Magnetic Resonance

Posted by jacob on July 7, 2013 under news | Comments are off for this article

Amino possesss on carbon sp3 nitrogen (C? N), what it leads to an absorption in d 40,00. In nitrilas, the carbon atom sp absorbs in d 115 ppm. The RMN specter 13C? DEPT (intensification of the distortion for polarization transference) is used in the determination of on the hydrogen atom number 13C. Logically, hidrogenados carbon atoms do not present signal, in this type of specter. DEPT 135 shows signals for low (indicating metilnicos carbons) and signals for top (indicating metnicos and methylic carbons). In DEPT 90, only signals appear of groups CH.

In the specter of RMN 13C of the etanoato of etila, the signals in d 15 and 30 corresponds to methylic carbon atoms and the signal in d 60 corresponds to metilnico carbon. The carbon atom of the group carbonila has signal in d 170. The RMN specter 13C? DEPT shows a signal for low (d 60), therefore indicates metilnico carbon, and the signals in d 15 and 30 for top, therefore they indicate methylic carbons. In this specter, the referring signal to carbonlico carbon is not verified (in d 170), since it is a carbon not hidrogenado. With this study of the RMN, it was verified that one ' ' aumento' ' of the electronic density on determined atom of hydrogen or carbon-13 it implies in ' ' reduo' ' of the value of the chemical displacement of the same (effect shield). For in such a way it is necessary to know some groups that intervene, of certain form, in the electronic density. This fact is marcante in benznicos rings, with the positions orto, goal and stops. Groups that ' ' doam' ' electrons for the ring (positive effect mesmero) increase, in this, the electronic density, in the positions orto and stop of the ring.

They are examples of these groups: amino, hidroxila, metoxila and alquilas. Groups that ' ' retiram' ' electrons of the ring (negative effect mesmero) diminish, in this, the electronic density. They are examples: nitro, sulfnico, carboxila and aldoxila. To classify them in orto/for leading controllers and goal is to take in consideration the reacional question (reactions of substitution in the ring). Much can be explored of the Nuclear and applied Magnetic Resonance in diverse areas (chemical organic: natural synthesis and products; pharmacy: pharmaceutical chemistry and quality control; vegetal biochemist, among others) being of much importance its knowledge.