13C nuclear magnetic resonance chemical shifts in styrenes; substituent and solvent effects

Abstract

The ¹³C n.m.r. chemical shifts of a series of meta- and para-X-substituted styrenes (X = H, NMe₂, OMe, Me, F, Cl, Br, I, CF₃, CO₂Me, Ac, CN, NO₂, NMe₃⁺)have been determined in seven different solvents (75%EtOH-D₂O,EtOH,Me₂SO, Me₂CO, CDCl₃, CCl₄, and C₆H₆). The data for the side-chain carbons and for the ring carbon para-to the substituent (C₆) in the meta-series have been analysed and used as a basis for assessing the effect of solvent on σ_l, σ_R^O, σ_R^BA, and σ_R^–.