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International audienceThe catalytic activity of four aminocarbonyl group containing 'boomerang'-type ring-closing metathesis catalysts have been studied for ten-membered lactone and compared well with the Grubbs I and II as well as the Hoveyda-Grubbs catalysts. The activity was found to be superior to the above three ring-closing metathesis catalysts and suggesting novel stereoselective total syntheses of herbarumin I and stagonolide A

C omm u n fi c a ft fi o n P o fl fl fi n a ft fi o n e c o fl o g y a n d f r u fi ft fi n g b e h a v fi o r o f P a v e ft ft a fi n d fi c a L . ( R u b fi a c e a e ) , a k e y s ft o n e s h r u b s p e c fi e s fi n ft h e s o u ft h e r n E a s ft e r n G h a ft s f o r e s ft , A n d h r a P r a d e s h , I n d fi a A . J . S o fl om o n R a j u , M . M a fl fl fi k a r j u n a R a o , K . V e n k a ft a R am a n a , C . P r a s a d a R a o & M . S u fl a k s h a n a

We report on the ultrafast (femtosecond) laser ablation of monocrystalline Si (100), polycrystalline Si, and Si (100) capped with a SiO2 layer. The target material was ablated using femtosecond laser pulses (~50 fs duration, 1 kHz repetition rate, and 800 nm wavelength) with an input energy of ~100 μJ in acetone medium to fabricate Si Nanoparticles (NPs). The average size of NPs produced by Si (100) was found to be less than that of the particles produced by poly Si. Ablation of Si caped with SiO2 resulted in bigger Si NPs together with a low concentration of SiO2 NPs. NPs were found to be of polycrystalline in all three cases irrespective of the initial phase.

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