Na doped ZnO quantum dots of average size 6 nm were prepared using wet chemical route at room temperature without any capping agents and the formation of nanoparticles is confirmed by transmission electron microscope (TEM) and x‐ray diffraction (XRD) analysis. Optical band gap of ZnO: Na is found to be blue shifted with decrease in size due to quantum size effects. Incorporation of Na in ZnO quantum dots is confirmed using inductively coupled plasma atomic emission spectroscopy (ICP‐AES). Strong room temperature photoluminescent emissions in the violet region due to native defects of ZnO and yellow region resulting from substitutional incorporation of Na in the Zn site was observed from the ZnO: Na quantum dots. Both emission wavelength and integral intensity of emission in the visible region can be well controlled by adjusting the concentration of the alkaline precursor used as the dopant. Highly luminescent bio‐friendly Na doped ZnO quantum dots can be used as fluorescent probes in biomedical applications.
Condensation of 1,3-diaminopropane-2-ol with diacetylmonoxime and acetylacetone yielded the tetradentate Schiff bases N,N'-(2-hydroxy) propylene-bis{(2-imino-3-oximino)butane} (H2L2) and N,N'-(2-hydroxy) propylene-bis(acetylacetoneimine) (H2L2), respectively. The ligands form mononuclear manganese(II) complexes of the type [Mn(II)(L-1)] (1) and [Mn(II)(L-2)] (3), which are used for the formation of the manganese(III) heterochelates of the type [Mn(III)(L)(L-L)] (where H2L = H2L1 or H2L2; L-L = anion of acetylacetone or salicylaldehyde). Cationic heterochelates of the type [Mn(L)(L-L)]ClO4 where H2L = H2L1 or H2L2 and L-L = ethylenediamine and N,N'-propylene-bis(benzaldimine) (L-3) have been synthesized by the reactions of bis(acetylacetonato)manganese(II) or bis(salicylaldehydato)manganese(H) with the preformed Schiff bases or by the reactions of [Mn(II)(L-1)] or [Mn(II)(L-2)] with L-L in absolute alcohol under reflux. Some of the complexes, synthesized here, may be used as precursors in the synthesis of higher nuclearity manganese complexes. Air oxidation of [Mn(II)(L-1)] (1) and [Mn(II)(L-2)] (3) in DMF yielded the dark-brown mu-dioxo-bis-[N,N'-(2-hydroxy)propylene-bis{(2-imino-3-oximino)butane}]dimangenese(IV) (2) and mu-dioxo-bis[N,N'-(2-hydroxy)propylenebis{(acetylacetoneimine)}]dimangenese(IV) (4) complexes, respectively. All of the complexes have been characterized with the help of elemental analyses, molar conductance values, molecular weights, magnetic moments, and spectroscopic (IR, UV-VIS, ESR) data.
Heterotrinuclear complexes of the type [Cu(ppn)(2)Cl-2{Ti(Cp)(2)}(2)] and [Cu(en)(2)(NO3)(2){Ti(Cp)(2)}(2)] have been synthesized and characterized by elemental analyses, IR, electronic, EPR, and H-1 NMR spectra, magnetic moments, and conductivity measurements. The results indicate that the trinuclear complexes are covalent with an octahedral environment around the copper(II) ion, while its mononuclear analogues, [Cu(ppn-H-2)(2)]Cl-2 and [Cu(en-H-2)(2)](NO3)(2), are square-planar and ionic in nature.
A series of transition metal complexes of α‐bromo‐ and ω‐bromoacetoacetanilide semicarbazones (L1H2 and L2H2, respectively) were prepared. Characterization of these compounds has been carried out by elemental analyses, infrared, electronic, and 1H NMR spectra and magnetic studies. These studies revealed that the ligands behave as tridentate mono‐ or di‐anions.
The synthesis, spectroscopic, magnetic susceptibility, and superoxide dismutase (SOD) activity measurements of the imidazolate-bridged complexes [(Salgly)Cu-Im-Cu(Salgly)]Na, [(Salgly)Cu-Im-Ni(Salgly)]Na, and [(Salgly)Cu-Im-Zn(Salgly)]Na, where Salgly = salicylideneglycinate, Im = imidazolate ion are described. Related copper(II) mononuclear complexes are also described. A pH-dependent EPR and UV-visible study of a 50% aqueous DMSO solution of the binuclear complexes suggest that the complexes are stable in the pH-range 6.50-10.50. At lower pH, the imidazolate bridge breaks apart with decreasing pH value.
Yttrium(III), lanthanum(III), and holmium(III) complexes with tris-(salicylideneamino)triethylenetetramine have been synthesized and characterized by elemental and spectral analyses as well as x-ray crystal diffraction. The FAB and TOF (time-of-flight) mass spectra reveal that the ligand acts as a heptadentate and that the metal versus ligand stoichiometry is 2: 2. The structure of the lanthanum(III) complex has been determined by x-ray single crystal diffraction. The lanthanum(III) ion is coordinated through the four nitrogen and the four oxygen atoms of the two ligands to form an eight-coordinate configuration. The two lanthanum(III) ions are bridged by the two phenolate oxygen atoms in the complex. The structure is similar to that of the ligand containing p-bromo substituents. The proton NMR spectra also show that the lanthanum(III) complex is a dimer.
Complexes of SnCl2.py with MCl2, where M = Mn(II), Fe(II), Co(II), Ni(II), and Cu(II), have been prepared and characterized by the elemental analysis, TGA, DTA, EPR, and IR spectra. All the compounds prepared are stable at room temperature but they are hygroscopic in nature. Substitution reactions of SnCl2.py(MCl2) by dithiocarbamate afforded (SnCl2.py)(2)M(dtc)(2). An octahedral geometry for the metal dithiocarbamates has been proposed.
The reactions of the lanthanide(III) ions Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, and Yb, with pyridine‐2‐carboxaldehyde‐4‐chlorobenzoylhydrazone (PpClBH) leads to the formation of complexes corresponding to the formulae [Ln(PpClBH)2(NO3)3], (Ln = La, Ce, and Pr) and [Ln(PpClBH)2(NO3)2]NO3 (Ln = Y, Nd, Eu, Gd, Tb, Dy, Ho, Er, and Yb). Twelve new compounds have been prepared. The complexes were characterized by means of elemental analyses, conductivity measurements, magnetic moments, and spectroscopic studies (IR, UV‐VIS, and 1H NMR). The coordination number of 12 have been proposed for the La, Ce, and Pr complexes, while for the Y, Nd, Eu, Gd, Tb, Dy, Ho, Er, and Yb compounds the coordination number is reduced to 10. This change in coordination number is consistent with the lanthanide contraction. Complexes having coordination numbers greater than ten appear to be limited to the lighter lanthanides. PpClBH has been characterized by elemental analysis, IR, UV, and 1H NMR. Keywords: LanthanideNitrateComplexesHydrazonesAntimicrobial
The complexes of two new ligands, 2-acetylnaphtho[2,1-b]furan oxime (L-1) and 2-benzoylnaphtho[2,1-b]furan oxime (L-2), with the metal ions Cu(II), Ni(II), Co(II), Cd(II), and Hg(II) have been synthesized and characterized on the basis of elemental analyses, conductance, magnetic susceptibility measurements, TGA, powder x-ray diffraction, NMR, UV-electronic, and IR spectral studies. Coordination of the ligand atoms to the metal ion was deduced by NMR and IR spectral data. Magnetic studies revealed the structures of the complexes. The stability of the complexes was studied by thermal analysis. Powder x-ray diffraction studies of the complexes have shown that they are crystalline in nature. All the complexes, ligands and metal salts have been screened for antimicrobial, anthelmintic, and analgesic activities.
The metal complexes of lanthanum(III) and cerium(III) with Schiff bases derived from the condensation of 2-hydroxy-1-naphthaldehyde with alpha-amino acids, viz. glycine, alanine, phenylalanine, valine, leucine and L-glutamine, have been prepared and studied. The structures of these complexes are assigned on the basis of elemental analyses, molar conductance, IR and H-1 NMR spectra and thermal analyses data. The results suggest that all of the Schiff bases behave as dianionic tridentate (ONO) ligands except the Schiff base derived from L-glutamine which behaves as dianionic tetradentate (OONO) ligand. The apparent formation constants of the various complexes were determined spectrophotometrically and are discussed.
New mono- and bis(crown ether) ligands have been synthesized by the condensation of the appropriate formylbenzo-15-crown-5 [(2) and (4)] with ethanolamine and 1,2-bis[(4-aminophenoxy)methyl]benzene (6), respectively. The diamine (6), was prepared by the reaction of 1,2-bis (bromomethyl)benzene and p-nitrophenol in the presence of NaOH forming the dinitro compound (5) which is subsequently reduced to compound (6) using hydrazine hydrate and Pd/C. Homonuclear sodium complexes of the mono- and bis(crown ether) ligands have been prepared with sodium perchlorate. The UV-VIS spectra of o-hydroxycrown ether Schiff bases (7), (8), (7a), and (8a) have been studied in various solvents. The results indicate that bands observed at higher values than 400 nm to be the result of the keto-amine form of the ligands and complexes. All of the crown ether ligands and their complexes have been characterized by elemental analyses, IR, UV, and NMR spectra.
The reactions of copper(II) halides with 1,3-bis(benzimidazol-2-yl)benzene and its N-methylated derivative afforded binuclear and mononuclear complexes respectively. Mononuclear perchlorate complexes have also been synthesized by the reactions of the aforesaid ligands with hydrated copper perchlorate. The complexes have been characterized by elemental analyses, conductivity and magnetic measurements, TGA studies, IR, electronic, and ESR spectral studies.
Several ruthenium(II) Schiff base complexes derived from bis(pyrrole-2-carboxaldehyde)-3,4-toluenediimine, bis(pyrrole-2-carboxaldehyde)-1,2-cyclohexanediimine, bis(pyrrole-2-carboxaldehyde)-1,8-naphthalindiimine, bis(pyrrole-2-carboxaldehyde)-1,3-propylenediimine, bis(pyrrole-2-carboxaldehyde)-1,2-phenylenediimine and bis(pyrrole-2-carboxaldehyde)-ethylenediimine, and lanthanide(III) Schiff base complexes derived from N-(2-pyrrolylmethylene)-2-aminophenol were synthesized. All the complexes were characterized by analytical and spectroscopic methods. The ruthenium Schiff base complexes were found to be effective catalysts for the oxidation of primary alcohols in the presence of N-methylmorpholine-N-oxide as oxidant.
Mixed-ligand complexes of Co(II), Ni(II), Cu(II), Zn(11), and Cd(II) with 5-fluorocytosine (5FC) and guanine (G) have been prepared in aqueous ethanol solution at pH of about 7. The prepared complexes were characterized by various physico-chemical methods viz. elemental analyses, infrared, UV-visible, magnetic measurements, and powder x-ray pattern. On the basis of IR studies, it is suggested that G acts as bidentate ligand coordinating through the N-3 and N-7 nitrogens whereas 5FC behaves as a monodentate and coordinates to the metal ions through the carbonyl oxygen only. These complexes were subjected to a screening system of Dalton's lymphoma (DL) tumor cells both in vivo and in vitro. Some complexes exhibit significant antitumor activity both in vivo and in vitro.
Some mixed toluene-3,4-dithiolatobismuth(III) alkyl dithiocarbonate derivatives of the type SC6II3(CH3)SBiS2COR (where R = Me, Et. n-Pr, i-Pr n-Bu, and i-Bu) have been synthesized by the reaction of the potassium salts of alkyl dithiocarbonates and toluene-3,4-dithiolatobismuth(ill) chloride in equimolar ratio in an anhydrous carbon disulfide/acetone mixture. These newly synthesized derivatives have been characterized by elemental analyses, melting point determinations, as well as IR and NMR spectral studies. On the basis of these studies, tentative structures for these derivatives have been proposed.
Binary mononuclear complexes of the Schiff base ligand 1,4-di(hydroxybenzylidene)thiosemicarbizide (H2L) and the transition metal ions Cu(II), Ni(II), Zn(H), and Fe(III) were prepared in the presence of various molar ratios of LiOH The binary complexes react with 8-hydroxyquinoline (8-HOqu) and oxalic acid (H(2)Ox) to form mixed-ligand complexes. The mixed ligand complexes were prepared by using various molar ratios of LiOH. The thermal Studies explored the stability of the mixed-ligands in their complexes as the isolated thermal products also contain the mixed ligands. All of the binary and mixed-ligand complexes have octahedral configurations except [CuHL]Cl and [ZnL], which have square-planar I geometrics. The Schiff base ligand (H2L) is coordinated to the central metal atom as a neutral, rnonoanionic and/or dianionic tetradentate ONNO ligand in the binary complexes and in the mixed-ligand complexes. The mixed-ligand, 8-HOqu behaves as a neutral or rnonoanionic bidentate ligand. The oxalato ligand coordinates as a dianionic bidentate or a bridged bidentate ligand towards Fe(Ill) ions. All complexes and the corresponding thermal products were isolated and their structures were elucidated by elemental analyses, conductance. IR and electronic absorption spectra. magnetic moments, H-1 NMR and TG-DSC measurements as well as by mass spectroscopy. The free ligand and H2L and its metal complexes showed higher antibacterial activity than some of, the investigated antibiotics, doxycillin, sulperazon, septrin, cefobid, nitrofurantion, and erythromycin.
The new ligands, 1,5,8,12-tetraaza-4-(1',1'-dimethylethyl)-2-(1",1",2", 2",3".3".3"-heptafluoropropyl)-9,11-(dimethyl)-cyclotetradeca-1,4,8,11-tetraene (L-1) and 2",3",3",3"-heptafluoropropyl)-10,12-(dimethyl)-cyclohexadeca-1,4,9,12-tetraene (L-2), have been prepared by the reaction of 1,1,2.2,3,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione with ethylenediamine and acetyl acetone (L) and 1,1,2,2,3,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione with 1.3-diaminopropane and acetylacetonc (L-2), respectively. Their complexes with Cr(III). Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(11) ions have also been synthesized and characterized by elemental analyses, magnetic susceptibility Measurements, molar conductance measurements, IR, EPR, H-1 NMR, and UV-Visible spectra. The molar conductance values show that the complexes of Fe(III) and Cr(III) are I : I electrolytes, the Ni(H) and Cu(H) complexes are I : 2 electrolytes while those of Mn(II), Co(H), and Zn(II) appear to be non-ionic. An octahedral Structure has been proposed for all of these metal ions except for those of Cu(II) and Ni(II), which appear to be square-planar. The beta values indicate a considerable orbital overlap in the metal-ligand bond. All of the compounds have been tested against grain-positive bacteria of Staphylococcus aureus and gram-negative bacteria of Escherichia coli. The results show that these compounds inhibit the growth of bacteria.
Nickel(II) complexes of the Schiff base 2,3-dimethyl-4-formyl-(benzhydrazide)-1-phenyl-3-pyrazolin-5-one (L) with the formulae [Ni(L)(2) (ClO4)]ClO4, [Ni(L)(2)(NO3)](NO3), and [Ni(L)(2)X-2] (X = Cl, Br, or I) have been synthesized and characterized by elemental analyses, electrical conductance in nonaqueous solvents, infrared and electronic spectra as well as magnetic susceptibility measurements. In these complexes, L acts as a neutral bidentate ligand coordinating through the azomethine nitrogen and the carbonyl oxygen of the pyrazolone ring. In the perchlorate and nitrate complexes one of the anions is coordinated to the metal ion in a bidentate fashion while in the halide complexes both the anions are coordinated. An octahedral geometry is assigned around the nickel(II) ion in all these complexes.
The complexes of Pd(II) and Cu(II) with the condensation products of usnic acid with hydrazides were prepared and characterized by elemental analyses, IR, H-1 NMR, and C-13 NMR spectroscopy. In all cases, the complexes appear to be monomeric and square-planar, with three binding sites occupied by the dianionic tridentate ligand, and the fourth position occupied by ethanol. The complexes were tested for in vitro growth inhibitory activity against Aspergillus niger, Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis and were found to possess significant activity. The cytotoxic tests were carried out by utilization of the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) microculture colorimetric assay in which human cervix carcinoma HeLa cells were treated by continuous exposure (48 h) to the test agents. All investigated compounds showed cytotoxic activity against HeLa cells with IC50 values between 1.8 and 86.0 muM.
Synthesis of 2-(thiomethyl-2'-benzimidazolyl)benzimidazole (L) and its metal complexes of the formulae ML2(ClO4)(2) . xH(2)O (M = Co, x = 3; M = Ni, Zn, or Cd, x = 2; M = Cu, x = 1) and MLBr2 (M = Co, Ni, Cu, Zn, or Cd) are described. They have been characterized by measuring physical properties, IR, NMR, and electronic spectral studies. The electronic spectral and magnetic moment data Suggest an octahedral geometry for the cobalt(H) and nickel(11) perchlorate complexes, a tetrahedral geometry for the cobalt(II) and nickel(II) bromo complexes and a pseudo tetrahedral geometry for the copper(H) perchlorate and copper(H) bromide complexes. Based on elemental analyses, conductivity measurements and IR and NMR spectral Studies, a six-coordinate geometry for cadmium perchlorate complex and various four-coordinate geometries for zinc perchlorate and bromo complexes of cadmium and zinc have been proposed.
