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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 245-249 
    ISSN: 1434-193X
    Keywords: Cycloadditions ; Cage compounds ; Dimerizations ; Steric hindrance ; Photochemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---On irradiation at λ ≥ 270 nm solutions of 4-aryl-1,4-dihydropyridines 1 yield cage dimers 2 as the main products beside small amounts of anti dimers 3. 1H-NMR data and X-ray crystal structure prove centrosymmetrical properties for both dimers with axially orientated 4-aryl substituents. Irradiation with filtered light (λ 〉 313 nm) leads to syn and anti dimers 4 and 3 in nearly equal yields. The poor yields of anti dimers 3 on irradiation with unfiltered light are demonstrated to result from a partial cleavage back to their monomeric starting materials 1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 59-63 
    ISSN: 1434-1948
    Keywords: Phosphorane imine ; Sulfur ligands ; Nickel ; Palladium ; Platinum ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of the trinuclear [M(′S3′)]3 complexes {M = Ni (4), Pd (5), Pt (6); ′S3′2- = bis(2-mercaptophenyl)sulfide (2-)} with HNPnPr3 yielded the new phosphorane imine complexes [M(NHPnPr3)(′S3′)] {M = Ni (1), Pd (2), Pt (3)}. The complexes 1-3 have been completely characterized and are rare examples of mononuclear phosphorane imine complexes with late transition metals. Spectroscopic and structural results indicate that the HNPnPr3 ligands favor the ylidic structure when binding to [M(′S3′)] fragments. X-ray structure determinations showed that [M(NHPnPr3)(′S3′)] complexes associate through N-H···S(thiolate) bridges to give centrosymmetric dimers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-1948
    Keywords: Ruthenium ; Sulfur ligands ; Exchange reactions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a quest for ruthenium complexes having [RuNS4] cores, a non-fluxional configuration, trans-thiolate donors, and exchangeable coligands L, [Ru(L)(‘pyS4’)] complexes have been synthesized [‘pyS4’2- = 2,6-bis(2-mercaptophenylthio)dimethylpyridine(2-)]. Treatment of [RuCl2(PPh3)3] with ‘pyS4’2- gave [Ru(PPh3)(‘pyS4’)] (1). Alkylation of 1 with excess MeI yielded [Ru(PPh3)(‘pyS4’-Me2)]I2 (2). [Ru(DMSO)(‘pyS4’)] (3) was obtained from [RuCl2(DMSO)4] and ‘pyS4’2-. The PPh3 or DMSO coligands in 1, 2, and 3 proved to be very inert to substitution. Only the DMSO could be displaced by CO under drastic conditions yielding [Ru(CO)(‘pyS4’)] (4). Treatment of [RuCl2(CH3CN)4] with ‘pyS4’2- yielded [Ru(‘pyS4’)]2 (5); in the presence of PEt3 or N2H4 mononuclear [Ru(PEt3)(‘pyS4’)] (6) and [Ru(N2H4)(‘pyS4’)] (7) were formed. Template alkylation of NBu4[Ru(NO)(S2C6H4)2] with 2,6-bis(tosyloxymethyl)pyridine gave [Ru(NO)(‘pyS4’)]Tos (8). Complex 8 proved to be the best suited precursor for L exchange reactions. Under reducing conditions, 8 releases its NO ligand and the resulting [Ru(‘pyS4’)] fragments can combine either with each other to give 5, or with PEt3 and N2H4 to yield 6 and 7, respectively. All complexes have been characterized by spectroscopic methods and elemental analysis; 1, 2, 3, and 4 have also been submitted to X-ray structure analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1213-1218 
    ISSN: 1434-193X
    Keywords: Cycloadditions ; Diazatetraasteranes ; Crystal structure ; Solid-state chemistry ; Photochemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upon irradiation, crystalline 4-methoxyphenyl-1,4-dihy-dropyridines 1 undergo nearly quantitative [2+2]cyclo-addition to form, via the ring-open intermediates 2, the centrosymmetric, polyfunctionalized 3,9-diazatetraasteranes 3. The centrosymmetric character of 3 was confirmed by 1H NMR spectral data as well as by X-ray crystal structure analysis. The dimerization reactions prove to be topochemically controlled by the nearest distance between potentially reacting double bonds, as well as by the conformationally determined packing restraints. This latter factor is shown by the X-ray crystal structure analysis of one dimerizing and one photostable derivative of the monomers 1.
    Type of Medium: Electronic Resource
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