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  • infrared  (4)
  • Crystal structure  (2)
  • corneal endothelium  (2)
  • 1
    ISSN: 1572-8854
    Schlagwort(e): Dinuclear ; copper ; triflate ; bipyrimidine ; azido ; infrared
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The structure of the title compound [Cu2(bipym)3(N3)2(CH3OH)2](CF3SO3)2(CH3OH)2 has been determined by X-ray diffraction. The crystals are triclinic, space group P1, with a = 8.1844(5), b = 11.0253(6), c = 12.9089(7) Å, α = 80.249(4), β, = 74.933(5), γ = 74.001(4)°, and Z = 1. The structure consists of a dinuclear Cu(II) unit formed of two didentate bipym ligands, one bis-didentate bipym ligand, two azido anions, and two coordinating methanol molecules. The Cu(II) atom is elongated tetragonally surrounded by two nitrogens of the didentate bipym ligand, one nitrogen of the bis-didentate ligand, and one nitrogen of the azido anion forming the equatorial plane with one nitrogen of the bis-didentate ligand and an oxygen atom of the methanol molecule as the axial atoms. A noncoordinating triflate anion and an additional methanol molecule are also in the crystal lattice and have a hydrogen bond distance of 2.801(3) Å with an angle of 157(4)°. The cations link by O – H ··· N bonds into infinite chains running in the c-direction.
    Materialart: Digitale Medien
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  • 2
    ISSN: 1572-8854
    Schlagwort(e): 2,2′-Bipyrimidine ; low-spin ; iron ; crystal structure ; infrared
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The compound [Fe(bipym)33](CF3SO3)2 (in which bipym = 2,2′-bipyrimidine) crystallizes in the space group P21/c, with a = 13.7641(11), b = 18.7557(19), c = 12.3627(11) Å, β = 103.085(8)° and Z = 4. The low-spin Fe(II) atom is octahedrally surrounded by six nitrogen atoms of three bipyrimidine groups with Fe—N distances that vary from 1.968(4) to 1.975(4) å. In the far-infrared region the Fe—N vibrations are observed at 359 and 372 cm-1.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1572-8854
    Schlagwort(e): azido ; crystal structure ; copper(II) ; infrared ; polymeric
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound, catena-[bis(azido-N)-copper(II)-μ(bis(2-benzimidazolyl)butane), [Cu(C18H18N4)(N3)2]n, was obtained from the reaction of the ligand bis(2-benzimidazolyl)butane and Cu(N3)2. The x-ray crystal structure is reported. The compound crystallizes in the monoclinic space group P21/c with a = 8.2524(10), b = 12.765(5), c = 9.1125(15) Å, β = 106.423(12)°, Z = 2. The Cu(II) ions are square-planar coordinated with trans-oriented end-on binding azido ligands. The structure is a polynuclear chain with the benzimidazole bridging at each end. In addition a N(ligand)-H···N(azido) H-bridge [N(ligand)···N(azido) = 2.994(7) Å] is present, resulting in a pseudo 2-dimensional lattice. The characteristic azido infrared vibrations are found at 2060 and 2077 cm−1 (νas(N3)) and 1284 and 1297 cm−1 (ν(N3)).
    Materialart: Digitale Medien
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  • 4
    ISSN: 1572-8854
    Schlagwort(e): copper ; bis(benzimidazoles) ; crystal structure ; infrared
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The structure of a mononuclear copper(II) compound with the ligand bis(2-benzimidazolyl)propane (abbreviated as tbz) is reported. The compound [Cu(tbz)2](CF3SO3)2(H2O) crystallizes in the triclinic space group P $$\bar 1$$ , with a = 12.363(6), b = 13.218(9), c = 15.365(8) Å, α = 82.74(5), β = 68.04(4), γ = 65.30(5), and Z = 2. The Cu(II) atom has a geometry intermediate between tetrahedral and square planar, consisting of four nitrogen atoms of two tbz ligands. The Cu—N—Cu angles are about 135°, while the dihedral angle between them amounts to 62° (0° for square planar and 90° for a tetrahedron). Ligand field bands are observed at 10.2 × 103, 13.8 × 103, and 20.3 × 103 cm−1, while the most characteristic infrared vibrations of the triflate anion are observed at 1273, 1260, 1238, 1221, 1171, and 1157 cm−1.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 547-549 
    ISSN: 1434-1948
    Schlagwort(e): Copper ; Trinuclear ; Formamidines ; Magnetism ; Crystal structure ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In situ reaction of CuII triflate with aminopyridine or aminopyrimidine and triethylorthoformate in ethanol results in unique linear trinuclear CuII complexes with the general formula [Cu3(L-)4](CF3SO3)2(EtOH)x (L = dehydronated ligand N,N′-bis(pyridine-2-yl)formamidine or the new ligand N,N′-bis(pyrimidine-2-yl)formamidine). The structure [Cu-Cu-Cu angle 175.19(2)°] consists of four nearly flat molecules of the ligand which contribute to the propeller-type structure around the Cu-Cu-Cu axis. A strong antiferromagnetic interaction between the CuII ions is observed, resulting in an S = 1/2 ground state below 100 K.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1434-1948
    Schlagwort(e): Copper ; Methoxo-bridged complexes ; Crystal structure ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A novel chelating ligand, synthesized in situ within the coordination sphere of CuII from 2-amino-3-methylpyridine, MeOH, and dioxygen from the air, is found to form a strongly coupled, dinuclear methoxo-bridged CuII compound with the formula [Cu(L)(CH3O)(NO3)]2 (L = 2-methoxymethylamino-3-methylpyridine). The geometry around the copper atom is square pyramidal and the Cu-Cu distance within the dinuclear unit is 3.011(2) Å with an Cu-O-Cu angle of 103.13(8)°. Synthesis, X-ray crystal structure, and magnetism are reported.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 6 (1985), S. 177-188 
    ISSN: 0197-8462
    Schlagwort(e): microwave irradiation ; specular microscopy ; monkey ; corneal endothelium ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Physik
    Notizen: Both eyes of anesthetized cynomolgus monkeys (Macaca fascicularis) were irradiated with 2.45-GHz microwaves, either pulsed or continuous wave. In vivo corneal endothelial abnormalities were observed by specular microscopy and confirmed through histologic techniques after a 16- to 48-hour postexposure period. Pulsed microwaves with an average power density of 10 mW/cm2 (equivalent to a specific absorption rate (SAR) = 2.6 W/kg) produced these effects, while levels of 20-30 mW/cm2 (equivalent to a SAR = 5.3 to 7.8 W/kg) with continuous wave irradiation were required to produce similar changes.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0197-8462
    Schlagwort(e): microwaves ; glaucoma drugs ; primates ; corneal endothelium ; iris ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Physik
    Notizen: Previous studies in our laboratory have established that pulsed microwaves at 2.45 GHz and 10 mW/cm2 are associated with production of corneal endothelial lesions and with disruption of the blood-aqueous barrier in the non-human primate eye. In the study reported here we examined ocular damage in monkeys (M. mulatta and M. fascicularis) following topical treatment with one of two ophthalmic drugs (timolol maleate and pilocarpine) that preceded exposure to pulsed microwaves. Anesthetized monkeys were sham exposed or exposed to pulsed, 2.45 GHz microwaves (10 μs, 100 pps) at average power densities of 0.2, 1, 5, 10, or 15 mW/cm2 4 h a day for 3 consecutive days (respective SARs were 0.052, 0.26, 1.3, 2.6, and 3.9 W/kg). Immediately before microwave exposure, one or both eyes were treated topically with one drop of 0.5% timolol maleate or of 2% pilocarpine. Following administration of a drug, we observed a significant reduction in the power-density threshold (from 10 to 1 mW/cm2) for induction of corneal endothelial lesions and for increased vascular permeability of the iris. Diagnostic procedures (in vivo specular microscopy and fluorescein iris angiography) were performed following each exposure protocol. In addition, increased vascular permeability was confirmed with horseradish peroxidase tracer techniques. Although we did not measure intraocular temperatures in experimental animals, the results suggest that a mechanism other than significant heating of the eye is involved. Our data indicate that pulsed microwaves at an average SAR of 0.26 W/kg, if administered after pretreatment with ophthalmic drugs, can produce significant ocular effects in the anesthetized primate. 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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