FG Metallorganische Chemie und Anorganische Materialien

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Synthesis of an electronically modified carbon nitride from a processable semiconductor, 3-amino-1,2,4-triazole oligomer, via a topotactic-like phase transition

Savateev, Aleksandr ; Pronkin, Sergey ; Epping, Jan Dirk ; Willinger, Marc Georg ; Antonietti, Markus ; Dontsova, Dariya (2017)

A thermally induced topotactic transformation of organic polymeric semiconductors is achieved using similarity of the chemical structures of two C,N,H-containing materials. Namely, the oligomer of 3-amino-1,2,4-triazole (OATA) is transformed into an electronically modified graphitic carbon nitride (OATA-CN) upon heating at 550 °C. During the transition, the flat band potential of the organic se...

Synthesis of a cyclopentadienyl(imino)stannylene and its direct conversion into halo(imino)stannylenes

Ochiai, Tatsumi ; Inoue, Shigeyoshi (2017)

The reaction of stannocene Cp2Sn with iminolithium LiNIPr (NIPr = bis(2,6-diisopropylphenyl)imidazolin-2-iminato) afforded the dimeric cyclopentadienyl(imino)stannylene [(η1-Cp)SnNIPr]2 (1). Compound 1 exhibits unexpected reactivity towards haloalkanes. The high-yield conversion of 1 into chlorostannylene [ClSnNIPr]2 (2) and bromostannylene [BrSnNIPr]2 (3) were accomplished by treatment with di...

Beiträge zur bioinspirierten Katalyse

Lindenmaier, Nils (2017)

In dieser Arbeit wurden einkernige Ni- und heterodimere [NiFe]-Komplexe im Kontext der von [NiFe]-H2ase und -CODH „bioinspirierten” Katalyse synthetisiert und untersucht. Im ersten Teil der Arbeit wurde ein neuartiger Silylen-Pyridin-Hybridligand für die Koordination von Nickel(II)- und Nickel(0)-Spezies entwickelt und auf seine σ-Donor- und π-Akzeptoreigenschaften hin analysiert. Der zweite Te...

Unprecedented silicon(II)-> calcium complexes with N-heterocyclic silylenes

Blom, Burgert ; Klatt, Günter ; Gallego, Daniel ; Tan, Gengwen ; Drieß, Matthias (2015)

The first N-heterocyclic silylene (NHSi) complexes of any s-block element to date are reported for calcium: [(eta(5)-C5Me5)(2)Ca<--:Si(O-C6H4-2-Bu-t){((NBu)-Bu-t)(2)CPh}] (6) and [(eta(5)-C5Me5)(2)Ca<--:Si((NBuCH)-Bu-t)(2)] (7). Complexes 6 and 7 are isolable in a facile way upon reaction of the corresponding free N-heterocyclic silylenes (NHSis) with [(eta(5)-C5Me5)(2)Ca] (2). Complexes 6 and ...

Using nickel manganese oxide catalysts for efficient water oxidation

Menezes, Prashanth W. ; Indra, Arindam ; Levy, Ophir ; Kailasam, Kamalakannan ; Gutkin, Vitaly ; Pfrommer, Johannes ; Drieß, Matthias (2015)

Nickel-manganese oxides with variable Ni : Mn ratios, synthesised from heterobimetallic single-source precursors, turned out to be efficient water oxidation catalysts. They were subjected to oxidant-driven, photo- and electro-catalytic water oxidation showing superior activity and remarkable stability. In addition, a structure-activity relation could be established.

Reductive cleavage of P-4 by iron(I) centres: synthesis and structural characterisation of Fe-2(P-2)(2) complexes with two bridging P-2(2-) ligands

Yao, Shenglai ; Szilvási, Tibor ; Lindenmaier, Nils ; Xiong, Yun ; Inoue, Shigeyoshi ; Adelhardt, Mario ; Sutter, Jörg ; Meyer, Karsten ; Drieß, Matthias (2015)

The selective transformation of white phosphorus with a beta-diketiminato iron(I) toluene complex under mild reaction conditions is reported which furnishes a new dinuclear iron(III) Fe-2(P-2)(2) complex with two bridging P-2(2-) ligands. Its reduction with potassium results in the formation of the first delocalised mixed-valent bis-diphosphido iron(II,III) complex which is isostructural with t...

Facile synthesis of new, highly efficient SnO2/carbon nitride composite photocatalysts for the hydrogen evolution reaction

Fettkenhauer, Christian ; Clavel, Guylhaine ; Kailasam, Kamalakannan ; Antonietti, Markus ; Dontsova, Dariya (2015)

Novel SnO2/carbon nitride photocatalysts having surface areas up to 220 m(2) g(-1) were prepared for the first time by condensation of dicyandiamide in alkali metal chloride/SnCl2-containing salt melts at 550 degrees C, without the use of hard templates. XRD and HR-TEM investigations showed that the obtained materials are composed of 5-10 nm SnO2 nanoparticles deposited onto nanosheets set up f...

Peripheral mechanism of a carbonyl hydrosilylation catalysed by an SiNSi iron pincer complex

Metsänen, Toni Tapio ; Gallego, Daniel ; Szilvasi, Tibor ; Drieß, Matthias ; Oestreich, Martin (2015)

Combined experimental and theoretical analysis of the carbonyl hydrosilylation catalysed by an iron(0) pincer complex reveals an unprecedented mechanism of action. The iron(0) complex is in fact a precatalyst that is converted into an iron(II) catalyst through oxidative addition of a hydrosilane. Neither the hydrogen atom nor the silicon atom bound to the iron(II) centre are subsequently transf...

Optimized immobilization of ZnO:Co electrocatalysts realizes 5% efficiency in photoassisted splitting of water

Azarpira, Anahita ; Pfrommer, Johannes ; Olech, Katarzyna ; Höhn, Christian ; Drieß, Matthias ; Stannowski, Bernd ; Schedel-Niedrig, Thomas ; Lublow, Michael (2016)

Organic solvents with varied electrophoretic mobility have been employed for deposition of nanocrystalline ZnO: Co particles onto fluorinated tin oxide supports. Evaluation of the electrochemical activity for the oxygen evolution reaction proves a clear solvent-dependence with highest activity upon deposition from acetonitrile and lowest activity upon deposition from ethanol. Analysis of the re...

Nickel as a co-catalyst for photocatalytic hydrogen evolution on graphitic-carbon nitride (sg-CN): what is the nature of the active species?

Indra, Arindam ; Menezes, Prashanth W. ; Kailasam, Kamalakannan ; Hollmann, Dirk ; Schröder, Marc ; Thomas, Arne ; Brückner, Angelika ; Drieß, Matthias (2016)

The nature of a nickel-based co-catalyst deposited on a sol-gel prepared porous graphitic-carbon nitride (sg-CN), for photocatalytic H-2 production from water, has been investigated. The formation of the active catalytic species, charge separation and recombination of the photogenerated electrons and holes during photochemical H-2 evolution has been determined for the first time using in situ E...

Uncovering the prominent role of metal ions in octahedral versus tetrahedral sites of cobalt-zinc oxide catalysts for efficient oxidation of water

Menezes, Prashanth W. ; Indra, Arindam ; Bergmann, Arno ; Chernev, Petko ; Walter, Carsten ; Dau, Holger ; Strasser, Peter ; Drieß, Matthias (2016)

The fabrication and design of earth-abundant and high-performance catalysts for the oxygen evolution reaction (OER) are very crucial for the development and commercialization of sustainable energy conversion technologies. Although spinel catalysts have been widely explored for the electrochemical oxygen evolution reaction (OER), the role of two geometrical sites that influence their activities ...

Heavier congeners of CO and CO2 as ligands: from zero-valent germanium ('germylone') to isolable monomeric GeX and GeX2 complexes (X = S, Se, Te)

Xiong, Yun ; Yao, Shenglai ; Karni, Miriam ; Kostenko, Arseni ; Burchert, Alexander ; Apeloig, Yitzhak ; Drieß, Matthias (2016)

In contrast to molecular CO and CO2, their heavier mono- and dichalcogenide homologues, EX and EX2 (E = Si, Ge, Sn, Pb; X = O, S, Se, Te), are important support materials (e.g., SiO2) and/or semiconductors (e.g., SiS2) and exist typically as insoluble crystalline or amorphous polymers under normal conditions. Herein, we report the first successful synthesis and characterisation of an extraordin...

Changing the chemical and physical properties of high valent heterobimetallic bis-(mu-oxido) Cu-Ni complexes by ligand effects

Kafentzi, Maria-Chrysanthi ; Orio, Maylis ; Réglier, Marius ; Yao, Shenglai ; Kuhlmann, Uwe ; Hildebrandt, Peter ; Drieß, Matthias ; Simaan, A. Jalila ; Ray, Kallol (2016)

Two new heterobimetallic [LNiO2Cu(RPY2)](+) (RPY2 = N-substituted bis 2-pyridyl(ethylamine) ligands with R = indane, 3a or R = Me, 3b) complexes have been spectroscopically trapped at low temperatures. They were prepared by reacting the mononuclear side-on LNiII superoxo precursor bearing a beta-diketiminate ligand (L = [HC-(CMeNC6H3(iPr)(2))(2)]) with the Cu(I) complexes. In contrast to the ox...

Depolymerisation von Polysiloxanen und die eisenvermittelte Aktivierung kleiner Moleküle

Döhlert, Peter (2016)

Die vorliegende Arbeit umfasst im ersten Teil Studien zum Recycling von Polysiloxanen. Dazu wurde ein Protokoll zur Depolymerisation entwickelt, bei dem ein Depolymerisationsreagenz und ein Lewis Säure Katalysator verwendet wurde. Nach der erfolgreichen Depolymerisation wurde im Anschluss daran die Polymerisation zu neuen Polysiloxanen gezeigt, sodass der vorliegende Prozess als Recyclingverfah...

Synthesis and reactivity of N-heterocyclic imino-substituted group 14 compounds

Ochiai, Tatsumi (2016)

The doctoral dissertation is divided into five parts. The main goal of my dissertation is to investigate unique electron-deficient and/or low-valent Group 14 compounds by taking advantage of kinetic and electronic stabilization of N-heterocyclic imines (NHIs).  In the first and second parts of the dissertation, the syntheses of the novel imino-substituted stannylenes and germylenes and their r...

Synthese und Reaktivität eines neuartigen NHC-stabilisierten Hydridosilylens

Eisenhut, Carsten (2016)

Die Arbeit ist in drei Teilabschnitte gegliedert. Im ersten Teilabschnitt dieser Arbeit wird die Synthese der neuen NHC-stabilisierten Akzeptor-freien Hydridosilylene 53 und 55 (tBu3Si(H)Si:←NHC) beschrieben. Beide Verbindungen wurden vollständig charakterisiert und auf ihre elektronische Natur hin untersucht. Im zweiten Abschnitt wurde das Hydridosilylen 53 auf seine Reaktivität gegenüber ung...

Modulare Synthese von bioinspirierten heterobimetallischen [NiFe]-Komplexen und Untersuchung ihrer Reaktivitäten

Rudolph, Robert (2016)

Die Dissertation beschreibt den modularen Aufbau von neuen bioinspirierten heterobimetallischen NiFe-Komplexen mit den einfach herzustellenden Pinzettenliganden PNPCy- und Beta-Diketiminatoliganden Nacnac. Des Weiteren beschreibt die Arbeit die strukturelle Untersuchung der synthtetisierten Komplexe, sowie deren elektronischen Eigenschaften (Oxidationszustände) und die Reaktivität gegenüber kle...

Formation of N-heterocyclic, donor-stabilized borenium ions

Someya, Chika I. ; Inoue, Shigeyoshi ; Präsang, Carsten ; Irran, Elisabeth ; Drieß, Matthias (2011)

Cationic and zwitterionic boryl bromide species and a borenium–boryl bromide cation have been synthesised which represent new N-donor stabilised cationic boron compounds with β-diketiminate ligands. The unexpected borenium–boryl bromide results from a head-to-tail dimerisation of the corresponding zwitterionic boryl bromide accompanied by proton migration. The electronic nature of these new spe...

Iron-based pre-catalyst supported on polyformamidine for C-C bond formation

Enthaler, Stephan ; Krackl, Sebastian ; Epping, Jan Dirk ; Eckhardt, Björn ; Weidner, Steffen M. ; Fischer, Anna (2012)

In the present study the incorporation of iron into an organic polymer, composed of formamidine subunits [R–N[double bond, length as m-dash]C(H)–NH–R], has been examined. The catalytic ability of the recyclable material was investigated in the iron-catalyzed formation of C–C bonds. After optimization of the reaction conditions, excellent yields and chemoselectivities were feasible.

Taming the germyliumylidene [CIGe:](+) and germathionium [CIGe=S](+) ions by donor-acceptor stabilization using 1,8-bis(tributylphosphazenyl)naphthalene

Xiong, Yun ; Yao, Shenglai ; Inoue, Shigeyoshi ; Berkefeld, Andreas ; Drieß, Matthias (2012)

The novel chlorogermyliumylidene complex L[ClGe:]+ (L = 1,8-bis(tri-n-butylphosphanzenyl)naphthalene) with a ‘naked’ Cl− as a counter anion was synthesized through reaction of L with Cl2Ge: and fully characterized. Its reaction with elemental sulfur afforded the first germathionium [ClGe[double bond, length as m-dash]S]+ cation containing species. The latter has also been fully characterized, i...