phenylglycine with H⁺ and with Ni(II), Cu(II), Zn(II) were determined. The ligand-metal coordination mode as well as the zwitterion level in percent in ligand/proton systems were determined by spectral analyses and equilibria studies.

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Komplexbildung der Methyl- und Phenylglycin-Derivate in ihren Verbindungen mit dem Proton und Ni(II), Cu(II) und Zn(II)

Zusammenfassung Der Einfluß des Lösungsmittels und der Substituenten auf die komplexbildenden Eigenschaften der Methyl- und Phenylglycin-Derivate wird diskutiert. Anhand einer Computer-Analyse von potentiometrischen Daten wurden die Zusammensetzung und die Beständigkeitskonstanten der Komplexe vonN-Methylglycin,N,N-Dimethylglycin,N-Phenylglycin und Phenylglycin mit H⁺, Ni(II), Cu(II) und Zn(II) festgestellt. Mittels spektroskopischer Methoden und Gleichgewichtstudien wurde der Koordinationstyp des Liganden mit dem Metall festgestellt sowie der Prozentanteil des Zwitterions im Ligand/Proton-System.

     

The Crystal and Molecular Structures of Pb(II) Complexes with Furan-2-Carboxylate and Furan-3-Carboxylate Ligands

The crystals of Pb(II) 2-furancarboxylate (title compound I) contain tetrameric structural units Pb₄(2-FCA)₈(H₂O₂) in which four Pb(II) ions are bridged by carboxylate oxygen atoms forming a circular moiety. In addition, pairs of Pb(II) ions are bridged by carboxylate oxygen atoms inside this moiety. The molecular pattern observed in Pb(II) 3-furancarboxylate (title compound II) is polymeric. It consists of Pb(3-FCA)₂(H₂O) structural units bridged by carboxylate oxygen atoms donated by the furan-3-carboxylate (3-FCA) ligands which are bidentate, using both their carboxylate oxygen atoms for chelation. The coordination around Pb(II) ions is eightfold and ninefold including, apart from carboxylate oxygen atoms, a water oxygen atom and oxygen atoms donated by the furan rings of the ligand molecules. Hydrogen bonds with the water molecule as the donor operate between adjacent ligand molecules. The stereochemical activity of the lone 6s ² electron pair on the Pb(II) is observed in title compound II.     

Preparation of Palladium(II) and Platinum(II) Phosphine Complexes Promoted by Phase-Transfer Catalysts

The synthesis of M(PR₃)₂Cl₂ (M = Pd and Pt, R = alkyl or aryl) front K₂MCl₄ (in H₂O) and PR₃ (in CH₂Cl₂) was promoted by the addition of phase-transfer catalysts (PTC). The greater the amount of PTC used, the more quickly the reaction completed. ³¹P NMR spectra of some M(PR₃)₂Cl₂ in the presence of free PR₃ were measured; these NMR resulls were used to explain problems encountered during the preparations.     

Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)

Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K₂[MCl₄] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]₂[M₂Cl₆] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]₂[MCl₄] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (¹H, ¹³C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P2₁/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P2₁/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M₂Cl₆]^2? anions of nearly D_2h symmetry and [K(18-cr-6)]⁺ cations, in which the distance of K⁺ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )).     

PdCl2Se6 und PdBr2Se6, neue chalkogenreiche Komplexe von Palladium(II)-Halogeniden mit Se6-Gruppen als Liganden

PdCl₂Se₆ and PdBr₂Se₆, New Chalcogenrich Complexes of Palladium(II) Halides with Se₆ Groups as Ligands PdCl₂Se₆ und PdBr₂Se₆, chalcogenrich complexes of palladium halides with Se₆ groups as ligands have been prepared by reactions of Pd metal with melts of selenium and SeX₄ (X = Cl, Br) at 180°C in closed silica ampoules. The new compounds have been characterized by vibrational spectra and thermal analysis. The X-ray analysis of PdCl₂Se₆ showed a polymeric structure, built up by chains of linear PdX₂ groups connected by Se₆ groups in a chair conformation.     

Synthesis and Characterization of Ni(II), Cu(II), Zn(II) and Cd(II) Complexes of a New Vic-Dioxime Ligand

In this study, 1,2-dihydroxyimino-3,7-di-aza-9,10-O-α-methyl benzal decane (LH₂) was synthesized starting from 1,2-O-α-methyl benzal-4-aza-7-amino heptane (RNH₂) and antichloroglyoxime. With this ligand, complexes were synthesized using Ni(II) and Cu(II) salts with a metal:ligand ratio of 1:2. However, the reaction of the ligand with salts of Zn(II) and Cd(II) gave products with metal:ligand ratio of 1:1. Structures of the ligand and its complexes are proposed based on elemental analyses, IR, ¹³C- and ¹H-NMR spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA).     

Hg(II), Tl(III), Cu(I), and Pd(II) Complexes with 2,2'-Diphenyl-4,4'-Bithiazole (DPBTZ), Syntheses and X-Ray Crystal Structure of [Hg(DPBTZ)(SCN)2]

Reaction of the ligand 2,2′-diphenyl-4,4′-bithiazole (DPBTZ) with Hg(SCN)₂, Tl(NO₃)₃, CuCl, and PdCl₂ gives complexes with stoichiometry [Hg(DPBTZ)(SCN)₂], [Tl(DPBTZ)(NO₃)₃], [Cu(DPBTZ)(H₂O)Cl]_, and [Pd(DPBTZ)Cl₂]. The new complexes were characterized by elemental analyses and infrared spectroscopy. The crystal structure of [Hg(DPBTZ)(SCN)₂] determined by X-ray crystallography. The Hg atom in the title monomeric complex, (2,2′-diphenyl-4,4′-bithiazole)mercury(II)bisthiocyanate, [Hg(C₁₈H₁₂N₂S₂)(SCN)₂], is four-coordinate having an irregular tetrahedral geometry composed of two S atoms of thiocyanate ions [Hg-S 2.4025(15) and 2.4073(15) Å] and two N atoms of 2,2′-diphenyl-4,4′-bithiazole ligand [Hg-N 2.411(4) and 2.459(4) Å]. The bond angle S(3)-Hg(1)-S(4) of 147.46(5)° has the greatest derivation from ideal tetrahedral geometry. Intermolecular interaction between Hg(1) and two S atoms of two neighboring molecules, 3.9318(15) and 3.9640(18) Å, make the Hg(1) distort from a tetrahedron to a disordered octahedron. The attempts for preparation complexes of Tl(I), Pb(II), Bi(III), Cd(II) ions with 2,2′-diphenyl-4,4′-bithiazole ligand were not successful and also the attempts for preparation complexes of 4,4′,5,5′-tetraphenyl-2,2′-bithizole ligand with Cu(II), Ni(II), Co(II), Co(III), Mn(II), Mn(III), Fe(II), Fe(III), Cr(III), Zn(II), Tl(III), Pb(II), Hg(II), Cu(I), Pd(II) were not successful. This point can be regarded as the initial electron withdrawing of phenyl rings and also their spatial steric effects.     

Palladium(II)-allyl complexes containing chiral N-donor ferrocenyl ligands

A study of the reactivity of enantiopure ferrocenylimine (S_C)-[FcCHN-CH(Me)(Ph)] {Fc =  (η⁵-C₅H₅)Fe{(η⁵-C₅H₄)-} (1a) with palladium(II)-allyl complexes [Pd(η³-1R¹,3R²-C₃H₃)(μ-Cl)]₂ {R¹ = H and R² = H (2), Ph (3) or R¹ = R² = Ph (4)} is reported. Treatment of 1a with 2 or 3 {in a molar ratio Pd(II):1a = 1} in CH₂Cl₂ at 298 K produced [Pd(η³-3R²-C₃H₄){FcCHN-CH(Me)(Ph)}Cl] {R² = H (5a) or Ph (6a)}. When the reaction was carried out under identical experimental conditions using complex 4 as starting material no evidence for the formation of [Pd(η³-1,3-Ph₂-C₃H₃){FcCHN-CH(Me)(Ph)}Cl] (7a) was found. Additional studies on the reactivity of (S_C)-[FcCHN-CH(R³)(CH₂OH)] {R³ = Me (1b) or CHMe₂ (1c)} with complex 4 showed the importance of the bulk of the substituents on the palladium(II) allyl-complex (2-4) or on the ferrocenylimines (1) in this type of reaction. The crystal structure of 5a showed that: (a) the ferrocenylimine adopts an anti-(E) conformation and behaves as an N-donor ligand, (b) the chloride is in acis-arrangement to the nitrogen and (c) the allyl group binds to the palladium(II) in a η³-fashion. Solution NMR studies of 5a and 6a and [Pd(η³-1,3-Ph₂-C₃H₃){FcCHN-CH(Me)(CH₂OH)}Cl] (7b) revealed the coexistence of several isomers in solution. The stoichiometric reaction between 6a and sodium diethyl 2-methylmalonate reveals that the formation of the achiral linear trans-(E) isomer of Ph-CHCH-CH₂Nu (8) was preferred over the branched derivative (9). A comparative study of the potential utility of ligand 1a, complex 5a and the amine (S_C)-H₂N-CH(Me)(Ph) (11) as catalysts in the allylic alkylation of (E)-3-phenyl-2-propenyl (cinnamyl) acetate with the nucleophile diethyl 2-methylmalonate (Nu⁻) is reported.     

Thermodynamics of Copper(II) Complexes of Diamino Diamides in Aqueous Solution

The equilibria occurring in aqueous solutions of N,N′-bis(β-carbamoylethyl)ethylenediamine, N,N′-bis(β-carbamoylethyl)trimethylenediamine, N,N′-bis(β-carbamoylethyl)-1,2-propylenediamine, and N,N′-bis(β-carbamoylethyl)-2-hydroxytrimethylenediamine with protons and copper(II) ions as well as the deprotonation reactions of the copper (II) complexes of these four ligands have been studied by calorimetry at T=25.0°C and I=0.10 mol dm^?3 (NaClO₄). The enthalpy changes and the entropy changes for these reactions are reported and discussed.     

Physicochemical Investigation on the Complexes of Co(II), Ni(II) and Cu(II) with Aminocyclodiphosph(V)azane Derivative

Co(II), Ni(II), and Cu(II) form 2:1 complexes with aminocyclodiphosph(V)azane derivative. The complexes have been investigated in solution by the spectrophometric molar ratio and conductometeric methods. The ligand and its complexes have been isolated in solid state and characterized on the basis of microanalytical, infrared, electronic, magnetic moment, 1 H NMR and mass spectral data. The cobalt and nickel complexes were assigned to be in tetrahedral structure while the copper complex is assigned to be in square planar.     

Synthesis,Crystal Structure and Magnetic Properties of an Oxalato-Bridged Dinickel(II) Complex Containing A MacrocyClic Ligand

A new binuclear nickel(II) complex [Ni(µ-C₂O₄)(rac-cth)₂](ClO₄)₂[rac-cth = rac -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane] has been prepared and its structure determined. It consists of centrosymmetric [Ni( µ -C₂O₄)(rac-cth)₂]²⁺ cations separated by perchlorate anions, with a centre of symmetry lying in the middle of the C-C bond of the bis-bidentate oxalate bridge. The tetraazamacrocycle adopts a folded conformation around the nickel atom, which is six coordinated in a distorted octahedral arrangement. Variable temperature magnetic susceptibility measurements (4-300 K) suggest a moderate intramolecular antiferromagnetic interaction between the metal ions ( J = -34.0 cm^-1, g = 2.07)