These notes are compiled from Fall 2024 lecture notes for Modern Organic Chemistry II. Using lectures, practice exams + keys, and the class textbook, these notes were thoughtfully put together in a way that is organized and easy to follow. This document includes white and colored text on black page...
ENERGY As PHOTONS spACE
HAS WAVE & PARTICLE PROPERTIES
·
ENERGY
Han Low
8
*
HIGH
3
Law
z
Law HIGH
E
Law /V HlaUX HIGU ElU Law I
RADIO MICROWAVE IR UV-VIS UV
X-RAY COSMIC RAY
↓ ↓
NUCLEAR Molecule will only absorb IR photon if it will
CHANGES CHANGES & 0 Y GBIV
↓ change the bond dipole. Otherwise, it is not IR
↓
SPIN STATE BOND ROTATION active. Cis orientations are active because their
HIGHER X LOWER X
angle can be changed.
·
MOLECULE MUST ABSORB PROTON TO GENERATE A SIGNAL
·
ABSORBING UV-PROTONS KNOCK Law
ENERGY ORBITAL TO A HIGHER ONE
;
IF KNOCKED INTO UU-US
RANGE IT WILL BE VISIBLE
,
·
ABSORBING IR PHOTONS CHANGES VIB .
ENERGY ,
THUS CHANGING DIPOLE
↳ STRONGER BOND MOMENT BIGGER DIPOLE
,
·
HIGHER WAVENUMBERS =
HIGHER fREQUENCY
Frequency ,
Mass, & BOND STRENGTH
-H e
DEPENDS
INTENSITY POLARITY /T ACTIVE / INACT
·
Of SIGNAL ON BOND
RC = CR RC = Chi RCCH RLEN C 0 C = 0
-
WEAK MED-STRONG
INACTIVE MEDIUM MED-STRONG
VERY STRONG
As
FREQUENCY OF LOWEST (GROND) STATE INCREASES , So DOES
FREQUENCY
OF
PHOTON
·
REQUIRED TO INCREASE VIB .
ENERGY
·
As MASS OF ATTACHED ATOMS INC GROUND STATE VIB . FREQ DECREASES (MINK BANS ON
.,
.
A SpRINa)
a↓ de
C
· As #OF BONDS INCREASES GROUND STATE VIB FREQ INC IMAGINING BONDS
33 T
. . .
,
As SPRINGS
O
, NUCLEAR MAGNETIC RESONANCE
Some NUCLEI HAVE
·
NON-ZERO "Spin STATES" I F 0 .
WHEN PLACED IN A MAGNETIC FIELD
,
THE BENAVE As IF
HAVE MAGNETIC MOMENTS
ThEy
1 NS
[N]
MAGNETIC
FELD
Th ⑭
·
DIFFS IN
ENERGY W/ OR AGAINST FIELD ARE SupER SMALL
&
RIGHT HAND RULE
S N
WITH FIELD -LawER
ENERGY AGAINST FIELD - HIGHER
ENERGY
·
STRONGER MAGNETIC FIELD - HIGHER FREQ . & FASTER PROCESSIONAL FREQ.
* RADIO FREQ . MUST MATCH PROCESS . FREQ . TO FLP NULLE
* RESONANCE WHEN RADIO FREQ . MATCHES PROCESSIONAL FREQ .
(FREQ . & WHICH NORM POLE PROCESSEs)
FIELD SWEEP
·
DOWN FIELD : LEFT
·
UpFIELD :
RIGHT
SHIELDING &
FRAM
e-DENSITY LESS MAGNETISM FELT LaVER PROCESSIONAL FREQ
·
-
.
PUISE With FOURIER TRANSFORM (FT)
·
MODERN NMR IS RADIO FREQ .
PULSE ; RESONANCE OCCURS ALL AT THE SAME TIME
·
HOLDS MAGNETIC FIELD (no] CONSTANT & "pULSES" SAMPLE With RADIO FREQ .
RADIATION
PROTON NMR : SIGMA SHIELDING
e-IN ESTABLISH A "WET-FLOW" ACCORDING "LEFT HAND RULE" FOR MOVEMENT
O-BOND TO OF
NEGATIVELY
·
CHARGED PARTICLES IN APPLIED (HO] . FLOw CREATES AN INDUCED FIELD [Hi] oppoSED To
AppLIED [Ho] , Thus
"SHIELDING" PROTON . HEFF :
Ho-Hi
↑
-
n
U:
VINYL STRONGLY DESHIELDED
AllyLIC U:
WEARLY DESHIELDED
HF-c AROMATIC H : VERY STRONGLY DESHIELDED
O
BENEYLIC H:
WEAKLY DESHIELDED
Il
-H
ALDEnyDIC H:
VERY STRONGLY DESHIELDED
, CHEMICAL EQUIVALENCE
DIASTEREOTOPIC H HAVING CENTERS ALWAYS
ATOMS
USUALLY OCCUR ON MOLECULES STEREOGENIC BUT NOT
·
,
CM de ON
ABOUT THE DOUBLE
SAME CARBON
BOND
BUT ARE DIFF BECAUSE TRE IS NO FREE Ron
**AYSWAPPEPout Up FOR A NON-PROTON I WLD BECOME A CHIREL
,
CENT
MULTIPLICITY
SIGNAL SPLITTING COMES FROM COUPLING With NON-EQUIVALENT
n+1 rule
·
VICINAL (NEIGHBORING) Hs
·
IDENTICAL I'S CAN COUPLE INSTEAD Of
SPLITTING
·
COUPLING WON'T OCCUR FOR 0-H/N-H & WILL APPEAR As
BROAD SINGLETS BLOF QUADRUPOLE INTERACTIONS
13C NMR
·
NEEDS PavERFUL MAGNET
, MANYSCANS ,
& PULSE/FT TECHNOLOGY
In & 13C
· HAVE
VASTLY DIFF .
PROCESSIONAL FREQ.
Fully B3CNMR THERE WILL BE A SIGNAL FOR EACH
IN DECOUPLED DISTINCT
CHEMICALLY
·
,
NON-EQUIV CARBON .
H
IN 1 # OF
·
NON-DECOUPLED, MULTIPLICITY IS DETERMINED
By
n +
,
WHERE n =
PARTICULAR CARBON
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