Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-46723 Wissenschaftlicher Artikel Mondal, Suvendu Sekhar; Dey, Subarna; Attallah, Ahmed G.; Krause-Rehberg, Reinhard; Janiak, Christoph; Holdt, Hans-Jürgen Insights into the pores of microwave-assisted metal-imidazolate frameworks showing enhanced gas sorption Microwave heating (MW)-assisted synthesis has been widely applied as an alternative method for the chemical synthesis of organic and inorganic materials. In this work, we report MW-assisted synthesis of three isostructural 3D frameworks with a flexible linker arm of the chelating linker 2-substituted imidazolate- 4-amide-5-imidate, named IFP-7-MW (M = Zn, R = OMe), IFP-8-MW (M = Co; R = OMe) and IFP-10-MW (M = Co; R = OEt) (IFP = Imidazolate Framework Potsdam). These chelating ligands were generated in situ by partial hydrolysis of 2-substituted 4,5-dicyanoimidazoles under MW-and also conventional electrical heating (CE)-assisted conditions in DMF. The structure of these materials was determined by IR spectroscopy and powder X-ray diffraction (PXRD) and the identity of the materials synthesized under CE-conditions was established. Materials obtained from MW-heating show many fold enhancement of CO2 and H-2 uptake capacities, compared to the analogous CE-heating method based materials. To understand the inner pore-sizes of IFP structures and variations of gas sorptions, we performed positron annihilation lifetime spectroscopy (PALS), which shows that MW-assisted materials have smaller pore sizes than materials synthesized under CE-conditions. The "kinetically controlled" MW-synthesized material has an inherent ability to trap extra linkers, thereby reducing the pore sizes of CE-materials to ultra/micropores. These ultramicropores are responsible for high gas sorption. Cambridge Royal Society of Chemistry 2017 10 Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry 46 4824 4833 10.1039/c7dt00350a Institut für Chemie OPUS4-48642 Wissenschaftlicher Artikel Alrefai, Anas; Mondal, Suvendu Sekhar; Wruck, Alexander; Kelling, Alexandra; Schilde, Uwe; Brandt, Philipp; Janiak, Christoph; Schoenfeld, Sophie; Weber, Birgit; Rybakowski, Lawrence; Herrman, Carmen; Brennenstuhl, Katlen; Eidner, Sascha; Kumke, Michael Uwe; Behrens, Karsten; Günter, Christina; Müller, Holger; Holdt, Hans-Jürgen Hydrogen-bonded supramolecular metal-imidazolate frameworks: gas sorption, magnetic and UV/Vis spectroscopic properties By varying reaction parameters for the syntheses of the hydrogen-bonded metal-imidazolate frameworks (HIF) HIF-1 and HIF-2 (featuring 14 Zn and 14 Co atoms, respectively) to increase their yields and crystallinity, we found that HIF-1 is generated in two different frameworks, named as HIF-1a and HIF-1b. HIF-1b is isostructural to HIF-2. We determined the gas sorption and magnetic properties of HIF-2. In comparison to HIF-1a (Brunauer-Emmett-Teller (BET) surface area of 471m(2) g(-1)), HIF-2 possesses overall very low gas sorption uptake capacities [BET(CO2) surface area=85m(2) g(-1)]. Variable temperature magnetic susceptibility measurement of HIF-2 showed antiferromagnetic exchange interactions between the cobalt(II) high-spin centres at lower temperature. Theoretical analysis by density functional theory confirmed this finding. The UV/Vis-reflection spectra of HIF-1 (mixture of HIF-1a and b), HIF-2 and HIF-3 (with 14 Cd atoms) were measured and showed a characteristic absorption band centered at 340nm, which was indicative for differences in the imidazolate framework. Dordrecht Springer 2019 11 Journal of Inclusion Phenomena and Macrocyclic Chemistry 94 3-4 155 165 10.1007/s10847-019-00926-6 Institut für Chemie OPUS4-8969 misc Mondal, Suvendu Sekhar; Marquardt, Dorothea; Janiak, Christoph; Holdt, Hans-Jürgen Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles 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. 2015 7 5476 5483 urn:nbn:de:kobv:517-opus4-89696 Institut für Chemie OPUS4-9436 misc Mondal, Suvendu Sekhar; Dey, Subarna; Baburin, Igor A.; Kelling, Alexandra; Schilde, Uwe; Seifert, Gotthard; Janiak, Christoph; Holdt, Hans-Jürgen Syntheses of two imidazolate-4-amide-5-imidate linker-based hexagonal metal-organic frameworks with flexible ethoxy substituent A rare example of in situ linker generation with the formation of soft porous Zn- and Co-MOFs (IFP-9 and -10, respectively) is reported. The flexible ethoxy groups of IFP-9 and -10 protrude into the 1D hexagonal channels. The gas-sorption behavior of both materials for H2, CO2 and CH4 showed wide hysteretic isotherms, typical for MOFs having a flexible substituent which can give rise to a gate effect. 2013 5 9394 9399 urn:nbn:de:kobv:517-opus4-94360 Institut für Chemie OPUS4-9442 misc Mondal, Suvendu Sekhar; Bhunia, Asamanjoy; Demeshko, Serhiy; Kelling, Alexandra; Schilde, Uwe; Janiak, Christoph; Holdt, Hans-Jürgen Synthesis of a Co(II)-imidazolate framework from an anionic linker precursor A Co(II)-imidazolate-4-amide-5-imidate based MOF, IFP-5, is synthesized by using an imidazolate anion-based novel ionic liquid as a linker precursor under solvothermal conditions. IFP-5 shows significant amounts of gas (N2, CO2, CH4 and H2) uptake capacities. IFP-5 exhibits an independent high spin Co(II) centre and antiferromagnetic coupling. 2013 3 39 42 urn:nbn:de:kobv:517-opus4-94424 Institut für Chemie OPUS4-7409 misc Mondal, Suvendu Sekhar; Bhunia, Asamanjoy; Kelling, Alexandra; Schilde, Uwe; Janiak, Christoph; Holdt, Hans-Jürgen A supramolecular Co(II)₁₄-metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)2·6H2O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)14-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms. 2014 3 169 5441 5443 urn:nbn:de:kobv:517-opus4-74098 Institut für Chemie OPUS4-9434 misc Mondal, Suvendu Sekhar; Bhunia, Asamanjoy; Baburin, Igor A.; Jäger, Christian; Kelling, Alexandra; Schilde, Uwe; Seifert, Gotthard; Janiak, Christoph; Holdt, Hans-Jürgen Gate effects in a hexagonal zinc-imidazolate-4-amide-5-imidate framework with flexible methoxy substituents and CO2 selectivity A new imidazolate-4-amide-5-imidate based MOF, IFP-7, is generated, having flexible methoxy groups, which act as molecular gates for guest molecules. This allows highly selective CO2 sorption over N2 and CH4 gases. 2013 2 7599 7601 urn:nbn:de:kobv:517-opus4-94341 Institut für Chemie OPUS4-8968 Wissenschaftlicher Artikel Mondal, Suvendu Sekhar; Marquardt, Dorothea; Janiak, Christoph; Holdt, Hans-Jürgen Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles 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. Cambridge Royal Society of Chemistry 2016 7 Dalton transactions : an international journal of inorganic chemistry 45 5476 5483 10.1039/C6DT00225K Institut für Chemie OPUS4-7407 Wissenschaftlicher Artikel Mondal, Suvendu Sekhar; Bhunia, Asamanjoy; Kelling, Alexandra; Schilde, Uwe; Janiak, Christoph; Holdt, Hans-Jürgen A supramolecular Co(II)₁₄-metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)2·6H2O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)14-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms. Royal Society of Chemistry 2014 3 Chemical communications : ChemComm 2014 41 5441 5443 10.1039/c3cc49698h Mathematisch-Naturwissenschaftliche Fakultät OPUS4-35313 Wissenschaftlicher Artikel Mondal, Suvendu Sekhar; Dey, Subarna; Baburin, Igor A.; Kelling, Alexandra; Schilde, Uwe; Seifert, Gotthard; Janiak, Christoph; Holdt, Hans-Jürgen Syntheses of two imidazolate-4-amide-5-imidate linker-based hexagonal metal-organic frameworks with flexible ethoxy substituent A rare example of in situ linker generation with the formation of soft porous Zn- and Co-MOFs (IFP-9 and -10, respectively) is reported. The flexible ethoxy groups of IFP-9 and -10 protrude into the 1D hexagonal channels. The gas-sorption behavior of both materials for H-2, CO2 and CH4 showed wide hysteretic isotherms, typical for MOFs having a flexible substituent which can give rise to a gate effect. Cambridge Royal Society of Chemistry 2013 6 CrystEngComm 15 45 9394 9399 10.1039/c3ce41632a Institut für Chemie