Communication: : The First Well Characterized Fe (phen) Cl₃ Complex : Structure of Aquo Mono(1,10-phenanthroline) Iron (III) Trichloride : [Fe (phen) Cl₃ (H₂O)]

The crystal structure of the neutralpseudo-octahedral mono phenanthroline iron (III) complex Fe (phen) Cl3H2O is reported which surprisingly is the first well-characterized Fe (phen) Cl3 complex (space group P1̄ a = 10224 (4) d b = 10603 (3) d c = 6628 (2) d alpha 10070 (2) °β = 10817 (2) °γ = 9206 (2) ° R = Rw = 0033) Of the three unidentate chloride ions two are coplanar with phenanthroline ligand while the third is out of plane and is trans to the water molecule The metal environment is distorted from regular octahedral due to the non-equivalent ligand donor set The N-Fe-N bite angle of 756° is compressed below right-angular with a corresponding opening of the other bond angles around the iron in this plane The Fe - Cl bonds are inequivalentranging from 225 to 235 d the axial Fe - Cl bond being elongated The axial aquo group is tilted towards the phenanthroline ringmaking an angle of 838° with N (1) and 818° with N (2) respectively Comparison with the Mn (III) analog yields the effect of changing from a high spin d 5 to a high spin d 4 center III)  phenanthroline  DNA intercalator

Cis Di-oxomolybdenum(VI) Complexes with a Tridentate ONO Donor Ligand; Synthesis, X-ray Crystal Structure, Spectroscopic Properties and Oxotransfer Chemistry

The molybdenum complexes of Schiff base ligands viz. [MoO2LH2O] where L1 = tris(hydroxymethyl)(salicylide-neamino)methane, L2 = tris(hydroxymethyl)(2,3-dihydroxybenzylideneamino)methane and L3 = tris(hydroxymethyl)(2,3,4-trihydroxybenzylideneamino)methane have been synthesized and characterized by spectroscopic and electrochemical techniques. The X-ray crystal structure of the complex [MoO2L1H2O] reveals a distorted octahedral geometry with one ligand and a water molecule coordinated to the MoO2 center. No previous complex of this type contains a coordinated water molecule. The complex undergoes an oxotransfer in the presence of Bu3P to form a -oxobridged molybdenum(V,V) dimer. This rules out Mo—S coordination as a prerequisite for oxotransfer in such molybdenum(VI) complexes

Hemiprotonated Dafone, a New Cationic Species. the Novel Di-dafonium Iron(III) Complex: [(Dafone)₂H]⁺[FeCl₄]⁻

The reaction of dafone (4,5-diazafluoren-9-one, 1) and iron(III) chloride in concentrated hydrochloric acid medium yields an unusual complex containing hemiprotonated dafone, [(dafone)2H]+[FeCl4]-. The crystal structure reveals that two coordinating ligands share a single proton to form the new cation [(dafone)2H]+ while the accompanying tetrachloroferrate(III) anion stabilizes the ion pair. The [FeCl4]- anion is close to tetrahedral in geometry with four chloro ligands in the first coordination sphere which is only slightly affected by the interactions with the di-dafonium unit. © 2003 Elsevier Science B.V. All rights reserved

Neutral Metal Complex in an Ionic Pocket: Synthesis, Physicochemical Properties and X-ray Structure of a Copper(II) Complex Containing Neutral as Well as Cationic Dafone Ligands and Dafonium Perchlorate

A neutral copper complex flanked by two protonated 4,5-diazafluoren-9-one (dafone, 1) ligands which are H-bonded with water molecules and perchlorate anions has been structurally and electrochemically characterized. The capped copper compound remains intact in solution, exhibiting a reversible Cu(II)/Cu(I) couple although undergoing a deformation along the Cu-N(2) axis and can serve as a good model of ionic pockets with metal active sites in some metalloproteins. © 2001 Elsevier Science B.V. All rights reserved

Characterization of tyrosinase and accompanying laccase from Amorphophallus campanulatus

40-45Tyrosinase and laccase activities were detected in the corm of Amorphophallus campanulatus after extraction with ethanol followed by ammonium sulphate precipitation (20-60%) and dialysis against 10 mM Na2HPO4 buffer at pH 7.0. Tyrosinase was found to be the predominant enzyme exhibiting mono- and di-phenolase activities, specificity for L-DOPA as substrate, optimum pH being 6.0, optimum temperature at 40ºC and Km at 1.05 mM. Laccase showed substrate specificity for p-phenylenediamine (p-PD), Km at 2.7 mM, optimum pH being 5.0 and was inactivated above 40ºC. Three isoforms of tyrosinase were detected on SDS-PAGE with apparent molecular mass ~127, 31 and 27 kDa respectively. On staining sections of A. campanulatus with L-DOPA as substrate and 3-methyl benzothiazolinone hydrazone (MBTH) for colour development, tyrosinase was detected in the intercellular spaces of the plant tissue. The cytosolic region did not show any colour indicating the absence of the enzyme

Metal Complexes as Anticancer Agents 2

The copper complex [Cu(ATICAR)2(H2O)]·2H2O (ATICAR = 5-amino-1-tolylimidazole-4-carboxylate) has been prepared and characterized by its crystal structure determination. The ligand geometry around the copper(II) center is best described as predominantly square pyramidal (2/3) with a trigonal bipyramidal component (1/3). The ATICAR ligands act as bidentates to form the distorted square pyramid base of N2O2 donor atoms and a coordinated water molecule at the apex is held with a Cu-O bond that is unusually short (2.148 A) for square pyramidal copper(II). Compound exhibits a dose-dependent antiproliferative effect on the growth of the B16F10 melanoma cell line while its lower IC50 value establish advantage by copper complexation. (C) 2000 Elsevier Science S.A

Synthesis, Structure, Spectroscopy and Antitumor Activity of Hydroxy Naphthoquinone Thiosemicarbazone and Its Metal Complexes Against MCF-7 Human Breast Cancer Cell Line

Coordinately unsaturated metal complexes of the stoichiometry [M(HL)Cl] and [Fe(HL)Cl 2].2H 2O have been isolated (where M=Cu(II), Ni(II), PD(II) and Pt(II); HL=tridentate anion of H 2L 3). The X-ray crystal structure for 4-hydroxy-3-methyl-1,2-naphthoquinone-1-thiosemicarbazone, 3 has been determined which crystallizes in space group P2 1/c, a = 7.430(3), b = 10.794(3), c = 17.216(5) Å, β =92.91(3)°. Z = 4, and have “E” configuration. The Cu(II) 3a, Ni(II) 3e, Pd(II) 3d and Pt(II) 3e complexes are found to possess square planar geometries, whereas Fe(III) complex 3b possesses a square pyramidal configuration. The in vitro activity of the synthesized compounds examined against human breast cancer cell line MCF-7 clearly indicates that metal complexation enhances antitumor activity, the highest being for the copper complex 3a

Tuning Up Superoxide Dismutase Activity of Copper Complex of Salicylaldehyde Semicarbazone by Heterocyclic Bases Pyridine and N-methyl Imidazole

The copper(II) complexes of the Schiff base salicylaldehyde semicarbazone (SALSC) have been prepared and structurally characterized. The compound possesses a distorted square planar geometry where the metal atom lies slightly below the ligand donor atom plane and exhibits a longer Cu-Cl bond distance (2.226 Å). The superoxide dismutase activity of the compound can be synergistically enhanced by the addition of heterocyclic bases. © 2001 Elsevier Science B.V

Comparative Studies on Copper(I) Complexes: Synthesis, X-ray Crystallography and Electrochemical Properties of [CuI(dafone)nX] Complexes (dafone=4,5-diaza-fluoren-9-one, X=Br, I, SCN)

The synthesis, X-ray structures and electrochemical properties of stable five-coordinate, trigonal-bipyramidal CuI complexes of dafone (4,5-diaza-fluoren-9-one) [Cu(dafone)2X] with X=Br (1) or I (2) as ancillary ligands are discussed. The thiocyanate-bridged polymeric CuI complex of dafone, [Cu(dafone)(SCN)]n (3), forms two-dimensional sheets in the crystal, held together by weak interactions involving the dafone ketone group, while the phenanthroline complex, [Cu(phen)(SCN)]n (4), a zigzag arrangement of the phen ligands leads to interchain π-stacking within the lattice. The electrochemical studies reveal that dafone stabilizes the CuI oxidation state more efficiently than phen due to its better π-acceptor ability as indicated by more positive redox potentials for the CuI/CuII couple. © 2002 Published by Elsevier Science B.V

Molecular Targets of Naturopathy in Cancer Research: Bridge to Modern Medicine

The relevance of naturopathy (defined as the practice of medicine for the treatment of human diseases with natural agents) in human cancer is beginning to be appreciated, as documented by renewed interest in nutraceutical research, the natural anticancer agents of dietary origin. Because of their pleiotropic effects and the ability to modulate multiple signaling pathways, which is a good attribute of natural agents, nutraceuticals have frequently been demonstrated to re-sensitize drug-resistant cancers. The effectiveness of nutraceuticals can be further enhanced if the tools for the relative assessment of their molecular targets are readily available. Such information can be critical for determining their most effective uses. Here, we discuss the anticancer potential of nutraceuticals and the associated challenges that have interfered with their translational potential as a naturopathic approach for the management of cancers. In the years to come, an efficient screening and assessment of molecular targets will be the key to make rapid progress in the area of drug design and discovery, especially focusing on evidence-based development of naturopathy for the treatment of human malignancies