نتایج جستجو برای: 18 and 24 crown ethers
تعداد نتایج: 16918122 فیلتر نتایج به سال:
Abstract Crown ethers containing an acridone or acridine unit are successfully applied opto- and electrochemical cation sensors. The heteroaromatic of these macrocycles can be in different forms during the applications, which have a strong influence on sensing behavior. Moreover, case acridono-macrocycles prototropic equilibrium takes place upon complexation, is effected by physicochemical char...
The asymmetric unit of the title compound, C(20)H(24)O(6), contains two mol-ecules that are identical within standard deviations concerning bond lengths and angles as well as their conformations. In the crystal structure, weak C-H⋯O inter-actions help to consolidate the packing.
The asymmetric unit of the title compound, [Co(C(44)H(28)N(4))]·C(12)H(24)O(6), contains one half of a Co(II)(TPP) (TPP is tetra-phenyl-porphyrin) complex and one half of an 18-crown-6 mol-ecule of crystallization, both lying on inversion centers. The Co(II)(TPP) complex exhibits a nearly planar conformation of the porphyrinate core [maximum deviation = 0.069 (2) Å] with an average Co-N distanc...
The title compound, C(2)H(2)·C(12)H(24)O(6)·2NH(3), was formed by co-crystallization of 18-crown-6 and acetyl-ene in liquid ammonia. The 18-crown-6 mol-ecule has threefold rotoinversion symmetry. The acteylene mol-ecule lies on the threefold axis and the whole mol-ecule is generated by an inversion center. The two ammonia mol-ecules are also located on the threefold axis and are related by inve...
An efficient procedure for preparing enantiopure polycyclic ethers is reported. The protocol is based on the photo-oxidation/conjugate addition sequence over a chiral functionalized furan, which was prepared from commercially available tri-O-acetyl-D-glucal. The Michael addition step afforded two products with the same absolute configuration from a mixture of diastereomers.
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