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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1319-1327 
    ISSN: 0887-624X
    Keywords: coumarin dimer ; photocleavage ; trans-2,2′-dihydroxystilbene ; interfacial polycondensation ; photocrosslinking ; characteristic curve ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The monomer, trans-2,2′-dihydroxystilbene (DHS), has been prepared by asymmetric photocleavage (254 nm) of coumarin dimer acid derived from coumarin dimer. Four new polyesters are successfully synthesized by interfacial polycondensation of the DHS with adipoyl chloride, azelaoyl chloride, sebacoyl chloride, and dodecanedioyl dichloride, respectively. The reduced viscosities of the polyesters decrease from 0.32 to 0.11 dL/g as the number of methylene unit in diacid chlorides increases from 4 to 10. From DSC investigation, it is found that the polyesters are semi-crystalline polymers with Tm = 39-192°C. Under 350 nm light, photocrosslinking behavior in solution and film-state is investigated by UV spectral change with irradiation time (350 nm). The photoreactive stilbene chromophores in the main chain dimerize to form cyclobutane derivatives, and lead to crosslinking of the polyesters. Photosensitivity in the film state has also been evaluated by their characteristic curves. Polyester from dodecanedioyl dichloride (5d) exhibits the highest initial reaction rate and ultimate crosslinking ratio. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1111
    Keywords: Crystal structure ; properties ; new copper(II) complex ; dioxocyclam ; 8-methylquinoline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new macrocyclic dioxotetraamine ligand 1-(quinolin-8-ylmethyl)-1,4,8,11-tetraazacyclotetradecane-5,7-dione (H2L) has been synthesized. The resulting dioxocyclam readily forms a 1 : 1 Cu(II) complex (CuL) with concomitant double deprotonation of the ligand. CuL has been isolated as single crystals and the structure was determined by X-ray diffraction analysis. CuL·5H2O (1·5H2O) crystallizes in monoclinic crystal system, P21/n space group with a = 12.979(2), b = 13.638(6), c = 13.634(4) Å, β = 103.02(2)°, V = 2351(2) Å3, Mr = 521.07, Z = 4, Dcalc = 1.472 g/cm3, μ = 9.78 cm-1, F(000) = 1100, room temperature, and R = 0.039, Rw = 0.042 for 2137 observed reflections with I 〉 3σ(I). In complex 1, the Cu atom is five coordinate to form a distorted square pyramid in which N(5) of the quinoline pendant is at the apical site. The Cu—N(5) bond distance (2.262(4) Å) is longer than the basal average Cu—N bond lengths (1.994(4) ring;). The behavior of CuL in solution has been studied further with ESR, UV-Vis and cyclic voltammetry.
    Type of Medium: Electronic Resource
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