Schedule

8:30-9:30am Continental breakfast (served outside LH 2)

9:30-9:35 Opening remarks

9:35-10:50am Oral Session 1 – Session Chair: Eike Bauer

Time Presenter Affiliation Title

9:35 Robert M. Marti Washington University CO2 Dynamics in pure and mixed-metal MOFs with open metal sites

10:00 Calvin Nyapete Saint Louis University Utilization of acrylic monomers as stabilization agent for aluminum nanoparticles

10:25 Chia-Hsin Chen Washington University Carbon capture on solid amine modified SBA15

10:50-11:10am Break (coffee/tea served outside LH 2)

11:10am-12:25pm Oral Session 2 – Session Chair: Nikolai Gerasimchuk

11:10 Eike Bauer University of Missouri – St Louis

Sterically and electronically tuned ruthenium

complexes and their ability to catalytically

activate propargylic alcohols

11:35 Wenhui Zeng Saint Louis University Investigation of environmentally responsive polymers as capping materials for aluminum nanoparticles

12:00 Naveen K. Mahenderkar

Missouri University of Science & Technology

Epitaxial lift-off of electrodeposited single-crystal gold foils for flexible electronics

12:25-1:00pm Lunch (served outside LH 2)

1:00-2:00pm Poster Session (outside LH 2)

2:00-3:15pm Oral Session 3 – Session Chair: Liviu Mirica

2:00 Nikolai Gerasimchuk

Missouri State University

Hydrated Ni(II) complexes with chelating cyanoximes: what happens when water is gone?

2:25 Sofia M. Smith Washington University Synthesis and reactivity of organometallic NiII and NiIII compounds

2:50 Allen Apblett Oklahoma State University

Ferrous pyruvic acid oxime: from an unusual formation mechanism to a material for sorption of arsenic from water

3:15-3:30am Break (refreshments served outside LH 2)

3:30-4:20pm Oral Session 4 – Session Chair: Janet Braddock-Wilking

3:30 Chideraa Nwachukwu

Missouri State University

Synthesis and characterization of a novel ligand and its Ag (I) and Pd (II) complexes

3:55 Paul Jelliss Saint Louis University Rhenacarborane complexes for peptide delivery across the blood-brain barrier (BBB)

4:20 Closing Remarks

Poster Presentations

Poster Presenter Affiliation Title

1 Matthew J. Stark

University of Missouri – St Louis

Towards a better understanding of fine-tuned ruthenium catalysts for propargyl substitution reactions

2 Waruni Jayawardana

University of Missouri – St Louis

Lithium diffusion coefficient in hard carbons with different structures via galvanostatic intermittent titration technique and open cell relaxation

3 Waruni Jayawardana

University of Missouri – St Louis

Influence of functionalized nanoporous carbons on the properties of confined NaAlH4

4 Snow Popis Missouri State University

The silver cyanoximate bullet: investigations into biocidal effects of silver complexes in medical resins

5 Alec Neeson Missouri State University

Synthesis and characterization of potential NIR emissive platinum complexes of cyanoximate ligands

6 Stephanie Dannen

Missouri State University

Cytoxicity of platinum and palldium cyanoximates on cervical and colon cancer cells

7 William M. Sanderson

Washington University Charge carrier dynamics in CdTe quantum wires

8 Giang N. Tran Washington University Study on low-valent nickel and palladium complexes

9 Yung-Ching Wang

Washington University Synthesis and reactivity of high-valent Pd-allyl complexes

10 Bruce Kowert Saint Louis University ESR studies of the molecular motion of the bis(maleonitriledithiolato)nickel monoanion and trianion in diglyme

11 Charles C. Kirkpatrick

Saint Louis University d-Electron count, ion-pairing and diagonal twist angles in metallo-bis(dithiolene) complexes

12 Xander Benziger Saint Louis University Carborane passivated aluminum nanoparticles

Abstracts – Oral Session

CO2 Dynamics in pure and mixed-metal MOFs with open metal sites Robert M. Marti, Joshua D. Howe, Cody R. Morelock,; Krista S. Walton, Mark S. Conradi, David S. Sholl, Sophia E. Hayes Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899 RMarti@wustl.edu

Metal-organic frameworks (MOFs), such as MOF-74, can have open metal sites to which adsorbates

such as CO2 preferentially bind. 13C NMR of 13CO2 is highly informative about the binding sites present in Mg-MOF-74, which are evident at different levels of CO2 loading and here at 295 K we

investigate ~0.2 to 1.3 atm of CO2. 13C lineshapes recorded as a function of loading can be

understood using analysis of the angular dependence () of CO2 with respect to the 1-dimensional channel of the MOF, reflected in the P2 Legendre polynomial. In the fast motional limit, the NMR

spectra reveal the time-averaged value of P2, where is the angle between the instantaneous CO2

axis and the channel axis. DFT calculations were used to determine a weighted average of the second-order Legendre polynomial in the fast motional regime and are in good agreement with

experimental data. Static variable temperature (VT) 13C NMR from cryogenic temperatures to room

temperature was used to investigate 13CO2 binding in Mg-MOF-74 loaded, revealing temperature-dependent lineshapes.

Figure 1: a.) Weighted average of CO2 loading dependence on the second order Legendre

polynomial, P2. b.) Static 13C NMR of Mg-MOF-74 loaded with variable amounts of CO2 at 295 K. The

number of CO2 molecules per metal are given on the left side of the diagram. A vertical line is

placed at 124.5 ppm to reference the isotropic chemical shift of free CO2.

Talk

9:35

Utilization of acrylic monomers as stabilization agent for aluminum nanoparticles Calvin Nyapete, Paul A. Jelliss, Steven W. Buckner

Department of Chemistry, Saint Louis University, St Louis, Missouri 63103

nyapete@slu.edu

We report on the polymerization of acrylic monomers on incipient aluminum nanoparticle cores and explore the effect of changing the monomer size and/or chain length on the resultant stability of the passivated particles. We also report on the utilization of these monomers in the presence of a cross linker and a photo-initiator to create hollow polymers capsules with capabilities to provide sites for nanoparticles fabrication. The synthesis protocol is based on decomposition of molecular alane reagent using titanium (IV) complex as a catalyst. The accessibility to the active aluminum core, with the different monomer sizes, is also evaluated and presented in this work using the hydrogen emission method. When varying the monomer chain lengths, the trend shows longer access time to the active metallic core with for long chained monomer caps. The ideal Gas Law is employed to determine the amount of active aluminum in the samples. We also present preliminary results from PXRD (powder X-ray diffraction), TEM (transmission electron microscopy), DSC/TGA (differential scanning calorimetry/thermal gravimetric analysis) and DLS (dynamic light scattering).

Figure 1. Schematic representation for Al fabrication.

Figure 2. PXRD of Al NPs capped with butylmethacrylate.

Talk

10:005

Carbon capture on solid amine modified SBA15

Chia-Hsin Chen, Daphna Shimmon, Jason J. Lee, Stephanie A. Didas, Anil K. Mehta, Carsten Sievers,

Christopher W. Jones, Sophia E. Hayes

Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899 chia-hsin@wustl.edu

Capturing high volumes of CO2 from power plants is an essential research topic as part of the effort to mitigate global warming. Solid modified mesoporous silica sorbents are promising materials for CO2

capture because the solid materials are less corrosive, have lower regeneration energy and cost less than the current technology of aqueous amine solutions.

The mesoporous silica systems are challenging to structurally characterize with conventional analytical techniques such as X-ray diffraction due to the lack of crystallinity. FTIR and solid-state nuclear

magnetic resonance (NMR) are two spectroscopies that can provide information about structure,

especially the local coordination environment of chemical moieties present in CO2 chemisorption products, even in amorphous and surface-bound sites.

Our goal is to characterize the chemisorbed products of 13CO2 adsorbed 3-aminopropylsilane (APS) SBA15. Multiple chemisorbed products can be formed under our experimental conditions, such as carbamic acid, ammonium carbamate, bicarbonate and so on. In this work we discuss a [15N] APS- SBA15 (15N labeled sample) with solid-state NMR, allowing interrogation of the chemisorbed products both with 15N{1H} cross-polarization magic-angle spinning (CPMAS) and 13C{1H} CPMAS experiments.

15N{1H} CPMAS after 13CO2 exposure on [15N] APS-SBA15 results in a new 15N resonance, assigned to ammonium carbamate based on the chemical shift information. Multiple 13C resonances are observed in 13C{1H} CPMAS, suggesting the formation of two possible chemisorbed products. 15N{13C} rotational-echo double-resonance (REDOR) and the complementary experiment of 13C{15N}

REDOR were conducted to help with the assignments of the chemisorbed products in the 13C and 15N spectra. These experiments result in interesting conclusions regarding the types of chemisorbed products in this system, as will be discussed.

Figure 1. Possible species in 13CO2 loaded APS-SBA15.

Talk

10:255

Sterically and electronically tuned ruthenium complexes and their ability to

catalytically activate propargylic alcohols

Matthew J. Stark, Nigam P. Rath, Eike B. Bauer

Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121

bauere@umsl.edu

The presentation describes the synthesis, structural characterization and application of ruthenium-based

complexes in the catalytic activation of propargylic alcohols.

Tuned ruthenium complexes find widespread applications as catalysts in reactions such as

oxidations, olefin metathesis, and a number of carbon-carbon, carbon-nitrogen and carbon-oxygen bond

forming reactions. The quest for sterically and electronically tuned ruthenium complexes is ongoing to

satisfy the growing need of such complexes in the area of medicinal chemistry, pharmaceutical and

organic syntheses as well as in the development of optical devices.

We synthesized a series of ruthenium complexes of the general formula [RuCl(ind)(PPh3)L], where

ind is the indenyl ligand η5-C9H7 and L is either fluorinated trisaryl phosphine ligands PAr3 or tris-(N-

pyrrolyl) phosphine P(pyr)3 (Figure 1). The new complexes were characterized structurally and by cyclic

voltammetry. They differed only slightly in their steric properties, as seen from comparison of bond

lengths and angles associated with the ruthenium center. However, their redox potentials, as determined

by cyclic voltammetry, are significantly higher than the one of the “parent” complex [RuCl(ind)(PPh3)2],

providing evidence that the ligands employed in the synthesis of the complexes are electron withdrawing.

As shown for a few examples, activation through chloride abstraction from the complexes resulted –

somewhat surprisingly – in a mixture of complexes.

All ruthenium complexes are active in the catalytic activation of propargylic alcohols to give

propargylic ethers and xanthenone derivatives (Scheme 1). The impact of the ligand structure on the

catalytic activity of the respective ruthenium complexes and the identity of possible reaction

intermediates is discussed.

Figure 1. Electronically tuned ruthenium complexes.

Figure 2. catalytic applications of electronically tuned ruthenium complexes in the synthesis of propargyl ethers (left) and xanthenone derivatives (right).

Talk

11:105

Investigation of environmentally responsive polymers as capping materials for aluminum nanoparticles Wenhui Zeng, Paul A. Jelliss, Steven W. Buckner

Department of Chemistry, Saint Louis University, St Louis, Missouri 63103 zengw@slu.edu

Environmentally responsive polymers have gained great attention due to their widely application in tissue engineering, drug delivery as well as catalysis. In this report, we explored the application of these ''smart'' polymers to energy and fuel area. We present the investigation of using photo-responsive polymer, poly(methyl methacrylate) (PMMA), and temperature responsive polymer, poly(N-isopropylacrylamide) (PNIPAM), as capping material for aluminum nanoparticles (Al NPs), respectively. The PMMA-Al NPs demonstrate good air stability, retaining high active aluminum content for many weeks after exposure under ambient air. After exposure to UV radiation, the PMMA-Al NPs react considerably faster with alkaline solutions to generate hydrogen, compared to unphotolyzed samples. The PNIPAM-Al NPs also demonstrate good air stability in a few weeks. The study indicates that the material reacted with dilute base much faster below the lower critical temperature (LSCT) than above. Powder X ray diffraction (PXRD) and Fourier transform infrared with total attenuated reflection (ATR-FTIR) spectroscopy confirms the crystalline aluminum cores and the presence of coating material, respectively. The Al NPs also characterized by Differential scanning calorimetry (DSC) coupled with thermogravimetric analysis (TGA) to study the thermal profiles for polymer combustion and metal ignition exotherms. Transmission Electron Microscopy (TEM) images show the visual information of the nanoparticles. Photolysis times of 1, 6, 24 and 52 hours were investigated to establish a minimum UV exposure time for the activation of the PMMA-Al NPs toward hydrolytic hydrogen gas generator. The results prove our concept that the energy storage in the material can be switch on when exposure to environmental stimuli.

Talk

11:355

Epitaxial lift-off of electrodeposited single-crystal gold foils for flexible

electronics

Naveen K. Mahenderkar, Qingzhi Chen, Ying-Chau Liu, Alexander R. Duchild, Seth Hofheins, Eric Chason,

Jay A. Switzer

Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409

nm53f@mst.edu

We introduce a simple and inexpensive procedure for epitaxial lift-off of wafer-size flexible and

transparent foils of single-crystal gold using silicon as a template.1 Lateral electrochemical

undergrowth of a sacrificial SiOx layer was achieved by photoelectrochemically oxidizing silicon under

light irradiation. A 28-nanometer-thick gold foil with a sheet resistance of 7 ohms per square showed only

a 4% increase in resistance after 4000 bending cycles. A flexible organic light- emitting diode based

on tris(bipyridyl)ruthenium(II) that was spin-coated on a foil exploited the transmittance and flexibility

of the gold foil. Cuprous oxide as an inorganic semiconductor that was epitaxially electrodeposited onto

the gold foils exhibited a diode quality factor n of 1.6 (where n = 1.0 for an ideal diode), compared with a

value of 3.1 for a polycrystalline deposit. Zinc oxide nanowires electrodeposited epitaxially on a gold foil

also showed flexibility, with the nanowires intact up to 500 bending cycles.

1. N. K. Mahenderkar, Q. Chen, Y.-C. Liu, A. R. Duchild, S. Hofheins, E. Chason, J. A. Switzer, Epitaxial

lift-off of electrodeposited single-crystal gold foils for flexible electronics. Science 355, 1203-1206

(2017).

Talk

12:005

Hydrated Ni(II) complexes with chelating cyanoximes: what happens when water is gone? Adademola Abraham Opalade,1 Carlos Gomez-Garcia,2 Nick Gerasimchuk1 1 Department of Chemistry, Missouri State University, Springfield, Missouri, USA 2 Institute Molecular Sciences, Valencia, Spain. NNGerasimchuk@MissouriState.edu

A series of Ni(II) complexes with chelating cyanoximes shown below was obtained at ambient conditions from aqueous solutions.

NC N

OH

OC2H5O

NC N

OH

ON

NC N

OH

ON

NC N

OH

OH2N

NC N

OH

N

HACO HECO HPyrCO HPiPCO H2PCO Synthesized metal complexes were characterized by elemental analysis, thermal analysis, IR and electronic (solid state, diffuse reflectance) spectroscopies and X-ray analysis.

Two metal complexes – [Ni(ACO)2(H2O)2] and [Ni(2PCO)2(H2O)2] – form molecular, island type structures with rhombically distorted octahedral Ni(II) environment. In both complexes the cyanoximes act as chelating ligands, adopt cis-anti, nitroso- structures and form complexes with cis-geometry of mutually oriented anions in equatorial plane. Water molecules occupy axial positions. These water molecules are engaged into the system of H-bonding that helps molecules to pack into crystals.

Careful heating of several Ni(II) complexes, such as [Ni(ACO)2(H2O)2], [Ni(ECO)2(H2O)2], [Ni(2PCO)2(H2O)2], [Ni(PyrCO)2(H2O)2] and [Ni(PiPCO)2(H2O)2], at pre-determined by the DSC/TG analysis temperatures, allowed removal of coordinated water. The process is reversible for the first four complexes. Data of the XRD powder diffraction shows that in some cases the lattice is changed upon dehydration.

Data of solid state electronic spectroscopy evidenced the retention of the geometry of central atoms during dehydration process in as [Ni(ECO)2], [Ni(ACO)2], [Ni(2PCO)2], [Ni(PyrCO)2] and [Ni(PiPCO)2], which suggests developing bridging function of cyanoximes in the lattice upon water loss. The latter was confirmed by thermos-magnetic measurements in the range of 6 – 300 K with evidence of the antiferromagnetic coupling in formed chain of NiL2.

Talk

2:00

Synthesis and reactivity of organometallic NiII and NiIII compounds Sofia M. Smith, Jason W. Schultz, Nigam P.Rath, Liviu M. Mirica

Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899 smsmith@wustl.edu

Recently, the isolation and characterization of various mononuclear Ni(II), Ni(III) and Ni(IV) complexes using the tetradentate ligand, N,N’-di-R-2,11- diaza[3.3](2,6)pyridinophane (R = tert-butyl or methyl) have been reported.1-3 As a result, other variations of the pyridinophane ligands have been synthesized and their effect on the stability and reactivity of the corresponding Ni complexes was studied. To better understand the importance of the tetradentate nature of these pyridinophane ligands, a modification was made to make the pyridinophane macrocycle act as a pseudo-tridentate ligand or bidentate ligand, hereby trying to destabilize the Ni center to prone faster reductive elimination leading to overall a faster reactivity. By studying the effects of the ligand on the Ni center, we aim to develop novel catalysts for oxidative C-C and C-heteroatom bond formation reactions.

1. Zheng B, Tang F, Luo J, Schultz J. W, Rath N. P, Mirica L. M. Organometallic nickel(III) complexes relevant

to cross-coupling and carbon-heteroatom bond formation reactions. J. Am. Chem. Soc. 2014; 136

(17): 6499-504.

2. Tang F, Rath N. P, Mirica L. M. Stable bis(trifluoromethyl)nickel(III) complexes. Chem. Commun. 2015;

51 (15): 3113-6.

3. Schultz J. W, Fuchigami K, Zheng B, Rath N. P, Mirica L. M. Isolated Organometallic Nickel(III) and

Nickel(IV) Complexes Relevant to Carbon-Carbon Bond Formation Reactions. J. Am. Chem. Soc. 2016;

138 (39): 12928-12934.

Talk

2:25

Ferrous pyruvic acid oxime: from an unusual formation mechanism to a material for sorption of arsenic from water Walleed Alamier, Travis Reed, Allen Apblett

Department of Chemistry, Oklahoma State University, Stillwater, OK 74078

allen.apblett@okstate.edu

Iron(II) pyruvic acid oxime, Fe(PAO)2 is a single source precursor for iron oxide that can be most directly synthesized as a powder by a precipitation reaction of aqueous solutions of ferrous chloride and sodium pyruvic acid oxime (NaPAO). However, it can also be produced in highly crystalline form by reaction of ferric chloride with three equivalents of NaPAO. This generates a dark red complex, presumably Fe(PAO)3, that slow converts to Fe(PAO)2 that grows as crystals. The kinetics of this transformation are unusual and will be discussed in light of a possible mechanism. Fe(PAO)2 decomposes at low temperature to produce acetonitrile, carbon dioxide, and water to produce an amorphous iron oxyhydroxide that is a useful sorbent for arsenic.

Talk

2:50

Synthesis and characterization of a novel ligand and its Ag (I) and Pd (II) complexes Chideraa Nwachukwu, Eric Bosch

Department of Chemistry, Missouri State University, Springfield

nwachukwu123@live.missouristate.edu

The research described here focusses on the preparation of a ligand specifically designed to complex silver and palladium with a long range goal of developing new ligands for the recovery of these metals from waste. Silver is one of the precious metals on earth, and is increasingly used in a wide variety of applications. These include the electronics industry, photography industry and in the medical field. Palladium, on the other hand is widely used as a catalyst for chemical transformations and in vehicle catalytic converters. In addition to economic incentives to recover these metals, it should be noted that these heavy metals often pose both environmental and health hazards. For example, low concentrations of silver has been shown to lead to the death of some aquatic species. The ditopic ligand is built on a 1,2-diethynylbenzene core that enables the trans coordination of metal cations such as silver (I) and palladium (II). In the design of this ligand, a pyridyl and an imidazoyl moiety are attached to the ethynyl groups to act as a linear bidentate ligand capable of deprotonation after metal ion complexation. Long range plans involve the attachment of these ligands to a polymer support for the extraction of these cations from waste.

Talk

3:30

Rhenacarborane complexes for peptide delivery across the blood-brain barrier (BBB)

Daniel G. Pruitt,1 Kristin Bullock,2 William A. Banks,2 Paul A. Jelliss1,*

1 Department of Chemistry, Saint Louis University, St Louis, Missouri 63103, USA. 2 Department Internal Medicine, University of Washington, Seattle, Washington, USA.

jellissp@slu.edu

The search for non-invasive neural therapeutics is a problematic pursuit often hindered by the blood-

brain barrier (BBB), a gatekeeper of endothelial cells and tight junctions closely regulating exchange

between the bloodstream and brain tissue. A recent study of the complex [3-NO-3,3-2-(2,2'-

N2C10H6(Me){(CH2)7131I}-4,4')-closo-3,1,2-ReC2B9H11] (1) (Figure 1) demonstrated its ability to not only

safely pass through the BBB but also cleanly efflux out of neural tissue, suggesting potential use as a

drug-delivery vehicle for Central Nervous System (CNS) infiltration.1 However, due to the practical

difficulty of asymmetric modification of the bipyridyl ligand, a more direct synthetic approach of

carborane cage vertex adaptation has been investigated with the hope of utilizing such species for CNS

therapeutics.2 A second prototype of [3,3-(CO)2-3-NO-closo-Re(8-O(CH2)2O(CH2)2131I-3,1,2-C2B9H10)] (2)

(Figure 1) was rapidly absorbed into the bloodstream from the subcutaneous site of injection and

displayed a 1 %Inj/g for peak brain uptake, which rapidly stabilized to 0.1 while the previous complex 1

merely peaked at 0.1 %Inj/g. It was also determined that peak brain uptake of 15 ml/g was higher than

lung and liver tissues, suggesting that the brain is somehow specifically targeted, while the exact

rationale for selectivity remains to be explored. Recent experiments suggest that peptidyl coupling with

both amino acids (tyrosine) and oligopeptides (methionine-enkephalin) has been successful. The latter

bioorganometallic conjugate is designed to target opiate receptors in the brain.

Figure 1.

1. P. Hawkins, N. Nonaka, W.A. Banks, P.A. Jelliss, and X. Shi, J. Pharmacol. Exp. Ther., 2009, 329, 608-

614.

2. D.G. Pruitt, S.M. Baumann, G.J. Place, A.N. Oyeamalu, E. Sinn, and P.A. Jelliss, J. Organomet. Chem., 2015, 798, 60-69.

Talk

3:55

2

Abstracts – Poster Session

3

Towards a better understanding of fine-tuned ruthenium catalysts for

propargyl substitution reactions

Matthew J. Stark, Michael J. Shaw, Arghavan Fadamin, Nigam P. Rath, and Eike B. Bauer*

Department of Chemistry, University of Missouri - Saint Louis, Saint Louis, Missouri 63121

mjs2qc@umsl.edu

As part of ongoing efforts in our laboratory, we have studied scenarios where the electronic tuning of ligands can affect catalytic performance. For this study, we hypothesized that we would observe a change in catalytic activity across different Ruthenium catalysts that contain ligands of increasing electron-withdrawing capacities. Catalytic propargyl etherification was compared using

three metal complexes of the formula [RuCl(η5-C9H7)(PPh3)(L)], where L is triphenylphosphine (PPh3),

tris(4-trifluoromethylphenyl)phosphine, or tris[3,5-bis (trifluoromethyl)phenyl]phosphine. The ligands were added to the ruthenium complex by thermal exchange of PPh3 with the trifluoromethyl-

containing aryl phohspines. Characterization of the metal complexes by cyclic voltammetry resulted in oxidation potentials that followed an expected trend; as the number of trifluoromethyl groups that were added to the phosphines increased, the oxidation potential also increased. The X-ray structures for the two new complexes were obtained; the Ru-P bond lengths showed no significant differences when comparing the trifluoromethyl-containing aryl phosphines to PPh3 only complex.

The metal complexes were then employed as catalysts in propargyl etherification reactions, where a handful of known reactions were compared for differences. Amongst the three tested metal complexes, all isolated yields were very similar, with small differences due to the reactivity of the starting materials that were used. Product formation was monitored via NMR over time to determine rates of catalysis for each complex. All three metal complexes performed within error of one another, supporting the findings of very similar isolated yields. Our studies may also seem to indicate a surprisingly large role of the counter-ion in this particular catalytic process.

Poster

1

4

Lithium diffusion coefficient in hard carbons with different structures via galvanostatic intermittent titration technique and open cell relaxation Waruni Jayawardana, Christopher Carr, Eric Majzoub

Department of Physics, University of Missouri-St. Louis, St. Louis, Missouri 63121

wjpp9@umsl.edu

Rechargeable Li-ion batteries operate through Li-ion insertion and deinsertion into active materials in both the anode and cathode. During lithium insertion into the graphite electrode ions transport across the electrolyte and diffuse into the active electrode material. The Li diffusion coefficient determines how fast Li ions can move in the electrode and how fast the battery may be charged or discharged, and is therefore important for high-C-rate charging characteristics. Current state-of-the-art Li-ion batteries utilize graphite, but hard (amorphous) carbons have larger capacity and may be prepared with ordered pore structures that have other benefits that include infiltrating the pores with higher capacity active material and providing an electrically conductive framework that also has some lithium intercalation capacity. We investigate the lithium diffusion coefficients of a variety of hard carbons of various preparation techniques, and possessing varied pore sizes and surface areas using a titration method related to the galvanostatic intermittent titration technique (GITT). In GITT one measures the equilibrium cell potential during galvanostatic charging. We compare the Diffusion coefficients from GITT with our new approach that extracts a time constant from the experimental relaxation curves between galvanostatic charging. The presented technique is able to measure the diffusion coefficient while on a voltage plateau. We discuss the diffusion coefficients as a function of the carbon pore volume, surface area, and long range ordering.

Poster

2

5

Influence of functionalized nanoporous carbons on the properties of confined NaAlH4 Christopher Carr, Waruni Jayawardana, Eric Majzoub

Department of Physics, University of Missouri-St. Louis, St. Louis, Missouri 63121

wjpp9@umsl.edu

The need for hydrogen-fueled vehicles is increasing due to energy, environmental and socioeconomic reasons. Efficiency and safety have become the main challenges in commercialization of hydrogen-fueled vehicles. The ideal properties of a hydrogen storage material would be reversibility, high energy density and the ability to release hydrogen at 1 bar overpressure with an enthalpy of 15-30 kJ/mol[H2] at temperatures around 100 °C. Sodium alanate (NaAlH4) is one of the few such candidate

materials. NaAlH4 is a complex metal hydride having high gravimetric hydrogen content (7.4 wt % H2)

and suitable thermodynamic properties for proton exchange membrane (PEM) fuel cell applications.

However, due to kinetic limitations, pure NaAlH4 is incapable of releasing enough hydrogen before its

melting temperature (180 °C). Nano-sizing, nano-confinement and mixing with catalysts are some of

the approaches to improve metal hydride kinetics. In this work, we use nano-confinement to

change the kinetic properties of NaAlH4 by increasing its surface-to-volume ratio and allowing interaction with the large surface area of the nano-framework. Our nano-frameworks used to confine the sodium alanate are carbon based, and the surface electron density of these carbons can be controlled via addition of boron or nitrogen to respectively decrease or increase the electron density and alter the interaction of the carbon surface with any infiltrates. Two types of carbon morphologies are used: (i) hexagonal packing of cylindrical pores, and (ii) the 3D compliment of this geometry. Each morphology is prepared in both nitrogen-doped and non-nitrogen doped versions. We

investigate and compare the kinetic properties between doped/un-doped carbons in both geometries

after melt infiltration with NaAlH4.

Poster

3

6

The silver cyanoximate bullet: investigations into biocidal effects of silver

complexes in medical resins

Snow Popis, Nikolay Gerasimchuk

Department of Chemistry, Missouri State University, Springfield, Missouri

snowmail87@gmail.com

The bacterial adhesion, and development of biofilms can occur after an implant surgery up until two-

years later with acrylic resins joint or dental implants, and bone cements in >1% of patients, requiring

drastic treatment. What is the long-term bioactivity of silver(I)cyanoximate complexes in acrylic resin

composites compared to silver nitrate for medical application? To evaluate, a modified flowable

dental composite, each enriched with one of the twelve light-stable silver cyanoximates

complexes at ranges from .05 to 5 wt% was made to test the minimum inhibitory concentrations

(MIC), with the biocide, chlorhexidine, against several common human biofilm forming pathogens.

Due to the modification of the polymeric resin, characterization of the silver doped resin was

required using The Standard Test Method for Compressive Properties for Rigid Cellular Plastics, and a

solution silver leaching test for ionization of silver (I) complex, related directly to complex stability

within resin.

These investigations seek to find if light stable silver(I)cyanoximates complexes able to prevent

biofilm formation on indwelling medical devices, while the medical implant retains its vital

characteristics.

Poster

4

7

Synthesis and characterization of potential NIR emissive platinum complexes of cyanoximate ligands Alec Neeson, Nikolay Gerasimchuck Department of Chemistry, Missouri State University, Springfield, Missouri Alec777@live.missouristate.edu

A novel set of potential NIR emissive platinum complexes with cyanoximate ligands have been synthesized. Extensive characterization of the 1-D polymeric structures and ligands were determined through use of X-ray crystallography, DSC-TCA, UV-Vis, Mass spectrometry, NMR spectroscopy, and Infrared spectroscopy. Of the several ligands, quantum yields have been obtained for HMCO and

HPiPCO complexes of platinum. These complexes of Pt(MCO)2 and Pt(PiPCO)2 have been shown to be NIR (near-infrared) emissive. NIR emissive compounds have been shown to be promising in the relatively new field of theranostics (diagnostic and therapeutic usage of drugs). Several other complexes of Pt are yet to be experimentally verified to have NIR emissive properties. These emissive properties are quite favorable for theranostic drugs due to human skin being virtually transparent to NIR radiation.

Poster

5

8

Cytoxicity of platinum and palldium cyanoximates on cervical and colon cancer cells Stephanie Dannen, Nikolay Gerasimchuk, Paul Durham

Department of Chemistry, Missouri State University, Springfield, Missouri

stephanie3553@live.missouristate.edu

Four novel platinum and palladium cyanoximate complexes were synthesized and tested in cytotoxicity assays of cultured HeLa (cervical adenocarcinoma) and WiDr (colon carcinoma) cells with Cisplatin as a positive control. Cyanoximes are a diverse group of ambidentate organic ligands which easily form organo-metallic complexes and have been shown to have substantial biological activity (growth regulating, antimicrobial, anticancer, etc). Combined with the anti-tumor activity of platinum and palladium, these compounds have shown levels of cytotoxicity comparable to Cisplatin in previous studies. Cisplatin and other platinum-based anti-cancer drugs are among the most often prescribed chemotherapeutic agents. However, side effects of such compounds can be severe and dose-limiting, and some types of cancer can develop resistance to current platinum based therapies. Limited solubility of these drugs in human tissues is also well known. Although palladium is a less toxic and more cost effective alternative to platinum based therapies, its cytotoxicity in human cells has not been as thoroughly studied.

Poster

6

9

Charge carrier dynamics in CdTe quantum wires

William M. Sanderson, Jessica Hoy, Fudong Wang, William E. Buhro, Richard A. Loomis

Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899 wsanderson@wustl.edu

Semiconducting nanocrystals have a wide impact in light energy harvesting materials, photovoltaics, and light-emitting devices. Our current research focuses on charge carrier dynamics in CdTe quantum wires (QWs), which offer the benefits of tunable band gaps, similar to quantum dots, but also the dimensionality for efficient charge transport over microscopic distance. As is true for most nanomaterials, the surfaces dictate the dynamics of charge carriers created in them. We passivate the surface of our CdTe QWs with CdS to form a pseudo-type I heterostructure, and observe an increase in photoluminescence quantum yield (PLQY) from 0.05 - 25%. We use transient absorption and time-correlated single-photon counting spectroscopy (TCSPC) to characterize the charge carrier relaxation dynamics in real time. A strong correlation between PLQY and the kinetics of the charge carriers is observed.

Poster

7

10

Study on low-valent nickel and palladium complexes

Giang N. Tran, Liviu M. Mirica

Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899

gtran@wustl.edu

A series of Ni(II) and Pd(II) complexes supported by multidentate ligands N2S2 and NCS2 (N2S2 = 2,11-

dithia[3.3](2,6)pyridinophane; NCS2 = 3,11-Dithia-17-azatricyclo[11.3.1.15,9]octadeca-1(17),5,7,9(18),13,15-hexaene) were synthesized and characterized in this project. Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) show that low-valent Ni(I) and Pd(I) complexes can be accessed. Future goals include structural investigation of those low-valent metal complexes and studies on their reactivity towards different cross-coupling reactions.

Poster

8

11

Synthesis and reactivity of high-valent Pd-allyl complexes

Yung-Ching Wang; Nigam P. Rath; Liviu M. Mirica

Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899

wang.yung-ching@wustl.edu

During the past two decades it has been shown that high-valent palladium complexes play an increasingly important role in C-C and C-heteroatom bond formation reactions. In our previous studies, we have shown that the tetradenate ligand N,N′-di-tertbutyl-2,11 -diaza[3.3](2,6) pyridinophane (N4) can efficiently stabilize high-valent PdIII/IV complexes that undergo reductive elimination to make new C-C and C-heteroatom bond. We reported herein the isolation, structural, and spectroscopic characterization of RN4PdII complexes with allyl, cinnamyl and 2-methylallyl ligands (Figure 1).

Cyclic voltammetry and electron paramagnetic resonance spectroscopy show that the (RN4)PdIII

complexes are accessible and we are currently working on isolating these systems. Initial reactivity

studies show that (RN4)PdII complexes can undergo C-N bond formation upon addition of the NFSI

(N-fluorobenzenesulfonimide) oxidant. Additional reactivity and spectroscopy results will also be

presented.

Poster

9

12

ESR studies of the molecular motion of the bis(maleonitriledithiolato)nickel

monoanion and trianion in diglyme

Bruce A. Kowert*

Dept. of Chemistry, Saint Louis University, St Louis, Missouri 63103-2010

kowertba@slu.edu

The bis(maleonitriledithiolato)nickel trianion, [Ni(mnt)2]3−, and monoanion, [Ni(mnt)2]

−, are

paramagnetic with S = ½. The molecular motion of [Ni(mnt)2]3− has been studied in diethylene glycol

dimethyl ether (diglyme) using X-band electron spin resonance (ESR); it was prepared by reducing the

dianion, [Ni(mnt)2]2−, with potassium metal. Simulations of the temperature-dependent spectra of the

trianion and the monoanion, also in diglyme, showed that different motional models were needed to

produce agreement with experiment. Isotropic Brownian rotational diffusion was used for [Ni(mnt)2]3−

while axially symmetric reorientation with a diffusion rate three times faster about the long in-plane axis

was required for [Ni(mnt)2]−; the calculated spectra also show the reorientation of [Ni(mnt)2]

3− to be

slower than that of [Ni(mnt)2]−. These models and reorientation rates indicated that the two ions have

different shapes and sizes in solution; they are consistent with [Ni(mnt)2]3− being ion-paired while, in

accord with conductivity, vapor phase osmometry, and translational diffusion data, [Ni(mnt)2]− is not.

Ion paring of the trianion has been confirmed by recent electronic structure calculations.

Poster

10

13

d-Electron count, ion-pairing and diagonal twist angles in metallo-bis(dithiolene) complexes

Charles C. Kirkpatrick, John N. Truong, Bruce A.Kowert Dept. of Chemistry, Saint Louis University, St Louis, Missouri 63103-2010

kirkpacc@slu.edu

Electronic structure calculations for late transition metals coordinated by two dithiolene ligands are found to be consistent with existing structures and also predict the geometries of Ni(I) species for which no solid state structures have been reported. Of particular interest are the compounds [M(mnt)2]

n− (M = Ni, Pd, and Pt with n = 1, 2, 3; M = Cu with n = 2). Calculations have been performed with and without ion-paring with M(diglyme)+ (M = Li, Na, K) and R4N

+ (R = Me, Bu). The diagonal twist angle between two NiS2 planes is found to depend on (i) the metal’s d-electron count, spanning from 0o (planar d7 and d8), to 42o (d9), to 90o (pseudo-tetrahedral d10), and (ii) the identity of the ion-paired cations. Calculated ion-pairing energies are functions of the cation size and charge-density, being larger for alkali-metal coordinated diglyme and smaller for tetra-alkyl ammonium cations.

Poster

11

14

Carborane passivated aluminum nanoparticles

Alexander Benziger, Michael West, Sophia E. Hayes, Steven W. Buckner, Paul A. Jelliss

Department of Chemistry, Saint Louis University, St. Louis, MO, 63110, USA

benzigerah@slu.edu

Aluminum nanoparticles have been synthesized and successfully passivated with an o-carborane

cap. Previous studies have performed this process using epoxides and alkenes with great success. Aluminum nanoparticles have been studied for many potential energy storage applications, such as potential fuel additives or solid rocket fuels. Boron nanoparticles have been studied for similar applications in energetic as fuel additives. Through passivating the nanoparticles with o-carborane, a highly stable and energetic material has been synthesized. This presentation will focus on the characterization of this novel material. Powder X-Ray Diffraction has been used to confirm the synthesis of fcc aluminum, and the presence of crystalline o-carborane. It is seen that over 24hours, the o carborane peaks disappear from the pattern; however the aluminum stays, suggesting the occurrence of a chemical transformation involving the carborane at the metal core surface. Transmission electron microscopy has been used in conjunction with Scherrer analysis to determine particle sizes. Nanoparticles have been destroyed in water, and the resulting solutions have been studied by 11B{1H} NMR spectroscopy. Solid State 11B NMR has also been performed on aged nanoparticles, in an attempt to identify the fate of the carborane.

Poster

12