Browsing by Subject "Molecules"

Now showing 1 - 4 of 4
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    Data for Wavelength Dependence of Plasmon-Induced Vibrational Energy Transfer in Fluorophore–Plasmonic Systems
    (2024-08-01) Christenson, Gerrit N; Yu, Ziwei; Frontiera, Renee R; rrf@umn.edu; Frontiera, Renee R; Materials Research Science & Engineering Center
    Understanding, predicting, and controlling plasmon–molecule energy transfer are important for improvements to plasmonic photocatalysis and photothermal therapies. Here, we use continuous wave surface-enhanced anti-Stokes and Stokes Raman spectroscopy to quantify the vibrational kinetic energy, equivalent to a molecular temperature under a Boltzmann approximation, of Raman-active vibrational modes of molecules at plasmonic interfaces. In previous work from our group, we observed an anomalous steady-state reduction in vibrational kinetic energies in benzenethiols absorbed onto the surface of gold nanoparticles. To further explore this effect, here, we quantify the wavelength dependence of vibrational energy in plasmon–fluorophore systems, where molecules can undergo electronic transitions with resonant excitation. We used three excitation wavelengths and three molecules with varying electronic resonance energies. We observe wavelength-dependent vibrational energy distributions, which we attribute to competing effects of on-resonance heating and off-resonance decrease in the population ratio. This work thus quantifies the resonance wavelength dependence of vibrational energy in plasmon molecular systems and helps to suggest future applications of tailored systems with controllable energy transfer pathways.
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    Organic Synthesis of a Small Novel Molecule to Target Prostate Cancer
    (2014) Just, Melissa J.
    The organic synthesis of several small molecules has shown limited general toxicity towards LNCaP cells. These molecules that have shown to be successful will be taken through further research. Continued synthesis will take place mimicking these molecules. After multiple toxicity assay’s have been conducted and successful results documented, these molecules will be taken further into proliferative binding assay tests with the presence of Dihyrotestosterone.
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    QSAR for anticancer activity by using mathematical descriptors.
    (2010-07) Zhu, Qianhong
    Quantitative structure-activity relationships (QSARs) have used physicochemical properties and calculated structural descriptors to predict biological activity of drugs and toxicants. Since experimental properties for the majority of chemicals are not known, QSARs based on calculated descriptors are becoming more popular in predicting bioactivity of molecules. Our QSARs for the anticancer property of a set of 43 derivatives of 2-phenylindole show that the combination of topological indices (TIs) and atom pairs (APs) gives a superior model (q2 = 0.867), as compared to the comparative molecular field analysis (CoMFA) approach (q2= 0.705). TIs and APs were also used to formulate QSARs for the anticancer activity of 18 Camptothecin derivatives. TI+AP gave the best models which outperformed those derived using linear free energy related (LFER) parameters. Models based on easily calculated descriptors like TIs and APs are emerging as useful tools in practical drug design.
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    Supporting data for Intermolecular Forces Dictate Vibrational Energy Transfer in Plasmonic–Molecule Systems
    (2022-02-22) Yu, Ziwei; Frontiera, Renee; rrf@umn.edu; Frontiera, Renee
    These files contain data along with associated output from described analysis supporting all results reported in Yu, Z.; Frontiera, R. R. Intermolecular Forces Dictate Vibrational Energy Transfer in Plasmonic–Molecule Systems. ACS Nano, 2022, 16, 1, 847–854. Anti-Stokes and Stokes scattering from aromatic thiols adsorbed on gold nanoparticles are monitored with ultrafast surface-enhanced Raman spectroscopy (SERS). Vibration population ratio changing kinetics of the aromatic thiols is obtained by conducting peak fitting with the acquired ultrafast anti-Stokes and Stokes SERS spectra and performing Boltzmann analysis. The as-obtained kinetic traces are fitted with exponential decay convoluted with the instrument response function to extract the temporal increase and lifetime of the population ratio kinetics, which are found to be correlated with the molecular property in a fashion that molecules with a stronger intermolecular interaction experience less temporal population ratio increase and shorter excited vibrational state lifetime.