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Near-Infrared Boron Difluoride Formazanate Dyes, Francis L. Buguis, Ryan R. Maar, Viktor N. Staroverov, Joe Gilroy
Near-Infrared Boron Difluoride Formazanate Dyes, Francis L. Buguis, Ryan R. Maar, Viktor N. Staroverov, Joe Gilroy
Chemistry Publications
Near-infrared (NIR) dyes are sought after for their utility in light harvesting, bioimaging, and light-mediated therapies. Since long-wavelength photoluminescence typically involves extensive p-conjugated systems of double bonds and aromatic rings, it is often assumed that NIR dyes have to be large molecules that require complex syntheses. We challenge this assumption by demonstrating that facile incorporation of tertiary amine groups into readily available 3-cyanoformazans affords efficient production of relatively simple NIR-active BF2 formazanate dyes (λabs = 691−760 nm, λPL = 834−904 nm in toluene). Cyclic voltammetry experiments on these compounds reveal multiple reversible redox waves linked to the …
Deciphering Tip-Enhanced Raman Imaging Of Carbon Nanotubes With Deep Learning Neural Networks., Usant Kajendirarajah, María Olivia Avilés, François Lagugné-Labarthet
Deciphering Tip-Enhanced Raman Imaging Of Carbon Nanotubes With Deep Learning Neural Networks., Usant Kajendirarajah, María Olivia Avilés, François Lagugné-Labarthet
Chemistry Publications
Recent release of open-source machine learning libraries presents opportunities to unify machine learning with nanoscale research, thus improving effectiveness of research methods and characterization protocols. This paper outlines and demonstrates the effectiveness of such a synergy with artificial neural networks to provide for an accelerated and enhanced characterization of individual carbon nanotubes deposited over a surface. Our algorithms provide a rapid diagnosis and analysis of tip-enhanced Raman spectroscopy mappings and the results show an improved spectral assignment of spectral features and spatial contrast of the collected images. Using several examples, we demonstrate the robustness and versatility of our deep learning …
Phosphonium Versus Ammonium Compact Polyelectrolyte Complex Networks With Alginate-Comparing Their Properties And Cargo Encapsulation., Tristan D. Harrison, Alexandre J. Salmon, John R. De Bruyn, Paul J. Ragogna, Elizabeth R. Gillies
Phosphonium Versus Ammonium Compact Polyelectrolyte Complex Networks With Alginate-Comparing Their Properties And Cargo Encapsulation., Tristan D. Harrison, Alexandre J. Salmon, John R. De Bruyn, Paul J. Ragogna, Elizabeth R. Gillies
Chemistry Publications
Phosphonium and ammonium polymers can be combined with polyanions to form polyelectrolyte complex (PEC) networks, with potential application in self-healing materials and drug delivery vehicles. While various structures and compositions have been explored, to the best of our knowledge, analogous ammonium and phosphonium networks have not been directly compared to evaluate the effects of phosphorus versus nitrogen cations on the network properties. In this study, we prepared PECs from sodium alginate and poly[triethyl(4-vinylbenzyl)phosphonium chloride], poly[triethyl(4-vinylbenzyl)ammonium chloride], poly[tri(
Gas Phase Protein Folding Triggered By Proton Stripping Generates Inside-Out Structures: A Molecular Dynamics Simulation Study., Alexander I M Sever, Lars Konermann
Gas Phase Protein Folding Triggered By Proton Stripping Generates Inside-Out Structures: A Molecular Dynamics Simulation Study., Alexander I M Sever, Lars Konermann
Chemistry Publications
The properties of electrosprayed protein ions continue to be enigmatic, owing to the absence of high-resolution structure determination methods in the gas phase. There is considerable evidence that under properly optimized conditions these ions preserve solution-like conformations and interactions. However, it is unlikely that these solution-like conformers represent the "intrinsic" structural preferences of gaseous proteins. In an effort to uncover what such intrinsically preferred conformers might look like, we performed molecular dynamics (MD) simulations of gaseous ubiquitin. Our work was inspired by recent gas phase experiments, where highly extended 13+ ubiquitin ions were transformed to compact 3+ species by proton …
Optoelectronic Properties Of Carbon-Bound Boron Difluoride Hydrazone Dimers, Daniela Cappello, Ryan R. Maar, Viktor N. Staroverov, Joe Gilroy
Optoelectronic Properties Of Carbon-Bound Boron Difluoride Hydrazone Dimers, Daniela Cappello, Ryan R. Maar, Viktor N. Staroverov, Joe Gilroy
Chemistry Publications
The creation of dimeric boron difluoride complexes of chelating N-donor ligands is a proven strategy for the enhancement of the optoelectronic properties of fluorescent dyes. We report dimers based on the boron difluoride hydrazone (BODIHY) framework, which offer unique and sometimes unexpected substituent-dependent absorption, emission, and electrochemical properties. BODIHY dimers have low-energy absorption bands (lmax = 421 to 479 nm, e = 17,200 to 39,900 M−1 cm−1) that are red-shifted relative to monomeric analogues. THF solutions of these dimers exhibit aggregation-induced emission upon addition of water, with emission enhancement factors ranging from 5 to 18. …
Redox Polymers Incorporating Pendant 6-Oxoverdazyl And Nitronyl Nitroxide Radicals, Michael Anghel, Francois Magnan, Sara D. Catingan, Matthew A. Mccready, Elaheh Aawani, Victor Wong, Deepa Singh, Giovanni Fanchini, Joe Gilroy
Redox Polymers Incorporating Pendant 6-Oxoverdazyl And Nitronyl Nitroxide Radicals, Michael Anghel, Francois Magnan, Sara D. Catingan, Matthew A. Mccready, Elaheh Aawani, Victor Wong, Deepa Singh, Giovanni Fanchini, Joe Gilroy
Chemistry Publications
Polymers comprised of redox-active organic radicals have emerged as promising materials for use in a variety of organic electronics, including fast-charging batteries. Despite these advances, relatively little attention has been focused on the diversification of the families of radicals that are commonly incorporated into polymer frameworks, with most radical polymers being comprised of nitroxide radicals. Here, we report two new examples prepared via ring-opening methathesis polymerization containing 6-oxoverdazyl and nitronyl nitroxide radicals appended to their backbones. The polymerization reaction and optoelectronic properties were explored in detail, revealing high radical content and redox activity that may be advantageous for their use …
Enhancing Protein Electrospray Charge States By Multivalent Metal Ions: Mechanistic Insights From Md Simulations And Mass Spectrometry Experiments., Leanne M Martin, Lars Konermann
Enhancing Protein Electrospray Charge States By Multivalent Metal Ions: Mechanistic Insights From Md Simulations And Mass Spectrometry Experiments., Leanne M Martin, Lars Konermann
Chemistry Publications
The structure and reactivity of electrosprayed protein ions is governed by their net charge. Native proteins in non-denaturing aqueous solutions produce low charge states. More highly charged ions are formed when electrospraying proteins that are unfolded and/or exposed to organic supercharging agents. Numerous studies have explored the electrospray process under these various conditions. One phenomenon that has received surprisingly little attention is the charge enhancement caused by multivalent metal ions such as La3+ when electrospraying proteins out of non-denaturing solutions. Here, we conducted mass spectrometry and ion mobility spectrometry experiments, in combination with molecular dynamics (MD) simulations, to uncover …
First Ionization Energy As The Asymptotic Limit Of The Average Local Electron Energy, Amer M. El-Samman, Egor Ospadov, Viktor N. Staroverov
First Ionization Energy As The Asymptotic Limit Of The Average Local Electron Energy, Amer M. El-Samman, Egor Ospadov, Viktor N. Staroverov
Chemistry Publications
The first vertical ionization energy of an atom or molecule is encoded in the rate of exponential decay of the exact natural orbitals. For natural orbitals represented in terms of Gaussian basis functions, this property does not hold even approximately. We show that it is nevertheless possible to deduce the first ionization energy from the long-range behavior of Gaussian-basis-set wavefunc- tions by evaluating the asymptotic limit of a quantity called the average local electron energy (ALEE), provided that the most diffuse functions of the basis set have suitable shape and location. The ALEE method exposes subtle qualitative differences between seemingly …
Asymptotic Behavior Of The Average Local Ionization Energy In Finite Basis Sets, Amer M. El-Samman, Viktor N. Staroverov
Asymptotic Behavior Of The Average Local Ionization Energy In Finite Basis Sets, Amer M. El-Samman, Viktor N. Staroverov
Chemistry Publications
The average local ionization energy (ALIE) has important applications in several areas of electronic structure theory. Theoretically, the ALIE should asymptotically approach the first vertical ionization energy (IE) of the system, as implied by the rate of exponential decay of the electron density; for one-determinantal wavefunctions, this IE is the negative of the highest-occupied orbital energy. In practice, finite-basis-set representations of the ALIE exhibit seemingly irregular and sometimes dramatic deviations from the expected asymptotic behavior. We analyze the long-range behavior of the ALIE in finite basis sets and explain the puzzling observations. The findings have implications for practical calculations of …