@article{BrietzkeKellingSchildeetal.2016, author = {Brietzke, Thomas Martin and Kelling, Alexandra and Schilde, Uwe and Mickler, Wulfhard and Holdt, Hans-J{\"u}rgen}, title = {Heterodinuclear Ruthenium(II) Complexes of the Bridging Ligand 1,6,7,12-Tetraazaperylene with Iron(II), Cobalt(II), Nickel(II), as well as Palladium(II) and Platinum(II)}, series = {Zeitschrift f{\~A}¼r anorganische und allgemeine Chemie}, volume = {642}, journal = {Zeitschrift f{\~A}¼r anorganische und allgemeine Chemie}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0044-2313}, doi = {10.1002/zaac.201500645}, pages = {8 -- 13}, year = {2016}, abstract = {The first heterodinuclear ruthenium(II) complexes of the 1,6,7,12-tetraazaperylene (tape) bridging ligand with iron(II), cobalt(II), and nickel(II) were synthesized and characterized. The metal coordination sphere in this complexes is filled by the tetradentate N,N-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane (L-N4Me2) ligand, yielding complexes of the general formula [(L-N4Me2)Ru(mu-tape)M(L-N4Me2)](ClO4)(2)(PF6)(2) with M = Fe {[2](ClO4)(2)(PF6)(2)}, Co {[3](ClO4)(2)(PF6)(2)}, and Ni {[4](ClO4)(2)(PF6)(2)}. Furthermore, the heterodinuclear tape ruthenium(II) complexes with palladium(II)- and platinum(II)-dichloride [(bpy)(2)Ru(-tape)PdCl2](PF6)(2) {[5](PF6)(2)} and [(dmbpy)(2)Ru(-tape)PtCl2](PF6)(2) {[6](PF6)(2)}, respectively were also prepared. The molecular structures of the complex cations [2](4+) and [4](4+) were discussed on the basis of the X-ray structures of [2](ClO4)(4)MeCN and [4](ClO4)(4)MeCN. The electrochemical behavior and the UV/Vis absorption spectra of the heterodinuclear tape ruthenium(II) complexes were explored and compared with the data of the analogous mono- and homodinuclear ruthenium(II) complexes of the tape bridging ligand.}, language = {en} } @article{BaierKellingSchildeetal.2016, author = {Baier, Heiko and Kelling, Alexandra and Schilde, Uwe and Holdt, Hans-J{\"u}rgen}, title = {Investigation of the Catalytic Activity of a 2-Phenylidenepyridine Palladium(II) Complex Bearing 4,5-Dicyano-1,3-bis(mesityl)imidazol-2-ylidene in the Mizoroki-Heck Reaction}, series = {Zeitschrift f{\~A}¼r anorganische und allgemeine Chemie}, volume = {642}, journal = {Zeitschrift f{\~A}¼r anorganische und allgemeine Chemie}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0044-2313}, doi = {10.1002/zaac.201500625}, pages = {140 -- 147}, year = {2016}, abstract = {The phenylidenepyridine (ppy) palladacycles [PdCl(ppy)(IMes)] (4) [IMes = 1,3-bis(mesityl) imidazol-2-ylidene] and [PdCl(ppy){(CN)(2)IMes}] (6) [(CN)(2)IMes = 4,5-dicyano-1,3-bis(mesityl) imidazol-2-ylidene] were prepared by facile two step syntheses, starting with the reaction of palladium(II) chloride with 2-phenylpyridine followed by subsequent addition of the NHC ligand to the precatalyst precursor [PdCl(ppy)](2). Suitable crystals for the X-ray analysis of the complexes 4 and 6 were obtained. It was shown that 6 has a shorter NHC-palladium bond than the IMes complex 4. The difference of the palladium carbene bond lengths based on the higher pi-acceptor strength of (CN)(2)IMes in comparison to IMes. Thus, (CN)(2)IMes should stabilize the catalytically active central palladium atom better than IMes. As a measure for the pi-acceptor strength of (CN)(2)IMes compared to IMes, the selone (CN)(2)IMes center dot Se (7) was prepared and characterized by Se-77-NMR spectroscopy. The pi-acceptor strength of 7 was illuminated by the shift of its Se-77-NMR signal. The Se-77-NMR signal of 7 was shifted to much higher frequencies than the Se-77-NMR signal of IMes center dot Se. Catalytic experiments using the Mizoroki-Heck reaction of aryl chlorides with n-butyl acrylate showed that 6 is the superior performer in comparison to 4. Using complex 6, an extensive substrate screening of 26 different aryl bromides with n-butyl acrylate was performed. Complex 6 is a suitable precatalyst for para-substituted aryl bromides. The catalytically active species was identified by mercury poisoning experiments to be palladium nanoparticles.}, language = {en} } @article{MondalMarquardtJaniaketal.2016, author = {Mondal, Suvendu Sekhar and Marquardt, Dorothea and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles}, series = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, volume = {45}, journal = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-9226}, doi = {10.1039/c6dt00225k}, pages = {5476 -- 5483}, year = {2016}, abstract = {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\&\#8242;-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 \&\#8722;22 to \&\#8722;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.}, language = {en} } @misc{MondalHoldt2016, author = {Mondal, Suvendu Sekhar and Holdt, Hans-J{\"u}rgen}, title = {Breaking Down Chemical Weapons by Metal-Organic Frameworks}, series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, volume = {55}, journal = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1433-7851}, doi = {10.1002/anie.201508407}, pages = {42 -- 44}, year = {2016}, abstract = {Seek and destroy: Filtration schemes and self-detoxifying protective fabrics based on the ZrIV-containing metal—organic frameworks (MOFs) MOF-808 and UiO-66 doped with LiOtBu have been developed that capture and hydrolytically detoxify simulants of nerve agents and mustard gas. Both MOFs function as highly catalytic elements in these applications.}, language = {en} } @article{SchwarzeSchneiderRiemeretal.2016, author = {Schwarze, Thomas and Schneider, Radu and Riemer, Janine and Holdt, Hans-J{\"u}rgen}, title = {A Highly K+-Selective Fluorescent Probe - Tuning the K+-Complex Stability and the K+/Na+ Selectivity by Varying the Lariat-Alkoxy Unit of a Phenylaza[18]crown-6 Ionophore}, series = {Chemistry : an Asian journal ; an ACES journal}, volume = {11}, journal = {Chemistry : an Asian journal ; an ACES journal}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1861-4728}, doi = {10.1002/asia.201500956}, pages = {241 -- 247}, year = {2016}, abstract = {A desirable goal is to synthesize easily accessible and highly K+/Na+-selective fluoroionophores to monitor physiological K+ levels in vitro and in vivo. Therefore, highly K+/Na+-selective ionophores have to be developed. Herein, we obtained in a sequence of only four synthetic steps a set of K+-responsive fluorescent probes 4, 5 and 6. In a systematic study, we investigated the influence of the alkoxy substitution in ortho position of the aniline moiety in -conjugated aniline-1,2,3-triazole-coumarin-fluoroionophores 4, 5 and 6 [R=MeO (4), EtO (5) and iPrO (6)] towards the K+-complex stability and K+/Na+ selectivity. The highest K+-complex stability showed fluoroionophore 4 with a dissociation constant K-d of 19mm, but the K-d value increases to 31mm in combined K+/Na+ solutions, indicating a poor K+/Na+ selectivity. By contrast, 6 showed even in the presence of competitive Na+ ions equal K-d values (K-d(K+)=45mm and K-d(K+/Na+)=45mm) and equal K+-induced fluorescence enhancement factors (FEFs=2.3). Thus, the fluorescent probe 6 showed an outstanding K+/Na+ selectivity and is a suitable fluorescent tool to measure physiological K+ levels in the range of 10-80mm in vitro. Further, the isopropoxy-substituted N-phenylaza[18]crown-6 ionophore in 6 is a highly K+-selective building block with a feasible synthetic route.}, language = {en} } @article{MondalBhuniaAttallahetal.2016, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Attallah, Ahmed G. and Matthes, Philipp R. and Kelling, Alexandra and Schilde, Uwe and M{\"u}ller-Buschbaum, Klaus and Krause-Rehberg, Reinhard and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Study of the Discrepancies between Crystallographic Porosity and Guest Access into Cadmium-Imidazolate Frameworks and Tunable Luminescence Properties by Incorporation of Lanthanides}, series = {Chemistry - a European journal}, volume = {22}, journal = {Chemistry - a European journal}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201504757}, pages = {6905 -- 6913}, year = {2016}, abstract = {An extended member of the isoreticular family of metal-imidazolate framework structures, IFP-6 (IFP=imidazolate framework Potsdam), based on cadmium metal and an in situ functionalized 2-methylimidazolate-4-amide-5-imidate linker is reported. A porous 3D framework with 1D hexagonal channels with accessible pore windows of 0.52nm has been synthesized by using an ionic liquid (IL) linker precursor. IFP-6 shows significant gas uptake capacity only for CO2 and CH4 at elevated pressure, whereas it does not adsorb N-2, H-2, and CH4 under atmospheric conditions. IFP-6 is assumed to deteriorate at the outside of the material during the activation process. This closing of the metal-organic framework (MOF) pores is proven by positron annihilation lifetime spectroscopy (PALS), which revealed inherent crystal defects. PALS results support the conservation of the inner pores of IFP-6. IFP-6 has also been successfully loaded with luminescent trivalent lanthanide ions (Ln(III)=Tb, Eu, and Sm) in a bottom-up one-pot reaction through the in situ generation of the linker ligand and in situ incorporation of photoluminescent Ln ions into the constituting network. The results of photoluminescence investigations and powder XRD provide evidence that the Ln ions are not doped as connectivity centers into the frameworks, but are instead located within the pores of the MOFs. Under UV light irradiation, Tb@IFP-6 and Eu@IFP-6 ((exc)=365nm) exhibit observable emission changes to a greenish and reddish color, respectively, as a result of strong Ln 4f emissions.}, language = {en} } @article{MondalMarquardtJaniaketal.2016, author = {Mondal, Suvendu Sekhar and Marquardt, Dorothea and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles}, series = {Dalton transactions : an international journal of inorganic chemistry}, journal = {Dalton transactions : an international journal of inorganic chemistry}, number = {45}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-9226}, doi = {10.1039/C6DT00225K}, pages = {5476 -- 5483}, year = {2016}, abstract = {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.}, language = {en} }