Substituent parameter analysis of the carbon-13 nuclear magnetic resonance chemical shifts of 4-substituted p-terphenyls

Conference · Fri Mar 26 04:00:00 EST 1982 · J. Org. Chem.; (United States)

OSTI ID:5318395

Wilson, N K; Zehr, R D

The effects, ..delta..delta values, of substituents at the 4-position of 1:1',4':1''-terphenyl on the /sup 13/C NMR chemical shifts were measured. For the set of substituents R = NO/sub 2/, COOCH/sub 3/ CN, H, CH/sub 3/, I, Br, Cl, NH/sub 2/, and N(CH/sub 3/)/sub 2/, correlations between ..delta..delta values and various inductive and resonance sigma parameters were sought by using three models: a single-parameter relationship, ..delta..delta = psigma; a dual substituent parameter (DSP) relationship, ..delta..delta = p/sub I/sigma/sub I/ + p/sub R/sigma/sub R/; a nonlinear dual substituent parameter (DSP-NLR) relationship, ..delta..delta = p/sub I/sigma/sub I/ + p/sub R/sigma/sub R//(1 - epsilonsigma/sub R/). No acceptable correlations were obtained for the /sup 13/C shifts of C-3,5 and C-4. A single parameter, sigma/sub R//sup 0/, was adequate at only two positions, C-2',6' and C-2'', 6''. At positions C-1, C-2,6, C-3',5', C-1'', C-3'',5'', and C-4'' the DSP model and sigma/sub R//sup 0/ were best. At para-type positions in the central ring (C-1' and C-4') the DSP-NLR model was best. The magnitude of the ratio lambda = p/sub R//p/sub I/ of mesomeric to inductive transmission of electronic substituent effects ranged from 0.535 to 4.58, indicating the importance of inductive electronic effects at nearly all positions in p-terphenyl, even at C-4'', the carbon farthest from the substituent, where lambda = 1.70.

• Research Organization: U.S Environmental Protection Agency, Research Triangle Park, NC
• OSTI ID: 5318395
• Conference Information: Journal Name: J. Org. Chem.; (United States) Journal Volume: 47:7
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
AROMATICS
CARBON 13
CARBON ISOTOPES
CHEMICAL ANALYSIS
CHEMICAL SHIFT
DATA
EQUATIONS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATHEMATICAL MODELS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
PARAMETRIC ANALYSIS
POLYPHENYLS
QUANTITATIVE CHEMICAL ANALYSIS
RESONANCE
SHIELDING
STABLE ISOTOPES
STATISTICAL DATA
TERPHENYLS