A series of crown ether complexes of potassium quinolin-8-olates were synthesized and characterized. Catalysis of these complexes towards the ring-opening polymerization of rac-lactide was evaluated. The crown ether complexes of potassium quinolin-8-olate and potassium 2-methylquinolin-8-olate exhibited high catalytic activity and good molecular weight control. The 18-crown-6 complex of potassi...

The title compound, C(25)H(28)N(2)O(5), is a product of the Petrenko-Kritchenko condensation of N-acetyl-piperidone with 1,5-bis-(2-formyl-phen-oxy)-3-oxapentane and ammonium acetate. The mol-ecule comprises a fused penta-cyclic system containing an aza-14-crown-3-ether macrocycle, two piperidone and two benzene rings. The aza-14-crown-3-ether ring adopts a bowl conformation. The dihedral angle...

The reaction of dimethyl-amine, 18-crown-6, and perchloric acid in methanol yields the title compound, C(2)H(8)N(+)·ClO(4) (-)·C(12)H(24)O(6)·H(2)O. The dimethyl-ammonium cation and the water mol-ecule inter-act with the 18-crown-6 unit: N-H⋯O hydrogen bonds are formed between the ammonium NH(2) (+) group and four O atoms of the crown ether, while the water mol-ecule on the other side of 18-cro...

A series of supramolecular complexes of various cytochrome c proteins with 18-crown-6 derivatives behave as cold-active synzymes in the H2O2 oxidation of racemic sulfoxides. This interesting behavior contrasts with native functionality, where the employed proteins act as electron transfer carriers. ESI-MS. UV, CD, and Raman spectroscopic characterizations reveal that four or five 18-crown-6 mol...

The title compound, C(31)H(34)N(2)O(9), is a product of the Michael addition of the cyclic secondary amine subunit of the (bis-pidino)aza-14-crown-4 ether to dimethyl acetyl-ene-dicarboxyl-ate. The mol-ecule comprises a tricyclic system containing the aza-14-crown-3 ether macrocycle and two six-membered piperidinone rings. The aza-14-crown-3-ether ring adopts a bowl conformation with a dihedral...

Simple chelating agents have been synthesized using a porphyrin and a covalently linked crown-ether. Depending on the relative spatial arrangement of both motifs, the resulting ligands, either a macrotricycle or bis-macrocycles, differ one from another by their flexibility or their aptitude to chelate bivalent or trivalent cations. The coordination chemistry as well as the structural study of t...

We investigate strategies for increasing the thermopower of crown-ether-bridged anthraquinones. The novel design feature of these molecules is the presence of either () crown-ether or () diaza-crown-ether bridges attached to the side of the current-carrying anthraquinone wire. The crown-ether side groups selectively bind alkali-metal cations and when combined with TCNE or TTF dopants, provide a...

New crown ether Schiff base derivatives were prepared by the condensation of 4'-formylbenzo-15-crown-5 or 4'-formyl-5'-hydroxybenzo-15-crown-5 with 1,2-bis(2-aminophenoxy)ethane. The structures of these new compounds were confirmed on the basis of elemental analysis, IR, (1)H- and (13)C-NMR, UV-Vis and mass spectroscopic data.