The Synthesis and Characterization of a Novel ( E,E )-Dioxime and its Mono- and Heterotrinuclear Complexes Containing an 18-Membered Dioxadithiadiazamacrocycle

The novel ( E , E )-dioxime, 5,6:17,18-dibenzo-11,12-(4'-nitrobenzo)-2,3-bis(hydroxyimino)-7,16-dithia-10,13-dioxa-1,4-diazacyclooctadecane) ( H 2 L ), has been synthesized from reaction of ( E , E )-dichloroglyoxime ( 1 ) with 2,3:14,15-dibenzo 8,9-(4'-nitrobenzo)-4,13-dithia-7,10-dioxa-1,16-diazahegzadecane ( 2 ). The mononuclear Co(III) complex ( 4 ) of this dioxime was prepared by oxidation of the cobalt (II) complex. The -capped Co(III) complex ( 5 ) was synthesized by using a precursor Co(III) complex and boron trifluoride dietherate. The heterotrinuclear complexes ( 6 ) and ( 7 ) were prepared by reaction of ( 5 ) with NiCl 2 ·6H 2 O and CdCl 2 ·H 2 O, respectively. In addition, the homotrinuclear Cu(II) complex ( 8 ), has also been prepared by the reaction of this dioxime with CuCl 2 ·H 2 O. The structures of the dioxime and its complexes were identified by using elemental analysis, 1 H- and 13 C-NMR, IR, and mass spectral data.     

Synthesis and Characterization of Mono- and Trinuclear Complexes of BF2+ Bridged Macrocycles

Dibenzo[e,k]-2,3-bis(hydroxyimino)-1,4-dithia-7,10-diaza-2,3,8,9-tetrahydrocyclododecine (H₂L) has been prepared from 1,2-bis(o-mercaptoanilino) ethane ( 4 ) and (E,E)-dichloroglyoxime. A mononuclear complex with a metal: ligand ratio of 1:2 has been isolated for cobalt(III). The Co^III complex of H₂L has been prepared with L′ = 2,6-lutidine, and with a chlorine ion as axial ligands. In addition to that, the synthesis of a new cobalt complex which contains BF₂⁺ bridges is achieved with the bis(E,E)-dioxime ligand. The trinuclear complex of this Co^III complex has been obtained by the reaction of BF₂⁺ bridged Co^III complex with Pd[bis(benzonitrile)]Cl₂. The structures of these complexes and (E,E)-dioxime were identified by using elemental analysis, ¹H and ¹³C-NMR, IR and MS spectral data.     

Synthesis and characterization of the free ligand 5,6:13,14-dibenzo-9,10-benzo(15-crown-5)-2,3-bis(hydroxyimino)-7,12-dioxo-1,4,8,11-tetraazacyclotetradecane and its mono and tri nuclear complexes

The novel (E,E)-dioxime 5,6:13,14-dibenzo-9,10-benzo(15-crown-5)-2,3-bis(hydroxyimino)-7,12-dioxo-1,4,8,11-tetraazacyclotetradecane (H₂L) has been synthesized by the reaction of 4′,5′-diaminobenzo(15-crown-5) with N,N′-bis(2-carbomethoxyphenyl)diaminoglyoxime (1). Only mononuclear Co^III and Ru^II complexes with a metal/ligand ratio of 1:2 have been isolated. The cobalt(III) complex bridged with BF₂⁺ is achieved with H-bonded cobalt(III) complex and borontrifluoride ethyl ether complex. The reaction of BF₂ bridged cobalt(III) complex with bis(benzonitril)palladium(II) chloride gives a trinuclear complex. The structures of dioxime and its complexes are proposed according to elemental analyses, ¹H and ¹³C-NMR, IR and mass spectral data.     

Synthesis and characterization of 2,3-bis(hydroxyimino)-1,2,3,4-tetrahydro-pyrido[2,3-b]pyrazine and its nickel(II), cobalt(II), copper(II), palladium(II), cadmium(II) and cobalt(III) complexes

Summary 2,3-Bis(hydroxyimino)-1,2,3,4-tetrahydro-pyrido[2,3-b]pyrazine (H₂L), prepared from 2,3-diaminopyridine and cyanogen-di-N-oxide has been converted into nickel(II), palladium(II), copper(II), cobalt(II), and cobalt(III) complexes (H₂L) with a 12 metal:ligand ratio. The ligands coordinate through the two N atoms, as do most vicinal dioximes. [(LH)Cl(H₂O)Cd], contains a six-membered chelate ring. [Co(HL)₂(L)Cl] has also been prepared using triphenylphosphine, triphenylarsine, thiophene and chloride as axial ligands. The structure of thevic-dioxime and its complexes are proposed on the basis of elemental analysis, i.r.,¹H-n.m.r. and uv-visible measurements.     

The synthesis and characterization of a new (E,E)-dioxime containing 20-membered tetraazadioxa macrocyclic moieties and its mononuclear complexes

A new (E,E)-dioxime, (2Z,3Z)-9,20-bis[(4-methylphenyl)sulfonyl]-1,4,7,8,9,10,11,12,14,15,17, 18,19,20,21,22-hexadecahydro-13,16-ethano[1,4,7,11,14,18]dioxatetraazacycloicosino[2,3-g] quinoxaline-2,3-dione dioxime (6) (H₂L) has been synthesized by reacting cyanogen-di-N-oxide (5) with 4,15-bis[(4-methylphenyl)sulfonyl]-2,3,4,5,6,7,9,10,12,13,14,15,16,17-tetradecahydro-8,11-ethano-1,18,4,8,11,15-benzodioxatetraazacycloicosine-20,21-diamine (4). Mononuclear complexes (7) and (8) of this ligand have been synthesized by reacting the vic-dioxime (H₂L) with NiCl₂.6H₂O and CoCl₂.6H₂O respectively. The BF₂⁺ capped Ni(II) and Co(III) complexes (9) and (10) of the dioxime have been synthesized from (7) and (8), respectively. The new compounds were characterized by a combination of elemental analysis, ¹H- and ¹³C-NMR, IR. and MS. spectral data.     

Syntheses and characterization of η 5-pentamethylcyclopentadienyl rhodium(III) and iridium(III) complexes containing polypyridyls

Reaction of [(η ⁵-C₅Me₅)M(μ-Cl)Cl]₂ {M?=?Rh (1), Ir (2)} and [(η ⁵-C₅Me₅)MCl₂(DBT)] (DBT?=?dibenzothiophene) {M?=?Rh (3), Ir (4)} with polypyridyl ligands 2,3-bis(2-pyridyl)pyrazine (bpp), 2,3-bis(2-pyridyl)quinoxaline (bpq), 1,3,5-tris(2-pyridyl)-2,4,6-triazine (tptz), 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz) and 4′-pyridyl-2,2′:6′,2′′-terpyridine (py-terpy) results in the formation of mononuclear cationic complexes, [(η ⁵-C₅Me₅)MCl(poly-py)]⁺ (poly-py?=?polypyridyl ligand). The complexes were isolated as hexafluorophosphate salts and characterized by IR and NMR spectroscopy.     

Synthesis and structural studies of (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}pyridin-2-yl)imino]butan-2-one oxime, ligand and its mono-, di- and trinuclear copper(II) complexes

A new dioxime ligand, (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}-pyridin-2-yl)imino]butan-2-one oxime, (H₂Pymdo) (3) has been synthesized in H₂O by reacting 2,3-butenedione monoxime (2) with 2,6-diaminopyridine. Mono-, di- and tri-nuclear copper(II) complexes of the dioxime ligand (H₂Pymdo) and/or 1,10-phenanthroline have been prepared. The dioxime ligand (H₂Pymdo) and its copper(II) complexes were characterized by ¹H-n.m.r., ¹³C-n.m.r. and elemental analyses, magnetic moments, i.r. and mass spectral studies. The mononuclear copper(II) complex of H₂Pymdo was found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The trinuclear copper(II) complex (6) was formed by coordination of the third Cu(II) ion with dianionic oxygen atoms of each of two molecules of the mononuclear copper(II) complexes. The data support the proposed structure of H₂Pymdo and its Cu(II) complexes.     

Chiral Tetraamines Based on (S)-2-(Aminomethyl)pyrrolidine: Template synthesis and properties of copper(II) complexes

The template reaction of {bis[(S)-2-(aminomethyl)pyrrolidine]}copper(II) with formaldehyde, nitroethane, and base in MeOH yields optically pure {1,7-bis[(S)-pyrrolidin-2-yl]-4-methyl-4-nitro-2,6-diazaheptane}- copper(II) ([Cu((S,S)-mnppm)]²⁺) in high yield. The same reaction with rac-2-(aminomethyl)pyrrolidine is also described. Preparative details and spectroscopic and electrochemical properties of the Cu^II complexes and of the free ligands are reported and compared with structural, spectroscopic and electrochemical data of the Cu^II complex of the unsubstituted parent ligand 1,7-bis[(S)-pyrrolidin-2-yl]-2,6-diazaheptane (ppm). The crystal structure of [Cu(ppm)]Cl ClO₄ has been determined by X-ray diffraction methods.     

Synthesis,Spectroscopic and Magnetic Studies on Metal Complexes of 5-Methyl-3-(2-Hydroxyphenyl)Pyrazole

A tridentate ONN donor ligand, 5-methyl-3-(2-hydroxyphenyl)pyrazole; H₂L, was synthesized by reaction of 2-(3-ketobutanoyl)phenol with hydrazine hydrate. The ligand was characterized by IR, ¹H NMR and mass spectra. ¹H NMR spectra indicated the presence of the phenolic OH group and the imine NH group of the heterocyclic moiety. Different types of mononuclear metal complexes of the following formulae [(HL)₂M][sdot]xH₂O (M=VO, Co, Ni, Cu, Zn and Cd), [(HL)₂M(H₂O)₂] (M=Mn and UO₂) and [(HL)LFe(H₂O)₂] were obtained. The Fe(III) complex, [(HL)LFe(H₂O)₂] undergoes solvatochromism. Elemental analyses, IR, electronic and ESR spectra as well as thermal, conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared metal complexes. A square-pyramidal geometry is suggested for the VO(IV) complex, square-planar for the Cu(II), Co(II) and Ni(II) complexes, octahedral for the Fe(III) and Mn(II) complexes and tetrahedral for the Zn(II) and Cd(II) complexes, while the UO₂(VI) complex is eight-coordinate. Transmetallation of the UO₂(VI) ion in its mononuclear complex by Fe(III), Ni(II) or Cu(II) ions occurred and mononuclear Fe(III), Ni(II) and Cu(II) complexes were obtained. IR spectra of the products did not have the characteristic UO₂ absorption band and the electronic spectra showed absorption bands similar to those obtained for the corresponding mononuclear complexes. Also, transmetallation of the Ni(II) ion in its mononuclear complex by Fe(III) has occurred. The antifungal activity of the ligand and the mononuclear complexes were investigated.     

Synthesis and Characterization of a New (E,E)-Dioxime and its Homonuclear Complexes

N′-(4′-Benzo[15-crown-5]naphthylaminoglyoxime (H₂L) and its sodium chloride complex (H₂L·NaCl) have been prepared from 2-naphthylchloroglyoxime, 4′-aminobenzo[15-crown-5] and sodium bicarbonate or sodium bicarbonate and sodium chloride. Nickel(II), cobalt(II) and copper(II) complexes of H₂L and H₂L·NaCl have a metal–ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The BF ₂ ⁺ -capped Ni(II), Co(III) and mononuclear complexes of thevic-dioxime were prepared. The macrocyclic ligands and their transition metal complexes have been characterized on the basis of IR, ¹H NMR spectroscopy and elemental analyses data.     

Synthesis and Structural Studies of 2-(hydroxyimino)-1-methylpropylideneamino-phenyliminobutan-2-one Oxime, Ligand and its Complexes with Cu(II) and Ni(II)

A new ligand incorporating a dioxime moiety, (2E,3E)-3-[(2-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}phenyl)imino]butan-2-one oxime, (H₂Phmdo) (3) has been prepared by reacting 2,3-butanedionemono-{O-[4-(1-methyl-2-oxo-propylideneaminooxy)-2,3-bis-(1-methyl-2-oxo-propylideneaminooxy-methyl)-but-2-enyl]-oxime} (2) with 1,2-phenylenediamine. Mono-, di- and trinuclear copper(II) and/or nickel(II) complexes of H₂Phmdo were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r. and mass spectral studies. The mononuclear copper(II) and nickel(II) complexes of H₂Phmdo were found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu^(II) or Ni^(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The data support the proposed structure of H₂Phmdo and its complexes.     

Synthesis and characterization of new copperphthalocyanine carrying mixed donor macrocyclic moieties

The new phthalocyanine peripherally substituted with a twelve-membered dioxadiaza macrocycle was synthesized by cyclotetramerization of 1,2-bis(2-{4′-[(4′-methylphenyl)-sulphonyl]-1′,7′-dioxa-4′,10′-diazacyclododecane})-4,5-dicyanobenzene (4) which was obtained from 1,2-bis(2-{4′-[(4′-methylphenyl)sulphonyl]-1′,7′-dioxa-4′,10′-diazacyclododecane})-4,5-dibromobenzene (3). Metallophthalocyanine was also prepared by the reaction of the dicyano-substituted macrocycle in the presence of anhydrous CuCN. The new compounds were characterized by a combination of elemental analysis, ¹H and ¹³C?NMR, IR, electronic and mass spectroscopies.     

Preparation,structures, and properties of nickel complexes containing 2,6-bis[4′,4′-dimethyloxazolin-2′-yl]pyridine,a pincer ligand

Five- and six-coordinate nickel complexes [(Dm-Pybox)NiCl₂], [(Dm-Pybox)Ni(H₂O)Cl₂], [(Dm-Pybox)Ni(H₂O)₂Cl]Cl (2a), and [(Dm-Pybox)Ni(MeOH)₂Cl]Cl (2b), where Dm-Pybox is 2,6-bis[4′,4′-dimethyloxazolin-2′-yl]pyridine, have been isolated and structurally characterized by single crystal X-ray diffraction. The solid state structures of 2a and 2b feature different modes of non-covalent interactions, C–H?Cl, C–H?O and O–H?Cl interactions. Spectroscopic and analytical methods, UV–vis and thermogravimetric analyses were done to further investigate chemical properties of the complexes.     

An efficient catalyst based on a water-soluble cobalt(II) complex of S,S′-bis(2-pyridylmethyl)-1,2-thiobenzene for electrochemical- and photochemical-driven hydrogen evolution

The reaction of S,S′-bis(2-pyridylmethyl)-1,2-thiobenzene and CoCl₂ affords a water-soluble cobalt(II) complex, [(bptb)CoCl₂], which has been characterized using various methods. Under blue light, together with CdS nanorods as a photosensitizer and ascorbic acid as a sacrificial electron donor, [(bptb)CoCl₂] can catalyze hydrogen generation from water and can work for 90 h. Under optimal conditions, this photocatalytic system achieves a turnover number (TON) of 22 900 moles of H₂ per mole of catalyst during 60 h of irradiation, and the highest apparent quantum yield is ca 26.63% at 469 nm. Moreover, [(bptb)CoCl₂] exhibits much higher activity than [(bpte)CoCl₂] (bpte = S,S′-bis(2-pyridylmethyl)-1,2-thioethane; TON = 6740 moles of H₂ per mole of catalyst during 60 h of irradiation), indicating that bptb can constitute a better catalyst for hydrogen production than bpte. This result can be attributed to the electronic properties of the ligands (bptb and bpte). The introduction of phenyl makes the electron distribution more uniform in the cobalt complex, allowing easier formation of the Co(III)–H species, further promoting the formation of hydrogen.     

Synthesis and Biological Activity of Novel (E,E)-vic-dioximes

A novel vic-dioxime ligand containing the thiourea group, (4E,5E)-1,3-bis{4-[(4-methylphenylamino)methyl] phenyl}- 2-thiooxaimidazoline-4,5-dione dioxime, (4) mmdH₂ has been prepared from N,N′-bis{4-[(4-methylphenylamino)methyl]phenyl}thiourea, (3) mft and cyanogen di-N-oxide. Mononuclear [M(mmdH)₂], where M = Ni^II, Co^II and Cu^II complexes of the (4) mmdH₂ bidentate ligand have been obtained with a 1:2 metal:ligand ratio, as do most the vic-dioximes. The complexes are formed by coordination of N, N atoms of the ligand. The vic-dioxime ligand and its some transition metal complexes have been characterized by elemental analyses, molar conductance data, magnetic susceptibility, i.r., ¹H-n.m.r and u.v.–vis. spectroscopy. Conductivity measurements have shown that mononuclear complexes are non-electrolytes. In addition, the ligands and metal complexes were screened for antibacterial and antifungal activities by agar well diffusion techniques using DMF as solvent.     

Studies on mononuclear transition metal chelates derived from a novel ( E,E )-dioxime: synthesis,characterization and biological activity

A novel vic-dioxime ligand with a thiourea moiety, (4E,5E)-1,3-bis{4-[(4-bromophenylamino)methylene]phenyl}-2-thiooxaimidazoline-4,5-dione dioxime (4) (bmdH₂) has been synthesized from N,N′-bis{4-[(4-bromophenylamino)methylene]phenyl}thiourea and (E,E)-dichloroglyoxime. The bmdH₂ ligand (4) forms transition metal complexes [M(bmdH)₂] with a metal?:?ligand ratio of 1?:?2 with M?=?Ni(II), Co(II), and Cu(II). The mononuclear Ni(II), Co(II) and Cu(II) complexes, [Ni(bmdH)₂] (5), [Co(bmdH)₂] (6) and [Cu(bmdH)₂] (7) have the metal ions coordinated through the two N,N atoms, as do most vic-dioximes. Elemental analyses, molar conductivity, magnetic susceptibility, IR, ¹H NMR spectra, and UV-Visible spectroscopy were used to elucidate the structures of the ligand and its complexes. Conductivity measurements have shown that the mononuclear complexes are non-electrolytes. In addition, the ligands and metal complexes were screened for antibacterial and antifungal activities by agar well diffusion techniques using DMF as solvent.     

SYNTHESIS AND COMPLEXATION OF A NOVEL SOLUBLE VIC-DIOXIME

Abstract

A new soluble vic-dioxime, l,4-bis(2-methoxyethyl-2, 3-bis(hydroxyimino)-5, 6-diphenylpiper-azine (LH₂) has been synthesized as a mixture of isomers from dicyan di-N-oxide and 1, 2-diphe-nyl-l,2-bis(2′-methoxyethylamino)ethane, 1, which has been prepared through the reduction of the condensation product of benzaldehyde and 2-methoxyethylamine with the aluminium amalgam. LH₂ gives N,N-coordinated planar metal complexes with Co^II, Ni^II, Cu^II and Pd^II Oxidation of (LH)₂Co in the presence of a base such as py or triphenylphoshine leads to octahedral complexes (LH)₂Co(B)Cl. The uranyl complex of LH₂ has a 1 :1 metal-ligand ratio and a binuclear structure with μ-hydroxo bridges.     

Synthesis,spectroscopic, thermal,and antimicrobial studies of tetradentate 12 and 14 member Schiff bases and their complexes with Fe(III), Co(II), and Cu(II)

Two Schiff bases, L¹ (5,6;11,12-dibenzophenone-2,3,8,9-tetramethyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene) and L² (6,7;13,14-dibenzophenone-2,4,9,11-tetramethyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene), bearing functionalized pendant arms have been synthesized by cyclocondensation of 3,4-diaminobenzophenone with 2,3-butanedione and 2,4-pentanedione, respectively. Mononuclear macrocyclic complexes [FeL¹Cl₂]Cl, [FeL²Cl₂]Cl, [ML¹Cl₂], and [ML²Cl₂] (where M?=?Co(II) and Cu(II)) have been prepared by reacting iron(III), cobalt(II), and copper(II) with the preformed Schiff base. The ligands and their corresponding metal complexes were characterized by elemental analyses, ESI-mass spectra, conductivity, magnetic moments, UV-Vis, EPR, IR, ¹H-, and ¹³C-NMR spectral studies, and TGA-DTA/DSC data. The TGA profiles exhibit a two-step pyrolysis, although the iron complexes decompose in three steps, leaving behind metal oxides as the final product. The ligands and complexes were screened in vitro against Gram-positive bacteria, Gram-negative bacteria, and fungi.     

Synthesis and Characterization of a Novel Macrocyclic vic‐Dioxime and Some of its Mono and Trinuclear Complexes

The (E, E)‐dioxime containing a dithia‐dioxa‐diaza macrocyclic moiety 5,6 : 11,12 : 17,18‐tribenzo‐2,3‐bis(hydroxyimino)‐1,4‐diaza‐7,16‐dithia‐10,12‐dioxacyclooctadecane ( H₂L ) has been synthesized in high yield by a 1 + 1 addition of cyanogendi‐N‐oxide with 2,3 : 8,9 : 14,15‐tribenzo‐1,16‐diamino‐4,13‐dithia‐7,10‐dioxahexadecane ( 3 ) which was obtained from condensation reaction with 2‐amino thiophenol and 1,2‐bis(2‐bromoethoxy)benzene, in dichloromethane at –10 °C. Two vic‐Dioxime ligands coordinate with Ni(II), Cu(II) and Co(III) through its hydroxyimino nitrogen donor atoms by the loss of the oxime protons. Homo and heterotrinuclear Cu^II₃ and Co^IIIPd^II₂ complexes of this ligand have been prepared; their two ligand molecules are connected via hydroxyimino or BF₂⁺‐bridging groups and two of the metal ions are coordinated by a diaza‐dithia mixed donor macrocyclic moiety. The macrocyclic ligand and its transition metal complexes have been characterized on the basis of ¹H‐, ¹³C‐NMR, IR and MS spectroscopy and elemental analysis data.