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31 Cards in this Set
- Front
- Back
isomers |
compounds with the same molecular formula but different structures |
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structural isomers |
Differ in how and where atoms are connected. Same formula, different framework and number of atoms bonded together |
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stereoisomers |
only differ in spatial orientation |
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cis-isomers |
both substituents are on the same same of the double bond |
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trans-isomers |
substituents are on opposite sides of double bond |
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(Z) |
both substituents with first priority are on the same side of the double bond (zee zame zide) |
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(E) |
both substituents with highest priority are on opposite sides of double bond (epposite) |
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chiral molecules |
non superimposable on mirror image, like your right and left hands |
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asymmetric atom |
carbon atoms with 4 substituent groups and no plane of symmetry |
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enantiomers |
chiral pairs of molecules that are not the same |
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Fischer projections |
3D representation of molecules horizontal lines = out of the page vertical lines = behind page If you switch 1 pair or rotate 90 degrees, it is the enantiomer |
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relative configuration |
configuration in relation to other chiral molecule |
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absolute configuration |
describes the spatial arrangement of a molecule using R or S. R goes clockwise, and S goes counterclockwise in numbering the substituents in order of priority ignoring #4. |
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optical activity |
Ability to rotate plane polarized light by an angle (alpha). Enantiomers rotate the plane of polarized light in opposite directions. Direction of rotation must be determined experimentally |
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dextrorotary |
rotates the plane clockwise, indicated by + |
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levorotarty |
rotates the plane counterclockwise, indicated by - |
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specific rotation |
observed rotation/(concentration(g/ml)xlength(dm)) |
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racemic mixture |
equal concentrations of + and - enantiomers |
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diastereomers |
stereoisomers that are not mirror images |
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epimers |
diastereoisomers that vary only at one carbone, important to chemistry of carbohydrates |
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meso compounds |
molecules with multiple chiral centers that also have an internal plane of symmetry, not optically active because the light rotation of one chiral center is matched by opposite rotation of other chiral center |
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conformational isomers |
differ only by rotation about one or more single bonds, same compounds in a slightly different position |
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Newman projection |
line of sight is alond a C-C bond so the second C is drawn as a circle |
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staggered conformation |
in a Newman projection, none of the atoms overlap |
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anti conformation |
groups are antiperiplanar to eachother, most stable conformation |
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gauche conformation |
atoms/groups are 60 degrees appart, must pass through eclipse phase to get to anti conformation |
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eclipse formation |
in Newman projection, all similar molecules line up, highest energy level, very unstable |
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cyclic conformations |
cycloalkanes attempt to adopts non planar conformations to alleviate angle, torsional, and nonbonded strains |
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cyclic conformations of cyclohexane |
chair=most stable, hydrogen groups are axial and equatorial boat=chair flips, hydrogens that were axial become equatorial and vice versa, all atoms are eclipsed twisted boat=atoms are in gauche formation, so they are slightly more stable |
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monosubstituted |
bulky groups prefer the equatorial position, so a large group can lock the molecule into one conformation |
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disubstituted |
cis=bone substituents are on the same side of ring trans=two groups on opposite sides of ring |