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The intramolecular and long-range ferromagnetic coupling between p-phenylenediamine radical cations in head-to-tail coupled oligo(1, 4-phenyleneethynylene)s and oligo(1,4-phenylenvinylene)s between neighbors and next-nearest neighbors is described. UV/vis/near-IR experiments show that the radical cations are localized in the pendant p-phenylenediamine units of the conjugated oligomers. The ESR spectra of these oligo(1,4-phenyleneethynylene) and oligo(1, 4-phenylenvinylene) di(radical cation)s are consistent with those of a triplet state. A linear behavior is observed for the doubly integrated ESR intensity of the DeltaM(s) = +/-1 and DeltaM(s) = +/-2 signals with the inverse temperature (I approximately 1/T), consistent with Curie's law. This behavior indicates a triplet ground-state diradical with a large triplet-singlet energy gap or possibly a degeneracy of singlet and triplet states. 相似文献
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Martinez-Diaz MV Rodriguez-Morgade MS Feiters MC van Kan PJ Nolte RJ Stoddart JF Torres T 《Organic letters》2000,2(8):1057-1060
[formula: see text] New unsymmetrically substituted DB24C8-phthalocyanines, which are able to form complexes with suitable dialkylammonium cations, have been prepared. These complexes most probably have a pseudorotaxane geometry. 相似文献
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M. Rosenberger D. Andrews F. DiMaria A. J. Duggan G. Saucy 《Helvetica chimica acta》1972,55(1):249-255
A novel and general synthesis of δ-lactones from glutaraldehyde is described. The dialdehyde is first reacted with an alkyl or substituted alkyl Grignard reagent to afford a δ-hydroxyaldehyde in good yield. These aldehydes exist preferentially in the cyclic hemiacetal form (δ-lactols). Oxidation of the latter compounds to give δ-lactones is readily achieved with silver oxide or bromine. The δ-lactols and δ-lactones serve as intermediates for the total synthesis of steroids. 相似文献
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Meroquinene (1), a key degradation product of quinine and an important intermediate in the preparation of the cinchona and other alkaloids,1 has only recently been synthesized 2 even though attempts were made at its preparation for over thirty years. These early attempts were frustrated primarily by the difficulty encountered in the introduction of a potential vinyl group onto a piperidine ring. Alkylation of 3-car-bethoxy-N-benzoyl-4-piperidone (2) with either phenoxyethyl chloride3 or dimethylaminoethyl chloride (3)4 resulted in exclusive formation of the O-alkylated product, even though alkylation of the presumably analogous 2-carbethoxycyclohexanone with 3 gave nearly equal amounts of C- and O- alkylated materials.4 The use of other piperidone derivatives in this reaction was precluded by the report that attempts to alkylate 3-car-bethoxy-N-alkyl-4-piperidones gave only the quaternary nitrogen product.5 相似文献