Structure Determination

how do you calculate empirical formula?

How do you obtain the molecular formula?

Alternative method to calculate molecular formula

How do you find the number of double bond equivalents?

1 DBE

2 DBE

4 DBE special case

Beer-Lambert Law

IR
600-1400 cm-1

IR
1600- 1850 cm-1

IR
2100-2300 cm-1

IR
2700-3000 cm-1

IR
3000-3200 cm-1

IR
3200-3450 cm-1

H NMR
δ7-δ8

H NMR
δ5-δ6

H NMR
δ2.5

H NMR
δ9-δ10

H NMR
δ10+

H NMR
~δ1-2

H NMR
~δ2.5

C NMR
δ165-210

C NMR
δ100-150

C NMR
δ65-90

C NMR
δ0-40

C NMR
δ75-95

C NMR
δ110-150

C NMR
δ30-65

H NMR
Withdrawing groups next to the proton

H NMR
Donating groups next to H

If resonance can occur such as a double bond near a carbonyl it is often the H nearest to the opposite end of the carbonyl that is more deshielded rather than the H nearest the withdrawing O because of the resonance sturucture. The same can be said for the Hs near donating groups. See pics

Three factors that affect J (coupling constant)

roofing

1H NMR exchange

13C NMR
Electronegative substituents

Intensity of signals in 13C NMR

13C-13C coupling

13C-1H coupling

13C-1H off resonance coupling