TY - JOUR T1 - DFT-GIAO-NBO and 13C NMR study of the delta-syn-axial effect in 2,4-disubstituted adamantanes N2 - Six groups of diastereomeric 2,4-disubstituted adamantanes were studied with DFT-GIAO-NBO (natural orbital analysis) methods. The calculated 13C chemical shifts reproduce well the experimental data. It was found that among all diastereomers, those bearing substituents in -syn-axial positions showed the largest overall deshielding, i.e. the sum of all 13C chemical shifts [;;(13C)] was the greatest and also had the highest delocalization contribution to the molecular energy evaluated with NBO. The higher delocalization energy is proposed to be the origin of the deshielding -syn-axial effect Y1 - 2008 UR - http://onlinelibrary.wiley.com/doi/10.1002/mrc.2333/pdf U6 - https://doi.org/10.1002/Mrc.2333 SN - 0749-1581 ER - TY - JOUR A1 - Starke, Ines A1 - Kammer, Stefan A1 - Grunwald, Nicolas A1 - Schilde, Uwe A1 - Holdt, Hans-Jürgen A1 - Kleinpeter, Erich T1 - Complexation of diazaperylene and bisisoquinoline with transition metal ions in the gas phase studied by electrospray ionization mass spectrometry N2 - The complex formation of the ligands 1,12-diazaperylene (dap), 1,1-bisisoquinoline (bis), 2,2-bipyridine (bpy) and 1,10-phenanthroline (phen) with transition metal ions (M = Fe, Co, Ni, Cu, Zn, Ru, Os, Re, Pd, Pt, Ag and Cd) in the gas phase has been studied by electrospray ionization mass spectrometry. With the exception of Ru, Os, Fe, Ni and Cu, singly charged complexes [MLn]+ (n = 1,2) were observed. The complexes of dap and bis with Ru, Os, Fe and Ni ions, and the mixed ligand complexes with bpy and phen, are preferably of the doubly charged type [ML3]2+. In addition, collision- induced dissociation (CID) measurements were employed to evaluate the relative stabilities of these complexes. The CID experiments of mixed-ligand complexes which contain both dap and phen or dap and bpy exhibit preferential elimination of bpy, indicating that bpy is a weaker ligand than phen and dap. Y1 - 2008 ER - TY - JOUR A1 - Steinbrück, Dörte A1 - Rasch, Claudia A1 - Kumke, Michael Uwe T1 - Photophysics of Ochratoxin A in aqueous solution Y1 - 2008 ER - TY - JOUR A1 - Kleinpeter, Erich T1 - Quantitative study and visualization of spherical 2(N + 1)2 homoaromaticity by through space NMR shieldings (TSNMRS) N2 - The through space NMR shielding (TSNMRS) values of adamantane, the 2(N + 1)2 spherical (4c, 2e) homoaromatic compounds 1,3-dehydro-5,7-adamantandiyl dication (C10H122+) and 1,3-dehydro-5,7-cubandiyl dication (C8H42+), and the (6c, 8e) homoaromatic compound 2,2;,4,4;,6,6;,8,8;,10,10;-dehydroadamantane tetracation (C10H44+) have been ab initio calculated, employing the NICS concept, and visualized as iso-chemical shielding surfaces (ICSSs). TSNMRS values can be successfully employed to study both the endohedral and exohedral aromaticity/ antiaromaticity of the compounds studied. Y1 - 2008 U6 - https://doi.org/10.1016/j.theochem.2007.11.029 ER - TY - JOUR A1 - Schilde, Uwe A1 - Kelling, Alexandra A1 - Umbreen, Sumaira A1 - Linker, Torsten T1 - Crystal structures of three bicyclic carbohydrate derivatives JF - Acta crystallographica Section E ; Crystallographic communications N2 - The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis(acetyloxy)-7-oxo-2-oxabicyclo- [4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acetyloxy-7- hydroxyimino-2-oxobicyclo[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis(acetyloxy)-2-oxooctahydropyrano[3,2-b]pyrrol-5- yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish for the first time the absolute configurations of all new stereocenters of the carbohydrate rings. KW - crystal structure KW - carbohydrate deriv­atives KW - conformation KW - configuration Y1 - 2016 U6 - https://doi.org/10.1107/S2056989016018727 SN - 2056-9890 VL - 72 IS - 12 SP - 1839 EP - 1844 PB - IUCR CY - Chester ER - TY - JOUR A1 - Meiling, Till Thomas A1 - Cywiński, Piotr J. A1 - Bald, Ilko T1 - White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis JF - Scientific reports N2 - In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst. KW - Fluorescence spectroscopy KW - Nanoparticles KW - Synthesis and processing Y1 - 2016 U6 - https://doi.org/10.1038/srep28557 VL - 6 PB - Nature Publishing Group CY - London ER - TY - JOUR A1 - Doriti, Afroditi A1 - Brosnan, Sarah M. A1 - Weidner, Steffen M. A1 - Schlaad, Helmut T1 - Synthesis of polysarcosine from air and moisture stable N-phenoxycarbonyl-N-methylglycine assisted by tertiary amine base JF - Polymer Chemistry N2 - Polysarcosine (Mn = 3650–20 000 g mol−1, Đ ∼ 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator. KW - ring-opening polymerization KW - activated urethane derivatives KW - phosgene-free synthesis KW - carboxyanhydrides KW - polypeptides KW - acids KW - copolymers Y1 - 2016 U6 - https://doi.org/10.1039/C6PY00221H SN - 1759-9954 SN - 1759-9962 VL - 7 SP - 3067 EP - 3070 PB - RSC Publ. CY - Cambridge ER - TY - JOUR A1 - Olejko, Lydia A1 - Cywiński, Piotr J. A1 - Bald, Ilko T1 - An ion-controlled four-color fluorescent telomeric switch on DNA origami structures JF - Nanoscale N2 - The folding of single-stranded telomeric DNA into guanine (G) quadruplexes is a conformational change that plays a major role in sensing and drug targeting. The telomeric DNA can be placed on DNA origami nanostructures to make the folding process extremely selective for K+ ions even in the presence of high Na+ concentrations. Here, we demonstrate that the K+-selective G-quadruplex formation is reversible when using a cryptand to remove K+ from the G-quadruplex. We present a full characterization of the reversible switching between single-stranded telomeric DNA and G-quadruplex structures using Förster resonance energy transfer (FRET) between the dyes fluorescein (FAM) and cyanine3 (Cy3). When attached to the DNA origami platform, the G-quadruplex switch can be incorporated into more complex photonic networks, which is demonstrated for a three-color and a four-color FRET cascade from FAM over Cy3 and Cy5 to IRDye700 with G-quadruplex-Cy3 acting as a switchable transmitter. KW - resonance energy-transfer KW - g-quadruplex KW - quantum dots KW - strand breakage KW - photonic wires KW - 3-color fret KW - nanostructures KW - recognition KW - sensitivity KW - assemblies Y1 - 2016 U6 - https://doi.org/10.1039/C6NR00119J SN - 2040-3372 SN - 2040-3364 VL - 8 SP - 10339 EP - 10347 PB - RSC Publ. CY - Cambridge ER - TY - JOUR A1 - Niedl, Robert Raimund A1 - Berenstein, Igal A1 - Beta, Carsten T1 - How imperfect mixing and differential diffusion accelerate the rate of nonlinear reactions in microfluidic channels JF - Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies N2 - In this paper, we show experimentally that inside a microfluidic device, where the reactants are segregated, the reaction rate of an autocatalytic clock reaction is accelerated in comparison to the case where all the reactants are well mixed. We also find that, when mixing is enhanced inside the microfluidic device by introducing obstacles into the flow, the clock reaction becomes slower in comparison to the device where mixing is less efficient. Based on numerical simulations, we show that this effect can be explained by the interplay of nonlinear reaction kinetics (cubic autocatalysis) and differential diffusion, where the autocatalytic species diffuses slower than the substrate. KW - arsenious acid KW - systems KW - poly(dimethylsiloxane) KW - fronts KW - scale KW - paper Y1 - 2016 U6 - https://doi.org/10.1039/c6cp00224b SN - 1463-9076 SN - 1463-9084 VL - 18 SP - 6451 EP - 6457 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Zabel, André A1 - Winter, Alette A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Strauch, Peter T1 - Tetrabromidocuprates(II)-Synthesis, Structure and EPR JF - International journal of molecular sciences N2 - Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several “onium” cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g|| and gK) of the tensors could be determined and information on the structural changes in the [CuBr4]2- anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids. KW - tetrabromidocuprate(II) KW - X-ray structure KW - electron paramagnetic resonance KW - copper(II) Y1 - 2016 U6 - https://doi.org/10.3390/ijms17040596 VL - 17 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Prinz, Julia A1 - Heck, Christian A1 - Ellerik, Lisa A1 - Merk, Virginia A1 - Bald, Ilko T1 - DNA origami based Au–Ag-core–shell nanoparticle dimers with single-molecule SERS sensitivity JF - Nanoscale N2 - DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. Y1 - 2016 U6 - https://doi.org/10.1039/C5NR08674D IS - 8 SP - 5612 EP - 5620 PB - RSC Publishing CY - Cambridge ER - TY - JOUR A1 - Mondal, Suvendu Sekhar A1 - Marquardt, Dorothea A1 - Janiak, Christoph A1 - Holdt, Hans-Jürgen T1 - Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles JF - Dalton transactions : an international journal of inorganic chemistry N2 - Sixteen new ionic liquids (ILs) with tetraethylammonium, 1-butyl-3-methylimidazolium, 3-methyl-1-octylimidazolium and tetrabutylphosphonium cations paired with 2-substituted 4,5-dicyanoimidazolate anions (substituent at C2 = methyl, trifluoromethyl, pentafluoroethyl, N,N′-dimethyl amino and nitro) have been synthesized and characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA). The effects of cation and anion type and structure of the resulting ILs, including several room temperature ionic liquids (RTILs), are reflected in the crystallization, melting points and thermal decomposition of the ILs. ILs exhibited large liquid and crystallization ranges and formed glasses on cooling with glass transition temperatures in the range of −22 to −71 °C. We selected one of the newly designed ILs due to its bigger size, compared to the common conventional IL anion and high electron-withdrawing nitrile group leads to an overall stabilization anion that may stabilize the metal nanoparticles. Stable and better separated iron and silver nanoparticles are obtained by the decomposition of corresponding Fe2(CO)9 and AgPF6, respectively, under N2-atmosphere in newly designed nitrile functionalized 4,5-dicyanoimidazolate anion based IL. Very small and uniform size for Fe-nanoparticles of about 1.8 ± 0.6 nm were achieved without any additional stabilizers or capping molecules. Comparatively bigger size of Ag-nanoparticles was obtained through the reduction of AgPF6 by hydrogen gas. Additionally, the AgPF6 precursor was decomposed under microwave irradiation (MWI), fabricating nut-in-shell-like, that is, core-separated-from-shell Ag-nano-structures. Y1 - 2016 U6 - https://doi.org/10.1039/C6DT00225K SN - 1477-9226 IS - 45 SP - 5476 EP - 5483 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Klaper, M. A1 - Wessig, Pablo A1 - Linker, Torsten T1 - Base catalysed decomposition of anthracene endoperoxide JF - Chemical communications : ChemComm N2 - Catalytic amounts of a weak base are sufficient to induce the decomposition of anthracene endoperoxides to anthraquinone. The mechanism has been elucidated by isolation of intermediates in combination with DFT calculations. The whole process is suitable for the convenient generation of hydrogen peroxide under very mild conditions. Y1 - 2015 U6 - https://doi.org/10.1039/C5CC08606J SN - 1364-548X IS - 52 SP - 1210 EP - 1213 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Matis, Jochen René A1 - Schönborn, Jan Boyke A1 - Saalfrank, Peter T1 - A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch JF - Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies N2 - Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single- and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S0 when starting from the S1–S0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability. Y1 - 2015 U6 - https://doi.org/10.1039/C5CP00987A SN - 1463-9076 SN - 1463-9084 IS - 17 SP - 14088 EP - 14095 PB - The Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Prestel, Andreas A1 - Möller, Heiko Michael T1 - Spatio-temporal control of cellular uptake achieved by photoswitchable cell-penetrating peptides JF - Chemical communications : ChemComm N2 - The selective uptake of compounds into specific cells of interest is a major objective in cell biology and drug delivery. By incorporation of a novel, thermostable azobenzene moiety we generated peptides that can be switched optically between an inactive state and an active, cell-penetrating state with excellent spatio-temporal control. Y1 - 2015 U6 - https://doi.org/10.1039/C5CC06848G SN - 1364-548X IS - 52 SP - 701 EP - 704 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Klier, Dennis Tobias A1 - Kumke, Michael Uwe T1 - Analysing the effect of the crystal structure on upconversion luminescence in Yb3+,Er3+-co-doped NaYF4 nanomaterials JF - Journal of materials chemistry C ; Materials for optical and electronic devices N2 - NaYF4:Yb:Er nanoparticles (UCNP) were synthesized under mild experimental conditions to obtain a pure cubic lattice. Upon annealing at different temperatures up to Tan = 700 °C phase transitions to the hexagonal phase and back to the cubic phase were induced. The UCNP materials obtained for different Tan were characterized with respect to the lattice phase using standard XRD and Raman spectroscopy as well as steady state and time resolved upconversion luminescence. The standard techniques showed that for the annealing temperature range 300 °C < Tan < 600 °C the hexagonal lattice phase was dominant. For Tan < 300 °C hardly any change in the lattice phase could be deduced, whereas for Tan > 600 °C a back transfer to the α-phase was observed. Complementarily, the luminescence upconversion properties of the annealed UCNP materials were characterized in steady state and time resolved luminescence measurements. Distinct differences in the upconversion luminescence intensity, the spectral intensity distribution and the luminescence decay kinetics were found for the cubic and hexagonal lattice phases, respectively, corroborating the results of the standard analytical techniques used. In laser power dependent measurements of the upconversion luminescence intensity it was found that the green (G1, G2) and red (R) emission of Er3+ showed different effects of Tan on the number of required photons reflecting the differences in the population routes of different energy levels involved. Furthermore, the intensity ratio of Gfull/R is highly effected by the laser power only when the β-phase is present, whereas the G1/G2 intensity ratio is only slightly effected regardless of the crystal phase. Moreover, based on different upconversion luminescence kinetics characteristics of the cubic and hexagonal phase time-resolved area normalized emission spectra (TRANES) proved to be a very sensitive tool to monitor the phase transition between cubic and hexagonal phases. Based on the TRANES analysis it was possible to resolve the lattice phase transition in more detail for 200 °C < Tan < 300 °C, which was not possible with the standard techniques. Y1 - 2015 U6 - https://doi.org/10.1039/C5TC02218E SN - 2050-7526 SN - 2050-7534 IS - 3 SP - 11228 EP - 11238 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Klier, Dennis Tobias A1 - Kumke, Michael Uwe T1 - Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale JF - RSC Advances : an international journal to further the chemical sciences N2 - In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure β crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP. Y1 - 2015 U6 - https://doi.org/10.1039/C5RA11502G SN - 2046-2069 IS - 5 SP - 67149 EP - 67156 PB - RSC Publishing CY - London ER - TY - JOUR A1 - de Carvalho, Sidney J. A1 - Metzler, Ralf A1 - Cherstvy, Andrey G. T1 - Inverted critical adsorption of polyelectrolytes in confinement JF - Soft matter N2 - What are the fundamental laws for the adsorption of charged polymers onto oppositely charged surfaces, for convex, planar, and concave geometries? This question is at the heart of surface coating applications, various complex formation phenomena, as well as in the context of cellular and viral biophysics. It has been a long-standing challenge in theoretical polymer physics; for realistic systems the quantitative understanding is however often achievable only by computer simulations. In this study, we present the findings of such extensive Monte-Carlo in silico experiments for polymer–surface adsorption in confined domains. We study the inverted critical adsorption of finite-length polyelectrolytes in three fundamental geometries: planar slit, cylindrical pore, and spherical cavity. The scaling relations extracted from simulations for the critical surface charge density sc—defining the adsorption–desorption transition—are in excellent agreement with our analytical calculations based on the ground-state analysis of the Edwards equation. In particular, we confirm the magnitude and scaling of sc for the concave interfaces versus the Debye screening length 1/k and the extent of confinement a for these three interfaces for small ka values. For large ka the critical adsorption condition approaches the known planar limit. The transition between the two regimes takes place when the radius of surface curvature or half of the slit thickness a is of the order of 1/k. We also rationalize how sc(k) dependence gets modified for semi-flexible versus flexible chains under external confinement. We examine the implications of the chain length for critical adsorption—the effect often hard to tackle theoretically—putting an emphasis on polymers inside attractive spherical cavities. The applications of our findings to some biological systems are discussed, for instance the adsorption of nucleic acids onto the inner surfaces of cylindrical and spherical viral capsids. Y1 - 2015 U6 - https://doi.org/10.1039/C5SM00635J SN - 1744-6848 SN - 1744-683X IS - 11 SP - 4430 EP - 4443 PB - Royal Society of Chemistry CY - London ER - TY - JOUR A1 - Hentrich, Doreen A1 - Junginger, Mathias A1 - Bruns, Michael A1 - Börner, Hans Gerhard A1 - Brandt, Jessica A1 - Brezesinski, Gerald A1 - Taubert, Andreas T1 - Interface-controlled calcium phosphate mineralization BT - effect of oligo(aspartic acid)-rich interfaces JF - CrystEngComm N2 - The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air–water and air–buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression–expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH. Y1 - 2015 U6 - https://doi.org/10.1039/C4CE02274B SN - 1466-8033 IS - 17 SP - 6901 EP - 6913 PB - Royal Society of Chemistry CY - London ER - TY - JOUR A1 - Banerjee, Shiladitya A1 - Stüker, Tony A1 - Saalfrank, Peter T1 - Vibrationally resolved optical spectra of modified diamondoids obtained from time-dependent correlation function methods JF - Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies N2 - Optical properties of modified diamondoids have been studied theoretically using vibrationally resolved electronic absorption, emission and resonance Raman spectra. A time-dependent correlation function approach has been used for electronic two-state models, comprising a ground state (g) and a bright, excited state (e), the latter determined from linear-response, time-dependent density functional theory (TD-DFT). The harmonic and Condon approximations were adopted. In most cases origin shifts, frequency alteration and Duschinsky rotation in excited states were considered. For other cases where no excited state geometry optimization and normal mode analysis were possible or desired, a short-time approximation was used. The optical properties and spectra have been computed for (i) a set of recently synthesized sp2/sp3 hybrid species with C[double bond, length as m-dash]C double-bond connected saturated diamondoid subunits, (ii) functionalized (mostly by thiol or thione groups) diamondoids and (iii) urotropine and other C-substituted diamondoids. The ultimate goal is to tailor optical and electronic features of diamondoids by electronic blending, functionalization and substitution, based on a molecular-level understanding of the ongoing photophysics. Y1 - 2015 U6 - https://doi.org/10.1039/C5CP02615F SN - 1463-9084 SN - 1463-9076 VL - 17 IS - 29 SP - 19656 EP - 19669 PB - Royal Society of Chemistry CY - Cambridge ER -