Mechanism of cationic ring-opening polymerisation of ε-caprolactone using metallocene/borate catalytic systems: a DFT and NCI study on chain initiation, propagation and termination.

We present a comprehensive DFT investigation on the cationic ring-opening polymerisation (CROP) of ε-caprolactone (CL) using zirconocene/borate catalyst systems. All possible pathways of the interaction between cationic species [CpZrMe] and counteranions, [A] = [MeB(CF)] and [B(CF)], were examined during chain initiation, propagation, and termination steps. The calculations reveal an active chain-end mechanism with -alkyl bond cleavage of the polymerisation.

Rare prenylated isoflavonoids from the young twigs of and their cytotoxic activities.

Three new isoflavonoids, millexatins N-P (1-3), along with seven known compounds (6-10), were isolated from the acetone extract of the young twigs of . The structures were characterized by NMR spectroscopic and mass spectrometric analyses. Millexatin N (1) is an unusual geminal diisoprenylated isoflavone with a modified ring A.

Desmoschinensisflavones A and B, two rare flavones having a hybrid benzyl benzoate ester-flavone structural framework from Lour.

Two rare flavones having a hybrid benzyl benzoate ester-flavone structural framework, desmoschinensisflavones A and B (1 and 2), together with 12 known compounds (3-14) were isolated from the fruit, leaf, and twig extracts of (red flower). The new structures were characterized by UV, IR, NMR, and HRESITOFMS data. Desmoschinensisflavones A and B have a distinctive skeleton of benzoate ester-flavones with a C-4'' and C-6 and C-8 connection a methylene group, respectively.