Ranjana Ghose

The effect of histidine on the structure and antitumor activity of metal-5-halouracil complexes

The ternary complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) ions with 5-halouracils, viz., 5-fluorouracil (5FU), 5-chlorouracil (5ClU), and 5-bromouracil (5BrU), and the biologically important ligand L-histidine (HISD) have been synthesized and characterized by elemental analysis, conductance measurements, infrared spectra, electronic spectra, and magnetic moment (room temperature) measurements. On the basis of these studies, the structures of the complexes have been proposed. All these ternary complexes were screened for their antitumor activity against Daltons lymphoma in C3H/He mice. It was found that only Mn(II)-5BrU-HISD, Co(II)-5BrU-HISD, Cu(II)-5ClU-HISD, Cu(II)-5BrU-HISD, Zn(II)-5FU-HISD, and Zn(II)-5BrU-HISD complexes have significant antitumor activity with T/C greater than 125% (where T and C represent mean lifespan of treated mice and control mice respectively). The Mn(II)-5FU-HISD, Co(II)-5FU-HISD, Co(II)-5ClU-HISD, Ni(II)-5ClU-HISD, Ni(II)-5BrU-HISD, and Zn(II)-5ClU-HISD complexes are also effective antitumor agents, with T/C greater than 115%. The complexes that showed effective antitumor action in vivo were also found to inhibit 3H-thymidine incorporation (DNA replication) in Daltons lymphoma cells in vitro.

Metal Complexation with Adenine and Thymine

Abstract Metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with adenine and thymine were synthesized from aqueous ethanol solutions at ∼ pH 7. The new complexes involve 2:1:1 metal to adenine to thymine molar ratios. The complexes are polymeric in nature involving adenine as well as hydroxyl group bridges between metal ions and hydrogen bonds between adenine and thymine molecules. Spectral studies suggest that adenine is coordinated to metal ions through the N(3) and N(7) nitrogens whereas thymine is coordinated through the C(2) = O group. All the metal ions are in the hexa-coordinate state in the complexes. Powder X-ray diffraction studies indicate ortho-rhombic symmetry for Co(II)-ADN-THY and Cu(II)-ADN-THY complexes.

Transition metal complexes of 5-chlorouracil

SummaryComplexes of 5-chlorouracil (5-ClU) (1) with 3d metal ions were characterized by elemental analysis, various spectroscopic methods (i.r., u.v. spectroscopy) and magnetic susceptibility measurements. The spectral evidence suggest that 5-ClU behaves as bidentate ligand in NiII, CuII, ZnII, and CdII compounds, coordinating through its one carbonyl oxygen and one nitrogen whereas with MnII and CoII it coordinates through the carbonyl oxygen only. The insolubility of the new complexes in organic solvents suggests that these are polymeric except for the CoII complex which is soluble in pyridine. There is probable OH bridging in the MnII and CuII complexes and the 5-ClU may bridge in the rest.

Complex formation of adenine-uracil base pair with some transition metal ions

Abstract Mixed complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with 6-aminopurine (adenine, ADN) and uracil (URL) were prepared from aqueous ethanol solution at pH about 7. The new complexes have the formulae M2(ADNURL)(OH)2·H2O for M = Mn(II), Zn(II), Cd(II) and M2(ADNURL)(OH)4·3H2O for M = Co(II), Ni(II), Cu(II). The mixed complexes were characterized by elemental, infrared, electronic, ESR spectral and magnetic measurements. ADN behaves as a bidentate ligand. The probable binding sites of ADN are N3 and N7 nitrogens and of URL is C2O. Polymeric structures have been suggested with ADN and OH as the bridging ligands.

Complexes of some trace metal ions with 5-fluorouracil

Abstract The preparation of 5-fluorouracil complexes with Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) are reported. The new complexes have been characterised by elemental analysis, solid-state infrared, electronic spectra and magnetic measurements. These measurements suggest that the ligand is bonded to the metal ions through the carbonyl group, behaving as a mono- dentate ligand. On the basis of the ν(OH)bending frequencies and the insolubility of the complexes in common organic solvents, polymeric structures have been proposed for the complexes, with bridging through OH groups. Mn(II), Zn(II) and Cd(II) form four-coordinated complexes, while six coordination numbers have been suggested for Co(II), Ni(II) and Cu(II).

Simple and mixed complexes of cobalt(II) and cobalt(III) ions

SummaryBivalent and trivalent cobalt complexes with 1-(2-pyridylazo)-2-naphthol (PAN), PAN+1, 10-phenanthroline and PAN+2, 2′-bipyridyl were prepared and characterized by physico-chemical and magnetic measurements. The spectral studies suggest that PAN behaves as a bidentate ligand and is coordinated to metal ions through oxygen and (pyridine) nitrogen, whereas 1, 10-phenanthroline and 2, 2′-bipyridyl are coordinated through (pyridine) nitrogen. The tentative ν(M−O) and ν(M−N) band assignments in the lower i.r. region, and magnetic moment data favour four coordination for the complexes studied.

Oxovanadium(IV) and Dioxouranium(VI) Complexes of Azo Dyes

Abstract Oxovanadium(IV) and dioxouranium(VI) complexes of 1-(2-pyridylazo)-2-naphthol (PAN) and 4-(2-pyridylazo) resorcinol (PAR) have been prepared and characterised by elemental analyses, various physico-chemical methods and magnetic measurements. The I. R. observations suggest that PAN is coordinated through oxygen and (pyridine) nitrogen, whereas PAR is coordinated through (pyridine) nitrogen and the ortho-hydroxyl group. The spectral-studies suggest that oxovanadium(IV) complexes have the coordination number five and dioxouranium(Vl) complexes have the coordination number six for the cations.

Oxovanadium(IV) and Dioxouranium(VI) Complexes with Nucleic Acid Bases

Abstract Simple and mixed ligand oxovanadium(IV) and dioxouranium(UI) complexes with adenine and uracil as well as with adenine and thymine have been synthesized. The new complexes were characterised by elemental analyses. Spectral studies suggest that adenine is coordinated to the metalions through the N(7) and N(9) atoms. Uracil is coordinated through the C4=O group while thymine through its C2=O group to the metalions. The complexes involving adenine are polymeric in nature with adenine bridges between metalions. The oxovanadium(IV) complexes exhibit the coordination number five and the dioxouranium(VI) complexes the coordination number six. Powder X-ray diffraction studies indicate orthorhombic symmetry for the oxovanadium(IV) and tetragonal symmetry for the dioxouranium(VI) mixed ligand complexes. Referee I: K. Moedritzer Referee II: G. A. Mirafzal

X-ray powder diffraction study of some cobalt (II) complexes

Co(II) complexes with benzoic acid and ternary complexes with ligands benzoic acid and histidine/aspartic acid have been synthesized and characterized using various spectroscopic methods. On the basis of infrared, UV-visible spectra, and magnetic data the complexes were found to be having octahedral polymeric geometry. X-ray powder diffraction results show that the crystal systems of Co(II)-Ben and Co(II)-Ben-Hist complexes are triclinic with lattice constants a =15.58 A, b =11.92 A, c =4.33 A, α =96.08°, β =104.68°, γ =88.46°, and V =774.15 A 3 and a =18.88 A, b =17.01 A, c =15.13 A, α =93.15°, β =89.41°, γ =100.71°, and V =4768.75 A 3 , respectively. The Co(II)-Ben-Asp complex is orthorhombic with lattice constants a =21.57 A, b =15.06 A, c =11.40 A. α = β = γ =90°, and V =3703.38 A 3 .