altering physical properties of energertic materials and other small molecules through template ...

337 Pages·2014·13.94 MB·English

by  Jessica Urbelis

ALTERING PHYSICAL PROPERTIES OF ENERGERTIC MATERIALS AND OTHER
SMALL MOLECULES THROUGH TEMPLATE-DIRECTED AND
CO-CRYSTALLIZATION METHODS

A Dissertation
submitted to the Faculty of the
Graduate School of Arts and Sciences
of Georgetown University
in partial fulfillment of the requirements for the
degree of
Doctor of Philosophy
in Chemistry

By

Jessica H. Urbelis, B.A.

Washington, DC

July 29, 2014
ALTERING PHYSICAL PROPERTIES OF ENERGERTIC MATERIALS AND OTHER
SMALL MOLECULES THROUGH TEMPLATE-DIRECTED AND
CO-CRYSTALLIZATION METHODS

Jessica H. Urbelis, B.A.

Thesis Advisor: Jennifer A. Swift, Ph.D.

ABSTRACT

The quality and performance of organic materials shape our everyday life. Organic
crystals have the propensity to be polymorphic, and properties between forms may be drastically
different. Crystallization of polymorphic compounds in the presence of 2-dimensional templates
is one potential means to control the nucleation and growth. CL-20 is a high-energy material that
is used in propellants, with its performance linked to phase, particle size/shape, and the presence
of defects and/or impurities. Perylene is a well-studied organic semiconductor, and its electrical
and optical properties are tied to 3D structure and molecular orientation. Crystallization of
perylene and CL-20 with gold-thiol self-assembled monolayers and functionalized siloxane
templates was studied for the ability of template-directed growth to affect crystal orientation,
morphology and phase relative to conventional solution growth. CL-20 generally yielded mixed
phases and morphologies from solution, however selectively grew high density -CL-20 on all
siloxanes in benzene, with preferred orientations varying by siloxane choice. The highest
nucleation densities were observed for surfaces capable of hydrogen bonding and carbonyl
interactions. For perylene, the majority of solvent/surface combinations yielded concomitant
growth of both forms, with preferred (100) orientations. Selective  growth was observed for Si-
OH in toluene, and selective growth of metastable -perylene was obtained on Si-3-NH in
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toluene.
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Another way to alter physical properties of a material is through co-crystal formation,
which has been studied by the pharmaceutical industry with APIs to generate compounds with
enhanced stability and bioavailability. The favorable interaction between CL-20 and carbonyl
groups observed in the surface study was extended to phosphonyls to form a 1:2 CL-20:TPPO co-
crystal. Additionally, co-crystallization was applied to a library of meta-substituted diphenyl ureas
which have been shown to crystallize with a strong hydrogen bonding network. Crystallization
with stronger hydrogen bond acceptors yielded new compounds which were analyzed for their
structural and physical properties. Five new 1:1 co-crystal structures were determined using XRD
for mCyPU:TPPO, mClPU;TPPO, mCF PU:TPPO, mClHPU:TPPO, mNHPU:TPPO, and one 1:1
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mCyPU:DMSO solvate. Polymorph solvent screening revealed additional phases for
mCyPU:TPPO (1-4), mClPU:TPPO (1-3), mNHPU:TPPO (1-3) and mClHU:TPPO (1-3).
Additional DMSO solvates were identified by TGA and 1H-NMR for mNHPU:DMSO,
mCF PU:DMSO and mClHPU:DMSO.
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“Equipped with his five senses, man explores the universe around him and calls the adventure
Science.”
~Edwin Powell Hubble, The Nature of Science, 1954

“If you're not part of the solution, you're part of the precipitate.”
~Henry J. Tillman

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ACKNOWLEDGEMENTS

I would like to first and foremost thank my mentor, Jennifer Swift, for her thoughtful
guidance and support over the years. It was a pleasure working with and learning from her, and I
appreciate her encouragement to let me test some of my more outlandish ideas. The dedication
she holds to her students’ successes both academically and personally is admirable, and I am
thankful she has helped shape me into a curious and determined scientist.
Many of the greatest achievements in science are fostered through collaboration. I learned
a great deal from the other members of the Swift group, both past and present. Thank you to the
older members Clare Perrin, Christina Capacci-Daniel, Janeth Presores, Ilana Goldberg, and
Amanuel Zellelow for mentoring and teaching me early on in my graduate career. To the newer
members Pranoti Navare, Liza “Cookies” Koch, Steven “Stove” Spangenberg, Nick Sapiezynski,
Marina Solomos, Frank Liu, Victoria Kugel and Cameron “Scams” Mohammadi, thank you for
all the laughs, the memories, and the thoughtful discussions. My time at Georgetown would also
not have been the same without the shenanigans of Will “Yams” Boncher, Travis Hall, Amanda
Smaniotto, and my coffee companion Billy “Norso” Hickling.
I owe a great deal of gratitude to the love and support of my parents and my brother, Ben.
Born from a family of lawyers and therapists, I understand that my choice to pursue a scientific
career first appeared as a twist towards the bizarre. Although I’m sure the bulk of my work was
not a daily hot topic for them, I must extend a smirk and my heartfelt thanks for keeping the jokes
to a minimum and enthusiastically reading it all anyway.
I would also like to thank my gaggle of fantastic friends that provided encouragement and
many laughs along the way. A special thanks to Nicki Kravec, Andrea Ippolito, Frankie
Goldstone, Lindsey Ulrey and Kendy Gable, you girls inspire me daily in all that you do. Thank
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you for the years of support. Lastly, my graduate career would not have been the same if it
weren’t for my DC family. To Nicholas Sciretta, Asha Venkataraman, Hilary Cohen, and
Zachary Wallace, thank you for keeping me motivated, for keeping me sane, and for making my
time in graduate school some of the best years of my life.

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Table of Contents

Chapter 1. Background………………………………………………………………………...1

1.1 Introduction…………………………………………………………….………….......…..1
1.2 Crystal Nucleation and Growth……………………………………….............…......….....3
1.3 Crystal Forms………………………………………………………………………...........7
1.4 Crystal Morphology………………………………………………………………......…...9
1.5 Self-Assembled Monolayers …...…………………………………………….…..............11
1.5.1 Au-Thiol Monolayers…………………………………………….....….…......14
1.5.2 Siloxane Monolayers…………………………………………………….........16
1.5.3 Use of 2D Templates for Crystallization............................................................18

1.6 Solid State Properties and Performance of Organic Small Molecules.................................18
1.6.1 Organic Semiconductors (Perylene)....................................................................18
1.6.2 High Energy Materials (CL-20)............................................................................22

1.7 Co-Crystallization................................................................................................................24
1.7.1 Hydrogen Bonding Co-Crystallization of Diphenyl Ureas.............................26

1.8 Overview of Project.............................................................................................................28
References...................................................................................................................................30

Chapter 2. Methods and Materials..............................................................................................50

2.1 Materials................................................................................................................................50
2.1.1 Thiol Monolayers...................................................................................................51

2.2 Preparation and Characterization of 2D Templates..............................................................52
2.2.1 Au-Thiol Monolayers.............................................................................................53
2.2.2 Silica-Siloxane Monolayers...................................................................................54
2.2.3 Fluorinated Glass Vials..........................................................................................56

2.3 Contact angle.........................................................................................................................58
2.3.1 Contact Angle: Heat and Solvent Dependence.......................................................62
2.3.2 Contact Angle: Time Dependence..........................................................................64

2.4 Crystallization Methods.........................................................................................................65
2.4.1 Solution Screening by Slow Evaporation...............................................................65
2.4.2 Growth on 2D Templates........................................................................................66
2.4.3 Co-Crystallization...................................................................................................67
2.4.3.1 Preparation of Co-crystals........................................................................69

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2.5 Optical Microscopy.............................................................................................................72

2.6 Thermal Methods................................................................................................................72
2.6.1 Hot Stage Microscopy..........................................................................................72
2.6.2 Differential Scanning Calorimetry (DSC)............................................................73
2.6.3 Thermogravimetric Analysis (TGA)....................................................................74

2.7 X-ray Diffraction.................................................................................................................74
2.7.1 Powder X-ray Diffraction (PXRD).......................................................................75
2.7.2 Oriented Powder X-ray Diffraction (Oriented PXRD).........................................75
2.7.3 Single Crystal X-ray Diffraction (XRD)...............................................................77
2.7.4 Face Indexing (Miller Indices) and Morphology Determination.........................78

2.8 Theory and Calculations.......................................................................................................79
2.8.1 Nucleation Density Calculations...........................................................................79
2.8.2 Atomic Force Microscopy (AFM).........................................................................80
2.8.3 Hirshfeld Surface Analysis....................................................................................81

References...................................................................................................................................82

Chapter 3. Perylene Crystal Growth……………………………………………………..........86

3.1 Introduction…………………………………………………………………………….....86

3.2 Perylene Solution Growth…………………………………………………………...........89
3.2.1 Perylene Solution Growth Morphology…………………………………….......90

3.3 Perylene Crystallization on Gold-Thiol and Siloxane Monolayers…………………........92
3.3.1 Perylene Crystal Growth on Au-Thiol Templates……………………………...93
3.3.2 Perylene Crystal Growth on Siloxane Templates……………………………....97
3.3.3 Oriented Powder X-ray Diffraction of Perylene on Siloxane Templates……....99

Conclusion…………………………………………………………………………………..104
References…………………………………………………………………………………...106

Chapter 4. CL-20 Crystal Growth and Solid State Properties………………………....……114

4.1 Introduction………………………………………………………………………….......114

4.2 Previous CL-20 Growth Studies…………………………………………………..….....116

4.3 Solution Growth of CL-20 in Single Solvents………………………………………......117

4.4 Solution Growth of CL-20 in Co-Solvent Systems………………………………....…..122

4.5 CL-20 Crystal Morphology………………………………………………………....…..125
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4.6 Hirshfeld Surface Analysis and Concomitant Growth…………………………....…......127

4.7 Template-Directed Growth of CL-20 on Siloxane Surfaces…………………....……….130

4.8 Growth of -CL-20 From Benzene on 2D Templates………………………...………....132
4.8.1 Effect of template on nucleation density of -CL-20 in benzene…………...... 132
4.8.2 Effect of template on preferred growth orientations of -CL-20 in benzene….135

4.9 Crystallization of CL-20 on 2D Templates in Other Solvents………………………......136
4.9.1 Selective CL-20 From Other Solvents………………………………….......137
4.9.2 Selective Growth and Preferred Orientation of Metastable 
4.9.3 Selective Growth and Orientation of Metastable 
4.9.4 Effect of Template on Nucleation Density in 1-Propanol and 2-Propanol…….147

4.10 Effect of Siloxanes on Cl-20 Morphology……………………………………………...149

Conclusion…………………………………………………………………………………....151
References………………………………………………………………………………….... 153

Chapter 5. CL-20 Co-Crystallization………………………………………………………...158

5.1 Introduction……………………………………………………………………………....158

5.2 Co-Crystallization of CL-20 and TPPO…………………………………………….........159
5.2.1 Powder X-ray Diffraction (PXRD) of CL-20: TPPO Co-Crystal……………..160
5.2.2 Thermal Analysis of CL-20: TPPO Co-Crystal…………………………….….162
5.2.3 Structural Data for 1:2 CL-20:TPPO Co-Crystal……………………………....163

5.3 Other CL-20 Co-Crystals…………………………………………………………….......174
Conclusion…………………………………………………………………………………...174
References………………………………………………………………………………..…..174

Chapter 6. Hydrogen Bond Directed Co-Crystallization of Meta-Substituted
Diphenyl Ureas and Guest Coformers...........................................................................178

6.1 Introduction..........................................................................................................................178

6.2 Crystallization of meta-Diphenyl Urea Host Compounds……………………....……….179
6.2.1 Crystal structure information for mPUs…………………………………....…..179
6.2.2 1,3 bis(m-trifluoromethylphenyl) urea (mCF PU)………………………..........182
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6.2.3 m-chloro diphenyl urea (mClHPU)……………………………………….........185
6.2.4 1,3 bis-(m-cyanophenyl) urea (mCyPU)…………………………………….....187
6.2.5 m-nitro diphenyl urea (mNHPU)………………………………………….........191
6.2.6 1,3-bis(m-chlorophenyl) urea (mClPU) ……………………………………......194
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6.2.7 1,3-bis(m-bromophenyl) urea (mBrPU)…………………………………….......195
6.2.8 1,3-bis(m-iodophenyl) urea (mIPU)………………………………………….....196

6.3 Growth on Siloxane Templates……………………………………………………….......197

6.4 Co-Crystallization of Meta-Substituted Diphenyl Ureas with TPPO……………..............198
6.4.1 Introduction…………………………………………………………………......198
6.4.2 Crystal structure and solid state properties of TPPO………………………........198

6.5 Crystal structures and solid state properties of 1:1 mPU:TPPO co-crystals ……...............201
6.5.1 Introduction…………………………………………………………………......201
6.5.2 Thermal and PXRD analysis of mPU: TPPO (1:1) co-crystals…………….......203
6.5.3 Co-Crystal morphology………………………………………………………....209

6.6 Structure Comparisons for all 1:1 Meta-Substituted Diphenyl Urea:TPPO
Co-crystals………………………………………………………………………….....210
6.6.1 Conformations………………………………………………………………......210
6.7.2 Hydrogen Bonding and Structure Analysis…………………………………......212
6.6.3 Structure and Packing Diagrams……………………………………………......215

Conclusion………………………………………………………………………………….....220
References………………………………………………………………………………….....221

Appendix A. Crystal Data for 1:2 CL-20: Triphenylphosphine Oxide Co-crystal……...........223

Appendix B. Crystal Data for 1:1 1,3-Bis(m-cyanophenyl) urea : Triphenylphosphine
Oxide Co-crystal……………………………………………………………………...246

Appendix C. Crystal Data for 1:1 1,3-Bis(m-trifluorotolylphenyl)urea
:Triphenylphosphine Oxide Co-crystal…………………………………………….....256

Appendix D. Crystal Data for 1:1 1,3-Bis(m-chlorophenyl) urea : Triphenylphosphine
Oxide Co-crystal……………………………………………………………………...264

Appendix E. Crystal Data for 1:1 m-nitro diphenyl urea : Triphenylphosphine Oxide
Co-crystal……………………………………………………………………………..273

Appendix F. Crystal Data for 1:1 m-chloro diphenylurea : Triphenylphosphine Oxide
Co-crystal……………………………………………………………………………..285

Appendix G. Crystal Data for 1:1 1,3-Bis(m-cyanophenyl) urea: dimethyl sulfoxide
solvate………………………………………………………………………………...294

Appendix H. PXRD Patterns of 1:1 mPU:TPPO Co-crystals and Polymorph
Screening........................................................................................................................302
References..................................................................................................................................312
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