Wodynski, Artur; Kraska-Dziadecka, Anna; Kubica, Dominika; Gryff-Keller, Adam published the artcile< Interpretation of the Longitudinal 13C Nuclear Spin Relaxation and Chemical Shift Data for Five Bromoazaheterocycles Supported by Nonrelativistic and Relativistic DFT Calculations>, Application of C4H2Br2N2, the main research area is longitudinal carbon nuclear spin relaxation chem shift bromoazaheterocycle.
The longitudinal relaxation times of 13C nuclei and NOE enhancement factors for 2-bromopyridine (1), 6-bromo-9-methylpurine (2), 3,5-dibromopyridine (3), 2,4-dibromopyrimidine (4), and 2,4,6-tribromopyrimidine (5) were measured at 25° and B0 = 11.7 T. The most important contributions to the overall relaxation rates of nonbrominated carbons, i.e., the relaxation rates due to the 13C-1H dipolar interactions and the shielding anisotropy mechanism, were separated out. For 3 and 5, addnl., the T2,q(14N) values were established from 14N NMR line widths. All of these data were used to determine rotational diffusion tensors for the studied mols. The measured saturation recovery curves of brominated carbons were decomposed into two components to yield relaxation times, which after proper corrections provided parameters characterizing the scalar relaxation of the 2nd kind for 13C nuclei of 79Br- and 81Br-bonded carbons. These parameters and theor. calculated quadrupole coupling constants for Br nuclei have allowed the values of 1-bond 13C-79Br spin-spin coupling constants to be calculated Independently, the coupling constants and magnetic shielding constants of the C nuclei were calculated theor. using the nonrelativistic and relativistic DFT methods F/6-311++G(2d,p)/PCM and so-ZORA/F/TZ2P/COSMO (F = BHandH or B3LYP), resp. The agreement between the exptl. and theor. values of these parameters is remarkably dependent on the theor. method used.
Journal of Physical Chemistry A published new progress about Magnetic relaxation (13C). 3921-01-5 belongs to class pyrimidines, and the molecular formula is C4H2Br2N2, Application of C4H2Br2N2.
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia