Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The crystal structure and IR spectra of μ-(bipyrimidine-N1,N1′,N5,N5′)-bis[(azido-N1)(methanol)(bipyrimidine-N1,N1′)copper(II)] bis(triflate) bis(methanol) (1998)
    Springer
    Journal of chemical crystallography 28 (1998), S. 427-432 
    Details
    ISSN: 1572-8854
    Keywords: Dinuclear ; copper ; triflate ; bipyrimidine ; azido ; infrared
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021760420238
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Crystal structure and spectroscopy of bis-[bis(2-benzimidazolyl)propane]copper(II) bis(triflate)monohydrate, a copper complex with a geometry intermediate between tetrahedral and square planar (2000)
    Springer
    Journal of chemical crystallography 30 (2000), S. 793-797 
    Details
    ISSN: 1572-8854
    Keywords: copper ; bis(benzimidazoles) ; crystal structure ; infrared
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1013276325343
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Crystal structure and spectroscopy of a most unusual Cu(II) coordination compound containing an infinite chain of lattice ligand interwoven with stacked sheets of neutral bis(2-aminopyrimidine-bridged) copper ions: X-ray structure of [Cu(ampym)2(H2O)2(CF3SO3)2](ampym)2(ampym)2 (2000)
    Springer
    Journal of chemical crystallography 30 (2000), S. 11-16 
    Details
    ISSN: 1572-8854
    Keywords: aminopyrimidine ; copper ; stacking ; hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Reaction of Cu(II) triflate with an excess of 2-aminopyrimidine (ampym) in ethanol followed by slow crystallization results in a most unusual crystal lattice, which can be considered as consisting of two interpenetrating sublattices. The compound analyzes as [Cu(ampym)2(H2O)2(CF3SO3)2(ampym)4]. Crystal data: Triclinic, P $$\overline 1$$ , a = 7.6179(5), b = 11.4311(14), c = 11.8373(13) Å, α = 84.098(9), β = 79.998(7), γ = 84.253(8)°, Vol = 1010.151(8) Å, Z = 1, Dcalc = 1.592 g/cm3. One part of the lattice consists of the unprecendented linear chain of neutral ampym molecules; the chain is built up by Watson–Crick type bis-hydrogen bonds between imine N atoms and N-H groups of the NH2. This ampym chain is apparently stabilized by the other part in the crystal lattice, which can best be described by starting from the centrosymmetric trans-CuII(ampym)2(H2O)2 ion (Cu-N = 2.01 Å; Cu-O = 1.94 Å). This Cu ion is coordinated by two monodentate ampym ligands, two water molecules and two semi-coordinating triflate oxygen atoms. The Cu chromophore is held in position by hydrogen bonding towards a triflate ion (two times for symmetry reasons), and (again two times) a free ampym ligand. The triflate ion bridges a water hydrogen to a next-neighboring free ampym ligand. The noncoordinating ampym molecule has four bonding sites, of which two are used in H-bonding with the coordinated ligand, one with the triflate and the last one with the water hydrogen atom. The noncoordination ampym molecules in this sublattice finally form aromatic stacks with coordinated ampym and with itself in pairs (ring-ring distance 3.77-3.80 Å).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009533729785
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Increased sensitivity of the non-human primate eye to microwave radiation following ophthalmic drug pretreatment (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 13 (1992), S. 379-393 
    Details
    ISSN: 0197-8462
    Keywords: microwaves ; glaucoma drugs ; primates ; corneal endothelium ; iris ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: 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.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250130505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Modification of membrane fluidity in melanin-containing cells by low-level microwave radiation (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 13 (1992), S. 131-146 
    Details
    ISSN: 0197-8462
    Keywords: microwaves ; cell membrane ; order ; melanin ; oxygen radicals ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The treatment of a B16 melanoma cell line with 2.45-GHz pulsed microwaves (10 mW/cm2, 10-μs pulses at 100 pps, 1-h exposure; SAR, 0.2 W/kg) resulted in changes of membrane ordering as measured by EPR (electron paramagnetic resonance) reporter techniques. The changes reflected a shift from a more fluid-like phase to a more solid (ordered) state of the cell membrane. Exposure of artificially prepared liposomes that were reconstituted with melanin produced similar results. In contrast, neither B16 melanoma cells treated with 5-Bromo-2-Deoxyuridine (3 μg/day × 7 days) to render them amelanotic, nor liposomes prepared without melanin, exhibited the microwave-facilitated increase of ordering. Inhibition of the ordering was achieved by the use of superoxide dismutase (SOD), which strongly implicates oxygen radicals as a cause of the membrane changes. The data indicate that a significant, specific alteration of cell-membrane ordering followed microwave exposure. This alteration was unique to melanotic membranes and was due, at least in part, to the generation of oxygen radicals. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250130207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...