The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform

Orhan Buyukgungor - One of the best experts on this subject based on the ideXlab platform.

  • Supramolecular architectures of cadmium(II)-Orotate complexes containing water clusters
    CrystEngComm, 2020
    Co-Authors: Okan Zafer Yesilel, Hakan Erer, Orhan Buyukgungor
    Abstract:

    Three novel cadmium(II) complexes containing Orotate ligand have been synthesized under different pH and characterized by X-ray crystallography, IR spectroscopy and thermal analyses measurements. In the complexes, the Orotate ligand exhibits three different coordination modes. In [Cd2(μ-HOr)2(H2O)4(NH3)2]·2H2O (1), the Orotate acts as a tridentate ligand, showing unprecedented coordination mode. The (NH4)2[Cd3(μ-HOr)2(HOr)2(H2O)8]·4H2O (2) is constructed from Orotate acting as both bidentate and tridentate bridging ligands. The Cd1 and Cd2 ions have two different coordination environments with four HOr, eight aqua ligands. Furthermore, 2 exhibits the novel 2D metal–water cluster layers. The (Hcha)4[Cd(HOr)2(H2O)(cha)][Cd(HOr)2(H2O)2]·H2O (3) (cha = cyclohexylamine, H3Or = orotic acid) consists of discrete cis and trans anionic complexes. The cha molecules exhibit chemically different functions by coordinating to Cd(II) ion in one form and being protonated and acting as counter–ions in other form. In the complexes, the supramolecular networks are constructed by novel N–H⋯O strong hydrogen bonds to form DA:AD motif, CO⋯π and π⋯π interactions.

  • co ii ni ii and zn ii Orotate complexes with n methylimidazole synthesis crystal structures and antimicrobial activities
    Polyhedron, 2011
    Co-Authors: Hakan Erer, Okan Zafer Yesilel, Cihan Darcan, Orhan Buyukgungor
    Abstract:

    Abstract Three Co(II), Ni(II) and Zn(II) complexes of Orotate with the N-methylimidazole ligand were synthesized and characterized by means of elemental and thermal analysis, magnetic susceptibilities, IR, UV–Vis spectroscopic and antimicrobial activity studies. The crystal structures of [Co(HOr)(H2O)2(Nmeim)2]3·H2O (1), [Ni(HOr)(H2O)2(Nmeim)2] (2) and [Zn(HOr)(H2O)(Nmeim)2] (3) were determined by the single crystal X-ray diffraction technique (H3Or = orotic acid and Nmeim = N-methylimidazole). In complexes 1 and 2, the Co(II) and Ni(II) ions have distorted octahedral geometries with two Nmeim, one Orotate and two aqua ligands. Complex 3 has a distorted trigonal bipyramidal geometry with two N-methylimidazole, one Orotate and one aqua ligands. In the complexes, the Orotate is coordinated to the metal(II) ions through the deprotonated nitrogen atom of the pyrimidine ring and the oxygen atom of the carboxylate group as a bidentate ligand. The complexes form a three-dimensional framework by hydrogen bonding, C–H ⋯ π and π ⋯ π stacking interactions. The MIC values of the complexes against selected microorganisms were determined to be in range 300–2400 μg/mL.

  • An unprecedented coordination mode of the Orotate ligand in novel polynuclear cadmium(II)–Orotate complexes
    Polyhedron, 2010
    Co-Authors: Okan Zafer Yesilel, Hakan Erer, Orhan Buyukgungor
    Abstract:

    Abstract Two novel carboxylate-bridged Cd(II)–Orotate polynuclear complexes with 2-(2-ethylamino)pyridine (2-etapy), [Cd(μ-HOr)(2-etapy)]n (1), and N,N-diethylethylenediamine (N,N-eten) ligands, {[Cd(μ-HOr)(H2O)(N,N-eten)]·H2O}n (2) (H3Or = orotic acid), have been synthesized and characterized by TGA–evolved gas analysis (TGA–EGA), IR spectroscopy and single crystal X-ray diffraction techniques. The Orotate ligand acts as a bridging ligand with two different coordination modes, showing an unprecedented tetradentate coordination mode. The HOr ligand simultaneously chelates Cd(II) ions through the carboxylate oxygen, deprotonated pyrimidine nitrogen atoms and carboxyl oxygen atoms as a tetradentate ligand in 1. In complex 2, the HOr ligand bridges two Cd(II) ions through the carboxylate oxygen and deprotonated pyrimidine nitrogen atoms and oxygen atom of a carboxylate group of a neighbouring complex unit. Three-dimensional (3D) supramolecular structures are generated by hydrogen-bonding, and π···π and C–H···π interactions between the closest chains in both complexes.

  • synthesis spectroscopic thermal studies antimicrobial activities and crystal structures of co ii ni ii cu ii and zn ii Orotate complexes with 2 methylimidazole
    Polyhedron, 2009
    Co-Authors: Hakan Erer, Okan Zafer Yesilel, Cihan Darcan, Orhan Buyukgungor
    Abstract:

    Abstract The 2-methylimidazole complexes of Co(II), Ni(II), Cu(II) and Zn(II) Orotates, mer -[Co(HOr)(H 2 O) 2 (2-meim) 2 ] ( 1 ), mer -[Ni(HOr)(H 2 O) 2 (2-meim) 2 ] ( 2 ), [Cu(HOr)(H 2 O) 2 (2-meim)] ( 3 ) and [Zn(HOr)(H 2 O) 2 (2-meim)] ( 4 ), were synthesized and characterized by elemental analysis, spectral (UV–Vis and FT-IR) methods, thermal analysis (TG, DTG and DTA), magnetic susceptibility, antimicrobial activity studies and single crystal X-ray diffraction technique. The complexes 1 and 2 have distorted octahedral geometries with two monodentate 2-methylimidazole and one bidentate Orotate and two aqua ligands. The complexes 3 and 4 have distorted square pyramidal and trigonal bipyramidal geometry, respectively, with one 2-methylimidazole, bidentate Orotate and aqua ligands. The Orotate coordinated to the metal(II) ions through deprotonated nitrogen atom of pyrimidine ring and oxygen atom of carboxylate group as a bidentate ligand. The antimicrobial activities of 1 and 4 were found to be more active gram (+) than gram (−) and 4 could be use for treatment Staphylococcus aureus .

  • syntheses spectral thermal and structural characterization of dinuclear and polynuclear copper ii Orotate complexes cu2 hor 2 h2o 4 and cu μ hor ba 2 n
    Polyhedron, 2009
    Co-Authors: Mustafa Serkan Soylu, Okan Zafer Yesilel, Bunyamin Karabulut, Orhan Buyukgungor
    Abstract:

    Abstract The novel catena-poly-μ-orotatobis(butylamine)copper(II), [Cu(μ-HOr)(ba)2]n (1), and diaqua(orotato)copper(II), [Cu2(HOr)2(H2O)4] (2), complexes have been prepared and characterized by elemental analysis, magnetic measurements, FT-IR spectroscopy, EPR spectroscopy, thermal analysis and X-ray diffraction. Both complexes crystallize in the monoclinic space group, C2/c in 1 and P21/n in 2. In the complexes, the copper(II) ion is chelated by a deprotonated pyrimidine nitrogen atom and a carboxylate oxygen atom of the Orotate. While the coordination sphere around Cu(II) is completed by two N atoms from butylamine groups and a carboxylic O atom in the axial position from a neighboring molecule in 1, the square-planar environment of Cu(II) is completed by two water atoms and one axial position is occupied by the carbonyl oxygen atom from the symmetry related molecule in 2. The coordination sphere should be described as a square pyramid and (4+1)-geometry in 1 and 2, respectively. While complex 1 shows a polymeric arrangement, compound 2 has a dimeric arrangement. The non-covalent Cu(II)-π binding force is very important for stabilizing the crystal structure of 2. The thermal decomposition of the complexes has been predicted by the help of thermal analysis (TG, DTG and DTA).

Okan Zafer Yesilel - One of the best experts on this subject based on the ideXlab platform.

  • Supramolecular architectures of cadmium(II)-Orotate complexes containing water clusters
    CrystEngComm, 2020
    Co-Authors: Okan Zafer Yesilel, Hakan Erer, Orhan Buyukgungor
    Abstract:

    Three novel cadmium(II) complexes containing Orotate ligand have been synthesized under different pH and characterized by X-ray crystallography, IR spectroscopy and thermal analyses measurements. In the complexes, the Orotate ligand exhibits three different coordination modes. In [Cd2(μ-HOr)2(H2O)4(NH3)2]·2H2O (1), the Orotate acts as a tridentate ligand, showing unprecedented coordination mode. The (NH4)2[Cd3(μ-HOr)2(HOr)2(H2O)8]·4H2O (2) is constructed from Orotate acting as both bidentate and tridentate bridging ligands. The Cd1 and Cd2 ions have two different coordination environments with four HOr, eight aqua ligands. Furthermore, 2 exhibits the novel 2D metal–water cluster layers. The (Hcha)4[Cd(HOr)2(H2O)(cha)][Cd(HOr)2(H2O)2]·H2O (3) (cha = cyclohexylamine, H3Or = orotic acid) consists of discrete cis and trans anionic complexes. The cha molecules exhibit chemically different functions by coordinating to Cd(II) ion in one form and being protonated and acting as counter–ions in other form. In the complexes, the supramolecular networks are constructed by novel N–H⋯O strong hydrogen bonds to form DA:AD motif, CO⋯π and π⋯π interactions.

  • co ii ni ii and zn ii Orotate complexes with n methylimidazole synthesis crystal structures and antimicrobial activities
    Polyhedron, 2011
    Co-Authors: Hakan Erer, Okan Zafer Yesilel, Cihan Darcan, Orhan Buyukgungor
    Abstract:

    Abstract Three Co(II), Ni(II) and Zn(II) complexes of Orotate with the N-methylimidazole ligand were synthesized and characterized by means of elemental and thermal analysis, magnetic susceptibilities, IR, UV–Vis spectroscopic and antimicrobial activity studies. The crystal structures of [Co(HOr)(H2O)2(Nmeim)2]3·H2O (1), [Ni(HOr)(H2O)2(Nmeim)2] (2) and [Zn(HOr)(H2O)(Nmeim)2] (3) were determined by the single crystal X-ray diffraction technique (H3Or = orotic acid and Nmeim = N-methylimidazole). In complexes 1 and 2, the Co(II) and Ni(II) ions have distorted octahedral geometries with two Nmeim, one Orotate and two aqua ligands. Complex 3 has a distorted trigonal bipyramidal geometry with two N-methylimidazole, one Orotate and one aqua ligands. In the complexes, the Orotate is coordinated to the metal(II) ions through the deprotonated nitrogen atom of the pyrimidine ring and the oxygen atom of the carboxylate group as a bidentate ligand. The complexes form a three-dimensional framework by hydrogen bonding, C–H ⋯ π and π ⋯ π stacking interactions. The MIC values of the complexes against selected microorganisms were determined to be in range 300–2400 μg/mL.

  • An unprecedented coordination mode of the Orotate ligand in novel polynuclear cadmium(II)–Orotate complexes
    Polyhedron, 2010
    Co-Authors: Okan Zafer Yesilel, Hakan Erer, Orhan Buyukgungor
    Abstract:

    Abstract Two novel carboxylate-bridged Cd(II)–Orotate polynuclear complexes with 2-(2-ethylamino)pyridine (2-etapy), [Cd(μ-HOr)(2-etapy)]n (1), and N,N-diethylethylenediamine (N,N-eten) ligands, {[Cd(μ-HOr)(H2O)(N,N-eten)]·H2O}n (2) (H3Or = orotic acid), have been synthesized and characterized by TGA–evolved gas analysis (TGA–EGA), IR spectroscopy and single crystal X-ray diffraction techniques. The Orotate ligand acts as a bridging ligand with two different coordination modes, showing an unprecedented tetradentate coordination mode. The HOr ligand simultaneously chelates Cd(II) ions through the carboxylate oxygen, deprotonated pyrimidine nitrogen atoms and carboxyl oxygen atoms as a tetradentate ligand in 1. In complex 2, the HOr ligand bridges two Cd(II) ions through the carboxylate oxygen and deprotonated pyrimidine nitrogen atoms and oxygen atom of a carboxylate group of a neighbouring complex unit. Three-dimensional (3D) supramolecular structures are generated by hydrogen-bonding, and π···π and C–H···π interactions between the closest chains in both complexes.

  • synthesis spectroscopic thermal studies antimicrobial activities and crystal structures of co ii ni ii cu ii and zn ii Orotate complexes with 2 methylimidazole
    Polyhedron, 2009
    Co-Authors: Hakan Erer, Okan Zafer Yesilel, Cihan Darcan, Orhan Buyukgungor
    Abstract:

    Abstract The 2-methylimidazole complexes of Co(II), Ni(II), Cu(II) and Zn(II) Orotates, mer -[Co(HOr)(H 2 O) 2 (2-meim) 2 ] ( 1 ), mer -[Ni(HOr)(H 2 O) 2 (2-meim) 2 ] ( 2 ), [Cu(HOr)(H 2 O) 2 (2-meim)] ( 3 ) and [Zn(HOr)(H 2 O) 2 (2-meim)] ( 4 ), were synthesized and characterized by elemental analysis, spectral (UV–Vis and FT-IR) methods, thermal analysis (TG, DTG and DTA), magnetic susceptibility, antimicrobial activity studies and single crystal X-ray diffraction technique. The complexes 1 and 2 have distorted octahedral geometries with two monodentate 2-methylimidazole and one bidentate Orotate and two aqua ligands. The complexes 3 and 4 have distorted square pyramidal and trigonal bipyramidal geometry, respectively, with one 2-methylimidazole, bidentate Orotate and aqua ligands. The Orotate coordinated to the metal(II) ions through deprotonated nitrogen atom of pyrimidine ring and oxygen atom of carboxylate group as a bidentate ligand. The antimicrobial activities of 1 and 4 were found to be more active gram (+) than gram (−) and 4 could be use for treatment Staphylococcus aureus .

  • syntheses spectral thermal and structural characterization of dinuclear and polynuclear copper ii Orotate complexes cu2 hor 2 h2o 4 and cu μ hor ba 2 n
    Polyhedron, 2009
    Co-Authors: Mustafa Serkan Soylu, Okan Zafer Yesilel, Bunyamin Karabulut, Orhan Buyukgungor
    Abstract:

    Abstract The novel catena-poly-μ-orotatobis(butylamine)copper(II), [Cu(μ-HOr)(ba)2]n (1), and diaqua(orotato)copper(II), [Cu2(HOr)2(H2O)4] (2), complexes have been prepared and characterized by elemental analysis, magnetic measurements, FT-IR spectroscopy, EPR spectroscopy, thermal analysis and X-ray diffraction. Both complexes crystallize in the monoclinic space group, C2/c in 1 and P21/n in 2. In the complexes, the copper(II) ion is chelated by a deprotonated pyrimidine nitrogen atom and a carboxylate oxygen atom of the Orotate. While the coordination sphere around Cu(II) is completed by two N atoms from butylamine groups and a carboxylic O atom in the axial position from a neighboring molecule in 1, the square-planar environment of Cu(II) is completed by two water atoms and one axial position is occupied by the carbonyl oxygen atom from the symmetry related molecule in 2. The coordination sphere should be described as a square pyramid and (4+1)-geometry in 1 and 2, respectively. While complex 1 shows a polymeric arrangement, compound 2 has a dimeric arrangement. The non-covalent Cu(II)-π binding force is very important for stabilizing the crystal structure of 2. The thermal decomposition of the complexes has been predicted by the help of thermal analysis (TG, DTG and DTA).

Hakan Erer - One of the best experts on this subject based on the ideXlab platform.

  • Supramolecular architectures of cadmium(II)-Orotate complexes containing water clusters
    CrystEngComm, 2020
    Co-Authors: Okan Zafer Yesilel, Hakan Erer, Orhan Buyukgungor
    Abstract:

    Three novel cadmium(II) complexes containing Orotate ligand have been synthesized under different pH and characterized by X-ray crystallography, IR spectroscopy and thermal analyses measurements. In the complexes, the Orotate ligand exhibits three different coordination modes. In [Cd2(μ-HOr)2(H2O)4(NH3)2]·2H2O (1), the Orotate acts as a tridentate ligand, showing unprecedented coordination mode. The (NH4)2[Cd3(μ-HOr)2(HOr)2(H2O)8]·4H2O (2) is constructed from Orotate acting as both bidentate and tridentate bridging ligands. The Cd1 and Cd2 ions have two different coordination environments with four HOr, eight aqua ligands. Furthermore, 2 exhibits the novel 2D metal–water cluster layers. The (Hcha)4[Cd(HOr)2(H2O)(cha)][Cd(HOr)2(H2O)2]·H2O (3) (cha = cyclohexylamine, H3Or = orotic acid) consists of discrete cis and trans anionic complexes. The cha molecules exhibit chemically different functions by coordinating to Cd(II) ion in one form and being protonated and acting as counter–ions in other form. In the complexes, the supramolecular networks are constructed by novel N–H⋯O strong hydrogen bonds to form DA:AD motif, CO⋯π and π⋯π interactions.

  • co ii ni ii and zn ii Orotate complexes with n methylimidazole synthesis crystal structures and antimicrobial activities
    Polyhedron, 2011
    Co-Authors: Hakan Erer, Okan Zafer Yesilel, Cihan Darcan, Orhan Buyukgungor
    Abstract:

    Abstract Three Co(II), Ni(II) and Zn(II) complexes of Orotate with the N-methylimidazole ligand were synthesized and characterized by means of elemental and thermal analysis, magnetic susceptibilities, IR, UV–Vis spectroscopic and antimicrobial activity studies. The crystal structures of [Co(HOr)(H2O)2(Nmeim)2]3·H2O (1), [Ni(HOr)(H2O)2(Nmeim)2] (2) and [Zn(HOr)(H2O)(Nmeim)2] (3) were determined by the single crystal X-ray diffraction technique (H3Or = orotic acid and Nmeim = N-methylimidazole). In complexes 1 and 2, the Co(II) and Ni(II) ions have distorted octahedral geometries with two Nmeim, one Orotate and two aqua ligands. Complex 3 has a distorted trigonal bipyramidal geometry with two N-methylimidazole, one Orotate and one aqua ligands. In the complexes, the Orotate is coordinated to the metal(II) ions through the deprotonated nitrogen atom of the pyrimidine ring and the oxygen atom of the carboxylate group as a bidentate ligand. The complexes form a three-dimensional framework by hydrogen bonding, C–H ⋯ π and π ⋯ π stacking interactions. The MIC values of the complexes against selected microorganisms were determined to be in range 300–2400 μg/mL.

  • An unprecedented coordination mode of the Orotate ligand in novel polynuclear cadmium(II)–Orotate complexes
    Polyhedron, 2010
    Co-Authors: Okan Zafer Yesilel, Hakan Erer, Orhan Buyukgungor
    Abstract:

    Abstract Two novel carboxylate-bridged Cd(II)–Orotate polynuclear complexes with 2-(2-ethylamino)pyridine (2-etapy), [Cd(μ-HOr)(2-etapy)]n (1), and N,N-diethylethylenediamine (N,N-eten) ligands, {[Cd(μ-HOr)(H2O)(N,N-eten)]·H2O}n (2) (H3Or = orotic acid), have been synthesized and characterized by TGA–evolved gas analysis (TGA–EGA), IR spectroscopy and single crystal X-ray diffraction techniques. The Orotate ligand acts as a bridging ligand with two different coordination modes, showing an unprecedented tetradentate coordination mode. The HOr ligand simultaneously chelates Cd(II) ions through the carboxylate oxygen, deprotonated pyrimidine nitrogen atoms and carboxyl oxygen atoms as a tetradentate ligand in 1. In complex 2, the HOr ligand bridges two Cd(II) ions through the carboxylate oxygen and deprotonated pyrimidine nitrogen atoms and oxygen atom of a carboxylate group of a neighbouring complex unit. Three-dimensional (3D) supramolecular structures are generated by hydrogen-bonding, and π···π and C–H···π interactions between the closest chains in both complexes.

  • synthesis spectroscopic thermal studies antimicrobial activities and crystal structures of co ii ni ii cu ii and zn ii Orotate complexes with 2 methylimidazole
    Polyhedron, 2009
    Co-Authors: Hakan Erer, Okan Zafer Yesilel, Cihan Darcan, Orhan Buyukgungor
    Abstract:

    Abstract The 2-methylimidazole complexes of Co(II), Ni(II), Cu(II) and Zn(II) Orotates, mer -[Co(HOr)(H 2 O) 2 (2-meim) 2 ] ( 1 ), mer -[Ni(HOr)(H 2 O) 2 (2-meim) 2 ] ( 2 ), [Cu(HOr)(H 2 O) 2 (2-meim)] ( 3 ) and [Zn(HOr)(H 2 O) 2 (2-meim)] ( 4 ), were synthesized and characterized by elemental analysis, spectral (UV–Vis and FT-IR) methods, thermal analysis (TG, DTG and DTA), magnetic susceptibility, antimicrobial activity studies and single crystal X-ray diffraction technique. The complexes 1 and 2 have distorted octahedral geometries with two monodentate 2-methylimidazole and one bidentate Orotate and two aqua ligands. The complexes 3 and 4 have distorted square pyramidal and trigonal bipyramidal geometry, respectively, with one 2-methylimidazole, bidentate Orotate and aqua ligands. The Orotate coordinated to the metal(II) ions through deprotonated nitrogen atom of pyrimidine ring and oxygen atom of carboxylate group as a bidentate ligand. The antimicrobial activities of 1 and 4 were found to be more active gram (+) than gram (−) and 4 could be use for treatment Staphylococcus aureus .

A I Martynow - One of the best experts on this subject based on the ideXlab platform.

  • Magnesium Orotate in severe congestive heart failure (MACH).
    International journal of cardiology, 2009
    Co-Authors: O B Stepura, A I Martynow
    Abstract:

    Aim of this study was to evaluate adjuvant magnesium Orotate on mortality and clinical symptoms in patients with severe heart failure under optimal cardiovascular medication. In a monocentric, controlled, double-blind study, 79 patients with severe congestive heart failure (NYHA IV) under optimal medical cardiovascular treatment were randomised to receive either magnesium Orotate (6000 mg for 1 month, 3000 mg for about 11 months, n = 40) or placebo (n = 39). Both groups were comparable in demographic data, duration of heart failure and pre- and concomitant treatment. After mean treatment duration of 1 year (magnesium Orotate: 364.1 +/- 14.7 days, placebo: 361.2 +/- 12.7 days) the survival rate was 75.7% compared to 51.6% under placebo (p < 0.05). Clinical symptoms improved in 38.5% of patients under magnesium Orotate, whereas they deteriorated in 56.3% of patients under placebo (p < 0.001). Magnesium Orotate may be used as adjuvant therapy in patients on optimal treatment for severe congestive heart failure, increasing survival rate and improving clinical symptoms and patient's quality of life.

  • magnesium Orotate in severe congestive heart failure mach
    International Journal of Cardiology, 2009
    Co-Authors: O B Stepura, A I Martynow
    Abstract:

    Abstract Background Aim of this study was to evaluate adjuvant magnesium Orotate on mortality and clinical symptoms in patients with severe heart failure under optimal cardiovascular medication. Methods In a monocentric, controlled, double-blind study, 79 patients with severe congestive heart failure (NYHA IV) under optimal medical cardiovascular treatment were randomised to receive either magnesium Orotate (6000 mg for 1 month, 3000 mg for about 11 months, n =40) or placebo ( n =39). Both groups were comparable in demographic data, duration of heart failure and pre- and concomitant treatment. Results After mean treatment duration of 1 year (magnesium Orotate: 364.1±14.7 days, placebo: 361.2±12.7 days) the survival rate was 75.7% compared to 51.6% under placebo ( p p Conclusion Magnesium Orotate may be used as adjuvant therapy in patients on optimal treatment for severe congestive heart failure, increasing survival rate and improving clinical symptoms and patient's quality of life.

Hubert Schmidbaur - One of the best experts on this subject based on the ideXlab platform.

  • Preparation and crystal structure of zinc bis[Orotate(1−)] octahydrate
    Zeitschrift für Naturforschung B, 1993
    Co-Authors: Otto Kumberger, Jürgen Riede, Hubert Schmidbaur
    Abstract:

    A discrete zinc bis[Orotate(1-)] complex of the composition Zn(OrH) 2 .8H 2 O has been isolated and characterized by a single-crystal X-ray structure analysis. The crystals are monoclinic, space group P2 1 /c (No. 14), Z=2, a=10.884(2), b=12.896(1), c=6.954(1) A, β= 98.27(1) o . The crystal lattice features hexaquo complexes of zinc, the Zn(H 2 O) 6 2+ cations being associated with two hydrated OrH - ions only through hydrogen bonds. The results are relevant for applications of zinc Orotates in medical treatment

  • Orotate complexes ii1 preparation and crystal structures of calcium and zinc Orotate 2 hydrates
    Chemische Berichte, 1991
    Co-Authors: Otto Kumberger, Jürgen Riede, Hubert Schmidbaur
    Abstract:

    From aqueous solutions containing Orotate (dianion of 1) and calcium or zinc ions in the molar ratio of 2:1, metal Orotate (2-) hydrates are readily obtained in crystalline form at pH 9.0 and 5.4, respectively. According to an X-ray crystal structure analysis, calcium Orotate tetrahydrate forms a one-dimensional coordination polymer with each Orotate ligand coordinated to no less than three neighboring calcium atoms. In this cation triple, the Orotate(2-) anion acts as a carboxylate-O/amide-N-chelating group for the central calcium ion, but also as a carboxylate-O/O-chelating group for the first neighboring calcium ion, and as a terminal amide-O donor for the second. Each calcium ion is thus octacoordinated and linked to three Orotate(2-) anions and three water molecules. The fourth water molecule is only engaged in hydrogen bonding. The new zinc Orotate(2-) phase features Zn(Or)(H2O)4 units. For the hexacoordinate zinc atom bearing four water molecules the Orotate(2-) ligand also acts as an O/N-chelating group. Unlike a discrete Zn(Or)(H2O)4 H2O phase reported earlier, the lattice of the new phase contains further disordered water of crystallization, with the overall composition approaching Zn(Or) 5.5 H2O. The apparent stability of the M(Or) units probably reflects the well-documented carrier function of the Orotate ligand for certain divalent metal ions in biological systems.

  • Orotate complexes synthesis and crystal structure of lithium Orotate i monohydrate and magnesium bis Orotate i octahydrate
    Chemische Berichte, 1990
    Co-Authors: I Bach, O Kumberger, Hubert Schmidbaur
    Abstract:

    Neutralization of orotic acid (OrH2) by lithium or magnesium hydroxide in aqueous medium yields the crystalline metal Orotate hydrates Li(OrH). H2O (1) and Mg(OrH)2. (H2O)6 (2). By single-crystal X-ray diffraction studies it has been shown that 1 (space group P1) forms a layer structure, with lithium in a tetrahedral environment of oxygen atoms from three different Orotate( - I) anions (one carboxylate and two uracil oxygen atoms) and the water molecule. 2 (space group P21/c) has been shown to feature a hexaquo complex of magnesium, the Mg(H2O)26 cations being associated with two hydrated OrH⊖ ions only through hydrogen bonds. The anions are also engaged in “base-pairing” hydrogen bonds between the planar uracil ring systems of different units. The results are relevant for applications of magnesium Orotates in magnesium therapy.