@article{MansourSolimanShehabetal.2017, author = {Mansour, Ahmed M. and Soliman, Fatma A. and Shehab, Ola R. and Abdel-Ghani, Nour T.}, title = {Photodegradation of sulfadiazine catalyzed by p-benzoquinones and picric acid: application to charge transfer complexes}, series = {RSC Advances}, volume = {7}, journal = {RSC Advances}, number = {63}, doi = {10.1039/c7ra05433e}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181507}, pages = {39989-39996}, year = {2017}, abstract = {As the treatment of effluents containing the antibiotic drug sulfadiazine (SZ) is one of the challenging problems in the field of environmental chemistry, it is essential to determine the concentration of SZ by a rapid and accurate method and then find a suitable method to degrade the assayed products into harmless chemicals. The color of the charge transfer (CT) complexes developed from the reaction of SZ with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), chloranilic acid (CHL) and picric acid (PA) was used to determine the concentration of SZ at 528, 510 and 410 nm, respectively. The Lambert-Beer's law is obeyed in the ranges of 6.80-68.06, 13.61-136.12 and 6.80-27.22 μg mL\(^{-1}\) for DDQ, CHL and PA complexes. The photolysis of SZ → DDQ in presence of sodium nitrite at 256 nm leads to faster degradation of SZ compared with the control experiments. This was simply spectrophotometrically followed by a decrease in the intensity of the CT band. The effect of some additives such as oxalic acid, and hematite nano particles was studied. For comparison, other π-acceptor reagents such as CHL and PA were used. About 80\% of SZ is degraded in 45 min upon the illumination of SZ → DDQ at 256 nm, whereas 90 min is required in the case of CHL and PA to attain the same degradation limit.}, language = {en} } @article{LiHanTessaroloetal.2019, author = {Li, Ru-Jin and Han, Muxin and Tessarolo, Jacopo and Holstein, Julian J. and L{\"u}bben, Jens and Dittrich, Birger and Volkmann, Christian and Finze, Maik and Jenne, Carsten and Clever, Guido H.}, title = {Successive Photoswitching and Derivatization Effects in Photochromic Dithienylethene-Based Coordination Cages}, series = {ChemPhotoChem}, volume = {3}, journal = {ChemPhotoChem}, doi = {10.1002/cptc.201900038}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236815}, pages = {378-383}, year = {2019}, abstract = {A new series of [Pd2(L)4] cages based on photochromic dithienylethene (DTE) ligands allowed us to gain insight into the successive photoswitching of multiple DTE moieties in a confined metallo-supramolecular assembly. Three new X-ray structures of [Pd2(o-L4)4], [Pd2(o-L1)2(c-L1)2] and [Pd2(c-L1)4] (o-L and c-L = open and closed forms of DTE ligands, respectively) were obtained. The structures deliver snapshots of three different combinations of DTE photoisomeric states within the cage, facilitating a comparison of the all-open with the all-closed, and most notably, an intermediate form where open and closed switches co-exist in the same cage. Moreover, a series of spherical anionic borate clusters was introduced in order to study their roles in the light-controllable host-guest chemistry. The binding guests show higher affinities with the flexible open cage [Pd2(o-L1)4] than with the rigid closed cage [Pd2(c-L1)4]. For the [B12F12]2- guest, thermodynamic data obtained from NMR experiments was compared to results from isothermal titration calorimetry (ITC).}, language = {en} } @article{SchwarzScharfScherpfetal.2019, author = {Schwarz, Christopher and Scharf, Lennart T. and Scherpf, Thorsten and Weismann, Julia and Gessner, Viktoria H.}, title = {Isolation of the Metalated Ylides [Ph3P-C-CN]M (M=Li, Na, K): Influence of the Metal Ion on the Structure and Bonding Situation}, series = {Chemistry - A European Journal}, volume = {25}, journal = {Chemistry - A European Journal}, doi = {10.1002/chem.201805421}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235445}, pages = {2793-2802}, year = {2019}, abstract = {The isolation and structural characterization of the cyanido-substituted metalated ylides [Ph3P-C-CN]M (1-M; M=Li, Na, K) are reported with lithium, sodium, and potassium as metal cations. In the solid-state, most different aggregates could be determined depending on the metal and additional Lewis bases. The crown-ether complexes of sodium (1-Na) and potassium (1-K) exhibited different structures, with sodium preferring coordination to the nitrogen end, whereas potassium binds in an unusual η2-coordination mode to the two central carbon atoms. The formation of the yldiide was accompanied by structural changes leading to shorter C-C and longer C-N bonds. This could be attributed to the delocalization of the free electron pairs at the carbon atom into the antibonding orbitals of the CN moiety, which was confirmed by IR spectroscopy and computational studies. Detailed density functional theory calculations show that the changes in the structure and the bonding situation were most pronounced in the lithium compounds due to the higher covalency.}, language = {en} } @article{DietzJohnsonMartinezMartinezetal.2019, author = {Dietz, Maximilian and Johnson, Alice and Mart{\´i}nez-Mart{\´i}nez, Antonio and Weller, Andrew S.}, title = {The [Rh(Xantphos)]+ catalyzed hydroboration of diphenylacetylene using trimethylamine-borane}, series = {Inorganica Chimica Acta}, volume = {491}, journal = {Inorganica Chimica Acta}, doi = {10.1016/j.ica.2019.03.032}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225352}, pages = {9-13}, year = {2019}, abstract = {The rhodium(I) complex [Rh(κ3-P,O,P-Xantphos)(η2-PhC≡CPh)][BArF4] (ArF = 3,5-(CF3)2C6H4) is an effective catalyst for the cis-selective hydroboration of the alkyne diphenylacetylene using the amine-borane H3B·NMe3. Detailed mechanistic studies, that include initial rate measurements, full simulation of temporal profiles for a variety of catalyst and substrate concentrations, and speciation experiments, suggest a mechanism that involves initial coordination of alkyne and a saturation kinetics regime for amine-borane binding. The solid-state molecular structure of a model complex that probes the proposed resting state is also reported, [Rh(κ3-P,O,P-Xantphos)(NCMe)(η2-PhC≡CPh)][BArF4].}, language = {en} } @article{DongKuzmanoskiWehneretal.2017, author = {Dong, Hailong and Kuzmanoski, Ana and Wehner, Tobias and Mueller-Buschbaum, Klaus and Feldmann, Claus}, title = {Microwave-assisted polyol synthesis of water dispersible red-emitting Eu\(^{3+}\)-modified carbon dots}, series = {Materials}, volume = {10}, journal = {Materials}, doi = {10.3390/ma10010025}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181674}, year = {2017}, abstract = {Eu\(^{3+}\)-modified carbon dots (C-dots), 3-5 nm in diameter, were prepared, functionalized, and stabilized via a one-pot polyol synthesis. The role of Eu\(^{2+}\)/Eu\(^{3+}\), the influence of O\(_2\) (oxidation) and H\(_2\)O (hydrolysis), as well as the impact of the heating procedure (conventional resistance heating and microwave (MW) heating) were explored. With the reducing conditions of the polyol at the elevated temperature of synthesis (200-230 °C), first of all, Eu\(^{2+}\) was obtained resulting in the blue emission of the C-dots. Subsequent to O\(_2\)-driven oxidation, Eu\(^{3+}\)-modified, red-emitting C-dots were realized. However, the Eu\(^{3+}\) emission is rapidly quenched by water for C-dots prepared via conventional resistance heating. In contrast to the hydroxyl functionalization of conventionally-heated C-dots, MW-heating results in a carboxylate functionalization of the C-dots. Carboxylate-coordinated Eu\(^{3+}\), however, turned out as highly stable even in water. Based on this fundamental understanding of synthesis and material, in sum, a one-pot polyol approach is established that results in H\(_2\)O-dispersable C-dots with intense red Eu\(^{3+}\)-line-type emission.}, language = {en} } @article{HaerterichMatlerDewhurstetal.2023, author = {H{\"a}rterich, Marcel and Matler, Alexander and Dewhurst, Rian D. and Sachs, Andreas and Oppel, Kai and Stoy, Andreas and Braunschweig, Holger}, title = {A step-for-step main-group replica of the Fischer carbene synthesis at a borylene carbonyl}, series = {Nature Communications}, volume = {14}, journal = {Nature Communications}, doi = {10.1038/s41467-023-36251-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357270}, year = {2023}, abstract = {The Fischer carbene synthesis, involving the conversion of a transition metal (TM)-bound CO ligand to a carbene ligand of the form [=C(OR')R] (R, R' = organyl groups), is one of the seminal reactions in the history of organometallic chemistry. Carbonyl complexes of p-block elements, of the form [E(CO)n] (E = main-group fragment), are much less abundant than their TM cousins; this scarcity and the general instability of low-valent p-block species means that replicating the historical reactions of TM carbonyls is often very difficult. Here we present a step-for-step replica of the Fischer carbene synthesis at a borylene carbonyl involving nucleophilic attack at the carbonyl carbon followed by electrophilic quenching at the resultant acylate oxygen atom. These reactions provide borylene acylates and alkoxy-/silyloxy-substituted alkylideneboranes, main-group analogues of the archetypal transition metal acylate and Fischer carbene families, respectively. When either the incoming electrophile or the boron center has a modest steric profile, the electrophile instead attacks at the boron atom, leading to carbene-stabilized acylboranes - boron analogues of the well-known transition metal acyl complexes. These results constitute faithful main-group replicas of a number of historical organometallic processes and pave the way to further advances in the field of main-group metallomimetics.}, language = {en} } @article{TumirPavlovićSaftićCrnolatacetal.2023, author = {Tumir, Lidija-Marija and Pavlović Saftić, Dijana and Crnolatac, Ivo and Ban, Željka and Maslać, Matea and Griesbeck, Stefanie and Marder, Todd B. and Piantanida, Ivo}, title = {The nature of the (oligo/hetero)arene linker connecting two triarylborane cations controls fluorimetric and circular dichroism sensing of various ds-DNAs and ds-RNAs}, series = {Molecules}, volume = {28}, journal = {Molecules}, number = {11}, issn = {1420-3049}, doi = {10.3390/molecules28114348}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-319322}, year = {2023}, abstract = {A series of tetracationic bis-triarylborane dyes, differing in the aromatic linker connecting two dicationic triarylborane moieties, showed very high submicromolar affinities toward ds-DNA and ds-RNA. The linker strongly influenced the emissive properties of triarylborane cations and controlled the fluorimetric response of dyes. The fluorene-analog shows the most selective fluorescence response between AT-DNA, GC-DNA, and AU-RNA, the pyrene-analog's emission is non-selectively enhanced by all DNA/RNA, and the dithienyl-diketopyrrolopyrrole analog's emission is strongly quenched upon DNA/RNA binding. The emission properties of the biphenyl-analog were not applicable, but the compound showed specific induced circular dichroism (ICD) signals only for AT-sequence-containing ds-DNAs, whereas the pyrene-analog ICD signals were specific for AT-DNA with respect to GC-DNA, and also recognized AU-RNA by giving a different ICD pattern from that observed upon interaction with AT-DNA. The fluorene- and dithienyl-diketopyrrolopyrrole analogs were ICD-signal silent. Thus, fine-tuning of the aromatic linker properties connecting two triarylborane dications can be used for the dual sensing (fluorimetric and CD) of various ds-DNA/RNA secondary structures, depending on the steric properties of the DNA/RNA grooves.}, language = {en} } @article{KošćakPeharBožinovićetal.2022, author = {Košćak, Marta and Pehar, Isabela and Božinović, Ksenija and Kole, Goutam Kumar and Sobočanec, Sandra and Podgorski, Iva I. and Pinterić, Marija and M{\"u}ller-Buschbaum, Klaus and Majhen, Dragomira and Piantanida, Ivo and Marder, Todd B.}, title = {Para-N-methylpyridinium pyrenes: impact of positive charge on ds-DNA/RNA and protein recognition, photo-induced bioactivity, and intracellular localisation}, series = {Pharmaceutics}, volume = {14}, journal = {Pharmaceutics}, number = {11}, issn = {1999-4923}, doi = {10.3390/pharmaceutics14112499}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-297247}, year = {2022}, abstract = {The 2- and 2,7- substituted para-N-methylpyridinium pyrene cations show high-affinity intercalation into ds-DNAs, whereas their non-methylated analogues interacted with ds-DNA/RNA only in the protonated form (at pH 5), but not at physiological conditions (pH 7). The fluorescence from non-methylated analogues was strongly dependent on the protonation of the pyridines; consequently, they act as fluorescence ratiometric probes for simultaneous detection of both ds-DNA and BSA at pH 5, relying on the ratio between intensities at 420 nm (BSA specific) and 520 nm (DNA specific), whereby exclusively ds-DNA sensing could be switched-off by adjustment to pH 7. Only methylated, permanently charged pyrenes show photoinduced cleavage of circular DNA, attributed to pyrene-mediated irradiation-induced production of singlet oxygen. Consequently, the moderate toxicity of these cations against human cell lines is strongly increased upon irradiation. Detailed studies revealed increased total ROS production in cells treated by the compounds studied, accompanied by cell swelling and augmentation of cellular complexity. The most photo-active 2-para-N-methylpyridinium pyrene showed significant localization at mitochondria, its photo-bioactivity likely due to mitochondrial DNA damage. Other derivatives were mostly non-selectively distributed between various cytoplasmic organelles, thus being less photoactive.}, language = {en} } @article{TaniniPecchiIgnat’evetal.2022, author = {Tanini, Damiano and Pecchi, Tommaso and Ignat'ev, Nikolai V. and Capperucci, Antonella}, title = {Ionic liquids-assisted ring opening of three-membered heterocycles with thio- and seleno-silanes}, series = {Catalysts}, volume = {12}, journal = {Catalysts}, number = {10}, issn = {2073-4344}, doi = {10.3390/catal12101259}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-290350}, year = {2022}, abstract = {Ring opening reactions of strained heterocycles (epoxides, aziridines, thiiranes) by silyl chalcogenides, such as thiosilanes and selenosilanes, can be efficiently performed in a variety of ionic liquids, which can behave as reaction media and in some cases also as catalysts. This protocol enables an alternative access to β-functionalized sulfides and selenides under mild conditions.}, language = {en} } @article{WildervanckHechtNowakKrol2022, author = {Wildervanck, Martijn J. and Hecht, Reinhard and Nowak-Kr{\´o}l, Agnieszka}, title = {Synthesis and strong solvatochromism of push-pull thienylthiazole boron complexes}, series = {Molecules}, volume = {27}, journal = {Molecules}, number = {17}, issn = {1420-3049}, doi = {10.3390/molecules27175510}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286186}, year = {2022}, abstract = {The solvatochromic behavior of two donor-π bridge-acceptor (D-π-A) compounds based on the 2-(3-boryl-2-thienyl)thiazole π-linker and indandione acceptor moiety are investigated. DFT/TD-DFT calculations were performed in combination with steady-state absorption and emission measurements, along with electrochemical studies, to elucidate the effect of two different strongly electron-donating hydrazonyl units on the solvatochromic and fluorescence behavior of these compounds. The Lippert-Mataga equation was used to estimate the change in dipole moments (Δµ) between ground and excited states based on the measured spectroscopic properties in solvents of varying polarity with the data being supported by theoretical studies. The two asymmetrical D-π-A molecules feature strong solvatochromic shifts in fluorescence of up to ~4300 cm\(^{-1}\) and a concomitant change of the emission color from yellow to red. These changes were accompanied by an increase in Stokes shift to reach values as large as ~5700-5800 cm\(^{-1}\). Quantum yields of ca. 0.75 could be observed for the N,N-dimethylhydrazonyl derivative in nonpolar solvents, which gradually decreased along with increasing solvent polarity, as opposed to the consistently reduced values obtained for the N,N-diphenylhydrazonyl derivative of up to ca. 0.20 in nonpolar solvents. These two push-pull molecules are contrasted with a structurally similar acceptor-π bridge-acceptor (A-π-A) compound.}, language = {en} }