Se afișează postările cu eticheta traduceri autorizate. Afișați toate postările
Se afișează postările cu eticheta traduceri autorizate. Afișați toate postările
vineri, 4 ianuarie 2013
Traduceri legalizate
Revin cu cateva precizari despre legalizarea traducerilor. Spuneam ca o traducere legalizata se realizeaza la notar si reprezinta o certificare a traducerii. Serviciul notarial se numeste "legalizarea semnaturii traducatorului". Mai simplu spus, in incheierea de legalizare notarul zice: "da, omul care a semnat si stampilat actul este intr-adevar traducator". Pentru ca notarul sa poata sa certifice acest lucru, traducatorul trebuie sa fie inscris in prealabil la notarul respectiv si sa depuna specimen de semnatura si stampila la acel notar, astfel notarul putand sa confrunte stampila si semnatura de pe documentele ce trebuie legalizate cu cele depuse de catre traducator. Atunci cand se inscrie la un notar si depune specimene de semnatura si stampila, traducatorul trebuie sa depuna si o copie dupa autorizatia de traducator emisa de Ministerul Justitiei.
marți, 8 februarie 2011
This May Be the Last Straw
So I bought this awesome laser pointer/pen/stylus 3-in-1 thingy for $20 from the bookstore, and the douchebag REU student who's too shy to ask to borrow it has both stolen and lost it. That I can deal with; after all, it's just a pen and my mom (via my student ID account) paid for it. But today...I walked into my office to find all my books pushed aside and the REU student's computer (courtesy of UK, the rotten bastards) on my desk.
So essentially, I have no desk. We can't isolate the PCN radical, all the parts for the matrix isolation system are in the machine shop, and now I have no desk.
And I was beginning to think not doing an REU was a good thing. Thanks for proving me wrong UK!
So essentially, I have no desk. We can't isolate the PCN radical, all the parts for the matrix isolation system are in the machine shop, and now I have no desk.
And I was beginning to think not doing an REU was a good thing. Thanks for proving me wrong UK!
PDA for PDIs!
This paper caught my eye because I recalled my one regular commenter (come on dear readers...where are you? :'-( ) working with perylenes in the past. The reactant in the middle is imide-substituted perylene diimide, PDI. DMP PDI, compound 1a, has some interesting solid-state photochemical quirks, so who knows, substituting the perylene core could lead to the next big thing in photonic organics. So the author says.
The first reaction described looks less than impressive: for 1a, 26% came out a mixture of dibrominated isomers (1,6-3a and 1,7-3a), 57% came out monobrominated, and 15% remained unreacted. Restricted rotation of the bulky R groups about the C-N bond meant two isomers for each potentially brominated carbon. The author goes on to describe a reaction using a refluxing solution of bromine that gives exclusively dibrominated product overnight, with a 1,7/1,6 ratio of 3:1. The regioisomers can be separated by recrystallization from a 1:1 solution of dichloromethane and hexane.
Sonogashira coupling of 2a with TMS acetylene works, as does nucleophilic substitution by piperidine.
Bromination causes an interesting "core twist" vibration involving, well, the twisting of the perylene core. Energy barriers associated with the motion were relatively low and thus interconversion between the two "twist states" of the molecule is relatively easy.
Latest on the Rotaxane Front
Something about rotaxanes intrigues me. If you think about it, the fact that such massive molecules can come together to form ordered, interlocked units is an outright entropic miracle. The field of rotaxane synthesis is particularly suited to what I like to call "miracle reactions," reactions with laughably simple procedures that give complicated molecules in disturbingly high yield. One such reaction can be found in this recent paper by Hirose et al. from Osaka University.
Their idea, stylized in the picture, was to first connect the center of a dumbbell to a ring, then use nucleophilic attack (specifically, aminolysis) by the other half of the dumbbell to form the final rotaxane. Hiratani did something similar to this back in 2002.
The ring is a phenolic crown ether with side groups attached. Why the phenol? Because the first step is an esterification involving the phenolic OH (which points inside the ring) and the half axle, a benzoyl chloride. The resulting "half-rotaxane" is just a benzene-stoppered ester of the crown ether. To form the final rotaxane, an amine with a bulky group attached is added to the half-rotaxane. Nitrogen attacks the carbonyl carbon of the ester group, and voila! The axle becomes an amide and the ring reverts back to a phenolic crown ether. Miraculously, this reaction requires no heat or special treatment of any kind aside from column chromatography. Put the stuff together, stir, wait three days, evaporate the solvent, and voila! Rotaxane city.
Their idea, stylized in the picture, was to first connect the center of a dumbbell to a ring, then use nucleophilic attack (specifically, aminolysis) by the other half of the dumbbell to form the final rotaxane. Hiratani did something similar to this back in 2002.
The ring is a phenolic crown ether with side groups attached. Why the phenol? Because the first step is an esterification involving the phenolic OH (which points inside the ring) and the half axle, a benzoyl chloride. The resulting "half-rotaxane" is just a benzene-stoppered ester of the crown ether. To form the final rotaxane, an amine with a bulky group attached is added to the half-rotaxane. Nitrogen attacks the carbonyl carbon of the ester group, and voila! The axle becomes an amide and the ring reverts back to a phenolic crown ether. Miraculously, this reaction requires no heat or special treatment of any kind aside from column chromatography. Put the stuff together, stir, wait three days, evaporate the solvent, and voila! Rotaxane city.
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