⁷⁷Se NMR spectroscopy as a sensitive probe for Hammett σ constants

TY - JOUR

T1 - 77Se NMR spectroscopy as a sensitive probe for Hammett σ constants

AU - Sørensen, Anne

AU - Rasmussen, Brian

AU - Pittelkow, Michael

PY - 2015/4/17

Y1 - 2015/4/17

N2 - Herein we showcase the use of a combination of 1H, 13C, and 77Se NMR spectroscopy as a sensitive tool for correlation analysis. A series of substituted O-aryl selenocarbamates [ArOC(Se)N(CH3)2] and Se-aryl selenocarbamates [ArSeC(O)N(CH3)2] have been investigated by means of 1H, 13C, and 77Se NMR spectroscopy. We have determined the 1H, 13C, and 77Se chemical shift values as well as both one- and two-bond heteronuclear 13C-77Se coupling constants, and the changes in both the chemical shift values and the coupling constants were found to obey linear free energy relationships with Hammett's σp and σp- constants. For the eight studied O-aryl selenocarbamates, we observe linear free energy correlations with two of the 13C and 77Se chemical shift values and as well as one 13C-77Se coupling constant. With the five examples of Se-aryl selenocarbamates, linear correlations are observed with three different 13C-77Se coupling constants. The strong internal consistency validates the use of 77Se NMR spectroscopy for correlation analysis. (Figure Presented).

AB - Herein we showcase the use of a combination of 1H, 13C, and 77Se NMR spectroscopy as a sensitive tool for correlation analysis. A series of substituted O-aryl selenocarbamates [ArOC(Se)N(CH3)2] and Se-aryl selenocarbamates [ArSeC(O)N(CH3)2] have been investigated by means of 1H, 13C, and 77Se NMR spectroscopy. We have determined the 1H, 13C, and 77Se chemical shift values as well as both one- and two-bond heteronuclear 13C-77Se coupling constants, and the changes in both the chemical shift values and the coupling constants were found to obey linear free energy relationships with Hammett's σp and σp- constants. For the eight studied O-aryl selenocarbamates, we observe linear free energy correlations with two of the 13C and 77Se chemical shift values and as well as one 13C-77Se coupling constant. With the five examples of Se-aryl selenocarbamates, linear correlations are observed with three different 13C-77Se coupling constants. The strong internal consistency validates the use of 77Se NMR spectroscopy for correlation analysis. (Figure Presented).

U2 - 10.1021/acs.joc.5b00108

DO - 10.1021/acs.joc.5b00108

M3 - Journal article

C2 - 25835812

SN - 0022-3263

VL - 80

SP - 3852

EP - 3857

JO - Journal of Organic Chemistry

JF - Journal of Organic Chemistry

IS - 8

ER -