Quantum Chemical Studies of Actinides and Lanthanides

218 Pages·2013·6.05 MB·English

Quantum Chemical Studies of Actinides and Lanthanides:
From Small Molecules to Nanoclusters
A DISSERTATION
SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL
OF THE UNIVERSITY OF MINNESOTA
BY
Bess Vlaisavljevich
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF
Doctor of Philosophy
Professor Laura Gagliardi
June, 2013
(cid:13)c Bess Vlaisavljevich 2013
ALL RIGHTS RESERVED
Acknowledgements
There are many people that I would like to thank for all of their support through my
graduateschoolyears. Firstofall,I’dliketothankmyadvisorProf. LauraGagliardifor
her encouragement, advice, and providing me with countless opportunities to develop
asascientist. Additionally, I’dliketothankProf. DavidBlankandProf. ChrisCramer
for taking the time to be great mentors in teaching. I would also like to thank Prof.
Chris Cramer for all of the helpful discussions in research as well.
I’d also like to thank the Chemistry faculty at the University of Minnesota – Twin
Cities for all they have taught me. I’d also like to thank Profs. Joe Alia, Nancy
Carpenter, Jenn Goodnough, Ted Pappenfus, and Jim Togeas at the University of
Minnesota – Morris for starting me off on the right foot in my chemistry career.
I would like thank all of the collaborators from outside the University of Minnesota
for the very useful discussions especially Prof. Thomas Albrecht-Schmidt, Prof. Lester
Andrews,Prof. CarlesBo,Prof. PeterBurns,Prof. ScottDaly,Prof. PaulaDiaconescu,
Prof. Greg Girolami, Dr. Ivan Infante, Dr. Jason Keith, Prof. Stephen Liddle, Prof.
May Nyman, Dr. Jie Qiu, Dr. Ginger Sigmon, Dr. Riccardo Spezia, and Dr. Tanya
Todorova. I’d especially like to thank Dr. Enrique Batista and Dr. Richard Martin for
provided a great learning environment during my short visit learning and working with
them at LANL.
Next, I’d like to thank Pere Mir´o for all of the love and support over the last few
years not only as my partner in crime but also as a colleague. The many hours we have
spent discussing chemistry always reminds me how much I enjoy research even through
the difficulties. It’s too bad you don’t want a cat.
A big thanks to the Gagliardi group members (past and present) for all of the
scientific help, for the great friends you have become, and of course good lunchtime
i
conversation. Thank you Abbas, Allison, Alison, Abdul, Becky, Chad, David, Daniel,
Danylo, Dongxia, Drew, Dylan, Ivan, Eileen, Giovanni, Huilang, Josh, Laura F., Laura
L.,Mike,R´emi,Sarah,andToni. IespeciallyliketothankAllisonDzubak,NoraPlanas,
and Dongxia Ma for keeping me company during many trips for coffee and always being
willing listen. I’d like to offer a special thanks to Dr. Ivan Infante and Dr. Abdul
Rehaman Moughal Shahi for taking the time during my first few years to answer my
many many questions. I’d also like to thank the current and former Cramer group
members especially Aaron, Ashley, Samat, Stuart, Josh, and Will. I’d also like to thank
the other graduate students in my year in particular Deanna, Jacqui, Emily, Darren,
Brian, Kelly, and Katie.
FinallyI’dliketothankallofmywonderfulfamilyandfriends. Mytimeingraduate
schoolwouldhavebeenmuchlessfunifIcouldn’tshareitwithallofyou. Andofcourse
I am forever in debt to parents, my siblings, and the “other V’s” (Dan, Molly, Ryan,
Anna, Lala, and Gerry). You guys are the best!
ii
Dedication
For
Pere Mir´o
my father Steve Vlaisavljevich
my mother Colleen Vlaisavljevich
my siblings Eli and Rose Vlaisavljevich
In memory of
my mother Theresa Vlaisavljevich
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Abstract
Research into actinides is of high interest because of their potential applications as
an energy source and for the environmental implications therein. Global concern has
arisen since the development of the actinide concept in the 1940s led to the industrial
scaleuseofthecommercialnuclearenergycycleandnuclearweaponsproduction. Large
quantities of waste have been generated from these processes inspiring efforts to address
fundamentalquestionsinactinidescience. Inthisregard, theobjectiveofthisworkisto
use theory to provide insight and predictions into actinide chemistry, where experimen-
tal work is extremely challenging because of the intrinsic difficulties of the experiments
themselves and the safety issues associated with this type of chemistry. This thesis
is a collection of theoretical studies of actinide chemistry falling into three categories:
quantum chemical and matrix isolation studies of small molecules, the electronic struc-
ture of organoactinide systems, and uranyl peroxide nanoclusters and other solid state
actinide compounds. The work herein not only spans a wide range of systems size but
also investigates a range of chemical problems. Various quantum chemical approaches
have been employed. Wave function-based methods have been used to study the elec-
tronic structure of actinide containing molecules of small to middle-size. Among these
methods, the complete active space self consistent field (CASSCF) approach with cor-
rections from second-order perturbation theory (CASPT2), the generalized active space
SCF (GASSCF) approach, and Møller-Plesset second-order perturbation theory (MP2)
have been employed. Likewise, density functional theory (DFT) has been used along
with analysis tools like bond energy decomposition, bond orders, and Bader’s Atoms
in Molecules. From these quantum chemical results, comparison with experimentally
obtained structures and spectra are made.
iv
Contents
Acknowledgements i
Dedication iii
Abstract iv
List of Tables viii
List of Figures xi
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
1 Introduction 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Organization of the Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2 Quantum Chemical and Matrix Isolation Studies of Small Molecules 18
2.1 UandP ReactionProducts: AQuantumChemicalandMatrixIsolation
4
Spectroscopic Investigation . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.1.2 Experimental and Computational Methods . . . . . . . . . . . . 20
2.1.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.1.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.1.5 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.2 Combined Triple and Double Bonds to Uranium: The N≡U=NH Uran-
imine Nitride Molecule Prepared in Solid Argon . . . . . . . . . . . . . . 35
v
2.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.2.2 Experimental and Computational Methods . . . . . . . . . . . . 36
2.2.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 37
2.2.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.2.5 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3 Combined Theoretical and Experimental Studies of Oraganoactinide
Compounds 49
3.1 OntheNatureofActinideandLanthanide–MetalBondsinHeterobimetal-
lic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.1.2 Results and Discussions . . . . . . . . . . . . . . . . . . . . . . . 53
3.1.3 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.1.4 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.2 Volatilities of Actinide and Lanthanide N,N-Dimethyl-aminodiboranate
Chemical Vapor Deposition Precursors: A DFT Study . . . . . . . . . . 74
3.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
3.2.2 Computational and Experimental Details . . . . . . . . . . . . . 77
3.2.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 78
3.2.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
3.2.5 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . 88
3.3 Investigations of the Electronic Structure of Arene-Bridged Diuranium
Complexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
3.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
3.3.2 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 90
3.3.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
3.3.4 Experimental Section . . . . . . . . . . . . . . . . . . . . . . . . 109
3.3.5 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
4 Uranyl Peroxides and Solid State Actinide Compounds 116
4.1 Understanding the Structure and Formation of Uranyl Peroxide Nan-
oclusters by Quantum Chemical Calculations . . . . . . . . . . . . . . . 117
4.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
vi
4.1.2 Theoretical Calculations . . . . . . . . . . . . . . . . . . . . . . . 119
4.1.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 121
4.1.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
4.1.5 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . 130
4.2 Uranyl-Peroxide Nanocapsules in Aqueous Solution . . . . . . . . . . . . 131
4.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
4.2.2 Computational Details . . . . . . . . . . . . . . . . . . . . . . . . 133
4.2.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
4.2.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
4.2.5 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . 146
4.3 Synthesis and Characterization of the First 2D Neptunyl Structure Sta-
bilized by Side-on Cation-Cation Interactions . . . . . . . . . . . . . . . 147
4.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
4.3.2 Experimental Section . . . . . . . . . . . . . . . . . . . . . . . . 155
4.3.3 Computational Details . . . . . . . . . . . . . . . . . . . . . . . . 156
4.3.4 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . 156
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Appendix A. Acronyms 194
vii
List of Tables
2.1 Calculated Structural Parameters and Harmonic Frequencies for UP and
UPa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.2 Comparison of Electronic States, Bond Orders, and Distances For Ura-
nium Pnictides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.3 Computed Energies for U and P Reaction Products . . . . . . . . . . . 26
4
2.4 Observed and Calculated Frequencies for NUNH Isotopic Molecules in
the 2∆ Ground Statea . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.1 Optimized bond distances in angstroms. . . . . . . . . . . . . . . . . . . 58
3.2 Bonding energy and charge transfer between the Ln/An and M fragments. 63
3.3 Comparison between calculated geometries for U–Re from the current
study and previous work by Gardner et al. . . . . . . . . . . . . . . . . . 66
3.4 Energy decomposition performed using Equation 3.1. The percentage of
the total attractive interaction of electrostatic and orbital interactions is
given in parentheses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.5 Theoretical bond critical point properties for the bimetallic species stud-
ied. All values are expressed in atomic units. . . . . . . . . . . . . . . . 71
3.6 Selected Geometric Parameters Obtained from Ground State Geome-
try Optimization; Average Distances Are Reported for the Two Central
Metal Centers (Part a of Figure 3.10) in ˚A; Average Individual Mayer
Bond Orders Are Given along with the Number of Such Bonds Per Metal
Centera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
viii