Organic Lab Spectra Quizzam Flashcards
Molecular fragments that have resonance are found further __________ (downfield or upfield) in NMR.
Downfield
An alkane fragment is found further ________ (downfield or upfield) than an alkene in NMR.
Upfield
Give an example of a heteroatom.
oxygen
What is the splitting pattern expected for a methyl adjacent to a methylene? (Look at the methyl) -CH2CH3
triplet
Name a functional group that has a broad peak in both IR and NMR.
Hydrogen bonding
What is the range and number of peaks for amines in the IR?
3000-3300 cm-1 and 2 peaks
Which peaks in the IR would have higher cm-1 values?triple bonds, double bonds or hydrogen bonds
hydrogen bonds
Which peaks are found b/w 2000 and 2400cm-1 in IR?
triple bonds
If a NMR peak is a singlet, how many neighboring hydrogens would be present?
0
What is the mass spec of Cl?
3 to 1 M+ to M+2
What is the mass spec of Br?
1 to 1 M+ to M+2
What is the mass spec of I?
large M+
What is the mass spec of N?
large M+ and very small M+1
What is the observed NMR peak from a cis or trans alkene?
a quartet b/w 5-6 ppm
What is the observed NMR peak of a para distributed benzene?
doublet of doublets at 7-8 ppm
What is the observed NMR peak of a mono distributed benzene?
a messy singlet at 7-8 ppm
What is the observed NMR peak of a methyl attached to a heteroatom?
singlet at 3.5 ppm
What is the observed NMR peak of a methyl attached to a carbonyl?
singlet at 2 ppm
What is the observed NMR peak of a ethyl group?
a triplet-quartet
What is the observed NMR peak of a isopropyl group?
a multiplet doublet
What is the observed NMR peak of a n-propyl group?
triplet-multiplet-triplet
What is the observed NMR peak of a terminal alkene?
multiplet-doublet of doublets at 5-6 ppm
In a C-13 NMR, if a spectrum has the same number of peaks as the number of carbons in the molecular formula, the molecule has symmetry. False/true?
False
Organize from lowest to highest in terms of IR.
CH sp3
CH sp
CH sp2
C=O
C=OCH sp3CH sp2CH sp
Describe C=O IR peak in IR.
Very large overall peak height in a vertical nature.
Why did grignard need to be dry?
Because the water in the grig react to make hydrocarbon and not the product you want.
Why did we wash cyclopentadiene with hexane several times?
To completely transfer the cyclopentadiene to the mixture.
Why is cyclopentadiene slowly distilled?
To minimize the possibility of bumping occurring during distillation.
Why is the claisen head necessary?
Because the dicyclopentadiene will likely bump during distillation. Claisen head acts as a catch for hot liquid from the boiling flask.
