Research



Our research interests are strongly rooted in creative chemical synthesis. This is an intentionally broad description. Since we draw no boundaries between inorganic and organic chemistry, we work with elements from all over the periodic table. The overall goal of our program is to develop novel and creative chemical solutions to the most urgent and challenging unsolved problems in synthetic chemistry. The unifying theme in our research is the strategic use of 3-dimensional aromatic carborane clusters. Nearly all molecules prepared in our lab contain at least one carborane.


What is a carborane?

A carborane is cluster of boron that contains at least one atom of carbon, and displays an open or closed polyhedral shape. At first glance the carbon and boron atoms of the carborane cluster depicted to the right may appear to defy the octet rule, since each of these atoms makes 6 chemical bonds. However, the bonds that hold the cluster together are not 2-center 2-electron bonds, but 3-center two electron bonds, which explains how each atom of the cluster does not exceed their octet. While we utilize several different kinds of carborane clusters, most of our work focuses on utilizing the icosahedral carba-closo-dodecaborate anion, depicted to the right (carba means there is one carbon, closo means the cluster is closed shell, dodeca means there are 12 faces in the polyhedron, borate indicates the cluster bears a negative charge). Traditionally such carborane anions have been used as spectator non-coordinating anions that are legendary for their inert properties. Our approach differs in that we incorporate the carborane anion into complex molecules via covalent linkages and leverage their special properties to create new directions in chemistry


Ligand and Transition Metal Catalyst Design

One of the most prominent themes in our group is transition metal catalyst design, which can allow for the development of novel chemical transformations that are useful for industries ranging from energy to pharma, and thus the general public. Ligands are essentially substituents around a metal center that can modulate the properties of a metals reactivity. In some cases the metal with bound ligands can act as a catalyst for useful organic transformations(e.g. Pd coupling reactions, olefin polymerization, olefin metathesis, etc.). One of the key themes in our group is incorporating anionic carborane clusters into ligand frameworks, with the specific intent of making novel and superior ligands for transition metal catalysts. One can think of a the anionic carborane group as a super alkyl or aryl group that is bigger and better.


Ionic Conducting Materials for Multivalent Ion Batteries Beyond Lithium

Lithium ion batteries are indispensable components for portable devices such as cell phones, laptops, and electric vehicles. However, Lithium is a non-abundant earth element (0.0017% of the earth's crust) and thus the technology is not sustainable. Moreover, Lithium batteries are prone to catastrophic failures that results in fires and explosions that pose a safety hazard. The LaVallo group aims to develop batteries that are safer, have higher energy density, and are sustainable in the long term. Our approach to solve these problems is the development of multivalent ion batteries. Such batteries can hold more than one electron and many multivalent elements are earth abundant. One of the key breakthroughs that we recently reported is a special magnesium battery which operation is facilicated by carborane containing materials developed by the LaVallo lab. We focus on the enabling chemistry in the battery development and actively collaborate with engineers and scientists at UCR as well as at several national laboratories.



Radical Chemistry

Radicals play important roles in conducting polymers, spin carriers for solar cell applications and a variety of other functional materials. We are developing new materials based on carborane clusters that display unusual physical and electronic properties. Similar to our approach with catalysis, we covalently link the carborane to platforms for elaboration. The spherical shape and delocalized skeletal electrons of the carborane core are utilized to produce materials with tunable redox properties. An exciting discovery in this area is our recent report of a family of isolable carborane-fused triazole radical anions. Also, we are currently in collaboration with multiple groups working towards the improvement of boron carbide materials, namely creating a more ductile boron carbide material through microalloying.