@article{choing_francis_clendenning_schuurman_sommer_tamblyn_weare_cuk_2015, title={Long-Lived LMCT in a d(0) Vanadium(V) Complex by Internal Conversion to a State of 3d(xy) Character}, volume={119}, ISSN={["1932-7447"]}, DOI={10.1021/acs.jpcc.5b00513}, abstractNote={The excited state dynamics of a d0 vanadium(V) oxido ligand-to-metal charge transfer (LMCT) complex, VOLF, were investigated via a combination of static optical and X-ray absorption (XAS) spectroscopy, transient optical absorption spectroscopy, and time-dependent density functional theory (TD-DFT). Upon excitation of the LMCT in the visible region, transient absorption data reveal that internal conversion traps the excited carrier population into a long-lived charge transfer state of 3dxy electron character, S1(dxy). The internal conversion is substantiated by an isosbestic point in the transient absorption data, two nearby charge transfer states that couple well by TD-DFT, multiple rates in the ground state recovery, and the decay kinetics of an excited state absorption with the energy of a d-d transition in O K-edge XAS spectra. The long lifetime (∼420 ps) of S1(dxy) can be ascribed to its poor optical and vibrational coupling to a distorted ground state (S0*) via a negligible electronic dipole transiti...}, number={30}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Choing, Stephanie N. and Francis, Aaron J. and Clendenning, Graham and Schuurman, Michael S. and Sommer, Roger D. and Tamblyn, Isaac and Weare, Walter W. and Cuk, Tanja}, year={2015}, month={Jul}, pages={17029–17038} }
 @article{deng_francis_weare_castellano_2015, title={Photochemical upconversion and triplet annihilation limit from a boron dipyrromethene emitter}, volume={14}, ISSN={["1474-9092"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84934293936&partnerID=MN8TOARS}, DOI={10.1039/c5pp00106d}, abstractNote={Non-coherent sensitized red-to-green upconversion has been achieved utilizing platinum(II) tetraphenyltetrabenzoporphyrin (PtTPTBP) as the triplet sensitizer and a nearly quantitatively fluorescent meso -(2,6-dichloropyridyl)-substituted boron dipyrromethene (Cl2PyBODIPY) chromophore ( Φ = 0.99 in toluene) as the energy acceptor/annihilator in deoxygenated toluene. Dynamic Stern–Volmer analysis revealed that PtTPTBP phosphorescence as quenched by C_l2PyBODIPY occurs with a K _SV of 108 000 M−1, yielding a triplet–triplet energy transfer rate constant of 2.3 × 109 M−1 s−1. Using a non-coherent red light-emitting diode excitation source centered at 626 nm, the incident power dependence responsible for generating singlet BODIPY fluorescence in the green was shown to traverse quadratic to linear regimes, the latter being achieved near 60 mW cm−2. These data were consistent with a photochemical upconversion mechanism being responsible for generating singlet fluorescence from the C_l2PyBODIPY chromophores through sensitized triplet–triplet annihilation (TTA). Integrated delayed fluorescence transients were utilized to reveal the TTA efficiency for the C_l2PyBODIPY chromophore and saturated near 46%, representing the lower limit for the TTA process. Kinetic modelling of the delayed fluorescence transient produced from 1.5 mJ laser pulses (λ_ex = 615 nm) revealed a maximum limiting TTA efficiency of 64% for this upconverting composition, implying that this is indeed an extremely relevant acceptor/annihilator composition for photochemical upconversion.}, number={7}, journal={PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES}, author={Deng, F. and Francis, A. J. and Weare, W. W. and Castellano, F. N.}, year={2015}, pages={1265–1270} }
 @article{carpenter_scholle_sadeghifar_francis_boltersdorf_weare_argyropoulos_maggard_ghiladi_2015, title={Synthesis, Characterization, and Antimicrobial Efficacy of Photomicrobicidal Cellulose Paper}, volume={16}, ISSN={["1526-4602"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84938937944&partnerID=MN8TOARS}, DOI={10.1021/acs.biomac.5b00758}, abstractNote={Toward our goal of scalable, antimicrobial materials based on photodynamic inactivation, paper sheets comprised of photosensitizer-conjugated cellulose fibers were prepared using porphyrin and BODIPY photosensitizers, and characterized by spectroscopic (infrared, UV-vis diffuse reflectance, inductively coupled plasma optical emission) and physical (gel permeation chromatography, elemental, and thermal gravimetric analyses) methods. Antibacterial efficacy was evaluated against Staphylococcus aureus (ATCC-2913), vancomycin-resistant Enterococcus faecium (ATCC-2320), Acinetobacter baumannii (ATCC-19606), Pseudomonas aeruginosa (ATCC-9027), and Klebsiella pneumoniae (ATCC-2146). Our best results were achieved with a cationic porphyrin-paper conjugate, Por((+))-paper, with inactivation upon illumination (30 min, 65 ± 5 mW/cm(2), 400-700 nm) of all bacterial strains studied by 99.99+% (4 log units), regardless of taxonomic classification. Por((+))-paper also inactivated dengue-1 virus (>99.995%), influenza A (∼ 99.5%), and human adenovirus-5 (∼ 99%). These results demonstrate the potential of cellulose materials to serve as scalable scaffolds for anti-infective or self-sterilizing materials against both bacteria and viruses when employing a photodynamic inactivation mode of action.}, number={8}, journal={BIOMACROMOLECULES}, author={Carpenter, Bradley L. and Scholle, Frank and Sadeghifar, Hasan and Francis, Aaron J. and Boltersdorf, Jonathan and Weare, Walter W. and Argyropoulos, Dimitris S. and Maggard, Paul A. and Ghiladi, Reza A.}, year={2015}, month={Aug}, pages={2482–2492} }
 @article{bartelmess_francis_el roz_castellano_weare_sommer_2014, title={Light-Driven Hydrogen Evolution by BODIPY-Sensitized Cobaloxime Catalysts}, volume={53}, ISSN={["1520-510X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84899787366&partnerID=MN8TOARS}, DOI={10.1021/ic500218q}, abstractNote={We report four photocatalytically active cobaloxime complexes for light-driven hydrogen evolution. The cobaloxime catalysts are sensitized by different meso-pyridyl boron dipyrromethene (BODIPY) chromophores, bearing either two bromo- or iodo-substituents on the BODIPY core. The pyridine linker between the BODIPY and cobaloxime is further modified by a methyl substituent on the pyridine, influencing the stability and electronic properties of the cobaloxime catalyst and thus the photocatalytic efficiency of each system. Four cobaloxime catalyst complexes and three novel BODIPY chromophores are synthesized and characterized by absorption, fluorescence, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and electrochemistry. Crystal structures for the BODIPY-cobaloxime complexes 2 and 3 are presented. In contrast to the photocatalytically inactive, nonhalogenated reference complex 1, the four newly reported molecules are active for photocatalytic hydrogen evolution, with a maximum turnover number (TON) of 30.9 mol equiv of H2 per catalyst for the meso-methylpyridyl 2,6-diiodo BODIPY-sensitized cobaloxime complex 5. We conclude that accessing the photoexcited triplet state of the BODIPY chromophore by introducing heavy atoms (i.e., bromine or iodine) is necessary for efficient electron transfer in this system, enabling catalytic hydrogen generation. In addition, relatively electron-donating pyridyl linkers improve the stability of the complex, increasing the overall TON for hydrogen production.}, number={9}, journal={INORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Bartelmess, Juergen and Francis, Aaron J. and El Roz, Karim A. and Castellano, Felix N. and Weare, Walter W. and Sommer, Roger D.}, year={2014}, month={May}, pages={4527–4534} }