Peculiarities of NMR ¹³C Spectra of Alkyl Groups in Functionalized Linear Alkanes of the General Formula ch₃(CH₂)_mY

The Influence of the Methyl Group Position on the Chemical Shifts Values of all Carbon Atoms Nuclei in 13C NMR Spectra of Monomethylalkane Molecules

“…As previously indicated [4], all "standard (etalon) compoundі" are longchain linear alkanes n contain in its molecule the six types of carbon atoms differing in their BSP magnitude. To calculate the mean base spectral parameter n-B-i for each C i (or [C-i]) carbon atom of long-chain linear alkanes (carbon chain of which contains at least 10 carbon atoms) we use the previously justified [4] If alkyl chain contains less than 10 carbon atoms (ie, in the cases of midchain alkanes), it becomes necessary to consider the perturbation of magnetic field of molecule occurring as a result of infinitely long linear alkane chain broke at both ends of the chain. In this cases the medial chain atoms, for instance, such as atoms [C-3], [C-4] and [C-5] in heptane g simultaneously be influenced both of the above factors.…”

“…Linear alkanes as well as their monomethylsubstituted derivatives (monomethylalkanes) depending upon the carbon chain length we conditionally divide into several groups [4]. First of all, it is longchain molecules (the chain of which comprises more than 10 carbon atoms), then, midchain (which chain comprises from 5 to 10 carbon atoms) and, at last, shortchain (the chain of which comprises from 2 to 4 carbon atoms) groups.…”

“…Among them, we plan to select no less than one midchain substance and no less than one longchain compound. Calculation of the base spectral parameters Nn-B-i we perform by the procedure described previously [4]. The next scheme used for the convenience of the calculation.…”