The title compound, C(15)H(18)O(3), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The seven-membered ring of the title compound shows a chair conformation, while the five-membered rings exibit different conformat...

The title compound, [Co(C24H28N2O6)] n , crystallizes as infinite chains related to one another by inversion centers, giving a centrosymmetric coordination polymer. The Co(II) ion, situated on a twofold rotation axis, forms a complex with the crown-4 moiety of the 3,3'-[(1,7-dioxa-4,10-di-aza-cyclo-do-decane-4,10-di-yl)bis-(meth-ylene)]dibenzoate anion. The dis-torted octahedral coordination sp...

Nylon 6, 6 is regarded as tough and ductile materials since it exhibit high tensile elongation to break and high drop weight impact strengths. However, under conditions of stress concentration such as in the presence of sharp notches or cracks, polyamides exhibit brittle failure. This property, evaluated as notched Izod or Charpy impact tests, indicates that unmodified polyamides exhibit relati...