Interactions between metal ions and carbohydrates. The coordination behavior of neutral erythritol to neodymium ion

A single crystal of a coordinated complex of neutral erythritol (C4H10O4,E) with a neodymium ion, NdE(II), was synthesized and studied using FT-IR and X-ray diffraction analysis. In NdE(II) (NdCl3.2.5C4H10O4.C2H5OH) the Nd3+ coordinates with one chloride ion and eight OH groups from three erythritol molecules. There are two neodymium centers linked by one erythritol molecule with same coordination structure in the molecule. Two erythritol molecules provide 1,3,4-hydroxyl groups to coordinate with a neodymium ion; another erythritol molecule coordinates to two Nd ions via its 1,2-hydroxyl groups and 3,4-hydroxyl groups, respectively. The OH groups of erythritol act as ligand to coordinate to neodymium ions, and OH groups of erythritol form hydrogen bond networks that link chain and layer together to build three-dimensional structures. The ratio of metal to ligand is 1:2.5. The structure of NdE(II) is more complicated than the previously reported NdE(I), which is NdCl3.C4H10O4.6H2O; in NdE(I), Nd3+ is coordinated to four hydroxyl groups from two erythritol molecules, four water molecules and one chloride ion. The results indicate the complexity of metal-sugar interaction.     

Interactions between metal ions and carbohydrates: the coordination behavior of neutral erythritol to zinc and europium nitrate

The single crystals of coordinated complexes of neutral erythritol (C4H10O4) with zinc nitrate and europium nitrate were synthesized and studied using FT-IR and single crystal X-ray diffraction analysis. In the structure of Zn(NO3)2.C4H10O4, ZnEN (E denotes erythritol, N represents nitrate), Zn2+ is coordinated to four hydroxyl groups from two erythritol molecules and two oxygen atoms from two nitrates. Two Zn2+ are connected by one erythritol molecule to form Zn(C4H10O4)(NO3)2 chain, and layers formed by above chain pile to produce 3D structures. In the structure of Eu(NO3)3.C4H10O4.C2H5OH, EuEN, Eu3+ is 10-coordinated by six oxygen atoms from three nitrate ions, three hydroxyl groups from one erythritol molecule and one hydroxyl group from ethanol. In the above erythritol complexes, two hydroxyl groups of erythritol coordinate to one metal ion and the other two to another metal ion or erythritol acts as three-hydroxyl groups donor. The OH groups of erythritol act as ligand to coordinate to metal ions on one hand, one the other hand, OH groups form hydrogen bonds network to build three-dimensional structures.     

Complexation of trivalent lanthanide cations by erythritol in the solid state. The crystal structure and FT-IR study of 2EuCl3.2C4H10O4.7H2O

Erythritol was chosen to study the interactions between metal ions and carbohydrates. FTIR spectroscopy results indicate that a EuCl3-erythritol complex different from a previously reported one was obtained. The crystal structure of EuCl3-erythritol complex, 2EuCl3.2C4H10O4.7H2O, Mr=443.49, a=13.846(3) A , b=7.4983(15) A, c=14.140(3) A, beta=116.39(3) degrees, V=1315.1(5) A(3), Z=4, mu=5.394 mm(-1) and R=0.0395 for 2965 observed reflections and 143 parameters, was determined. Characteristic of this complex is the presence of binuclear europium ions with different coordination structures. One Eu3+ ion is nine-coordinated, with five Eu-O bonds from water molecules, and four from hydroxyl groups of two erythritol molecules and another Eu3+ is eight-coordinated with two water molecules, two chloride ions, and four hydroxyl groups from two erythritol molecules. Erythritol provides two hydroxyl groups to one lanthanide ion and the other two to another rare earth ion. The OH, CO stretching and other vibrations are shifted in the IR spectra of the complexes and the results are consistent with the crystal structure.     

Crystal structure and nuclease activity of mono(1,10-phenanthroline) copper complex

The hydroxo-bridged dinuclear copper (II)/phen complex [Cu(2)(phen)(2)(OH)(2)(H(2)O)(2)][Cu(2)(phen)(2)(OH)(2)Cl(2)]Cl(2).6H(2)O (phen=1,10-phenanthroline) has been prepared and characterized by single crystal X-ray diffraction. The coordinated area of the complex shows two distorted [CuN(2)O(2)O(w)] and [CuN(2)O(2)Cl] square-pyramidal and one strictly planar configuration CuO(2)Cu involving two O atoms of hydroxo-bridged, Cu(2+) cations, N atoms of two phen ligands and disorder solvate water and chlorine anions. In the presence of H(2)O(2), the complex of mono(1,10-phenanthroline)copper exhibits higher activity as a nuclease than bis(1,10-phenanthroline)copper.     

Interactions of metal ions with a 2,4-diaminopyrimidine derivative (trimethoprim). Antibacterial studies

The interaction of copper (II), zinc(II) and cadmium(II) with Trimethoprim (2,4-diamino-5-(3',4',5'-trimethoxybenzyl) pyrimidine) has been studied. The crystal structures of [Zn(Trim)2Cl2] (2) and [Cd(Trim)Cl2(CH3OH)]n (4) are reported. Compound (2) exhibits a distorted tetrahedral environment around the metal center and crystallizes in the triclinic space group P1 with a=10.2397(6), b=10.4500(6), c=16.3336(16) A, alpha=96.141(8), beta=106.085(5), gamma=96.551(5) degrees and Z=2. In complex (4), the Cd(II) centers are bridged sequentially by two chlorine ions to form infinite chains and present a six-coordinated environment; the compound crystallizes in the monoclinic P2(1)/C space group with a=13.958(5), b=7.532(2), c=18.390(2) A, alpha=90, beta=97.32(5), gamma=90 degrees and Z=4. In both structures the Trimethoprim acts as a monodentate ligand through the pyrimidinic nitrogen N(1) atom. The characterization of the Cu(Trim)2(CH3O)(ClO4) complex through EPR and magnetic measurements suggests a binuclear or polinuclear nature, with bridging methoxo groups. The complexes were screened for their activity against several bacteria, showing activity similar to that of trimethoprim.     

Copper(II)-cis,cis-1,3,5-triaminocyclohexane complex-promoted hydrolysis of dipeptides: kinetic, speciation and structural studies

The hydrolysis of glycylglycine (GylGly), glycyl-L-leucine (GlyLeu), L-leucylglycine (LeuGly) and glycyl-DL-serine (GlySer) promoted by a copper(II)- cis, cis-1,3,5-triaminocyclohexane complex [Cu(II)TACH] was investigated at 70 degrees C and pH 7-10, using HPLC. The observed pseudo-first-order rate constants (k(obs)) and rate enhancing factors (REF) were as follows: 4.1x10(-3 )h(-1)(REF=23) for GylGly, 1.6x10(-3 )h(-1)(REF=21) for GlyLeu, 5.1x10(-3 )h(-1)(REF=64) for LeuGly and 9.2x10(-2 )h(-1)(REF=47) for GlySer [pH 8.1, dipeptide 2 mM, copper(II) 2 mM and TACH 2 mM]. Based on the pH dependence and dipeptide concentration dependence of the initial rates and speciation of the Cu(II)-TACH-dipeptide system at 25 degrees C and I=0.1, the reactions proceed via the formation of a ternary complex [Cu(TACH)(dipeptide)](+) as an intermediate followed by OH(-)-dependent and OH(-)-independent paths to give amino acid(s). GylGly, GlyLeu and LeuGly preferred the OH(-)-dependent path, while GlySer preferred the OH(-)-independent path. The latter can be explained by the intramolecular attack of the amide carbonyl group coordinated with its oxygen atom by the OH group in the serine residue. The X-ray crystal structure of [Cu(TACH)(GlyGly)]BPh(4).MeOH confirmed that GlyGly coordinates to copper(II) ion with its terminal amino N and amide O atoms. The crystal structures of [Cu(TACH)(Gly)]BPh(4) and [Cu(2)(TACH)(2)(OH)(2)](ClO(4))(2).NaClO(4).H(2)O are also reported.     

Spectroscopic studies on the anticancer antibiotic Altromycin H and the interaction with copper(II) ions

The antitumor antibiotic Altromycin H was studied using electronic absorption (UV-Vis.) and circular dichroism (CD) spectroscopy. The dissociation constants of the phenolic groups on C(5) and C(11) were estimated as pK(1)=6.7 and pK(2)=11.8 at 25 degrees C, respectively, and a complete assignment of the CD and UV-Vis. bands is proposed. The interaction of Cu(II) ions with the Altromycin H has been also investigated by UV-Vis., CD and electron paramagnetic resonance (EPR) spectroscopy. A pH depended stepwise complex formation was observed. At pH<4 no copper-Altromycin H interactions were detected. At the 4相似文献   

Synthesis,characterization of some transition metal(II) complexes of acetone <Emphasis Type="Italic">p-</Emphasis>amino acetophenone salicyloyl hydrazone and their anti microbial activity

Complexes of the type [M(apash)Cl] and [M(Hapash)(H2O)SO4], where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hapash = acetone p-amino acetophenone salicyloyl hydrazone have been synthesized and characterized by elemental analyses, molar conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies (TGA & DTA) and X-ray diffraction studies. The ligand coordinates through two >C=N and a deprotonated enolate group in all the chloro complexes, whereas through two >C=N- and a >C=O group in all the sulfato complexes. The electronic spectra suggest a square planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and an octahedral geometry for the sulfate complexes. ESR data show an isotropic symmetry for [Cu(apash)Cl] and [Cu(Hapash)(H2O)SO4] in solid state. However, ESR spectra of both Cu(II) complexes indicate the presence of unpaired electron in d x2-y2. The X-ray diffraction parameters for [Co(apash)Cl] and [Cu(Hapash)(H2O)SO4] complexes correspond to a tetragonal and an orthorhombic crystal lattices, respectively. Thermal studies of [Co(apash)Cl] complex shows a multi-step decomposition pattern. Most of the complexes show better antifungal activity than the standard miconazole against a number of pathogenic fungi. The antibacterial activity of these complexes has been evaluated against E. coli and Clostridium sp. which shows a moderate activity.     

Synthesis, physico-chemical studies of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes with some p-substituted acetophenone benzoylhydrazones and their antimicrobial activity

Complexes of the type [M(pabh)(H2O)Cl], [M(pcbh)(H2O)Cl] and [M(Hpabh)(H2O)2 (SO4)] where, M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpabh = p-amino acetophenone benzoyl hydrazone and Hpcbh = p-chloro acetophenone benzoyl hydrazone have been synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic susceptibility measurements, electronic, ESR and IR spectra, thermal (TGA & DTA) and X-ray diffraction studies. Co(II), Ni(II) and Cu(II) chloride complexes are square planar, whereas their sulfate complexes have spin-free octahedral geometry. ESR spectra of Cu(II) complexes with Hpabh are axial and suggest d(x(2)-y(2) as the ground state. The ligand is bidentate bonding through > C = N--and deprotonated enolate group in all the chloro complexes, whereas, >C = N and >C = O groups in all the sulfato complexes. Thermal studies (TGA & DTA) on [Cu(Hpabh)(H2O)2(SO4)] indicate a multistep decomposition pattern, which are both exothermic and endothermic in nature. X-ray powder diffraction parameters for [Co(pabh)(H2O)Cl] and [Ni(Hpabh)(H2O)2(SO4)] correspond to tetragonal and orthorhombic crystal lattices, respectively. The ligands as well as their complexes show a significant antifungal and antibacterial activity. The metal complexes are more active than the ligand.     

Synthesis, crystal structures and cytotoxicities of some transition metal complexes with N-[2-{(pyridin-2-ylmethylidene)amino}ethyl]acetamide

The synthesis and spectroscopic (IR, (1)H and (13)C NMR) characterization of new complexes of Pt(II), Pd(II), Cu(II), and Hg(II) with the Schiff base ligand MeCONHCH(2)CH(2)N=CHPy (L) (Py=pyridine) are reported, together with studies on the cytotoxicities of these complexes, L and [ReBr(CO)(3)(L)] against human leukemia (MOLT-4), breast cancer (MCF-7) and Chang Liver (non-cancerous) cells. The crystal structures of [Pt(L)Cl(2)] (2), [Cu(L)Cl(2)] (4) and [Hg(L)Cl(2)](2) (5) are also reported. Of the complexes studied, [Cu(L)Cl(2)] (4) was identified as the most cytotoxic active derivative against cells of neoplastic origin (MOLT-4, and MCF-7), while having low toxicity on cells of benign origin (Chang Liver).     

Interactions between metal ions and carbohydrates. Syntheses and spectroscopic studies of several lanthanide nitrate-D-galactitol complexes

Two complexes of neutral D-galactitol (C(6)H(14)O(6), G) with terbium nitrate, TbGN(I) and TbGN(II), and one complex with samarium nitrate SmGN were synthesized and characterized. From IR, FIR, THz and luminescence spectra the possible coordinations were suggested, and the single-crystal X-ray diffraction results confirm the spectroscopic conclusions. In TbGN(I) (Tb(NO(3))(3)·C(6)H(14)O(6)·3H(2)O), the Tb(3+) is 9-coordinated with three water molecules and six OH groups from two D-galactitol molecules. Nitrate ions do not coordinate to metal ions, which is different from other reported lanthanide nitrate-D-galactitol complexes. In TbGN(II) and SmGN (Ln(NO(3))(3)·C(6)H(14)O(6)), Ln(3+) is 10-coordinated with six OH groups from two D-galactitol molecules and four oxygen from two bidentate nitrate ions, and one nitrate ion is hydrogen bonded. No water exists in the structures. D-Galactitol molecules provide their 1-, 2- and 3-hydroxyl groups to coordinate with one metal ion and their 4-, 5- and 6-hydroxyl groups to coordinate with another metal ion in the three structures. There is still a new topological structure that can be observed for lanthanide-d-galactitol complexes, which indicates that the coordinations between hydroxyl groups and metal ions are complicated.     

Design, synthesis, and metal binding of novel Pseudo- oligopeptides containing two phosphinic acid groups

Phosphinic compounds have potential as amide-bond mimetics in the development of novel peptidomimetics, enzyme inhibitors, and metal-binding ligands. Novel pseudo-oligopeptides with two phosphinic acid groups embedded in the peptide backbone serving as amide-bond surrogates, Psi[P(O,OH)--CH(2)], were targeted. A series of linear and cyclic pseudo-oligopeptides with two phosphinic acid groups arrayed at different positions in the peptide sequence were designed, including Ac--Phe--{(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly}(2)--NH(2) (P2), Ac--NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--NH(2) (P3), Ac--NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe--Phe--(R,S) --AlaPsi[P(O,OH)--CH(2)]Gly--NH(2) (P4), cyclo{NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe}(2) (P5), and cyclo[NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe--Phe](2) (P6). They were synthesized via conventional Fmoc chemistry on solid support utilizing Fmoc-protected phosphinic acid-containing pseudo-dipeptide fragment, i.e. Fmoc--(R,S)--AlaPsi[P(O,OCH(3))--CH(2)]Gly--OH. The pseudo-peptides containing two phosphinic acid groups exhibited the highest binding affinity and selectivity for Fe(III) among the 10-metal ions screened by ESI-MS analysis--Cu(II), Zn(II), Co(II), Ni(II), Mn(II), Fe(II), Fe(III), Al(III), Ga(III), and Gd(III). P4 and P6 with 11-atom linkages between the two phosphinic acids preferred intramolecular metal binding to form 1:1 ligand/metal complexes. As revealed by competition experiments, P4 showed the highest relative binding affinity among the six compounds tested. Noteworthy, P4 also showed higher relative binding affinity than similar dihydroxamate-containing pseudo-peptides reported previously. The novel structural prototype and facile synthesis along with selective and potent Fe(III) binding strongly suggest that pseudo-peptides containing the two or more phosphinic groups as amide-bond surrogates deserve further exploration in medicinal chemistry.     

Mixed-valence Cu(II)/Cu(I) complex of quinolone ciprofloxacin isolated by a hydrothermal reaction in the presence of L-histidine: comparison of biological activities of various copper-ciprofloxacin compounds

A new quinolone-metal complex was prepared by a hydrothermal reaction in the presence of L-histidine that served as a reducing agent for a metal. The title compound [Cu(II)(cfH)(2)(Cu(I)Cl(2))(2)] (1) is a mixed-valence Cu(II)-Cu(I) complex, which contains two ciprofloxacin (cfH) molecules bonded to the central copper(II) atom and two almost planar [Cu(I)Cl(2)](-) moieties. Both metal centers are connected through two bridging atoms (chloride and quinolone oxygen). The electrochemical methods (differential-pulse polarography and cyclovoltammetric measurements) confirmed the presence of various copper-ciprofloxacin complex species in aqueous solution at low concentrations used in biological activity tests and also indicated that the equilibria in this system are very complex. The biological properties of the title compound and some previously isolated copper-ciprofloxacin complexes ([Cu(cfH)(2)Cl(2)].6H(2)O (2) and [CuCl(cfH)(phen)]Cl.2H(2)O (3)) (phen=1, 10-phenantroline) were determined and compared. The DNA gyrase inhibition tests and antibacterial activity tests have shown that the effect of copper complexes is comparable to that of free quinolone. Additionally, an interesting DNA cleavage activity of the title compound was also discovered.     

Copper(II) complexes of 1,10-phenanthroline-derived ligands: studies on DNA binding properties and nuclease activity

A series of copper(II) complexes of the type [Cu(L)]2+, where L = N,N'-dialkyl-1,10-phenanthroline-2,9-dimethanamine and R = methyl (L1), n-propyl (L2), isopropyl (L3), sec-butyl (L4), or tert-butyl (L5) group, have been synthesized. The interaction of the complexes with DNA has been studied by DNA fiber electron paramagnetic resonance (EPR) spectroscopy, emission, viscosity and electrochemical measurements and agarose gel electrophoresis. In the X-ray crystal structure of [Cu(HL2)Cl2]NO3, copper(II) is coordinated to two ring nitrogens and one of the two secondary amine nitrogens of the side chains and two chloride ions as well and the coordination geometry is best described as trigonal bipyramidal distorted square based pyramidal (TBDSBP). Electronic and EPR spectral studies reveal that all the complexes in aqueous solution around pH 7 possess CuN3O2 rather than CuN4O chromophore with one of the alkylamino side chain not involved in coordination. The structures of the complexes in aqueous solution around pH 7 change from distorted tetragonal to trigonal bipyramidal as the size of the alkyl group is increased. The observed changes in the physicochemical features of the complexes on binding to DNA suggest that the complexes, except [Cu(L5)]2+, bind to DNA with partial intercalation of the derivatised phen ring in between the DNA base pairs. Electrochemical studies reveal that the complexes prefer to bind to DNA in Cu(II) rather than Cu(I) oxidation state. Interestingly, [Cu(L5)]2+ shows the highest DNA cleavage activity among all the present copper(II) complexes suggesting that the bulky N-tert-butyl group plays an important role in modifying the coordination environment around the copper(II) center, the Cu(II)/Cu(I) redox potential and hence the formation of activated oxidant responsible for the cleavage. These results were compared with those for bis(1,10-phenanthroline)copper(II), [Cu(phen)2]2+.     

Antibacterial,antifungal and in vitro antileukaemia activity of metal complexes with thiosemicarbazones

1‐phenyl‐3‐methyl‐4‐benzoyl‐5‐pyrazolone 4‐ethyl‐thiosemicarbazone (HL) and its copper(II), vanadium(V) and nickel(II) complexes: [Cu(L)(Cl)]·C₂H₅OH·( 1 ), [Cu(L)₂]·H₂O ( 2 ), [Cu(L)(Br)]·H₂O·CH₃OH ( 3 ), [Cu(L)(NO₃)]·2C₂H₅OH ( 4 ), [VO₂(L)]·2H₂O ( 5 ), [Ni(L)₂]·H₂O ( 6 ), were synthesized and characterized. The ligand has been characterized by elemental analyses, IR, ¹H NMR and ¹³C NMR spectroscopy. The tridentate nature of the ligand is evident from the IR spectra. The copper(II), vanadium(V) and nickel(II) complexes have been characterized by different physico‐chemical techniques such as molar conductivity, magnetic susceptibility measurements and electronic, infrared and electron paramagnetic resonance spectral studies. The structures of the ligand and its copper(II) ( 2 , 4 ), and vanadium(V) ( 5 ) complexes have been determined by single‐crystal X‐ray diffraction. The composition of the coordination polyhedron of the central atom in 2 , 4 and 5 is different. The tetrahedral coordination geometry of Cu was found in complex 2 while in complex 4 , it is square planar, in complex 5 the coordination polyhedron of the central ion is distorted square pyramid. The in vitro antibacterial activity of the complexes against Escherichia coli, Salmonella abony, Staphylococcus aureus, Bacillus cereus and the antifungal activity against Candida albicans strains was higher for the metal complexes than for free ligand. The effect of the free ligand and its metal complexes on the proliferation of HL‐60 cells was tested.     

Transition metal complexes of buparvaquone as potent new antimalarial agents. 1. Synthesis,X-ray crystal-structures,electrochemistry and antimalarial activity against Plasmodium falciparum

New Cu(II), Ni(II), Co(II), Fe(II), and Mn(II) metal complexes of buparvaquone [3-trans(4-tert.-butylcyclohexyl)methyl-2-hydroxy-1,4-naphthoquione] (L1H) have been synthesized and characterized using IR, electron paramagnetic resonance (EPR) spectroscopy, microanalytical methods and single crystal X-ray diffraction methods. The single crystal structures were determined for ligand L1H [space group P-1 with a=6.2072(14) A, b=10.379 (2) A, c=13.840 (3) A, V=878.7(3) A(3), Z=2, D(calcd.)=1.234 mg/m(3)] and copper complex [Cu(L1)(2)(C(2)H(5)OH)(2)] C1 [space group I2/a with a=17.149(14) A, b=9.4492(8) A, c=26.946(3) A, V=4335.3(7)A(3), Z=4, D(calcd.)=1.233 mg/m(3)]. All the metal complexes along with the parent ligand have been studied for their electrochemical properties using cyclic voltammetric techniques. The compounds were tested for their in vitro antimalarial activity against Plasmodium falciparum strains. A correlation between the antimalarial activity and the redox property of these complexes is presented. The copper complex C1 exhibits significantly higher growth inhibitory activity both in vitro and in vivo than the parent ligand.     

Supramolecular structures of metronidazole and its copper(II), cobalt(II) and zinc(II) coordination compounds

In this work we present the synthesis and structural and spectroscopic characterization of Cu(II), Co(II) and Zn(II) coordination compounds with the antibiotic metronidazole ([double bond]emni). Coordination to metal ions is through its imidazolic nitrogen, while the hydroxyethyl and nitro groups act as supramolecular synthons. [Co(emni)(2)Br(2)], and [Zn(emni)(2)X(2)] (X(-)=Cl, Br) stabilize zig-zag chains, and a 2D supramolecular structure is formed by inter-chain contacts through inter-molecular hydrogen-bonding. Pleated sheet or layers are formed by [Co(emni)(2)Cl(2)] and [Cu(emni)(2)Cl(H(2)O)](2)Cl(2), respectively. The dinuclear Cu(II) compound [Cu(emni)mu(O(2)CMe)(2)](2) gives a one-dimensional zig-zag arrangement. The contribution of metal ions in metronidazole coordination compounds is shown in the stabilization of the different aggregate structures.     

Spontaneous resolution of binary copper(II) complexes with racemic dipeptides: crystal structures of glycyl-L-alpha-amino-n-butyrato copper(II) monohydrate, glycyl-D-valinato copper(II) hemihydrate, and glycyl-L-valinato copper(II) hemihydrate

Copper(II) complexes with glycyl-DL-alpha-amino-n-butyric acid (H2gly-DL-but), glycyl-DL-valine (H2gly-DL-val), glycyl-DL-norleucine (H2gly-DL-norleu), glycyl-DL-threonine (H2gly-DL-thr), glycyl-DL-serine (H2gly-DL-ser), glycyl-DL-phenylalanine (H2gly-DL-phe), and glycyl-L-valine (H2gly-L-val), have been prepared and characterized by IR, powder diffuse reflection, CD and ORD spectra, and magnetic susceptibility measurements, and by single-crystal X-ray diffraction. The crystal structures of the copper complex with H2gly-DL-but, the copper complex with H2gly-DL-val, and [Cu(gly-L-val)]n.0.5nH2O have been determined by a single-crystal X-ray diffraction method. As for the structure of the copper complex with H2gly-DL-but, the configuration around the asymmetric carbon atom is similar to that of [Cu(gly-L-val)]n.0.5nH2O. Therefore it is concluded that the copper complex with H2gly-DL-but is [Cu(gly-L-but)]n.nH2O. On the contrary, as for the structure of the copper complex with H2gly-DL-val, the configuration around the asymmetric carbon atom is different from that of [Cu(gly-L-val)]n.0.5nH2O. Therefore it is concluded that the copper complex with H2gly-dl-val is [Cu(gly-D-val)]n.0.5nH2O. So during the crystallization of the copper(II) complexes with H2gly-DL-but and H2gly-DL-val, spontaneous resolution has been observed; the four complexes have separated as [Cu(gly-D-but)]n.nH2O, [Cu(gly-L-but)]n.nH2O, [Cu(gly-D-val)]n.0.5nH2O, and [Cu(gly-L-val)]n.0.5nH2O, respectively. [Cu(gly-L-but)]n.nH2O is orthorhombic with the space group P2(1)2(1)2(1). [Cu(gly-D-val)]n.0.5nH2O and [Cu(gly-L-val)]n.0.5nH2O are monoclinic with the space group C2. In these complexes, the copper atom is in a square-pyramidal geometry, ligated by a peptide nitrogen atom, an amino nitrogen atom, a carboxyl oxygen atom, and a carboxyl oxygen atom and a peptide oxygen atom from neighboring molecules. So these complexes consist of a two-dimensional polymer chain bridged by a carboxyl oxygen atom and a peptide oxygen atom from neighboring molecules. The axial oxygen atom is located above the basal plane and the side chain of an amino acid is located below it. These polymer chains consist of only one or the other type of optical isomers; no racemic dipeptides are found. Therefore, spontaneous resolution has been observed in the crystallization of copper(II) complexes with H2gly-DL-but and H2gly-DL-val. The crystal structure of [Cu(gly-D-val)]n.0.5nH2O agrees almost completely with that of [Cu(gly-L-val)]n.0.5nH2O, except for the configuration around the asymmetric carbon atom.     

Zinc(II) complexes with potent cyclin-dependent kinase inhibitors derived from 6-benzylaminopurine: synthesis, characterization, X-ray structures and biological activity

The synthesis, characterization and biological activity of the first zinc(II) complexes with potent inhibitors of cyclin-dependent kinases (CDKs) derived from 6-benzylaminopurine are described. Based on the results following from elemental analyses, infrared, NMR and ES+MS (electrospray mass spectra in the positive ion mode) spectroscopies, conductivity data, thermal analysis and X-ray structures, the tetrahedral Zn(II) complexes of the compositions [Zn(Olo)Cl(2)](n) (1), [Zn(iprOlo)Cl(2)](n) (2), [Zn(BohH(+))Cl(3)] x H(2)O (3) and [Zn(iprOloH(+))Cl(3)] x H(2)O (4) have been prepared, where Olo=2-(2-hydroxyethylamino)-6-benzylamino-9-methylpurine (Olomoucine), iprOlo=2-(2-hydroxyethylamino)-6-benzylamino-9-isopropylpurine (i-propyl-Olomoucine), Boh=2-(3-hydroxypropylamino)-6-benzylamino-9-isopropylpurine (Bohemine). The 1D-polymeric chain structure for [Zn(Olo)Cl(2)](n) (1) as well as the monomeric one for [Zn(BohH(+))Cl(3)] x H(2)O (3) and [Zn(iprOloH(+))Cl(3)] x H(2)O (4) have been revealed unambiguously by single crystal X-ray analyses. The 1D-polymeric chain of 1 consists of Zn(Olo)Cl(2) monomeric units in which the Zn(II) ion is coordinated by two chlorine atoms and one oxygen atom of the 2-hydroxyethylamino group of Olomoucine. The next monomeric unit is bonded to Zn(II) through the N7 atom of a purine ring. Thus, each of Zn(II) ions is tetrahedrally coordinated and a ZnCl(2)NO chromophore occurs in the complex 1. The complexes 3 and 4 are mononuclear species with a distorted tetrahedral arrangement of donor atoms around the Zn(II) ion with a ZnCl(3)N chromophore. The corresponding CDK inhibitor, i.e., both Boh and iprOlo, is coordinated to Zn(II) via the N7 atom of the purine ring in 3 and 4. The cytotoxicity of the zinc(II) complexes against human melanoma, sarcoma, leukaemia and carcinoma cell lines has been determined as well as the inhibition of the CDK2/cyclin E kinase. A relationship between the structure and biological activity of the complexes is also discussed.     

Sugar interaction with metal ions. The coordination behavior of neutral galactitol to Ca(II) and lanthanide ions

The crystal structures of CaCl(2).galactitol.4 H(2)O and 2EuCl(3).galactitol.14 H(2)O were determined to compare the coordination behavior of Ca and lanthanide ions. The crystal system of the Ca-galactitol complex, CaCl(2).C(6)H(14)O(6).4 H(2)O, is monoclinic, Cc space group. Each Ca ion is coordinated to eight oxygen atoms, four from two galactitol molecules and four from water molecules. Galactitol provides O-2, -3 to coordinate to one Ca(2+), and O-4, -5 with another Ca(2+), to form a chain structure. The crystal system of the Eu-galactitol complex, 2EuCl(3).C(6)H(14)O(6).14 H(2)O, is triclinic, P1; space group. Each Eu ion is coordinated to nine oxygen atoms, three from an alditol molecule and six from water molecules. Each galactitol provides O-1, -2, -3 to coordinate with one Eu(3+) and O-4, -5, -6 with another Eu(3+). The other water molecules are hydrogen-bonded in the structure. The similar IR spectra of Pr-, Nd-, Sm-, Eu-, Dy-, and Er-galactitol complexes show that those lanthanide ions have the same coordination mode to neutral galactitol. The Raman spectra also confirm the formation of metal ion-carbohydrate complexes.