Equilibria in complexes of N-heterocyclic molecules,part XII. The reaction of hydroxide and alkoxide Ions with platinum(II) complexes of 5-nitro-1,10-phenanthroline and 2,2′-bipyridyl

Summary Bis-(5-nitro-1,10-phenanthroline)platinum(II) dichloride and diperchlorate have been prepared. The reaction between the parent cation and hydroxide ion has been studied using 1 FI n.m.r. spectroscopy and found to involve attack at the ligand. The bis-(2,2-bipyridyl)platinum(II) ion has been shown to be highly reactive towards methoxide ion. The dissociation of a 2,2-bipyridyl ligand is preceded by attack at the ligand.Part XI: R. D. Gillard, t.. A. P. Kane-Maguire and P. A. Williams,Transition Met. Chem., 2, 47 (1977).On leave from the University of Baghdad, Iraq.     

Equilibria in complexes ofN-heterocyclic molecules. Part XXXII. Dissociation oftris-(5-halo-1,10-phenanthroline)iron(III) ions in acid solution

Summary The kinetics of reaction of thetris-(5-X-1,10-phenanthroline) iron(III) ions where X=Br or Cl have been studied in detail in 0–100% sulphuric acid solutions. Relationships between the rates of reactions and the activity of water have been examined. No reaction occurs without water present. The reactions are interpreted in terms of covalent hydrate and pseudo-base formation. By taking into account previous studies, rates and magnitudes of hydrate formation for these and some other related complexes can be estimated.phen 1,10-phenanthroline - bipy 2,2-bipyridyl - terpy 2,2; 6,2-terpyridyl Part XXXI: R. D. Gillard, D. W. Knight and P. A. Williams,Transition Met. Chem., 5, 321 (1980)     

Photophysical properties of lanthanide complexes with 5-nitro-1,10-phenanthroline

Abstract  

Five novel lanthanide (Eu³⁺, Tb³⁺, Sm³⁺, Dy³⁺, and Gd³⁺) complexes with 5-nitro-1,10-phenanthroline (phenNO₂) have been synthesized and characterized by elemental analysis, IR, UV, and luminescence spectra. The triplet state energy of phenNO₂ was determined to be 20,048 cm⁻¹ via the phosphorescence spectra of phenNO₂ and its gadolinium complex. The photophysical properties of these complexes indicated that the triplet state energy of the ligand is suitable for the sensitization of the luminescence of Eu³⁺ and Sm³⁺, especially the former.     

Spectral and kinetic evidence for attack at coordinated phenanthroline in the reaction between aliphatic amines and transition metal complexes of 5-nitro-1,10-phenanthroline

Various transition metal complexes of 5-nitro-1,10-phenanthroline react with aliphatic amines in dipolar aprotic solvents to give deeply coloured species. The spectral changes, which can be reversed upon addition of acid or of the appropriate protonated amine, do not depend either on the nature of the metal and the ancillary ligands or on the geometry of the complexes; this has been taken as evidence that the colour forming process is due to a specific interaction of aliphatic amines with coordinated phenanthroline. While the rate of reaction of [Pt(5-NO₂phen)Cl₂] and [Pd(5-NO₂phen)Cl₂] with Br^?, which is known to displace Cl^? in the substrates, depends strongly on the nature of the central atom, the second order rate constant at 25°C being 3.2 × 10^?4 dm³mol^?1s^?1 and 1.35 dm³mol^?1s^?1 for the platinum and the palladium derivative respectively, the rate of reaction with n-propylamine has a comparable value for both substrates. This is further evidence that amines attack the coordinated phenanthroline, rather than the central atom. On the basis of the spectral features and the reaction stoicheiometry, the adducts of metal complexes of 5-NO₂phen and aliphatic amines are presumably Meisenheimer-like complexes.     

Equilibria in complexes ofN-heterocyclic molecules,part X. The pH dependent racemization of tris-(1,10-phenanthroline)nickel(II)

Summary Circular dichroism and electronic spectral measurements have established the existence of a covalent hydrate and a pseudobase arising from attack of H₂O or HO^– at the ligand in tris-(1,10-phenanthroline)nickel(II). In anhydrous solvents and strongly acidic solution, the complex is largely unsolvated. Over a large pH range the dominant species present in aqueous solution is the covalent hydrate while at high pH, this is converted into the pseudo-base. The existence of these species, and the equilibria between them in aqueous solution elegantly explains the pH dependent dissociation and racemization of the parent molecule. It further explains the non-linear variation of these reactions in mixed solvents and indicates that more than one mechanism is responsible over the range of solvents studied here and previously.Part IX,Transition Met. Chem., 2, 12 (1977).This ready change was pointed out to one of us (R.D.G.) some years ago by Professor B. Bosnich.     

Equilibria in complexes ofN-heterocyclic molecules,part IX. Circular dichroism study of nucleophilic attack at tris-(5-nitro1,10-phenanthroline)ruthenium(II)

Summary The reactions between Ho^–, CN^–, MeO^– and EtO^– and -(-)-tris-(5-vitro-1,10-phenantliroline)ruthenium(II) ion in solution were followed by c.d. measurements. The results support the earlier findings that these reactions proceed through the formation of pseudo-bases with the ligand.Part VIII: R. D. Gillard, L. A. P. Kane-Maguire and P. A. Williams,J. Chem. Soc. Dalton Trans. in press.     

Extractive spectrophotometry of the molybdenum (III) 1,10-phenanthroline thiocyanate and 2,2'-bipyridyl thiocyanate complexes

New extraction spectrophotometric methods for the determination of small amounts of molybdenum have been developed, using thiocyanate and 1,10-phenanthroline or 2,2'-bipyridyl as reagents in the presence of chlorostannous acid. Extracts of the ternary complexes of tervalent molybdenum in 1,2-dichloroethane obey Beer's law in the range 1-10 mug/ml at 525 nm. A 10-fold excess of iron and vanadium and 100-fold excess of tungsten, phosphorus and silicate do not interfere.     

Coordination of 2,2'-bipyridyl and 1,10-phenanthroline to yttrium and lanthanum complexes based on a scorpionate ligand

Reaction of yttrium and lanthanum trichloride with 1 equiv of sodium or potassium hydrotris(3,5-dimethylpyrazolyl)borate and 1 equiv of 2,2'-bipyridine gives good yields of the complexes [MCl(2)(Tp(Me2))(C(10)H(8)N(2))] (M = Y (1), La (2)). The analogous compounds with 1,10-phenanthroline, [MCl(2)(Tp(Me2))(C(12)H(8)N(2))] (M = Y (3), La (4)), have been obtained by a similar procedure. The solid-state structures of 2-4 were determined by single-crystal X-ray diffraction and revealed that the compounds are all seven-coordinate with capped octahedral geometry. In contrast, reaction of yttrium trichloride with 1 equiv of sodium hydrotris(3,5-dimethylpyrazolyl)borate in the presence of 1 equiv of neocuproine affords [YCl(3)(Tp(Me2))][Na(neoc)(3))] (5). Compounds 1 and 2 provide an entry for the synthesis of complexes containing the bipyridyl ligand in a radical anionic form or in a dianionic form. Reaction of 1 and 2 with an excess of sodium amalgam gives [Y(Tp(Me2))(bipy)(THF)(2)] (6) and [La(Tp(Me2))(2)(bipy)] (7), respectively. The structures of both compounds have been determined by X-ray crystallography. Compound 7 can be oxidized with iodine to give [La(Tp(Me2))(2)(bipy)]I (8).     

Equilibria in complexes ofN-heterocyclic molecules,Part XXIV. The reaction of nucleophiles with tris-(2,2′-bipyrimidine)iron(II) ion and its ruthenium(II) analogue

Summary The reactions of [Fe(bipym)₃]²⁺ and [Ru(bipym)₃]²⁺ with hydroxide ion in aqueous solution have been followed. The [Ru(bipym)₃]²⁺ species undergoes nucleophilic attack at the ligand to yield [Ru(bipym)₂(pyrimidine)(OH)]⁺ and [HCO₂]^– ion, involving cleavage of one pyrimidyl ring. Intermediates can be observed in the reaction of [Fe(bipym)₃]²⁺ with HO^–, N₃ ^– and SCN^–. The kinetics of the first reaction have been followed and the results are compared with those known for the reactions of [Fe(bipy)₃]²⁺, [Fe(phen)₃]²⁺ and similar compounds.Part XXIII: P. A. Williams,Transition Met. Chem., 78/84.     

Synthesis and biological activity of novel heavy metal complexes of 5-amino-1, 10-phenanthroline and 1,10-phenanthroline

Novel heavy metal complexes: Sr(5-NH₂-phen)₄(NO₃)(OH)(H₂O)₂ (1) (synthesized via a static self-assembly process) and Sn(phen)(NO₃)(OH)(H₂O) (2), Sn(5-NH₂-phen)(OH)(Cl)(H₂O) (3), Pb(5-NH₂-phen)(NO₃)₂(H₂O) (4) (obtained via metal competitive reactions under mild conditions) were reported. The coordination compounds were characterized by elemental analysis, FTIR-spectroscopy and FAB-mass spectrometry. Their cytotoxicity was measured by MTS-test towards human tumour (MDA-MB-231, HT-29, HeLa, HepG2) and non-tumour diploid (Lep-3) cell lines. The most pronounced cytotoxic effect on all cancer lines showed 1 and 4 at their high concentrations as well as 1 at its lower ones (≤ 4×10⁻² mg). Therefore, strontium complex of 5-amino-o-phenanthroline (1) exhibited the widest antitumour spectrum activity, having no toxicity to non-tumour cells at quantities ≤ 4×10⁻² mg. The computed EC₅₀ values of 1–4 against MDA-MB-231, HT-29, HeLa, HepG2 varied from 1.40×10⁻³ to 6.31×10⁻⁶ M. Towards Lep-3 substances 2–4 showed IC₅₀ 7.52×10⁻⁴ − 0.44 M. Substance 1 possess EC₅₀=1.26×10⁻⁷ M to the non-tumour cells.      

Synthesis and spectroscopic studies of mixed-ligand and polymeric dinuclear transition metal complexes with bis-acylhydrazone tetradentate ligands and 1,10-phenanthroline

Two types of dinuclear copper(II) and nickel(II) complexes with two tetradentate N2O2 donor ligands 1,4-bis(1-anthranoylhydrazonoethyl)benzene (L1), 1,4-bis(1-salicyloylhydrazonoethyl)benzene (L2) and N,N'-bidentate heterocyclic base [1,10-phenonthroline (phen)] have been synthesized and characterized by elemental analysis, infrared spectra, UV-vis electronic absorption spectra and magnetic susceptibility measurements. The reaction of metal(II) acetates with the solution containing ligand and 1,10-phenonthroline in methanol gives mixed-ligand dinuclear metal(II) complexes with general formula [M2L(phen)2]Cl2 (L=L1 or L2), whereas, the ligands react with metal(II) acetates to form polymeric dinuclear complexes with general formula [(M2L2)n] (L=L1 or L2). In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and amino groups of aroylhydrazone moiety do not participate in coordination. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes has been investigated.     

Synthesis,structures, photophysical properties,and catalytic characteristics of 2,9-dimesityl-1,10-phenanthroline (dmesp) transition metal complexes

The syntheses of the 2,9-dimesityl-1,10-phenanthroline ( dmesp ) metal complexes, [Cu(dmesp)(MeCN)]PF₆ ( 1 ), [Cu(dmesp)₂]PF₆ ( 2 ), Fe(dmesp)Cl₂ ( 3 ), Co(dmesp)Cl₂ ( 4 ), Ni(dmesp)Cl₂ ( 5 ), Zn(dmesp)Cl₂ ( 6 ), Pd(dmesp)MeCl ( 7 ), Cu(dmesp)Cl ( 8 ), and Pd(dmesp)₂Cl₂ ( 9 ), in good to high yields are described. These complexes were characterized by ¹H and ¹³C NMR spectroscopy, HR–MS (ESI and/or APPI), and elemental analysis (CHN). The solid-state structures of complexes 1 – 8 were determined by single-crystal X-ray analysis and their photophysical properties were also characterized. To demonstrate the versatility of this new platform, complexes 3 – 5 , 8 , and 9 were employed in the catalytic oligomerization of ethylene using modified methyl aluminoxane (MMAO) as the cocatalyst, where Co(II) and Ni(II) complexes ( 4 and 5 , respectively) were found to exhibit moderate selectivity for catalytic dimerization of ethylene to butenes over tri- or tetramerization. Complex 8 is an effective catalyst of both the commonly encountered “click” reaction and amine arylation chemistries. Complexes 6 and 9 were found to be excellent catalysts for Friedel-Crafts alkylation and Suzuki-Miyaura coupling, respectively.     

Synthesis and NMR characterization of cobalt(III) complexes with triethylenetetramine, 2,2-bipyridine and 1,10-phenanthroline

The compounds α-cis?[Co(trien)(bipy)]Cl₃ and α-cis?[Co(trien)(phen)]Cl₃ were synthesized and characterized by one- and two-dimensional NMR spectroscopy. Compared to α-cis?[Co(trien)(NO₂)₂]Cl, the proton spectra of these two complexes were spread to a wider spectral width. With the aid of two-dimensional experiments, it was possible to assign three multiplets to specific protons, and the remaining multiplet was found to arise from overlap of three separate resonances.     

Synthesis,features and thermal decomposition of hexachlorostannates and hexachloroplatinates of tris(2,2′-dipyridyl)metal(II) and tris(1,10-phenanthroline)metal(II) (metal=Ru,Fe, Ni)

Several complex salts of general formula [M^II(dipy)₃]M^IVCl₆ or [M^II(phen)₃]M^IVCl₆ (whereM ^II=Ru, Fe, Ni andM ^IV=Sn, Pt) were synthetized and subjected to thermal analyses. Heating of these derivatives leads to the release of organic fragments and chlorine, which are often involved in oxidation processes. The residues comprise metal oxides or pure metals (e.g. Pt). Differences in the structures and features of the ligand molecules, revealed on the basis of quantum-chemistry calculations, account qualitatively for the differences in behaviour and stability of the complex compounds studied.This work was financed by the Polish State Committee for Scientific Research (KBN) under grant 2 0679 91 01 (contract no. 1156/2/91).     

Thermal decomposition of metal complexes: II. Mixed complexes of iron(II) iodide with 1,10-phenanthroline,and 4,7-disubstituted-1,10-phenanthrolines

The thermal behavior of the Fe(II) iodide mixed complexes with 1,10-phenanthroline and 4,7-disubstituted phenanthrolines in nitrogen atmosphere is investigated.In order to determine to what extent small changes in ligand field symmetries influence the “activation energy” E_a, this energy is determined. The results are discussed in relation to the changes of the σ and π bonds.     

Magnetic properties of transition metal complexes with 2,2′-bipyridin-5-yl t-butyl nitroxide

Complexes [Mn^II(5bpno)₃(ClO₄)₂], [Mn^II(5bpno)(CH₃OH)₂Cl₂], [Cu^II(5bpno)₂(ClO₄)₂], and [Cu^II(5bpno)Cl₂] were prepared, where 5bpno stands for 2,2′-bipyridin-5-yl t-butyl nitroxide. X-ray crystallographic analysis clarified that the Cu ion in [Cu(5bpno)₂(ClO₄)₂] was tetra-coordinate with four nitrogen atoms forming two chelate rings. Magnetic measurements revealed the presence of ferromagnetic couplings in the Mn complexes, whereas the Cu complexes showed antiferromagnetic couplings. Magnetic exchange couplings between the metal and radical spins through the intervening pyridine ring can be explained in terms of the spin-polarization mechanism.     

Syntheses,crystal structures,and properties of four transition metal complexes based on 5-nitro-8-hydroxyquinoline

Four new complexes, [M(C₉H₅N₂O₃)₂(H₂O)₂]·CH₃OH (M?=?Zn(II), Cd(II) and Mn(II)) (1–3) and [Cu(C₉H₅N₂O₃)₂] (4), have been synthesized by reactions of 5-nitro-quinoline-8-yl acetate (NQA) and corresponding metal salts at room temperature and characterized by elemental analysis, IR, thermal gravimetric analysis (TGA), fluorescence measurement and single crystal X-ray diffraction. 1–3 are mononuclear, further extended to 2-D layers by hydrogen bonds. For 4, Cu²⁺ is coordinated by two N atoms and two O atoms from two NQ ligands. TGA indicates that 1–4 have good thermal stabilities. Furthermore, 1 and 2 show excellent luminescence in the solid state at room temperature.     

XPS studies on the host-guest interaction of 2,2′-Bipyridyl, 1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline intercalated inα-zirconium phosphate

The host-guest interactions of 2,2-bipyridyl, 1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline intercalated between the layers of crystalline-zirconium monohydrogen phosphate have been studied by X-ray photoelectron spectroscopy. Evidence that, on average, only one of the two nitrogen atoms of each aromatic diamine is protonated by the P-OH groups of the host is given. The acid-base interaction is strongly reduced on dehydration of the materials. The role of the cointercalated water is discussed, together with the probable disposition of the guests within the interlayer region.