About

Chao Yu is an Assistant Professor of Integrated Marketing Communications at Northwestern University’s Medill School of Journalism, Media, and Integrated Marketing Communications. His research primarily explores the social impacts of new media, with a particular focus on digital commercial platforms that gather consumer behaviors. He employs big data analytics to uncover underlying patterns in new media platforms that may contribute to biases or inequalities. His goal is to identify effective policies and strategies to mitigate these issues and promote equitable outcomes. His academic background includes a PhD in Communication from Cornell University and a BA in Journalism from Peking University. His work has been published in high-impact journals such as Science Advances, New Media & Society, and the International Journal of Hospitality Management. His research contributions include studies on racial discrimination, bias reduction, and the social implications of online reviews and social media discussions, especially in the context of platforms like Airbnb and Yelp.

Research topics

• Physics
• Materials science
• Quantum mechanics
• Nanotechnology
• Chemistry
• Computer Science
• Nuclear magnetic resonance
• Condensed matter physics
• Computational biology
• Chemical physics

Selected publications

• Metal-hydrogen-pi-bonded organic frameworks

  Dalton Transactions · 2022-01-01 · 25 citations

  articleOpen access

  -a net topology. This unusual topology is enabled by the presence of free hydroxamic acid groups, which lead to the formation of a diverse network of cooperative interactions comprising metal-hydroxamate coordination interactions at single metal nodes, staggered π-π interactions between linkers, and H-bonding interactions between metal-coordinated and free hydroxamate groups. Such extensive, multimodal interconnectivity is reminiscent of the complex, noncovalent interaction networks of proteins and endows M-HAF-2 frameworks with high thermal and chemical stability and allows them to readily undergo postsynthetic metal ion exchange (PSE) between trivalent metal ions. We demonstrate that M-HAF-2 can serve as versatile porous materials for ionic separations, aided by one-dimensional channels lined by continuously π-stacked aromatic groups and H-bonding hydroxamate functionalities. As an addition to the small group of hydroxamic acid-based MOFs, M-HAF-2 represents a structural merger between MOFs and hydrogen-bonded organic frameworks (HOFs) and illustrates the utility of non-canonical metal-coordinating functionalities in the discovery of new bonding and topological patterns in reticular materials.

  PublisherOA PDFDOI

• A Molecular Approach to Quantum Sensing

  ACS Central Science · 2021 · 199 citations

  1st authorCorresponding
  • Computer Science
  • Computer Science
  • Nanotechnology

  The second quantum revolution hinges on the creation of materials that unite atomic structural precision with electronic and structural tunability. A molecular approach to quantum information science (QIS) promises to enable the bottom-up creation of quantum systems. Within the broad reach of QIS, which spans fields ranging from quantum computation to quantum communication, we will focus on quantum sensing. Quantum sensing harnesses quantum control to interrogate the world around us. A broadly applicable class of quantum sensors would feature adaptable environmental compatibility, control over distance from the target analyte, and a tunable energy range of interaction. Molecules enable customizable "designer" quantum sensors with tunable functionality and compatibility across a range of environments. These capabilities offer the potential to bring unmatched sensitivity and spatial resolution to address a wide range of sensing tasks from the characterization of dynamic biological processes to the detection of emergent phenomena in condensed matter. In this Outlook, we outline the concepts and design criteria central to quantum sensors and look toward the next generation of designer quantum sensors based on new classes of molecular sensors.

  PublisherOA PDFDOI

• Metal-Hydrogen-Pi-Bonded Organic Frameworks

  ChemRxiv · 2021-12-17

  preprintOpen access

  We report the synthesis and characterization of a new series of permanently porous, three-dimensional metal-organic frameworks (MOFs), M-HAF-2 (M= Fe, Ga or In), constructed from tetratopic, hydroxamate-based, chelating linkers. The structure of M-HAF-2 was determined by three-dimensional electron diffraction (3DED), revealing a unique interpenetrated hcb-a net topology. This unusual topology is enabled by the presence of free hydroxamate groups, which lead to the formation of a diverse network of cooperative interactions comprising single metal-hydroxamate nodes, staggered π–π interactions between linkers and H-bonding interactions between metal-coordinated and free hydroxamate groups. Such extensive, multimodal interconnectivity is reminiscent of the complex noncovalent interaction networks of proteins and endows M-HAF-2 frameworks with good thermal and exceptionally high chemical stability and allows them to readily undergo post-synthetic metal exchange (PSE). We demonstrate that M-HAF-2 can serve as versatile porous materials for ionic separations, likely aided by one-dimensional channels lined by continuously π-stacked aromatic groups and H-bonding hydroxamate functionalities. As a new addition to the small group of hydroxamate-based MOFs, M-HAF-2 represents a structural merger between MOFs and hydrogen-bonded organic frameworks (HOFs).

  PublisherOA PDFDOI

• Protein Assembly by Design

  Chemical Reviews · 2021 · 275 citations

  • Chemistry
  • Computational biology

  Proteins are nature's primary building blocks for the construction of sophisticated molecular machines and dynamic materials, ranging from protein complexes such as photosystem II and nitrogenase that drive biogeochemical cycles to cytoskeletal assemblies and muscle fibers for motion. Such natural systems have inspired extensive efforts in the rational design of artificial protein assemblies in the last two decades. As molecular building blocks, proteins are highly complex, in terms of both their three-dimensional structures and chemical compositions. To enable control over the self-assembly of such complex molecules, scientists have devised many creative strategies by combining tools and principles of experimental and computational biophysics, supramolecular chemistry, inorganic chemistry, materials science, and polymer chemistry, among others. Owing to these innovative strategies, what started as a purely structure-building exercise two decades ago has, in short order, led to artificial protein assemblies with unprecedented structures and functions and protein-based materials with unusual properties. Our goal in this review is to give an overview of this exciting and highly interdisciplinary area of research, first outlining the design strategies and tools that have been devised for controlling protein self-assembly, then describing the diverse structures of artificial protein assemblies, and finally highlighting the emergent properties and functions of these assemblies.

  PublisherOA PDFDOI

• Chemical Approaches to Quantum Information Science

  Bulletin of the American Physical Society · 2020-03-03

  article
  Publisher

• Dynamic Nuclear Polarization with Vanadium(IV) Metal Centers

  Chem · 2020-11-12 · 50 citations

  articleOpen access
  PublisherOA PDFDOI

• Spin and Phonon Design in Modular Arrays of Molecular Qubits

  Chemistry of Materials · 2020 · 76 citations

  1st authorCorresponding
  • Chemical physics
  • Condensed matter physics
  • Chemistry

  The transformative applications of quantum information science (QIS) require precise design and integration of networks of qubits, the fundamental units of QIS systems. Chemical synthesis is a powerful approach, offering routes to modular, atomically precise arrangements of identical qubits. Herein, we employed the versatility of framework chemistry to investigate spin and lattice dynamics of the expanded copper(II) porphyrinic framework Zr–Cu–NU-1102 (2) possessing Cu–Cu distances of 18.0 Å. Pulse electron paramagnetic resonance spectroscopy revealed a significant reduction in relaxation processes mediated by qubit–qubit interactions compared with the more spin-dense Cu–PCN-224 (1) framework. With the reduction in the spin–spin relaxation process, phonon-mediated processes emerged as the primary driver of spin–lattice relaxation. We synthesized the isoreticular Hf–Cu–NU-1102 (3) to elucidate the impact of the nodes versus the ligands on the phonon-mediated relaxation process. Measurement of 3 revealed identical spin–lattice relaxation dynamics to 2, thereby excluding involvement of node-centered or bulk framework acoustic modes. Supported by theoretical calculations of the ligand vibrational modes, these results implicated linker-based motions as dominant contributors to phonon-mediated spin–lattice relaxation. These findings provide clear guidelines for synthetic design to control spin and phonon interactions in modular arrays of molecular qubits.

  PublisherOA PDFDOI

• Vanadium_proton_DNP_data

  Figshare · 2020-01-01

  datasetOpen access

  The file contains Raw data acquired on 6.9T magnet at 4K static conditions with and without microwave irradiation to record vanadium to proton polarization transfer. The data contains polarization buildup curves, DNP frequency profiles and T2 filtered data to separate the narrow and broad components in the proton NMR spectra. The .ai files as well as text files of the processed data are included together with the matlab script used to plot the data.

  PublisherDOI

• Tracing Dynamic Nuclear Polarization Pathways Using Transition Metal - Nuclear Spin Rulers

  ChemRxiv · 2019-12-17

  preprintOpen access

  <p><a></a>The ubiquitous technique of nuclear magnetic resonance (NMR) spectroscopy suffers from relatively low sensitivity due to the low polarization of nuclei. For decades, the technique of dynamic nuclear polarization (DNP) has been harnessed to increase the sensitivity of NMR, enabling detection of low abundance nuclei such as <sup>17</sup>O and elucidation of protein structures. Yet, the catalogue of DNP agents today is limited to organic radical species, accompanied by a handful of metal ions (Cr<sup>3+</sup>, Mn<sup>2+</sup>, and Gd<sup>3+</sup>). This study significantly expands the scope and catalogue of DNP with the first demonstration of amplification of nuclear spin polarization at a set distance from a transition metal center (V<sup>4+</sup>) that has g-values significantly varied from 2 and anisotropic EPR line that is more than 3GHz broad.We showed that <sup>1</sup>H NMR signal enhancements of up to 33 can be achieved at 6.9T field and 4K temperature using a home-built DNP instrumentation that allows microwave irradiation over a frequency range of more than 10 GHz with pulse shaping capabilities by arbitrary waveform generator. A series of systematically designed vanadyl complexes, with V<sup>4+</sup>-<sup>1</sup>H distances in range 4.0 Å to 13.6 Å, was used to trace the polarization pathway of DNP and determine the size of the spin-diffusion barrier.<br></p>

  PublisherOA PDFDOI

• Tracing Dynamic Nuclear Polarization Pathways Using Transition Metal - Nuclear Spin Rulers

  ChemRxiv · 2019-12-16

  preprintOpen access

  The ubiquitous technique of nuclear magnetic resonance (NMR) spectroscopy suffers from relatively low sensitivity due to the low polarization of nuclei. For decades, the technique of dynamic nuclear polarization (DNP) has been harnessed to increase the sensitivity of NMR, enabling detection of low abundance nuclei such as 17 O and elucidation of protein structures. Yet, the catalogue of DNP agents today is limited to organic radical species, accompanied by a handful of metal ions (Cr 3+ , Mn 2+ , and Gd 3+ ). This study significantly expands the scope and catalogue of DNP with the first demonstration of amplification of nuclear spin polarization at a set distance from a transition metal center (V 4+ ) that has g-values significantly varied from 2 and anisotropic EPR line that is more than 3GHz broad.We showed that 1 H NMR signal enhancements of up to 33 can be achieved at 6.9T field and 4K temperature using a home-built DNP instrumentation that allows microwave irradiation over a frequency range of more than 10 GHz with pulse shaping capabilities by arbitrary waveform generator. A series of systematically designed vanadyl complexes, with V 4+ - 1 H distances in range 4.0 Å to 13.6 Å, was used to trace the polarization pathway of DNP and determine the size of the spin-diffusion barrier.

  PublisherDOI

Frequent coauthors

• Pulak Dutta

  26 shared

• A. G. Richter

  Valparaiso University

  20 shared

• Danna E. Freedman

  Massachusetts Institute of Technology

  19 shared

• Kwanwoo Shin

  Sogang University

  18 shared

• Dongjin Choi

  18 shared

• Byeongdo Kwak

  16 shared

• Jing Hua

  Lund University

  16 shared

• Young‐Soo Seo

  Sejong University

  16 shared