Inorganic chemistry; organometallic chemistry; materials chemistry and solid state science; new sensor development, renewable energy systems (photovoltaic), forensic science

New Designs in Photovoltaic Materials: We are working on the

development of a new designs for future generations of photovoltaic materials, focusing on overcoming several of the considerable obstacles currently limiting existing devises. One of our approaches, involves a pathway that has not thus far been explored and utilizes a multi-component system incorporating an electron reservoir macrocyclic system that is coupled to both a photosensitizer, such as a dye molecule, and a semiconductor electron transport material. In this arrangement, an absorbed photon can cause a one-electron photoreduction of the reservoir via photon absorption, electronic excitation and injection from an

attached dye or donor molecule into the reservoir. Spatial and orbital barriers to recombination can be designed to provide a sufficient lifetime of this reservoir’s excited state for promotion of the electron into a high enough energy level through independent photochemical steps to be either irreversibly injected into the conduction band of the attached semiconductor, or by the removal of the hole by the electrolyte, typically through a diffusion-controlled process. Several types of electron reservoirs are being investigated, including carborane-based macrocycles and donor-bridge-acceptor systems (such as shown in Figure 1). Functionalized borane and carborane cages are well known to be exceedingly stable species that undergo multiple redox steps, and molecular orbital calculations suggest that these macrocycles will serve well in the electron-reservoir capacity These systems provide a significant degree of potential chemical tailoring of electronic properties that should make them particularly interesting as new and efficient photovoltaic cells.

Caption. An example of a cluster-based reservoir built of carborane units with pendant dye molecules, shown in geometry-optimized space-filling and line-structure forms.

A second approach uses the straightforward noncovalent functionalization and solubilization of hexagonal-boron nitride nanosheets (BNNSs) by reacting various polymers, such as polythiophene or polyvinylpyrrolidone polymers, with exfoliated BNNSs. BNNS are boron analogs of grapheme, but with some quite different chemical and electrical properties desirable for various applications. The boron nitride nanosheets apparently form strong π − π stacking interactions with the polymers to yield stable derivatized nanosheets with modified properties. These functionalized polymers, tethered to the exfoliated BNNSs, can be further coordinated to pre-formed TiO2 nanoparticles to form more complex BNNS-polythiophene-(CH2)n-COO-TiO2 hybrid nanomaterials through covalent binding, including electron delocalized systems. The resultant stable BNNS-polythiophene heterostructures form a platform for entirely new hybrid systems combining both boron nitride nanosheets and inorganic nanoparticles. These heterostructures have now been found to generate a photocurrent upon exposure to light.

Caption: Schematic for the formation of BNNS-polythiophene-TiO2 hybrid nanomaterials.

Caption: Piezoelectric crystal sensor motion induced by electric field oscillation.

New Ultra Sensitive and Selective Sensors:
In the second area of our work, we are developing exciting new generations of sensors with extreme response and selectivity properties. These sensors are based upon the use of modified and/or functionalized piezoelectric solid state systems, especially Quartz Crystal Monitor-based (QCM) devices. QCM-based devices, utilizing this approach, have been used for decades for measuring mass changes during deposition processes. Sensors based upon the electronic response (e.g., frequency, phase and/or jitter) of such piezoelectric devices to surface-bound mass provides an excellent platform for the selective detection of key target molecules. In our work, we are employing piezoelectric-based functionalized solid state materials to detect with ppb (or better) sensitivity and exceptional selectivity molecules of specific targeted interest. We are collaborating with a group from engineering to prepare devices with unique properties for a variety of technological problems, including rapid medical diagnostics, environmental monitoring and threat agent detection. Recent advances for our team regarding the measurement and processing of electronic information from these systems have the potential to significantly enhance the operation and increase the sensitivity of these devices.

Caption: Cluster building block (top, synthesized) and one of many possible nanostructures made from these units (bottom, calculated structure).

Polyhedral Chemistry:
In a third area of our work, we are exploring the chemistry of main group polyhedral clusters. The field spans the boundaries of traditional areas of inorganic, organometallic, and materials chemistry. Specifically, our research has focused upon the study of polyhedral based as new nonlinear optical compounds, the photochemical reactions of clusters, and the use of cluster and rigid molecules as molecular building blocks in the directed formation of nanoscale architectures. Main group and organometallic clusters have presented considerable challenges to synthetic, structural, materials and theoretical chemists since their discovery nearly ninety years ago. The quest for a detailed understanding of the bonding and structural relationships of these species has led to an understanding of some of the fundamental chemistry of molecular polyhedra in general.

The study of polyhedra, many-faced solids, has long intrigued and fascinated scientists and philosophers. Plato first described a series of five "pure" polyhedral bodies from which Archimedes later elegantly derived 13 semi-regular polyhedra. The field of cluster chemistry, however, most closely ties together the abstract study of pure polyhedra with the physical and chemical world. In particular, cluster chemistry may be thought of as the practical bridge between small molecule behavior, with more localized bonding, and that of extended solid arrays, with extensively delocalized electronic structures.

Caption: Neodymium boride materials prepared in our group.

A further aspect of our work focuses upon the development of new solid state boron-based materials as thin films, nanoparticles, and nanotubes. These materials display an enormous range of physical and chemical properties that have direct application to many areas. We have recently discovered several new chemical pathways for the formation of thin films of metal borides, along with the first-reported pathways for the fabrication of boron-based nanotubes and nanorod structures. These unique structures, for instance, are readily prepared, are remarkably uniform, and display very large aspect ratios.

Caption: Chemical vapor deposition (CVD) reactor

• Chancellor's Citation for Excellence, 2013.
• Distinguished Achievements in Boron Science, 2000
• Laura J. and L. Douglas Meredith Professor, 2009 to present
• Excellence in Teaching Award, University College, Syracuse University, May 2009
• Member, New York Academy of Science, 2012 to present and American Academy of Forensic Science, Criminalistics Division, 2010 to present.

• Associate Dean for Science, Mathematics, and Research, College of Arts and Sciences, Jan. 2009 to June 2014. Chair, College Science and Math Council.
• Founder and First Executive Director, Syracuse University Forensic and National Security Sciences Institute.
• Director, Syracuse University Soling Program, 2004 to 2009.
• Interim Director, Renée Crown University Honors Program, 2010 to 2011.
• Core Faculty Member, Honors Program, 2004 to 2009.
• American Academy of Forensic Science, Criminalistics Division, 2010 to present.
• Founding Director at SU for the National Science Foundation Research Experiences for Undergraduates (REU) Site (1988 - 1994).
• Music Director, Syracuse University Brass Ensemble, 1987 to present.

• Miller, R.W. "The Synthesis and Reactivities of Organometallic Palladium Compounds and Phosphorus Containing Borane Cages", Syracuse University Ph.D Thesis, Department of Chemistry, October 1990.
• Cendrowski-Guillaume, Sophie M. "Solution Chemistry and Reactivity of Samarium(II) with Borane and Carborane Clusters and Solution Stability and Reactivity of Pentaborane(9)", Syracuse University Ph.D Thesis, Department of Chemistry, April 1992.
• Goodreau, Bruce H. "Inorganometallic Chemistry: A Study of Main Group and Iron Substituted Pentaboranes" Syracuse University Ph.D Thesis, Department of Chemistry, June 1992.
• Kher, Shreyas S. "New Synthetic Routes to Metal Boride Thin Films and Metallaboranes" Syracuse University Ph.D Thesis, Department of Chemistry, February 1993.
• Davis, Craig M. "Boron Hydrides: Photochemistry, Transition-Metal Derivatives, and Reactions with Novel Phosphorus Reagents" Syracuse University Ph.D Thesis, Department of Chemistry, March 1993.
• Glass, John A., Jr. "Theoretical and Materials Chemistry of Some Group III and V Elements" Syracuse University Ph.D Thesis, Department of Chemistry, November 1993.
• Tan, Yexin "Studies of Main Group Materials" Syracuse University Ph.D Thesis, Department of Chemistry, April 1995.
• Taylor, Jesse “The Synthesis and Characterization of New Metallaborane and Carborane Derivatives on the Way to Novel Nonlinear Optical Materials and Molecular Nanosystems” Syracuse University Ph.D Thesis, Department of Chemistry, 2001.
• Newlon, Amy "The Synthesis and Structure of Novel Carborane Based and Related Nonlinear Optical Materials" Syracuse University Ph.D Thesis, Department of Chemistry, 2003.
• Caruso, John D. "A Study of the Role of Polyhedral Borane Compounds in Solid State Materials, Nanotechnology and Main Group Cluster Substitution Chemistry" Syracuse University Ph.D Thesis, Department of Chemistry, 2003.
• Allis, Damian G. "Computational Quantum Chemistry In Initial Designs and Final Analyses. Approximate Methods in Nonlinear Optical Materials Design, Molecular Electronics, Molecular Nanotechnology, Inelastic Neutron Scattering Spectroscopy, and Molecular Crystal Engineering" Syracuse University Ph.D Thesis, Department of Chemistry, 2004.
• Romero, Jennifer V. “A Study on the Formation of Solid State Nanoscale Materials Using Polyhedral Borane Compounds” Syracuse University Ph.D Thesis, Department of Chemistry, September 2008.
• Ma, Pei “Thermal and photochemical reactions of large metallaborane clusters and functionalizations of boron nitride nanosheets”, Syracuse University Ph.D Thesis, Department of Chemistry, August 2013.
• Chris Petrelli “The synthesis, characterization, and application of carborane-cluster based macrocycles and boron nitride nanosheets in photovoltaics” Ph.D. Dissertation, Syracuse University, Dec. 2014.
• Tyna Meeks “Assessing the Quantified Impact of POGIL on an Introductory Forensic Science Survey Course” Syracuse University Ph.D Thesis, Department of Science Teaching, Dec. 2015.
• Casey Simons “The synthesis, characterization, and application of new rigid species for application as nonlinear optical materials and organometallic catalysts” Ph.D. Dissertation, Syracuse University, Mar. 2015.
• Craig Shewood “ Photochemical reactions or organoborane cluster species and the synthesis and characterizations of new constrained organoboron compounds” Ph.D. Dissertation, Syracuse University, in progress.
• Harvey Mosher “The formation, characterization and application of chemically functionalized nQCM surfaces for the selective detection of chemical and biological species” Ph.D. Dissertation, Syracuse University, in progress.

• Kher, S. S.; Romero, J.V.; Caruso, J.D.; Spencer, J. T. Chemical Vapor Deposition of Metal Borides. 6. The Formation of Neodymium Boride Thin Film Materials from Polyhedral Boron Clusters and Metal Halides by Chemical Vapor Deposition. Appl. Organomet. Chem. 2008, 22, 300-307.
• Taylor, J.; Vargas, W.; Torvisco, A.; Ruhlandt-Senge, K.; Spencer, J. T. “Synthesis and Characterization of Cyano-Substituted Carborane-based Compounds. Molecular Structure of [1-(4-C7H7)-12-(C5H3-3-(CN)-3,4-(CH3)2)-C2B10H10].” Dalton Trans. 2011, 40, 20585-91.
• Ma, Pei; Smith, Tiffany M.; Zubieta, Jon; Spencer, James T. “Synthesis of Alkoxy Derivatives of the 10-Vertex Manganadecaborane [nido-6-Mn(CO)3B9H13][NMe4]” Inorg. Chem. Commun. 2014, 46, 223-225.
• Ma, Pei; Spencer, James T. “Non-covalent Stabilization and Functionalization of Boron Nitride Nanosheets (BNNSs) by Organic Polymers: Formation of Complex BNNSs-containing Structures.” J. Materials Science 2015, 50(1), 313-323.
• Schlereth, F.H.; Mahabalagiri, A.K; Khadeer, A.; McLoed, T.; Spencer, J.T.; Sweder, K.S. “Frequency Measurement for QCM Applications” Proc. IEEE, International Conference on Industrial Instrumentation and Control (ICIC 2015), 2015, 1140 – 1143.
• Petrelli, Christopher; Goos, Alan; Ruhlandt-Senge Karin; Spencer , James T. “Functionalization of Boron Nitride Nanosheets (BNNSs) by Organic Polymers: Formation of Subtituted Polythiophene-BNNS Structures” in press J. Materials Science 2016.
• Ma, Pei; Smith, Tiffany M.; Zubieta, Jon; Spencer, James T. “Thermal Versus Photochemical Pathways of a Manganese 10-Vertex Metalladecaborane: [nido-6-Mn(CO)3B9H13][NMe4]” in press Polyhedron 2016.
• Textbook: James T. Spencer, Textbook in Forensic Science “Introduction to Forensic Science: The Science of Criminalistics”, Cengage Learning (completed and under contract, due out 2017).
• Ma, Pei; Spencer, James T. “Photochemistry: a new avenue for borane and metallaborane cluster chemistry?” Inorganic Chemistry Communications 2018, 89, 78-82.
• Ma, Pei; Smith Pellerizi, Tiffany M.; Zubieta, Jon; Spencer, James T. “Thermal and Photochemical Pathways of a 10-Vertex rhodium Metalladecaborane” Inorganica Chimica Acta 2018, 477, 242-247.
• Ma, Pei; Spencer, James T. “Nido-manganadecaborane: [nido-6-Mn(CO)3B9H13][ NMe4] Cyclodimerization of isocyanates promoted by one large vertex metallaborane” Polyhedron 2018, 149, 148-152.
• De Faria, R. A.: Abatti, P.J.; Spencer, J. T.; Sponsler, M. B. “Preparing of SU-8 to Build Nano-Gratings in QCM Surfaces for Micro Trace Detection” Proc. 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Engineering in Medicine and Biology Society, 2018 (July 17-21, Honolulu, HI, USA).
• Ma, Pei; Spencer, James T.  “Catalytic activity of a large rhodium metallaborane towards the [2+2+2] cycloaddition of alkynes” Inorganica Chimica Acta 2018, 482, 67-69.
• (87) Ma, Pei; Smith, Tiffany M.; Zubieta, Jon; Spencer, James T.  “Synthesis and characterization of oxonium functionalized Rhenium Metalloborane” Journal of Chemical Crystallography, 2019, 49, 1-7. (ISSN: 1074-1542 [Print], 1572-8854 [Online, https://doi.org/10.1007/s10870-018-0749-8])
• Romero, J.V.; Spencer, J. T. "Boron-containing Multiwalled Carbon Nanotubes Generated from the Aerosol Pyrolysis of Metal Boride Precursors" in preparation.
• Spencer, J. T. and F. Schlereth “Improved Piezoelectric Sensors and Quartz Crystal Monitors” Submitted US Patent Office Sept. 8, 2017:  USP No. 10295504 USPTO issued May 21, 2019 (100884 Utility Patent Application Number: 15/698,762 and 100884 Patent Cooperation Treaty (PCT) Application Number: PCT/US17/50595).
• Meeks, T.L.; Spencer, J.T. “Assessing the Quantified Impact of a Hybrid POGIL Methodology on Student Performance in and Introductory Forensic Science Course” J. Research Science Teaching, in preparation.