Mid-infrared signatures of hydroxyl containing water clusters: Infrared laser Stark spectroscopy of OH–H2O and OH(D2O)n (n = 1-3)

Small water clusters containing a single hydroxyl radical are synthesized in liquid helium droplets. The OH–H2O and OH(D2O)n clusters (n = 1-3) are probed with infrared laser spectroscopy in the vicinity of the hydroxyl radical OH stretch vibration. Experimental band origins are qualitatively consistent with ab initio calculations of the global minimum structures; however, frequency shifts from isolated OH are significantly over-predicted by both B3LYP and MP2 methods. An effective Hamiltonian that accounts for partial quenching of electronic angular momentum is used to analyze Stark spectra of the OH–H2O and OH–D2O binary complexes, revealing a 3.70(5) D permanent electric dipole moment. Computations of the dipole moment are in good agreement with experiment when large-amplitude vibrational averaging is taken into account. Polarization spectroscopy is employed to characterize two vibrational bands assigned to OH(D2O)2, revealing two nearly isoenergetic cyclic isomers that differ in the orientation of the non-hydrogen-bonded deuterium atoms relative to the plane of the three oxygen atoms. The dipole moments for these clusters are determined to be approximately 2.5 and 1.8 D for “up-up” and “up-down” structures, respectively. Hydroxyl stretching bands of larger clusters containing three or more D2O molecules are observed shifted approximately 300 cm−1 to the red of the isolated OH radical. Pressure dependence studies and ab initio calculations imply the presence of multiple cyclic isomers of OH(D2O)3.Fil: Hernández, Federico Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. University of Georgia; Estados UnidosFil: Brice, Joseph T.. University of Georgia; Estados UnidosFil: Leavitt, Christopher M.. University of Georgia; Estados UnidosFil: Liang, Tao. University of Georgia; Estados UnidosFil: Raston, Paul L.. James Madison University. Department of Chemistry and Biochemistry; Estados UnidosFil: Pino, Gustavo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Douberly, Gary E.. University of Georgia; Estados Unido

Paclitaxel-loaded phosphonated calixarene nanovesicles as a modular drug delivery platform

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/A modular p-phosphonated calix[4]arene vesicle (PCV) loaded with paclitaxel (PTX) and conjugated with folic acid as a cancer targeting ligand has been prepared using a thin film-sonication method. It has a pH-responsive capacity to trigger the release of the encapsulated PTX payload under mildly acidic conditions. PTX-loaded PCV conjugated with alkyne-modified PEG-folic acid ligands prepared via click ligation (fP-PCVPTX) has enhanced potency against folate receptor (FR)-positive SKOV-3 ovarian tumour cells over FR-negative A549 lung tumour cells. Moreover, fP-PCVPTX is also four times more potent than the non-targeting PCVPTX platform towards SKOV-3 cells. Overall, as a delivery platform the PCVs have the potential to enhance efficacy of anticancer drugs by targeting a chemotherapeutic payload specifically to tumours and triggering the release of the encapsulated drug in the vicinity of cancer cells

INFRARED AND MICROWAVE-INFRARED DOUBLE RESONANCE SPECTROSCOPY OF METHANOL EMBEDDED IN SUPERFLUID HELIUM NANODROPLETS

Author Institution: Department of Chemistry, University of Alberta, Edmonton, Alberta T6G-2G2, CanadaMethanol is one of the simplest torsional oscillators, and has been extensively studied in the gas phase by various spectroscopic techniques. At 300 K, a large number of rotational, torsional, and vibrational energy levels are populated, and this makes for a rather complicated infrared spectrum which is still not fully understood. It is expected that in going from 300 K to 0.4 K (the temperature of helium nanodroplets) that the population distribution of methanol will collapse into one of two states; the \textit{J,K} = 0,0 level for the \textit{A} symmetry species, and the \textit{J,K} = 1,-1 level for the \textit{E} symmetry species. This results in a simplified spectrum that consists of narrow \textit{a}-type lines and broader \textit{b}-type lines in the OH stretching region. Microwave-infrared double resonance spectroscopy is used to help assign the \textit{a}-type infrared lines

INFRARED-ACTIVE VIBRON BANDS ASSOCIATED WITH RARE GAS SUBSTITUTIONAL IMPURITIES IN SOLID HYDROGEN

{R. J. Hinde, J. Chem. Phys. 119, 6 (2003).Author Institution: Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838Solid para-hydrogen (pH$_2$) crystals doped with part per million concentrations of rare gas (Rg) atoms display a new zero phonon absorption feature which correlates with the pH$_2$ pure vibrational Q$_1$(0) transition. This Rg induced Q$_1$(0) absorption has been studied at high resolution for Ne, Ar, Kr, and Xe doped pH$_2$ crystals. The more polarizable the Rg atom, the more intense and red shifted is the induced pH$_2$ Q$_1$(0) feature. The frequency and lineshape of the transition provides information on how localized the vibron is around the Rg impurity. Comparison of the experimental data with a recent theoretical model is very favourable.} In addition, the Rg atom perturbs the S$_1$(0) pH$_2$ transition resulting in peaks that show fine structure which is interpreted as a lifting in the $m$$_J$ degeneracy of this $J$=2 upper state. Preliminary studies of Xe atom doped ortho-deuterium will also be presented and discussed

PROBING EXCITON DYNAMICS IN THE FREQUENCY DOMAIN

Author Institution: Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838We report high-resolution infrared absorption measurements of H$_2$ rovibrational transitions in chemically doped solid parahydrogen crystals which access both bound and delocalized exciton states. The excitons in this case correspond to vibrational (vibron) and rotational (roton) excitation of the H$_2$ molecules that make up the solid. Originally studied in the seminal work of Van Kranendonk,} our group and others are now studying how the exciton dynamics in solid parahydrogen are altered when the solid is doped with small concentrations of atoms. Recently, we have studied rare gas atoms and halogen atoms doped in solid parahydrogen. In the case of the halogen atom studies (Cl and Br to date), exciton decay channels include both reactive and non-reactive pathways. Special emphasis will be given to spectroscopic examples where the high-resolution lineshape reveals broadening and splitting due to delocalization of the exciton around the atomic impurity. Some of the lineshapes are understood in terms of the exciton dynamics they encode; however, some of the lineshapes await theoretical interpretation

ROTATIONAL SPECTROSCOPY OF SINGLE CARBONYL SULFIDE MOLECULES EMBEDDED IN SUPERFLUID HELIUM NANODROPLETS

S. S.Author Institution: \textit{Department of Chemistry, University of Alberta, Edmonton, Alberta T6G-2G2, Canada}The pure rotation spectrum of carbonyl sulfide embedded in superfluid helium nanodroplets was measured in the frequency range from 4 to 15.5{\nobreakspace}GHz. Four lines, corresponding to the \textit{J} = 1-0, \textit{J} = 2-1, \textit{J} = 3-2, and \textit{J} = 4-3 transitions were found. The line widths increase with \textit{J}, and are about twice that of the corresponding rovibrational lines}Grebenev, M. Hartmann, M.{\nobreakspace}Havenith, B. Sartakov, J.{\nobreakspace}P. Toennies, and A.{\nobreakspace}F. Vilesov, \textit{J. Chem. Phys.}, \textbf{112}, 4485 (2000).}, indicating faster rotational relaxation within the ground vibrational manifold. The comparison of the pure rotational spectrum with the microwave-infrared double resonance spectrum}Grebenev, M.{\nobreakspace}Havenith, F.{\nobreakspace}Madeja, J.{\nobreakspace}P. Toennies, and A.{\nobreakspace}F. Vilesov, \textit{J. Chem. Phys.}, \textbf{113}, 9060 (2000).} reveals that the double resonance measurement mainly probes rotational transitions within the upper vibrational manifold