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  • 1
    Electronic Resource
    Electronic Resource
    Hydrogen-bonded hexagonal and pseudo-hexagonal grid motifs in supramolecular cobalt(II) and nickel(II) cupferronato complexes incorporating neutral N-donors with intermolecular NH2 connectors and solvent molecules (2001)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 303-310 
    Details
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The cobalt(II) and nickel(II) cupferronato (N-nitroso-N-phenylhydroxylaminato) mixed-ligand complexes of 2-aminopyridine (2-NH2py) [Co(PhN2O2)2(2-NH2py)2] (1), [Ni(PhN2O2)2(2-NH2py)2] (2) and 2,6-diamino-4-phenyl-1,3,5-triazine (dpt) [Co(PhN2O2)2(dpt)2]·[Co(PhN2O2)2(EtOH)2] (3) have been synthesized and characterized by X-ray diffraction analysis. The cobalt (1) and nickel (2) complexes are isostructural. The crystal lattice of (3) contains different neutral cobalt(II) complexes [Co(PhN2O2)2(dpt)2] (3a) and [Co(PhN2O2)2(EtOH)2] (3b). Molecules of (1)–(3) contain octahedral metal centres with all-cis-(1) and -(2) and all-trans-(3) disposal of the ligands. Intramolecular N—H...O hydrogen bonding between the NH2 groups and the O atom of the cupferronato anion can be observed in (1)–(3). Intermolecular N—H...O and N—H...N interactions between symmetry-related molecules of (1) and (2) led to hexameric aggregates which connect through common edges into a two-dimensional supramolecular network of hexagonal-grid type. In complex (3) the self-complementary dpt units of the (3a) molecules are maintained by intermolecular N—H...N hydrogen bonds, generating infinite chains. These (3a) chains are crosslinked by the (3b) subunits via N—H...O and O—H...N hydrogen bonds, thus completing the parallel two-dimensional supramolecular network consisting of pseudo-hexagonal-grid sheets. In each crystal structure the two-dimensional supramolecular networks are controlled by both hydrogen bonds and π...π stacking interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108768101004426
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  • 2
    Electronic Resource
    Electronic Resource
    Electrophysiologic alterations in patients with optic nerve hypoplasia (1994)
    Springer
    Documenta ophthalmologica 86 (1994), S. 247-257 
    Details
    ISSN: 1573-2622
    Keywords: Electroretinogram ; Optic nerve hypoplasia ; Visual evoked response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The clinical and electrophysiologic data (electroretinograms and visual evoked potentials) were studied in 45 patients with optic nerve hypoplasia. The patients were divided into three fairly distinct groups on the basis of their electrophysiologic alterations. Group 1 consisted of 13 patients with almost extinguished visual evoked potentials and with mild electroretinographic alterations. These were the cases that are traditionally recognized as optic nerve hypoplasia. The serious visual impairment in these cases was accompanied by various developmental ophthalmologic and nonophthalmologic abnormalities. Group 2 included 26 patients without any significant visual evoked potential or electroretinographic alterations, but with overt funduscopic signs of optic nerve hypoplasia. These patients were consistently suffering from strabismus and/or amblyopia. The visual functions based on visual evoked potential and electroretinographic recordings could be fairly normal apart from a pathologic ophthalmoscopic picture characteristic of optic nerve hypoplasia. Group 3 included six patients with abnormal albeit well-recordable visual evoked potentials and subnormal or negative-type electroretinograms that suggested an accompanying retinal disease. This finding seems to prove that a subset of patients with optic nerve hypoplasia with nystagmus may have a primary retinal abnormality. Our study provides further evidence that optic nerve hypoplasia is not a uniform disease entity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01203548
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and Structural Characterization of Tin(IV) N-nitroso-N-phenylhydroxylaminato Complexes: Crystal Structures of Sn(O2N2Ph)4, Ph2Sn(O2N2Ph)2 and [Me2Sn(O2N2Ph)2]2 (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 127-132 
    Details
    ISSN: 1434-1948
    Keywords: Coordination chemistry ; Inorganic rings ; O ligands ; Structure elucidation ; Tin ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of cupferron [NH4L, L = PhN(O)NO-] with tin(IV), diphenyltin(IV) and dimethyltin(IV) halides yields the cupferronato complexes SnL4 (1), Ph2SnL2 (2) and [Me2SnL2]2 (3). All were characterized by FT-IR, FT-Raman, NMR (1H, 13C and 119Sn) spectroscopic methods and X-ray structural analysis. An almost ideal, very rare dodecahedral geometry is found in the structure of 1. The hexacoordinated tin center exhibits a bicapped tetrahedral geometry in complex 2. The tin centers are heptacoordinated in a pentagonal bipyramidal geometry in the dimeric complex 3. These complexes incorporate five-membered SnO2N2 and four-membered Sn2O2 inorganic rings. Vibrational spectral data are consistent with the structures determined. The 119Sn NMR spectra indicate that in solution 1 retains its octacoordinated nature; in compound 2 the tin atom is hexacoordinated, while in 3 the tin atom is pentacoordinated.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Main Group Metal Directed Self-Assembly in a Tetrameric Trimethyltin(IV) N-nitroso-N-phenylhydroxylaminato Complex Containing an Unprecedented 20-Membered Inorganic (Carbon-Free) Metallamacrocycle (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1593-1596 
    Details
    ISSN: 1434-1948
    Keywords: Metallamacrocycles ; Structure elucidation ; Supramolecular chemistry ; Tin(IV) compounds ; Vibrational spectroscopy ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrakis[trimethyl(N-nitroso-N-phenylhydroxylaminato)tin(IV)] was synthesized by reaction of cupferron ([PhN(O)NO]NH4) with trimethyltin(IV) chloride. The complex was characterized by X-ray diffraction analysis, FT-IR and FT-Raman spectroscopy. An X-ray structural analysis of the title complex [Me3Sn(O2N2Ph)]4 reveals the first example of a bridging coordinated cupferronato ligand. This coordination pattern leads to an unprecedented inorganic 20-membered (carbon-free) metallamacrocycle Sn4O8N8 in which four Me3Sn and four PhN2O2 subunits are self-assembled.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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