Ruthenium(III)-carbonyl and ruthenium(II)-nitrosyl complexes of nitrogen-containing ligands with ethoxysilane groups

Reactions of γ-aminopropyltriethoxysilane and 4-(diethylamino)salicylaldehyde in ethanol afforded a Schiff base L1H, which reacted with [Ru(CO)₂Cl₂]_n in the presence of Et₃N in THF giving a ruthenium(III) carbonyl complex RuCl(CO)₂(η¹-O-L1)(η²-O,N-L1) (1). Treatment of γ-aminopropyltriethoxysilane with 4-pyridinecarboxaldehyde gave the Schiff base L2. Interactions of L2, γ-aminopropyltriethoxysilane, and Ru(NO)Cl₃?H₂O in THF led to the formation of a ruthenium(II) nitrosyl complex RuCl₃(NO)(L2)[H₂N(CH₂)₃Si(OEt)₃] (2) with linear N≡O ligand. Complexes 1 and 2 were characterized by microanalyses and IR and MS spectroscopies and confirmed by single-crystal X-ray diffraction.     

Cyclometallated ruthenium(III) complexes: Synthesis,structure and properties

Reactions of Schiff bases (H₂apahR) derived from acetophenone and acid hydrazides, triethylamine and [Ru(PPh₃)₃Cl₂] (1:2:1 mole ratio) in methanol provide cyclometallated ruthenium(III) complexes of formula trans-[Ru(apahR)(PPh₃)₂Cl] in 74–81% yields. The complexes have been characterized by elemental analysis, magnetic susceptibility, spectroscopic (infrared, electronic and EPR) and electrochemical measurements. X-ray crystal structures of two representative complexes have been determined. In each complex, the metal centre is in distorted octahedral CNOClP₂ coordination sphere assembled by the C,N,O-donor meridionally spanning apahR^2?, the chloride and the two mutually trans-oriented PPh₃ molecules. All the complexes are one-electron paramagnetic (μ_eff. = 1.85–1.98 μ_B) and display rhombic EPR spectra in frozen (120 K) dichloromethane-toluene (1:1) solution. Electronic spectra of the complexes display several absorptions within 470–270 nm due to ligand-to-metal charge transfer and ligand centred transitions. The complexes are redox active and display a Ru(III) → Ru(II) reduction and a Ru(III) → Ru(IV) oxidation in the potential ranges ?0.66 to ?0.70 V and 0.75 to 0.80 V (vs. Ag/AgCl), respectively.     

Synthesis,spectroscopic characterization and antibacterial sensitivity of some chloro dimethylsulfoxide/tetramethylenesulfoxide ruthenium(II) and ruthenium(III) complexes with 2-aminobenzothiazole

Synthesis and characterization of seven ruthenium(II) and ruthenium(III) complexes of sulfoxide with 2-aminobenzothiazole are reported. Three different formulations exist: [cis,cis,cis-RuCl₂(SO)₂(2-abtz)₂] and [trans,trans,trans-RuCl₂(SO)₂(2-abtz)₂] and [trans-RuCl₄(SO)(2-abtz)] ^? [X]⁺ (where SO?=?dimethyl sulfoxide (dmso) or tetramethylenesulfoxide (tmso); 2-abtz?=?2-aminobenzothiazole and [X]⁺?=?[H(abtz)]⁺, [Na⁺]. These complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility, FTIR, ¹H NMR, ¹³C{¹H} NMR and electronic spectroscopy. Some of the complexes were screened for their antibacterial activity and are found to be potent against the gram negative bacteria Escherichia coli.     

Synthesis,characterization, catalytic and antimicrobial studies of ruthenium(III) complexes

Ru(III) complexes of the type [RuXB(L)2] have been prepared by the reaction of 3,4-dihydropyrimidin-2(1H)-ones/thiones (HL¹–HL⁴) with the precursors of the type [RuX₃B₃] where X=Cl or Br; B=PPh₃ or AsPh₃ and L is the deprotonated ligand. The synthesized complexes were characterized by physico-chemical methods, electrochemical and magnetic moment data. The catalytic efficiency of the complexes were examined in the oxidation of alcohols and antimicrobial studies were also carried out.      

Synthesis and spectroscopic studies of some halogen-dimethylsulphoxide/tetramethylenesulphoxide-ruthenium(II) and ruthenium(III) complexes with 2-aminobenzimidazole

Synthesis and characterization of seven ruthenium(II) and ruthenium(III) complexes of sulphoxide with 2-aminobenzimidazole are reported. Three different formulations exist; [cis-RuCl₂(SO)₃(2-ABZ)]; [trans-RuCl₂(SO)₃)(2-ABZ)]; and [trans-RuCl₄(SO)(2-ABZ (where SO?=?dimethylsulphoxide(DMSO)/tetramethylenesulphoxide(TMSO); 2-ABZ?=?2-aminobenzimidazole). These complexes are characterized by elemental analysis, conductivity magnetic susceptibility, ¹H-NMR, ¹³C{¹H}-NMR and electronic spectroscopy.     

Synthesis,structural, electrochemical,and spectroscopic studies of some (diimine)ruthenium nitrile complexes

The syntheses of cationic ruthenium(II) complexes [Ru(Me₂-bpy)(PPh₃)₂RR?][PF₆]_x {Me₂-bpy = 4,4?-dimethyl-2,2?-bipyridine, (3) R = Cl, R? = N≡CMe, x = 1, (4) R = Cl, R? = N≡CPh, x = 1, (5) R = R? = N≡CMe, x = 2} and [Ru(Me₂-bpy)(κ²-dppf)RR?][PF₆]_x {dppf = 1,1?-bis(diphenylphosphino)ferrocene, (6) R = Cl, R? = N≡CMe, x = 1, (7) R = Cl, R? = N≡CPh, x = 1, (8) R = R? = N≡CMe, x = 2} are reported, together with their structural confirmation by NMR (³¹P, ¹H) and IR spectroscopy and elemental analysis, and, in the case of trans-[Ru(Me₂-bpy)(PPh₃)₂(N≡CCH₃)Cl][PF₆] (3), by X-ray crystallography. Electronic absorption and emission spectra of the complexes reveal that all complexes except 4 and 6 are emissive in the range 370–400 nm with 8 exhibiting an emission in the blue. Cyclic voltammetry studies of 3–8 show reversible or quasi-reversible redox processes at ca. 1 V, assigned to the Ru(II/III) couple.     

Paramagnetic ruthenium(III) cyclometallated complex. Synthesis, spectroscopic studies and electron-transfer properties

The reaction of Ru^II(PPh₃)₃X₂ (X = Cl, Br) with o-(OH)C₆H₄C(H)=N-CH₂C₆H₅ (HL) under aerobic conditions affords Ru^II(L)₂(PPh₃)₂, 1, in which both the ligands (L) are bound to the metal center at the phenolic oxygen (deprotonated) and azomethine nitrogen and Ru^III(L¹)(L²)(PPh₃), 2, in which one L is in bidentate N,O form like in complex 1 and the other ligand is in tridentate C,N,O mode where cyclometallation takes place from the ortho carbon atom (deprotonated) of the benzyl amine fragment. The complex 1 is unstable in solution, and undergoes spontaneous oxidative internal transformation to complex 2. In solid state upon heating, 1 initially converts to 2 quantitatively and further heating causes the rearrangement of complex 2 to the stable RuL₃ complex. The presence of symmetry in the diamagnetic, electrically neutral complex 1 is confirmed by ¹H and ³¹P NMR spectroscopy. It exhibits an Ru^II → L, MLCT transition at 460 nm and a ligand based transition at 340 nm. The complex 1 undergoes quasi-reversible ruthenium(II)—ruthenium(III) oxidation at 1.27V vs. SCE. The one-electron paramagnetic cyclometallated ruthenium(III) complex 2 displays an L → Ru^III, LMCT transition at 658 nm. The ligand based transition is observed to take place at 343 nm. The complex 2 shows reversible ruthenium(III)—ruthenium(IV) oxidation at 0.875V and irreversible ruthenium(III)—ruthenium(II) reduction at −0.68V vs. SCE. It exhibits a rhombic EPR spectrum, that has been analysed to furnish values of axial (6560 cm⁻¹) and rhombic (5630 cm⁻¹) distortion parameters as well as the energies of the two expected ligand field transitions (3877 cm⁻¹ and 9540 cm⁻¹) within the t₂ shell. One of the transitions has been experimentally observed in the predicted region (9090 cm⁻¹). The first order rate constants at different temperatures and the activation parameter ΔH^#/ΔS^# values of the conversion process of 1 → 2 have been determined spectrophotometrically in chloroform solution.     

Synthesis and spectroscopic studies of novel mononuclear and binuclear ruthenium(III) complexes with bidentate and tridentate acyclic hydrazones

Nine novel acyclic hydrazone ligands, FINH?=?N-(furylidene)-N′-isonicotinoylhydrazine, FNH?=?N-(furylidene)-N′-nicotinoylhydrazine, PINH?=?N-(pyrienylidene)-N′-isonicotinoylhydrazine, PNH?=?N-(pyrienylidene)-N′-nicotinoylhydrazine, TINH?=?N-(thienylidene)-N′-isonicotinoylhydrazine, TNH?=?N-(thienylidene)-N′-nicotinoylhydrazine, FSH?=?N-(furylidene)-N′-salicyloylhydrazine, PSH?=?N-(pyrienylidene)-N′-salicyloylhydrazine and TSH?=?N-(thienylidene)-N′-salicyloylhydrazine, have been synthesized. Their corresponding mononuclear and binuclear ruthenium(III) complexes have been prepared by the reaction of the ligand with RuCl₃·3H₂O in 1?:?2 and 2?:?2 molar ratio and are characterized by elemental analyses, thermogravimetric analyses (TGA and DTG), IR, electronic, magnetic susceptibility and electrical conductance measurements. Electronic spectra and magnetic susceptibility measurements of the solid complexes (both mono- and binuclear) indicate an octahedral geometry around ruthenium(III). Particular emphasis is given to the binuclear complexes in which FSH, PSH and TSH behave as tridentate ligands and chloride bridges the Ru(III) ions. Conductance measurements show the mononuclear complexes are electrolytic and binuclear complexes are of non-electrolytic. The fungicidal activities of the ligands and metal complexes against Fusarium oxysporium and Aspergillus niger are described.     

Synthesis,spectroscopic and thermal studies on ruthenium(III), rhodium(III) and iridium(III) complexes with hydrazones derived from 2,6-diacetylpyridine and different aromatic hydrazides

Summary The reactions of MCl₃·3H₂O (M=Ru, Rh or Ir) with hydrazones have been studied by three different methods and complexes of the types [M(LH₂)(H₂O)₂]Cl₃, [M(L)Cl(H₂O)] and [M(LH₂)Cl₂]Cl·H₂O have been isolated. Tentative structural conclusions are drawn for these products based upon elemental analysis, electrical conductance, magnetic moment, and i.r. and¹H n.m.r. data. The thermal stability and mode of decomposition for the complexes have been studied by t.g.a., d.t.g. and d.s.c. techniques.     

Synthesis, characterization, and DNA binding of new water-soluble cyclopentadienyl ruthenium(II) complexes incorporating phosphines

The new water-soluble ruthenium(II) chiral complexes [RuCpX(L)(L')](n+) (X = Cl, I. L = PPh3; L' = PTA, mPTA; L = L' = PTA, mPTA) (PTA = 1,3,5-triaza-7-phosphaadamantane; mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane) have been synthesized and characterized by NMR and IR spectroscopy and elemental analysis. The salt mPTA(OSO2CF3) was also prepared and fully characterized by spectroscopic techniques. X-ray crystal structures of [RuClCp(PPh3)(PTA)] (2), [RuCpI(PPh3)(PTA)] (3), and [RuCpI(mPTA)(PPh3)](OSO2CF3) (9) have been determined. The binding properties toward DNA of the new hydrosoluble complexes have been studied using the mobility shift assay. The ruthenium chloride complexes interact with DNA depending on the hydrosoluble phosphine bonded to the metal, while the corresponding compounds with iodide, [RuCpI(PTA)2] (1), [RuCpI(PPh3)(PTA)] (3), [RuCpI(mPTA)2](OSO2CF3)2 (6), and [RuCpI(mPTA)(PPh3)](OSO2CF3) (9), do not bind to DNA.     

Synthesis and spectroscopic studies of Sb(III) and Bi(III) complexes of semicarbazones

Summary New complexes of Sb(III) and Bi(III) with semicarbazones of the general formulae SbCl₃ L and BiCl₃ L (whereL=semicarbazones) have been prepared and characterized by IR,¹H- and¹³C-NMR spectral measurements. The results of the spectroscopic studies indicate that the semicarbazone ligands act as bidentate in all the complexes. All complexes are non-electrolytes inDMF solution. The molecular weight determinations indicate that the compounds are monomeric.

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Synthese und spektroskopische Untersuchungen von Sb(III)- und Bi(III)-Komplexen mit Semlcarbazonen

Zusammenfassung Es wurden neue Komplexe von Sb(III) und Bi(III) mit Semicarbazonen von der allgemeinen Formel SbCl₃ L und BiCl₃ L (L=verschiedenene Semicarbazone) dargestellt und mittels IR,¹H- und¹³C-NMR charakterisiert. Die spektroskopischen Untersuchungen zeigten, daß die Semicarbazon-Liganden in allen Komplexen zweizähnig agieren. Molekulargewichtsbestimmungen zeigten die monomere Natur der Verbindungen an.

     

Synthesis,characterization and superoxide dismutase mimetic activity of ruthenium(III) oxime complexes

Vicinal carbonyl-oxime and oxime-imine ligands were used in the synthesis of new RuIII oxime complexes and the isolated chelates were characterized by elemental analysis, electrical conductance and magnetic moment measurements. I.r., u.v.–vis. and e.s.r. spectroscopic analysis methods were also employed. The spectral data were utilized to compute the important ligand field parameters B, β and Dq. The carbonyl-oxime ligand coordinates through the nitrogen of =N-OH to form a five-membered chelate ring. Replacement of the C=O group by C=N-NH2 induces the =N-OH group to coordinate through the oxygen, forming thereby a six-membered chelate ring. The quadridentate tetraaza ligand (L7) coordinates with RuIII through its nitrogen donors in the equatorial position with loss of one of the oxime protons and concomitant formation of an intramolecular hydrogen bond. The spectral and magnetic results suggest a slightly distorted octahedral environment around the RuIII ion. The superoxide dismutase (SOD) mimetic activity of the prepared complexes was assessed for their ability to inhibit the reduction of nitroblue tetrazolium (NBT). The results demonstrate that most of the complexes have promising SOD-mimetic activity. A probable mechanism for the catalytic scavenging of O2− by RuIII oximes is proposed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis,crystal structures and spectroscopic studies of praseodymium(III) malonate complexes

Reactions of malonic acid (H₂mal) with PrCl₃·6H₂O afforded the known complex [Pr₂(mal)₃(H₂O)₆]_n (1), and compounds [Pr₂(mal)₃(H₂O)₆]_n·2nH₂O (2·2nH₂O), [PrCl(mal)(H₂O)₃]_n·0.5nH₂O (3·0.5nH₂O) and [Pr(mal)(Hmal)(H₂O)₃]_n·nH₂O (4·nH₂O) using various reaction ratios, reaction media (H₂O, MeOH) and pH values. Analogous reactions with CeCl₃·7H₂O afforded compounds [Ce₂(mal)₃(H₂O)₆]_n (5), [CeCl(mal)(H₂O)₃]_n·nH₂O (6·nH₂O) and [Ce(mal)(Hmal)(H₂O)₃]_n·nH₂O (7·nH₂O). Compounds 2·2nH₂O and 3·0.5nH₂O were characterized by X-ray crystallography, and 4–7 by microanalytical and spectroscopic data. The malonate(-2) ligand adopts three different coordination modes in the structures of 1–3, i.e., the μ₂-κO:κO′:κO″ and the μ₄-κ²O:κO′:κ²O″:κO? in 1 and 2 leading to a 3D network structure, and the μ₃-κ²O:κO′:κ²O″:κO? in 3 promoting an 1D structure. The thermal decomposition of 1 and 3·0.5nH₂O was monitored by TG/DTA and TG/DTG measurements. The structural features of 1–3 are discussed in terms of known malonato(-2) Ln^III and Ca^II complexes. The bioinorganic chemistry relevance of our results is discussed.     

DNA binding and topoisomerase II inhibitory activity of water-soluble ruthenium(II) and rhodium(III) complexes

Water-soluble piano-stool arene ruthenium complexes based on 1-(4-cyanophenyl)imidazole (CPI) and 4-cyanopyridine (CNPy) with the formulas [(eta6-arene)RuCl2(L)] (L = CPI, eta6-arene = benzene (1), p-cymene (2), hexamethylbenzene (3); L = CNPy, eta6-arene = benzene (4), p-cymene (5), hexamethylbenzene (6)) have been prepared by our earlier methods. The molecular structure of [(eta6-C6Me6)RuCl2(CNPy)] (6) has been determined crystallographically. Analogous rhodium(III) complex [(eta5-C5Me5)RhCl2(CPI)] (7) has also been prepared and characterized. DNA interaction with the arene ruthenium complexes and the rhodium complex has been examined by spectroscopic and gel mobility shift assay; condensation of DNA and B-->Z transition have also been described. Arene ruthenium(II) and EPh3 (E = P, As)-containing arene ruthenium(II) complexes exhibited strong binding behavior, however, rhodium(III) complexes were found to be Topo II inhibitors with an inhibition percentage of 70% (7) and 30% (7a). Furthermore, arene ruthenium complexes containing polypyridyl ligands also act as mild Topo II inhibitors (10%, 3c and 40%, 3d) in contrast to their precursor complexes. Complexes 4-6 also show significant inhibition of beta-hematin/hemozoin formation activity.     

In vitro anticancer and antibacterial activities of octahedral ruthenium(III) complexes with hydroxamic acids. Synthesis and spectroscopic characterization

Five new ruthenium(III) complexes of the general formulas [RuCl(H₂O)L₂] (1–4) and [RuCl₃(H₂O)(HL)₂] (5), where L = benzohydroximato (1), salicylhydroximato (2), acetohydroximato (3), hydroxyureato (4), LH = N-hydroxy-N-phenylbenzamide (5), were synthesized by reaction of RuCl₃ · 3H₂O with the corresponding hydroxamic acids at a molar ratio of 1: 2 molar. The complexes were characterized by elemental analyses and FT-IR, UV-Vis, ¹H and ¹³C NMR, and mass spectra. The complexes showed higher antibacterial activity against ten pathogenic bacterial strains than the corresponding ligands. The anticancer activity of the complexes against IMR-32 (neuroblastoma) cancer and CHO (Chinese hamster ovary) normal cell lines was evaluated using MTT assay with respect to camptothecin as control. Complex 5 was found to exhibit an appreciable cytotoxicity against IMR-32 cell line with an IC₅₀ value of 102.27 μM.     

Synthesis, spectroscopic, redox, catalytic and antimicrobial properties of some ruthenium(II) Schiff base complexes

A new series of mixed ligand semicarbazone or thiosemicarbazone complexes of Ru(II) having the general formula [RuCO(EPh₃)(B)L] (where E = P or As; B = PPh₃, AsPh₃ or Pyridine; L = dibasic tridentate ligand derived by the condensation of ethylacetoacetate/methylacetoacetate and thiosemicarbazide/semicarbazide) have been synthesized and characterized by physico-chemical, spectroscopic and electrochemical studies. A comparative study on the catalysis of oxidation of benzyl alcohol, cyclohexanol, cinnamyl alcohol, n-butanol, n-propanol and iso-butyl alcohol has been done with N-methylmorpholine-N-oxide and molecular oxygen as co-oxidants. Catalytic activity studies of the complexes in coupling reactions have been carried out. The antibacterial properties of the complexes have also been examined.     

Synthesis,characterization, and spectroscopic studies of tetradentate Schiff base chromium(III) complexes

Eight chromium(III) complexes of tetradentate Schiff bases have been prepared in situ by condensing of a substituted salicylaldehyde compound with ethylenediamine. These were characterized by elemental analysis, m.p., IR, molar conductivity, magnetic moment measurements, and electronic spectra. The free ligands were also characterized by ¹H and ¹³C NMR spectra. The ¹³C NMR spectra are discussed in terms of possible substituent effects. The IR and electronic spectra of the free ligand and the complexes are compared and discussed. The electrospray ionization (ESI) mass spectra of four free ligands and their complexes were measured. The deconvolution of the visible spectra of the complexes, C_2v symmetry, in DMSO yields three peaks at ca. 15 600–17 600, 18 400–20 400 and 20 000–23 100, and are assigned to the three d–d transitions, ⁴B_1g → ⁴E_g(⁴T_2g); ⁴B_1g → ⁴B_2g(⁴T_2g); ⁴B_1g → ⁴E_g(⁴T_1g), respectively. The complexes showed magnetic moment in the range of 3.5–4.2 BM which corresponds to three unpaired electrons.     

Mononuclear ruthenium(III) complexes containing chelating thiosemicarbazones: Synthesis,characterization and catalytic property

Mononuclear ruthenium(III) complexes of the type [RuX(EPh₃)₂(L)] (E = P or As; X = Cl or Br; L = dibasic terdentate dehydroacetic acid thiosemicarbazones) have been synthesized from the reaction of thiosemicarbazone ligands with ruthenium(III) precursors, [RuX₃(EPh₃)₃] (where E = P, X = Cl; E = As, X = Cl or Br) and [RuBr₃(PPh₃)₂(CH₃OH)] in benzene. The compositions of the complexes have been established by elemental analysis, magnetic susceptibility measurement, FT-IR, UV–vis and EPR spectral data. These complexes are paramagnetic and show intense d–d and charge transfer transitions in dichloromethane. The complexes show rhombic EPR spectra at LNT which are typical of low-spin distorted octahedral ruthenium(III) species. All the complexes are redox active and display an irreversible metal centered redox processes. Complex [RuCl(PPh₃)₂(DHA–PTSC)] (5) was used as catalyst for transfer hydrogenation of ketones in the presence of isopropanol/KOH and was found to be the active species.     

Synthesis, structural, and spectroscopic characterization and reactivities of mononuclear cobalt(III)-peroxo complexes

Metal-dioxygen adducts are key intermediates detected in the catalytic cycles of dioxygen activation by metalloenzymes and biomimetic compounds. In this study, mononuclear cobalt(III)-peroxo complexes bearing tetraazamacrocyclic ligands, [Co(12-TMC)(O(2))](+) and [Co(13-TMC)(O(2))](+), were synthesized by reacting [Co(12-TMC)(CH(3)CN)](2+) and [Co(13-TMC)(CH(3)CN)](2+), respectively, with H(2)O(2) in the presence of triethylamine. The mononuclear cobalt(III)-peroxo intermediates were isolated and characterized by various spectroscopic techniques and X-ray crystallography, and the structural and spectroscopic characterization demonstrated unambiguously that the peroxo ligand is bound in a side-on η(2) fashion. The O-O bond stretching frequency of [Co(12-TMC)(O(2))](+) and [Co(13-TMC)(O(2))](+) was determined to be 902 cm(-1) by resonance Raman spectroscopy. The structural properties of the CoO(2) core in both complexes are nearly identical; the O-O bond distances of [Co(12-TMC)(O(2))](+) and [Co(13-TMC)(O(2))](+) were 1.4389(17) ? and 1.438(6) ?, respectively. The cobalt(III)-peroxo complexes showed reactivities in the oxidation of aldehydes and O(2)-transfer reactions. In the aldehyde oxidation reactions, the nucleophilic reactivity of the cobalt-peroxo complexes was significantly dependent on the ring size of the macrocyclic ligands, with the reactivity of [Co(13-TMC)(O(2))](+) > [Co(12-TMC)(O(2))](+). In the O(2)-transfer reactions, the cobalt(III)-peroxo complexes transferred the bound peroxo group to a manganese(II) complex, affording the corresponding cobalt(II) and manganese(III)-peroxo complexes. The reactivity of the cobalt-peroxo complexes in O(2)-transfer was also significantly dependent on the ring size of tetraazamacrocycles, and the reactivity order in the O(2)-transfer reactions was the same as that observed in the aldehyde oxidation reactions.     

Synthesis,spectroscopic characterization and antibacterial studies of some derivatives of chlorodimethylsulphoxide/tetramethylenesulphoxide ruthenium(II) and ruthenium(III) with 4-aminoantipyrine

We report the synthesis of five complexes of three different formulations viz. [cis-RuCl₂(4-antp)₂], [trans-RuCl₂(4-antp)₂] and [X]⁺[trans-RuCl₄(4-antp)₂]^? (X⁺ = [(DMSO)₂H]⁺, Na⁺, or [(TMSO)H]⁺ and 4-antp = 4-aminoantipyrine) from different routes. These complexes were characterized on the basis of elemental analyses, molar conductance measurements, magnetic susceptibility, electronic spectra, FTIR, ¹H-NMR and ¹³C{¹H}-NMR spectroscopy. Complexes were screened for antibacterial activity and found to be potent against gram negative bacteria Escherichia coli.