@article{NchiozemNgnitedemSperlichMatietaetal.2023, author = {Nchiozem-Ngnitedem, Vaderament-Alexe and Sperlich, Eric and Matieta, Valaire Yemene and Kuete, Jenifer Reine Ngnouzouba and Kuete, Victor and Omer, Ejlal A. A. and Efferth, Thomas and Schmidt, Bernd}, title = {Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues}, series = {Journal of natural products : Lloydia}, volume = {86}, journal = {Journal of natural products : Lloydia}, number = {6}, publisher = {American Chemical Society}, address = {Washington, DC}, issn = {0163-3864}, doi = {10.1021/acs.jnatprod.3c00219}, pages = {1520 -- 1528}, year = {2023}, abstract = {FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold.}, language = {en} } @article{SperlichKoeckerling2023, author = {Sperlich, Eric and K{\"o}ckerling, Martin}, title = {The double cluster compound [Nb6Cl14(MeCN)(4)] [Nb6Cl14(pyz)(4)].6MeCN (Me: methyl, pyz: pyrazine) with a layered structure resulting from weak intermolecular interactions}, series = {Zeitschrift f{\"u}r Naturforschung}, volume = {78}, journal = {Zeitschrift f{\"u}r Naturforschung}, number = {5}, publisher = {De Gruyter}, address = {Berlin}, issn = {0932-0776}, doi = {10.1515/znb-2023-0001}, pages = {279 -- 283}, year = {2023}, abstract = {The synthesis and the crystal structure of the double cluster compound [Nb6Cl14(MeCN)(4)][Nb6Cl14(pyz)(4)]middot6CH(3)CN are described. The synthesis is based on a partial ligand exchange reaction, which proceeds upon dissolving [Nb6Cl14(pyz)(4)]middot2CH(2)Cl(2) in acetonitrile. The compound is built up of two discrete neutral cluster units, which consist of octahedra of Nb-6 atoms coordinated by 12 edge-bridging chlorido and two terminal chlorido ligands, and four acetonitrile ligands on one and four pyrazine ligands on the other cluster unit. Co-crystallized acetonitrile molecules are also present. The single-crystal structure determination has revealed a cluster arrangement in which the [Nb6Cl14(pyz)(4)] units are connected by (halogen) lone-pair-(pyrazine) pi interactions. These lead to chains of [Nb6Cl14(pyz)(4)] clusters. These chains are further connected to cluster layers by (nitrile-halogen) dipole-dipole interactions, in which the [Nb6Cl14(MeCN)(4)] and co-crystallized MeCN molecules are also involved. These cluster layers are arranged parallel to the crystallographic {011} plane.}, language = {en} } @misc{WessigJohnSperlichetal.2020, author = {Wessig, Pablo and John, Leonard and Sperlich, Eric and Kelling, Alexandra}, title = {Sulfur tuning of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {3}, issn = {1866-8372}, doi = {10.25932/publishup-56624}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-566241}, pages = {15}, year = {2020}, abstract = {The replacement of oxygen by sulfur atoms of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes is an efficient way to adjust the photophysical properties (sulfur tuning). While previously developed S-4-DBD dyes exhibit considerably red-shifted absorption and emission wavelength, the heavy atom effect of four sulfur atoms cause low fluorescence quantum yields and short fluorescence lifetimes. Herein, we demonstrate that the replacement of less than four sulfur atoms (S-1-DBD, 1,2-S-2-DBD, and 1,4-S-2-DBD dyes) permits a fine-tuning of the photophysical properties. In some cases, a similar influence on the wavelength without the detrimental effect on the quantum yields and lifetimes is observed. Furthermore, the synthetic accessibility of S-1- and S-2-DBD dyes is improved, compared with S-4-DBD dyes. For coupling with biomolecules a series of reactive derivatives of the new dyes were developed (azides, OSu esters, alkynes, maleimides).}, language = {en} } @article{SperlichKoeckerling2021, author = {Sperlich, Eric and K{\"o}ckerling, Martin}, title = {Cluster salts [Nb6Cl12(HIm)(6)]A(n) (with HIm=1H-imidazole and A=Mineral Acid Anion, n=1 or 2) made in and with Bronsted-basic ionic liquids and liquid mixtures}, series = {ChemistryOpen}, volume = {10}, journal = {ChemistryOpen}, number = {2}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2191-1363}, doi = {10.1002/open.202000266}, pages = {248 -- 254}, year = {2021}, abstract = {Four new hexanuclear niobium cluster compounds of the general formula [Nb6Cl12(HIm)(6)](A)(n) . x(solvent molecule) (HIm=1H-imidazole, A=mineral acid anion, Cl- (n=2) (1), (SO4)(2-) (n=1) (2), (CrO4)(2-) (n=1) (3), and (HAsO4)(2-) (n=1) (4)) were prepared. Their synthesis can be done in basic ionic liquids, which form on the addition of a mineral acid, which also delivers the counter anion for the final cluster compound, to an excess of the 1H-imidazole. Some addition of an auxiliary solvent, like methanol, improves the speed of crystallisation. The cluster unit comprises a hexanuclear Nb-6 unit of octahedral shape with the edges bridged by Cl atoms and the exo sites being occupied by N-bonded 1H-imidazole ligands. The cluster cation carries sixteen cluster-based electrons. Between the NH groups of the ligands of the cluster unit, the anions and the co-crystallised water (1), or 1H-imidazole and methanol molecules (2, 3, and 4) a network of hydrogen bonds exists.}, language = {en} } @article{BalischewskiBhattacharyyaSperlichetal.2022, author = {Balischewski, Christian and Bhattacharyya, Biswajit and Sperlich, Eric and G{\"u}nter, Christina and Beqiraj, Alkit and Klamroth, Tillmann and Behrens, Karsten and Mies, Stefan and Kelling, Alexandra and Lubahn, Susanne and Holtzheimer, Lea and Nitschke, Anne and Taubert, Andreas}, title = {Tetrahalidometallate(II) ionic liquids with more than one metal}, series = {Chemistry - a European journal}, volume = {28}, journal = {Chemistry - a European journal}, number = {64}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-3765}, doi = {10.1002/chem.202201068}, pages = {13}, year = {2022}, abstract = {Fifteen N-butylpyridinium salts - five monometallic [C4Py](2)[MBr4] and ten bimetallic [C4Py](2)[(M0.5M0.5Br4)-M-a-Br-b] (M=Co, Cu, Mn, Ni, Zn) - were synthesized, and their structures and thermal and electrochemical properties were studied. All the compounds are ionic liquids (ILs) with melting points between 64 and 101 degrees C. Powder and single-crystal X-ray diffraction show that all ILs are isostructural. The electrochemical stability windows of the ILs are between 2 and 3 V. The conductivities at room temperature are between 10(-5) and 10(-6) S cm(-1). At elevated temperatures, the conductivities reach up to 10(-4) S cm(-1) at 70 degrees C. The structures and properties of the current bromide-based ILs were also compared with those of previous examples using chloride ligands, which illustrated differences and similarities between the two groups of ILs.}, language = {en} } @article{SperlichKoeckerling2022, author = {Sperlich, Eric and K{\"o}ckerling, Martin}, title = {[Nb6Cl14(pyrazine)(4)], a versatile precursor for ligand-supported hexanuclear niobium cluster compounds: synthesis, characterization, follow-up reactions, and intermolecular interactions}, series = {Inorganic chemistry}, volume = {61}, journal = {Inorganic chemistry}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0020-1669}, doi = {10.1021/acs.inorgchem.1c03109}, pages = {2409 -- 2420}, year = {2022}, abstract = {The compound [Nb6Cl14(pyrazine)(4)]center dot 2CH(2)Cl(2) (1) was investigated for its suitability as a starting compound for new ligand-supported hexanuclear niobium cluster compounds. The synthesis, stability to air and increased temperature, solubility and usability for subsequent reactions of 1, and purification and separation of the reaction products are discussed. The compounds with cluster units [Nb6Cl14L4], where L = iso-quinoline N-oxides (2), 1,1-dimethylethylenediamines (3), or thiazoles (4), and [Nb6Cl14(PEt3)(3.76)(Et3PO)(0.24)]-[Nb6Cl14(MeCN)(4)]center dot 4MeCN (5) are presented as follow-up products. The crystal structures of compounds 1-5 are analyzed, and the structures are discussed with respect to their intraand intermolecular bonding situations and crystal packing. In addition to hydrogen bonds and pi-pi interactions, the appearance of chalcogen and halogen bonds and lone pair-pi interactions between Nb-6 cluster units was observed for the first time.}, language = {en} } @article{SperlichKoeckerling2021, author = {Sperlich, Eric and K{\"o}ckerling, Martin}, title = {[Nb6Cl12(CH3OH)4(OCH3)2] ⋅ DABCO ⋅ 1.66 CH2Cl2}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie : ZAAC = Journal of inorganic and general chemistry}, volume = {647}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie : ZAAC = Journal of inorganic and general chemistry}, number = {18}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0044-2313}, doi = {10.1002/zaac.202100138}, pages = {1759 -- 1763}, year = {2021}, abstract = {An easy-to-do synthesis for the hexanuclear niobium cluster compound [Nb6Cl12(CH3OH)(4)(OCH3)(2)] . DABCO . 1.66 CH2Cl2 has been developed. An one-pot reaction between the cluster precursor [Nb6Cl14(H2O)(4)] . 4H(2)O and methanol with the addition of DABCO leads to the crystallization of the title compound in high yield within a few minutes. The single-crystal X-ray structure of this cluster compound has been determined. Very strong, nearly symmetric intercluster hydrogen bonds Nb-6-MeO...H...OMe-Nb-6 are present between the cluster units. A bridging co-crystalline DABCO molecule is also involved in a three-dimensional hydrogen-bonding network.}, language = {en} } @misc{BhattacharyyaBalischewskiSperlichetal.2023, author = {Bhattacharyya, Biswajit and Balischewski, Christian and Sperlich, Eric and G{\"u}nter, Christina and Mies, Stefan and Kelling, Alexandra and Taubert, Andreas}, title = {N-Butyl Pyridinium Diiodido Argentate(I)}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1341}, issn = {1866-8372}, doi = {10.25932/publishup-60487}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-604874}, pages = {7}, year = {2023}, abstract = {A new solid-state material, N-butyl pyridinium diiodido argentate(I), is synthesized using a simple and effective one-pot approach. In the solid state, the compound exhibits 1D ([AgI2](-))(n) chains that are stabilized by the N-butyl pyridinium cation. The 1D structure is further manifested by the formation of long, needle-like crystals, as revealed from electron microscopy. As the general composition is derived from metal halide-based ionic liquids, the compound has a low melting point of 100-101 degrees C, as confirmed by differential scanning calorimetry. Most importantly, the compound has a conductivity of 10(-6) S cm(-1) at room temperature. At higher temperatures the conductivity increases and reaches to 10(-4 )S cm(-1) at 70 degrees C. In contrast to AgI, however, the current material has a highly anisotropic 1D arrangement of the ionic domains. This provides direct and tuneable access to fast and anisotropic ionic conduction. The material is thus a significant step forward beyond current ion conductors and a highly promising prototype for the rational design of highly conductive ionic solid-state conductors for battery or solar cell applications.}, language = {en} } @article{BhattacharyyaBalischewskiSperlichetal.2023, author = {Bhattacharyya, Biswajit and Balischewski, Christian and Sperlich, Eric and G{\"u}nter, Christina and Mies, Stefan and Kelling, Alexandra and Taubert, Andreas}, title = {N-Butyl Pyridinium Diiodido Argentate(I)}, series = {Advanced materials interfaces}, volume = {10}, journal = {Advanced materials interfaces}, number = {12}, publisher = {Wiley}, address = {Hoboken}, issn = {2196-7350}, doi = {10.1002/admi.202202363}, pages = {7}, year = {2023}, abstract = {A new solid-state material, N-butyl pyridinium diiodido argentate(I), is synthesized using a simple and effective one-pot approach. In the solid state, the compound exhibits 1D ([AgI2](-))(n) chains that are stabilized by the N-butyl pyridinium cation. The 1D structure is further manifested by the formation of long, needle-like crystals, as revealed from electron microscopy. As the general composition is derived from metal halide-based ionic liquids, the compound has a low melting point of 100-101 degrees C, as confirmed by differential scanning calorimetry. Most importantly, the compound has a conductivity of 10(-6) S cm(-1) at room temperature. At higher temperatures the conductivity increases and reaches to 10(-4 )S cm(-1) at 70 degrees C. In contrast to AgI, however, the current material has a highly anisotropic 1D arrangement of the ionic domains. This provides direct and tuneable access to fast and anisotropic ionic conduction. The material is thus a significant step forward beyond current ion conductors and a highly promising prototype for the rational design of highly conductive ionic solid-state conductors for battery or solar cell applications.}, language = {en} } @misc{BehrensBalischewskiSperlichetal.2022, author = {Behrens, Karsten and Balischewski, Christian and Sperlich, Eric and Menski, Antonia Isabell and Balderas-Valadez, Ruth Fabiola and Pacholski, Claudia and G{\"u}nter, Christina and Lubahn, Susanne and Kelling, Alexandra and Taubert, Andreas}, title = {Mixed chloridometallate(ii) ionic liquids with tunable color and optical response for potential ammonia sensors}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1316}, issn = {1866-8372}, doi = {10.25932/publishup-58751}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-587512}, pages = {35072 -- 35082}, year = {2022}, abstract = {Eight d-metal-containing N-butylpyridinium ionic liquids (ILs) with the nominal composition (C4Py)2[Ni0.5M0.5Cl4] or (C4Py)2[Zn0.5M0.5Cl4] (M = Cu, Co, Mn, Ni, Zn; C4Py = N-butylpyridinium) were synthesized, characterized, and investigated for their optical properties. Single crystal and powder X-ray analysis shows that the compounds are isostructural to existing examples based on other d-metal ions. Inductively coupled plasma optical emission spectroscopy measurements confirm that the metal/metal ratio is around 50 : 50. UV-Vis spectroscopy shows that the optical absorption can be tuned by selection of the constituent metals. Moreover, the compounds can act as an optical sensor for the detection of gases such as ammonia as demonstrated via a simple prototype setup.}, language = {en} }