Archive for August 17th, 2016

The Specter

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In hydro-carbons, signals in 1380, 1450 and 2900 cm-1 are characteristic and indicate angular deformation of linking H? C? H (in groups metilas terminals), angular deformation of too much linkings H? C? H and axial deformation of linking C? H, respectively. Valley to affirm that the signal in 2900 cm-1 presents a strong band, for the generated polarity. The axial deformation of linking C? H occurs in 3100 cm-1 (= C? H) and in 3300 cm-1 (if the carbon will be sp). In C? H, the axial deformation of linking C? It occurs it in 1100 cm-1 and? H in 3330 cm-1 (broad band and strong). These data are deriving of oxigenadas functions (alcohol, ether). The carbonlicos composites ester ketone possesss specters IV with bands of absorption in 1735 and 1715 cm-1, respectively, that they are characteristic of axial deformation of the double linking of its carbonilas (C =).

In the case of ester, can be verified a band in 1180 cm-1, referring to the axial deformation of linking C? , What she does not occur in ketones. The characteristic signal of the deformation of the linking C =, is presented as a strong band. Also, it is noticed influence of the phenomenon ' ' ressonncia' ' in the interpretation of this type of specter. In composites with double linking type C = C, is verified a band of absorption between the frequencies 1640 and 1680 cm-1, relative to the axial deformation of the double linking, whereas, in composites with two conjugated double linkings (that is, ' ' separadas' ' for a simple linking), the corresponding signal to the axial deformation of the double linkings occurs between the frequencies 1600 and 1630 cm-1, visa that these linkings acquire ' ' carter' ' of simple linkings, which had to the process of resonance, characteristic of groups C = C? C = C. cyclical Systems influences in frequencies of absorption of functional groups, as for example, in carbonila (C =). In cicloexanona, axial deformation of the linking C = in 1715 cm-1 occurs (the same value of acclica ketone), whereas, in ciclobutanona, this fact is verified in the frequency 1775 cm-1.

It is noticed that, to the diminished being the size of the ring (of six for four members), occurs an increase in the numerical value of the frequency, which had to the increase of the tension in the ring. In this manner, the influence of a cyclical chain in the absorption frequency is related to the size of the chain (or ring) and the tension in the ring. It is possible, also, to occur absorption IV with sprouting of two bands in the specter. Such fact occurs in the analysis of an aldehyde, with the double linking (C =) absorbing in 1725 cm-1 and linking C? H (of HC =) absorbing in 2800 and 2700 cm-1, for axial deformation. If it cannot wait of a specter IV, facilitating ' ' montagem' ' of the chemical structure of a composition taken for analysis. Other organic functions, such as acid carboxlicos, amides, amino, become related with the data shown in this study. This implies that the presented technique is applied to some areas of the knowledge (chemical of natural products, organic synthesis, even though the botany) and of professional performance (chemical, pharmacy, biology, agronomy). Whichever the purpose (scientific, chemical research or analytical toxicologia, clinical analyses, quality control), this presented technique will be of much utility and deserves to be studied and to be practised with ' ' entusiasmo' '.

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