Nitrogen-14 nuclear magnetic resonance. Part II. Additivity rules for chemical shifts in nitroalkanes
Abstract
Simple empirical rules for 14N chemical shifts in the systems R1R2R3C·NO2 are found. The contributions to the shift from CH3, RCH2, and Cl are additive; a small modification is required when further nitro-groups are introduced. In most cases, the agreement between the calculated and observed values is within 1 p.p.m. or about 1–2% of the 70 p.p.m. range of 14N chemical shifts observed for nitroalkanes.