Synthesis and characterization of chiral tetraaza macrocyclic nickel(II) and palladium(II) complexes

Chiral tetraaza macrocyclic nickel(II) and palladium(II) complexes 2a-e, containing one or two (R,R)-(-)-1,2-cyclohexanediyl bridges, were synthesized by template condensation reactions and characterized by (1)H and (13)C NMR, IR, UV-vis, and mass spectrometry. The electrophilic reactivity of 2a was explored. Crystal structures of Ni complex 2b and metal-free ligand 5 were determined by single-crystal X-ray diffraction.     

Synthesis and solid state characterisation of mononuclear 2-benzoylpyridine N-methyl-N-phenylhydrazone palladium(II) complexes

2-Benzoylpyridine N-methyl-N-phenylhydrazone, HL, is a versatile ligand which reacts with [Pd(PhCN)2Cl2] forming the coordination compound [HLPdCl2], 1, characterized by the presence of the N(py)/N(im) chelate ring. When HL reacts with [Pd3(OAc)6] this gives rise to the orthometallated complex [LPd(OAc)],. In this case the Pd(II) environment consists of a N(py)/N(im) ring fused to the N(im)/C palladacycle and a monodentate acetate anion. Complex undergoes methatetical reactions with alkaline halides and complexes of general formula [LPdX](3: X = Cl; 4: X = Br; 5: X = I) are obtained. The molecular structures 3-5 of determined by single-crystal X-ray analysis proved the formation in all cases of mononuclear Pd(II) complexes containing a N(py)/N(im)/C terdentate ligand. As solid samples only compounds 3-5 exhibited luminescence at room temperature (lambdamax approximately 610 nm). This property, quite unusual in Pd(II) complexes, is discussed in terms of pi-pi] interactions, which are mainly responsible for the existence in the crystalline solid state of dimeric units.     

Syntheses and characterisation of some triphenylcyanoborate complexes of rhodium(II) and palladium(II)

The triphenylcyanoborate (N-bonded) complexes {η⁵-(C₅Me₅)Rh(SS)-NCBPh₃} (SS? =^?S₂PMe₂,^?S₂PPh₂,^?S₂CNMe₂), {η⁶-(C₆H₆)Ru(S₂PPh₂)-NCBPh₃} and [Pd(S₂ CNEt₂)(PMe₂Ph)(NCBPh₃) have been synthesised and characterised by both spectroscopic and X-ray structural methods.     

Manganese(II) and palladium(II) complexes containing a new macrocyclic Schiff base ligand: antibacterial properties

Complexes of tetradentate macrocyclic Schiff base ligand, L, with Mn^II and Pd^II ions have been synthesized by the template condensation of 1,10-phenanthroline-2, 9-dicarboxaldehyde, 2,3-diamino-1,4-naphthoquinone and 1,2-dibromoethane in EtOH. The complexes were characterized by physicochemical and spectroscopic methods and an octahedral geometry is suggested for their structure. They have been screened for antibacterial activity against several bacteria, and the results are compared with the activity of penicillin.     

Synthesis, characterisation and in vitro evaluation of palladium(II) iminophosphine complexes for anticancer activity

Palladium(II) complexes have been obtained from the reactions of the iminophosphine ligands, (L1–L7), respectively, with [PdCl₂(COD)] and [PdMeCl(COD)] in CH₂Cl₂ at room temperature. The palladium(II) complexes were characterised using elemental analysis, electro spray ionisation–mass spectrometry (ESI–MS), NMR (¹H and ³¹P), IR spectroscopy and X-ray diffraction studies. Single-crystal X-ray diffraction analysis for complexes 2, 7 and 8 revealed that the complexes exhibited a slightly distorted square planar geometry. In vitro cytotoxic study results show that the palladium complexes exhibit moderate activity and block the proliferation of WHCO1 cells with an IC₅₀ range of 19.02–45.27 μM, and IC₅₀ range of 10.03–68.54 μM for the KYSE450 cell lines.     

Synthesis and characterisation of copper(II), nickel(II) and palladium(II) complexes of some schiff bases of dehydroacetic acid

Summary Tri-and quadri-dentate Schiff bases have been synthesized from the reaction of dehydroacetic acid with diamines, aminoacids, aminophenols and aminoalcohols. The copper(II) and some nickel(II) and palladium(II) chelates of these ligands as well as copper(II) complexes of bidentate Schiff bases of dehydroacetic acid with anilines have been prepared and characterised by electronic, i.r. and n.m.r. spectral measurements and magnetic moments.     

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.     

Synthesis and characterisation of β-carboalkoxyruthenium(II) complexes

Methyl, ethyl, and butyl acrylates have been found to insert into the hydridoruthenium complex, HRuClCO(PPh₃)₃ under mild conditions to give RuC σ-bonded mononuclear complexes of the type RuClCO(PPh₃)₂CH₂CH₂COOR. The ruthenium atom is six coordinated in these complexes     

New biimidazole and bibenzimidazole derivatives: mono and binuclear palladium(II) or platinum(II) complexes and heterobinuclear palladium(II)-rhodium(I) or platinum(II)-rhodium(I) complexes

Novel neutral biimidazolate or bibenzimidazolate palladium(II) and platinum(II) complexes of the type M(NN)₂(dpe) [M = Pd, Pt; (NN)₂^2? = BiIm^2?, BiBzIm^2?. dpe = 1,2-bis(diphenylphosphino) ethane] have been obtained by reacting MCl₂(dpe) with TI₂(NN)₂. Complexes M(NN)₂(dpe) which are Lewis bases react with HClO₄ or [M(dpe)(Me₂CO)₂](ClO₄)₂ to yield, respectively, mononuclear cationic complexes of general formula [M{H₂(NN)₂](dpe) (M = Pd, Pt; H₂(NN)₂ = H₂BiIm, H₂BiBzIm) and homobinuclear palladium(II) or platinum(II) cationic complexes of the type [M₂{μ - (NN)₂}(dpe)₂](ClO₄)₂. Reactions of M(BiBzIm)(dpe) with [Rh(COD) (Me₂CO)_X](ClO₄) render similar heterobinuclear palladium(II)-rhodium(I) and platinum(II)-rhodium(I) cationic complexes, of general formula [(dpe)M(μ-BiBzIm)Rh(COD)](ClO₄) (M = Pd, Pt; COD = 1,5-cyclooctadiene). Di- and mono-carbonyl derivatives [(dpe)M(μ-BiBzIm)Rh(CO)L](ClO₄) (M = Pd, Pt; L = CO, PPh₃) have also been prepared. The structures of the resulting complexes have been elucidated by conductance studies and IR spectroscopy.     

Synthesis and characterization of five-coordinate macrocyclic complexes of nickel(II) and copper(II)

The template condensation of the ligand 1,29,10-tetraphenyl-3,4,7,8-tetraazonona-2,4,6,8-tetraen-1,10-dione and aliphatic diamines like ethanediamine and 1,2-propanediamine in the presence of metal ions, viz. Ni²⁺ and Cu²⁺, resulted in the formation of pentacoordinate square pyramidal complexes with the hydroxyl ion occupying the axial position. The macrocyclic ligand is coordinated to the central metal ion through four imine nitrogen atoms in a planar fashion. Electronic, IR and ESR spectra as well as magnetic and conductance data corrobarate the above proposition. The electrochemistry of these complexes in DMF has also been discussed.     

Synthesis and characterization of palladium(II) and platinum(II) complexes with ferrocenylimidazole

The synthesis and characterization of ferrocenylimidazole complexes of platinum(II) and palladium(II) are described. Reaction of ferrocenylimidazoles with K₂MCl₄ (M = Pd, Pt) using a biphasic system of dichloromethane and ethanol/water provided the corresponding complexes 2a–2j in good yields. New synthetic routes for the synthesis of ferrocenylbenzylethers 2k–2o, bis(4-ferrocenylbenzyl)carbonate [2p] and 4-ferrocenylbenzylacetate [2q] are also described. These products were obtained by the reaction of 4-ferrocenylbenzyl-1H-imidazole-carboxylate and K₂PtCl₄ under various conditions. Compounds 2k–2o were also obtained by alternative routes which do not involve the use of a platinum salt. The crystal structures of 2b, 2q and plausible mechanisms for the formation of 2k, 2p and 2q are reported.     

Synthesis and catalytic properties of cationic palladium(II) and rhodium(I) complexes bearing diphosphinidinecyclobutene ligands

Cationic palladium(II) and rhodium(I) complexes bearing 1,2-diaryl-3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]cyclobutene ligands (DPCB–Y) were prepared and their structures and catalytic activity were examined (aryl = phenyl (DPCB), 4-methoxyphenyl (DPCB–OMe), 4-(trifluoromethyl)phenyl (DPCB–CF₃)). The palladium complexes [Pd(MeCN)₂(DPCB–Y)]X₂ (X = OTf, BF₄, BAr₄ (Ar = 3,5-bis(trifluoromethyl)phenyl)) were prepared by the reactions of DPCB–Y with [Pd(MeCN)₄]X₂, which were generated from Pd(OAc)₂ and HX in MeCN. On the other hand, the rhodium complexes [Rh(MeCN)₂(DPCB–Y)]OTf were prepared by the treatment of [Rh(μ-Cl)(cyclooctene)₂]₂ with DPCB–Y in CH₂Cl₂, followed by treatment with AgOTf in the presence of MeCN. The cationic complexes catalyzed conjugate addition of benzyl carbamate to α,β-unsaturated ketones.     

Synthesis and characterization of new macrocyclic diimine complexes of nickel(II)

Summary The reaction of 3,4-thiophenedicarboxaldehyde and 1,3-diaminopropane in EtOH gives a tetraazamacrocylic ligand (L). Two Ni^II complexes of L were prepared by a simple addition reaction, while other macrocyclic Ni^II complexes were prepared by metal-controlled condensation reactions between 3,4-thiophenedicarboxaldehyde and aliphatic diamines. On the basis of various physical properties, the complexes can be described as six co-ordinate pseudo-octahedral structures. Simple reactions led to the isolation of isothiocyanate and percholorate derivatives.     

Metal-proton interactions in palladium(II) and rhodium(I) complexes ofortho-alkylanilines

Summary Reaction of 1 equivalent ofo-alkylaniline with Pd(OAc)₂ gave the acetate bridged complexes [Pd(OAc)₂L]₂. The^*H n.m.r. spectra showed downfield shifts for theo-benzylic protons indicating an above-plane geometry involving a significant interaction with the metal orbitals. Similar interactions were found for Pd(OAc)₂L₂ and Pd(OAc)₂L(L) (L= differento-alkylaniline; t-butylpyridineetc.) prepared from the dimer and for Rh(CO)₂Cl(L) complexes. Theo-benzylic carbons of the palladium complexes did not show downfield shifts in the¹³C n.m.r. spectra.     

Binuclear palladium(I) and palladium(II) complexes of ortho-functionalized 1,3-bis(aryl)triazenido ligands

Three new bis(aryl)triazene ligands, Ar-NNNH-Ar' [Ar = o-C(6)H(4)-CO(2)Me, Ar' = p-C(6)H(4)-CH(3) (2); Ar = Ar' = o-C(6)H(4)-CO(2)Me (3); Ar = o-C(6)H(4)-SMe, Ar' = p-C(6)H(4)-CH(3)) (4)], have been synthesized. The reaction of 1-4 with PdCl(2)(NCCH(3))(2) in the presence of a base afforded a series of binuclear diamagnetic palladium complexes. In these reactions, ligands 1-3 afforded the palladium(I) complexes [Pd(I)(o-MeO(2)C-C(6)H(4)-NNN-o-C(6)H(4)-CO(2)Me)](2) (5, monoclinic, space group P21/c, a = 8.6070(10) Angstrom, b = 14.3220(10) Angstrom, c = 12.7310(10) Angstrom, beta = 100.2950(10) degrees, Z = 2), [Pd(I)(o-MeO-C(6)H(4)-NNN-o-C(6)H(4)-OMe)](2) (6, triclinic, space group P, a = 6.6288(5) Angstrom, b = 10.2631(10) Angstrom, c = 11.0246(11) Angstrom, alpha = 85.579(6) degrees, beta = 80.885(6) degrees, gamma = 74.607(6) degrees, Z = 1), and [Pd(I)(o-MeO(2)C-C(6)H(4)-NNN-p-C(6)H(4)-CH(3))](2) (7, tetragonal, space group I41/a, a = 20.866(3) Angstrom, b = 20.866(3) Angstrom, c = 13.156(2) Angstrom, Z = 8). In contrast, the reaction of ligand 4 with PdCl(2)(NCCH(3))(2) resulted in the formation of a palladium(II) dimer, [Pd(II)(o-MeS-C(6)H(4)-NNN-p-C(6)H(4)-CH(3))Cl](2) (8, orthorhombic, space group P2(1)2(1)2, a = 10.4058(5) Angstrom, b = 16.2488(8) Angstrom, c = 9.9500(5) Angstrom, Z = 2).     

Synthesis,spectral and thermal properties of macrocyclic zinc(II) complexes

The new zinc ternary complexes [Zn(cyclen)NO₃]ClO4 (I), [Zn₂(cyclen)₂(m-nic)](ClO₄)₃ (II), [Zn₂(cyclen)₂(m-pic)](ClO₄)₃ (III) (cyclen=1,4,7,10-tetraazacyclododecane; nic=nicotinic acid; pic=picolinic acid) were synthesized and their spectral and thermal properties were investigated. The compounds were characterized by elemental analysis, IR spectroscopy and TG/DTG, DTA methods. Moreover, the way of coordination of pyridinecarboxylate anions was proposed on the basis of the spectral data and consequently proved with results of X-ray structure analysis. This revised version was published online in August 2006 with corrections to the Cover Date.