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281.
Haley JE Krein DM Monahan JL Burke AR McLean DG Slagle JE Fratini A Cooper TM 《The journal of physical chemistry. A》2011,115(3):265-273
To explore spectroscopic structure-property relationships in platinum acetylides, we synthesized a series of complexes having the molecular formula trans-bis(tributylphosphine)-bis(4-((9,9-diethyl-7-ethynyl-9H-fluoren-2-yl)ethynyl)-R)-platinum. The substituent, R = NH(2), OCH(3), N(phenyl)(2), t-butyl, CH(3), H, F, benzothiazole, CF(3), CN, and NO(2), was chosen for a systematic variation in electron-donating and -withdrawing properties as described by the Hammett parameter σ(p). UV/vis, fluorescence, and phosphorescence spectra, transient absorption spectra on the fs-ps time scale, and longer time scale flash photolysis on the ns time scale were collected. DFT and TDDFT calculations of the T(1) and S(1) energies were performed. The E(S) and E(T) values measured from linear spectra correlate well with the calculated results, giving evidence for the delocalized MLCT character of the S(1) state and confinement of the T(1) exciton on one ligand. The calculated T(1) state dipole moment ranges from 0.5 to 14 D, showing the polar, charge-transfer character of the T(1) state. The ultrafast absorption spectra have broad absorption bands from 575 to 675 nm and long wavelength contribution, which is shown from flash photolysis measurements to be from the T(1) state. The T(1) energy obtained from phosphorescence, the T(1)-T(n) transition energy obtained from flash photolysis measurements, and the triplet-state radiative rate constant are functions of the calculated spin density distribution on the ligand. The calculations show that the triplet exciton of chromophores with electron-withdrawing substituents is localized away from the central platinum atom, red-shifting the spectra and increasing the triplet-state lifetime. Electron-donating substituents have the opposite effect on the location of the triplet exciton, the spectra, and the triplet-state lifetime. The relation between the intersystem crossing rate constant and the S(1)-T(1) energy gap shows a Marcus relationship with a reorganization energy of 0.83 eV. The calculations show that intersystem crossing occurs by conversion from a nonpolar, delocalized S(1) state to a polar, charge-transfer T(1) state confined to one ligand, accompanied by conformation changes and charge transfer, supporting the experimental evidence for Marcus behavior. 相似文献
282.
Chiral DNA Origami Nanotubes with Well‐Defined and Addressable Inside and Outside Surfaces 下载免费PDF全文
Dr. Florence Benn Dr. Natalie E. C. Haley Dr. Alexandra E. Lucas Emma Silvester Dr. Seham Helmi Dr. Robert Schreiber Dr. Jonathan Bath Prof. Andrew J. Turberfield 《Angewandte Chemie (International ed. in English)》2018,57(26):7687-7690
We report the design and assembly of chiral DNA nanotubes with well‐defined and addressable inside and outside surfaces. We demonstrate that the outside surface can be functionalised with a chiral arrangement of gold nanoparticles to create a plasmonic device and that the inside surface can be functionalised with a track for a molecular motor allowing transport of a cargo within the central cavity. 相似文献
283.
Gregory B. Kharas Sara M. Rocus Haley E. Aynessazian Zachary L. Christy-Aronson Iris C. Chaoui-Boudrane Rachel M. Lange 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(6):335-339
Electrophilic trisubstituted ethylenes, halogen ring-disubstituted butyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2C4H9 where R is 2-chloro-4-fluoro, 2-chloro-6-fluoro, 3-chloro-2-fluoro, 3-chloro-4-fluoro, 4-chloro-3-fluoro, 2-fluoro-5-iodo, 3-(3,4-dichlorophenoxy), 4-(2,4-dichlorophenoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and butyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1H and 13C-NMR.Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (1.7–6.8% wt), which then decomposed in the 500–800°C range. 相似文献
284.
Seven new bis(dehydrobenzo[18]annuleno)benzenes (bis[18]DBAs) functionalized with electron-donating dibutylamino groups and/or accepting nitro groups at various positions along the peripheries of the chromophores have been prepared. The effects of varying the donor/acceptor charge transfer pathways, chromophore lengths and molecular symmetries upon the optical band gaps are studied using UV-visible spectroscopy, and structure-property correlations are identified. It is found that bis[18]DBAs possessing donor-pi-donor and acceptor-pi-acceptor pathways exhibit the smallest band gaps, especially when an acceptor-pi-acceptor pathway is situated along the longest chromophore length in the molecule. The all-donor species is also found to exhibit efficient fluorescence with dramatic solvatochromism. The results may have value to the rational design of future NLO/TPA device components. 相似文献
285.
286.
Jonathan D. White Lindsay E. Guzman Lev N. Zakharov Michael M. Haley Victoria J. DeRose 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(3):1046-1049
To better understand the range of cellular interactions of PtII‐based chemotherapeutics, robust and efficient methods to track and analyze Pt targets are needed. A powerful approach is to functionalize PtII compounds with alkyne or azide moieties for post‐treatment conjugation through the azide–alkyne cycloaddition (click) reaction. Herein, we report an alkyne‐appended cis‐diamine PtII compound, cis‐[Pt(2‐(5‐hexynyl)amido‐1,3‐propanediamine)Cl2] ( 1 ), the X‐ray crystal structure of which exhibits a combination of unusual radially distributed CH/π(CC) interactions, Pt Pt bonding, and NH:O/NH:Cl hydrogen bonds. In solution, 1 exhibits no Pt alkyne interactions and binds readily to DNA. Subsequent click reactivity with nonfluorescent dansyl azide results in a 70‐fold fluorescence increase. This result demonstrates the potential for this new class of alkyne‐modified Pt compound for the comprehensive detection and isolation of Pt‐bound biomolecules. 相似文献
287.
In this work we describe and evaluate a simple scheme by which the refractive index (λ = 589 nm) of non-absorbing components common to secondary organic aerosols (SOA) may be predicted from molecular formula and density (g cm(-3)). The QSPR approach described is based on three parameters linked to refractive index-molecular polarizability, the ratio of mass density to molecular weight, and degree of unsaturation. After computing these quantities for a training set of 111 compounds common to atmospheric aerosols, multi-linear regression analysis was conducted to establish a quantitative relationship between the parameters and accepted value of refractive index. The resulting quantitative relationship can often estimate refractive index to ±0.01 when averaged across a variety of compound classes. A notable exception is for alcohols for which the model consistently underestimates refractive index. Homogenous internal mixtures can conceivably be addressed through use of either the volume or mole fraction mixing rules commonly used in the aerosol community. Predicted refractive indices reconstructed from chemical composition data presented in the literature generally agree with previous reports of SOA refractive index. Additionally, the predicted refractive indices lie near measured values we report for λ = 532 nm for SOA generated from vapors of α-pinene (R.I. 1.49-1.51) and toluene (R.I. 1.49-1.50). We envision the QSPR method may find use in reconstructing optical scattering of organic aerosols if mass composition data is known. Alternatively, the method described could be incorporated into in models of organic aerosol formation/phase partitioning to better constrain organic aerosol optical properties. 相似文献
288.
Journal of the Operational Research Society - 相似文献
289.
Edward F. Elslager Donald F. Worth Neil F. Haley S. C. Perricone 《Journal of heterocyclic chemistry》1968,5(5):609-613
Catalytic reductive scission of phthalazine (II) utilizing a two-stage palladium-Raney nickel procedure afforded o-xylene-α,α′-diamine (III) in 97% yield. Treatment of III with carbon disulfide gave [o-(aminomethyl)benzyl]dithiocarbamic acid (IV), which upon thermal cyclization furnished 1,2,4,5-tetrahydro-3H-2,4-benzodiazepine-3-thione (V). Reaction of V with 1,2-dibromoethane, chloro-2-propanone, ethyl 2-chloroacetoacetate, ethyl chloroacetate, and ethyl 2-bromohexanoate gave 2,3,5,10-tetrahydrothiazolo[3,2-b][2,4]benzodiazepine (VII) and substituted 5,10-dihydrothiazolo[3,2-b][2,4]benzodiazepines (Villa and b, IX, and X), respectively. Condensation of V with 2-chlorocyclohexanone and 3-bromothiochroman-4-one afforded 1,2,3,4,7,12-hexahydrobenzothiazolo[3,2-b][2,4]benzodiazepine (XII) and 9,14-dihydro-6H-[1]benzothiopyrano[4′,3′:4,5]thiazolo[3,2-b][2,4]benzodiazepine(XIll). None of the compounds possessed appreciable biological activity. 相似文献