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preface to fifteenth edition

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7.118 SECTION 7<br />

TABLE 7.70<br />

Fluorine-19 Chemical Shifts for Standards<br />

Substance Formula , ppm<br />

Trichlorofluoromethane CFCl 3 0.0<br />

,,-Trifluoro<strong>to</strong>luene C 6 H 5 CF 3 63.8<br />

Trifluoroacetic acid CF 3 COOH 76.5<br />

Carbon tetrafluoride CF 4 76.7<br />

Fluorobenzene C 6 H 5 F 113.1<br />

Perfluorocyclobutane C 4 F 8 138.0<br />

TABLE 7.71<br />

Fluorine-19 <strong>to</strong> Fluorine-19 Spin Coupling Constants<br />

Structure<br />

J FF ,Hz<br />

F 2<br />

C<br />

cycloalkane<br />

gem 212–260<br />

Unsaturated compounds C"C<br />

gem 30–90<br />

trans 115–130<br />

cis 9–58<br />

Aromatic compounds, monocyclic<br />

ortho 18–22<br />

meta 0–7<br />

para 12–15<br />

Alkanes<br />

CFCl 2 9CF 2 9CFCl 2 6<br />

CFCl 2 9CF 2 9CCl 3 5<br />

CF 2 Cl9CF 2 9CF 2 Cl 1<br />

CF 3 9CF 2 9CF 2 Cl (or 9CF 3 )<br />

1<br />

CF 3 9CF 2 9CF 2 Cl 2<br />

CF 3 9CF 2 9CF 2 Cl 9<br />

CF 3 9CF 2 9CF 3 7<br />

TABLE 7.72 Silicon-29 Chemical Shifts<br />

Values given in ppm on the scale relative <strong>to</strong> tetramethylsilane.<br />

Substituent group X in<br />

(CH 3 ) 4–n SiX n<br />

1 2 3 4<br />

n<br />

9F 35 9 52 109<br />

9Cl 30 32 13 19<br />

9Br 26 20 18 94<br />

9I 9 34 18 346<br />

9H 19 42 65 93<br />

9C 2 H 5 2 5 7 8<br />

9C 6 H 5 5 9 12<br />

9CH"CH 2 7 14 21 23<br />

9Oalkyl 14–17 3 <strong>to</strong>6 41 <strong>to</strong> 45 79 <strong>to</strong> 83<br />

9Oaryl 17 6 54 101<br />

9O9CO9alkyl 22 4 43 75<br />

9N(CH 3 ) 2 6 2 18 28

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