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  • 1
    Electronic Resource
    Electronic Resource
    Complexity theory of three-dimensional manifolds (1990)
    Springer
    Acta applicandae mathematicae 19 (1990), S. 101-130 
    Details
    ISSN: 1572-9036
    Keywords: 57Nxx ; Three-manifold ; special spine ; graph manifold
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The complexity of a 3-manifold is a whole number which measures how complicated a combinatorial description of the manifold must be. It has many pleasant properties, among which are the finiteness property and additivity property. The table of all closed orientable 3-manifolds of complexity ≤6 is given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00049576
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and complexing properties ofcis,cis-1,3,5-tri-[2-(diphenylphosphinyI)ethylamino]cyclohexane (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 1218-1221 
    Details
    ISSN: 1573-9171
    Keywords: complex formation ; polydentate organophosphorus ligands ; synthesis ; acid-base properties ; potentiometric titration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A novel polydentate phosphorus-containing complexing agent,cis,cis-1,3,5-tri[2-(diphenyl-phosphinyl)ethylamino]cyclohexane, has been prepared on the basis ofcis,cis-1,3,5-triamino-cyclohexane. The method of potentiometric titration in an aqueous—organic medium (70% ethanol, ionic strength 0.01M LiNO3, 298 K) has been used to study the acid-base and complexing properties of the title compound. The ligand thus prepared forms 1∶1 complexes with Cu2+, Co2+, Zn2+, and Ni2+ cations; formation of hydroxocomplexes MOHL+ has been observed in the case of Zn2+ and Cd2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702011
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  • 3
    Electronic Resource
    Electronic Resource
    Spectral study of complexation ofcis,cis-1,3,5-tri[2-(diphenylphosphinyl)ethylamino]cyclohexane with copper(ii) and cobalt(ii) ions (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 1140-1144 
    Details
    ISSN: 1573-9171
    Keywords: complexation ; cyclopendant ligands ; phosphinyl groups ; structure of complexes ; UV-Vis ; ESR ; IR spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The complexation ofcis,cis-1,3,5-tri[2-(diphenylphosphinyl)ethylamino]cyclohexane (L1) with Cu2+ and Co2+ cations has been studied in different solvents by means of UV-Vis, ESR, and IR spectroscopy. It has been shown that in the CuL1 complex the metal ion is pentacoordinated by three nitrogen atoms and two phosphinyl groups of the ligand and has a tetragonal-pyramidal environment. The conformation of the coordination polyhedron for the CuL1 complex depends on the solvent. In the CoL1 complex, as well as in the CoL2 complex, where L2 is 1,4,7-tris(2-diphenylphosphinylethyl)-1,4,7-triazacyclononane, the Co2+ ion has an octahedral environment and is bound to all donor atoms of the ligands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00701991
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and acid-base properties of phosphorylated diazacycloalkanes and their cyclic analogs (1994)
    Springer
    Russian chemical bulletin 43 (1994), S. 1895-1901 
    Details
    ISSN: 1573-9171
    Keywords: cyclopendant ligands ; phosphorylated diazacycloalkanes ; protonation constants ; potentiometric titration ; intramolecular hydrogen bonds ; conformational analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Novel cyclopendant organophosphorus complexing agents,viz. 1,5-bis(2-diphenylphosphorylmethyl (or ethyl))-1,5-diazacyclooctane (1, 2) and l-methyl-4-(2-diphenylphosphorylethyl) piperazine (3), were synthesized on the basis of 1,5-diazacyclooctane and piperazine. The protonation constants of the compounds synthesized and some of their analogs were determined by potentiometric titration in 70 % aqueous ethanol and in nitromethane. The nitrogen atoms of the ring are the protonation sites in all of the systems studied. The regularities of the variation of protonation constants have been explained by the formation of intramolecular hydrogen bonds. The conformational possibilities of the formation of H-bonds in the cations of the ligands have been examined by molecular mechanics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696324
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  • 5
    Electronic Resource
    Electronic Resource
    Hydrogen bonds and the structure of perchlorates of phosphorylated diazacycloalkanes (1994)
    Springer
    Russian chemical bulletin 43 (1994), S. 1902-1907 
    Details
    ISSN: 1573-9171
    Keywords: phosphorylated diazacycloalkanes ; perchlorates ; structure of protonation products ; H-bonds ; IR spectroscopy ; conformational analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mono- and diperchlorates of phosphorylated diazacycloalkanes (PDAC),viz. 1,5-bis(2-diphenylphosphorylethyl) -1,5-diazacyclooctanes (1a, 1b), 1,4-bis(2-diphenylphosphorylethyl)- 1,4-piperazine (2a), and 1-methyl-4-(2-diphenylphosphorylethyl)-1,4-piperazines (3a, 3b), were prepared. The formation of inter- and intramolecular hydrogen bonds in PDAC perchlorates and some model compounds in the solid state and in solution was investigated by IR spectroscopy. The dependence between the effect of the hydrogen bond formation and association of the ions in solution was analyzed. Conformational analysis of the cations of PDAC was carried out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696325
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