Transcript Mo(CO) - Drew University

IN PURSUIT OF A TRANSCHELATING DIPHOSPHINE LIGAND
Jacqueline Dragon; Samuel Flanzman; Johann Frias; Michael Gao; JinOh Jeong;
Angela Jin; Meeki Lad; Kevin Lin; Yuzki Oey; Jessica Teipel; Mathini Vaikunthan;
Evan Zou
Advisor: Dr. Mary-Ann Pearsall
Assistant: Nicholas Chiappini
NJGSS 2014 Drew University – Team Project 3
INTRODUCTION
Coordination Complexes
e-
C
e-
M
A
B
INTRODUCTION
Ligands and Chelation
Halides
Amines
Carbonyls
Diphosphine
Phosphines
INTRODUCTION
The Experimental Goal
INTRODUCTION
Experimental Obstacles
CO
PPh
CO 2
CO
CO
PPh2
CO
CO
CO
CO
CO
CO
PPh
2
CO
PPh
CO 2
CO
PPh2
PPh2
CO CO
PPh2
Mo
PPh
CO 2
Mo
CO
PPh2
Mo
CO CO
PPh2
PPh2
PPh
CO 2
PPh2
INTRODUCTION
Activated Precursor Complexes
CO
PPh
2
CO
Use weak ligand (piperidine)
Mo
Resulting activated precursor complex
always involves disubstitution and
occurs in the cis form
Replace piperidine with
diphosphine
CO
CO 2
PPh
CO
CO 22
PPh
PPh
pip
pip
pip
Heat to convert to trans
pip
pip
pip
INTRODUCTION
Varying Hydrocarbon
Length
LIGANDS
INTRODUCTION
Expectations
Hypotheses
As the length of the
hydrocarbon chain
increases, the trans
isomer will become
more favorable.
Past a certain number
of carbons, the
hydrocarbon chain
will be so long that it
will form unintended
alternate bonds.
EXPERIMENTAL
Procedure and Rationale
Mo(CO)
+ [(Ph
)n(PPh
(PPh2)]
cisMo(CO)
4(pip)42 [(Ph
2P)(CH
2P)(CH
2)2n
Mo(CO)6 + 2 pip
PPh
CO 2
CO
CO
Mo
CO
pip
CO 2
PPh
CO
PPh
CO 22
PPh
pip
Day
3:
Day 2:
Day
1:
Heat
cisMo(CO)
P)(CH
+ 2 pip
transMo(CO)
HeatHeat
4 [(Ph
2)n(PPh
4 2[(Ph
2P)(CH
2)2)]
n(PPh
2)]
Mo(CO)
(pip)
+
2
CO
4
2
EXPERIMENTAL
Collecting Data – IR
pip
Number of
Distinct
Dipole
Shifts:
13
pip
Expected
Peaks:
13
EXPERIMENTAL
Collecting Data – Nuclear Magnetic
Resonance Spectroscopy
RESULTS
Control Group, Ligand PPh3
RESULTS
1,12 Group, Ligand (PPh2)2(CH2)12
RESULTS
1,8 Group, Ligand (PPh2)2(CH2)8
RESULTS
1,4 Group, Ligand (PPh2)2(CH2)4
RESULTS
1,5 Group, Ligand (PPh2)2(CH2)5
RESULTS
1,6 Group, Ligand (PPh2)2(CH2)6
ANALYSIS
Discussion: Conclusions
# of
Carbon
s in
Ligand
Ligand
(Chemical)
4
[(Ph2P)(CH2)4(PPh2)]
5
[(Ph2P)(CH2)4(PPh2)]
6
[(Ph2P)(CH2)4(PPh2)]
8
[(Ph2P)(CH2)4(PPh2)]
12
[(Ph2P)(CH2)4(PPh2)]
Ligand
(Structural)
cis-trans
Conversion
Notes
No
Conversion
No
Conversion
Some
Conversion
Mostly
Conversion
Mostly
Conversion
Ancillary Points
Hypothesis was
based solely on balland-stick models and
was proven correct
Knowledge of the
spatial geometry can
help predict the
complex’s properties
as well as those of
similar complexes.
Applications of transchelating
diphosphine ligands
in catalysis can now
be explored.
Acknowledgments
 Dr. Mary-Ann Pearsall
 Nicholas Chiappini
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Independent College Fund of NJ/Johnson & Johnson
AT&T
Actavis Pharmaceuticals
Celgene
Novartis
Bayer Healthcare
Laura (NJGSS ’86) and John Overdeck
NJGSS Alumnae and Parents of Alumnae
Board of Overseers, New Jersey Governor’s Schools
State of New Jersey
Drew University