Manfred Scheer

Universität Regensburg, Ratisbon, Bavaria, Germany

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Publications (303)1172.67 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The selective formation of the dinuclear butterfly complexes [{Cp′′′Fe(CO)2}2(μ,η1:1-E4)] (E=P (1 a), As (1 b)) and [{Cp*Cr(CO)3}2(μ,η1:1-E4)] (E=P (2 a), As (2 b)) as new representatives of this rare class of compounds was found by reaction of E4 with the corresponding dimeric carbonyl complexes. Complexes 1 b and 2 b are the first As4 butterfly compounds with a bridging coordination mode. Moreover, first studies regarding the reactivity of 1 b and 2 b are presented, revealing the formation of the unprecedented As8 cuneane complexes [{Cp′′′Fe(CO)2}2{Cp′′′Fe(CO)}2(μ4,η1:1:2:2-As8)] (3 b) and [{Cp*Cr(CO)3}4(μ4,η1:1:1:1-As8)] (4). The compounds are fully characterized by NMR and IR spectroscopy as well as by X-ray structure analysis. In addition, DFT calculations give insight into the transformation pathway from the E4 butterfly to the corresponding cuneane structural motif.
    Angewandte Chemie International Edition 08/2014; 53(34). · 11.34 Impact Factor
  • Manfred Scheer, Sebastian Heinl
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    ABSTRACT: The bulky dimeric iron complex, [CpBIGFe(CO)2]2, readily activates elemental chalcogens (S8, Sered and α-Te) under mild conditions at room temperature. Six compounds containing (Q2)2- ligands (Q = S, Se) and a Te2- ligand, respectively, were isolated and completely characterized, including by X-ray diffraction techniques.
    Dalton Transactions 07/2014; · 3.81 Impact Factor
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    ABSTRACT: Durch die Reaktion von [Cp*Fe(η5-P5)] (1; Cp* = η5-C5Me5) mit verschiedenen Nucleophilen werden beispiellose funktionalisierte Produkte mit einem η4-P5-Ring erhalten. Mit LiCH2SiMe3 und LiNMe2 werden die Monoanionen [Cp*Fe(η4-P5CH2SiMe3)]− bzw. [Cp*Fe(η4-P5NMe2)]− gebildet. Die Reaktion von 1 mit NaNH2 führt zur Bildung des Trianions [{Cp*Fe(η4-P5)}2N]3−, während die Reaktion mit LiPH2 [Cp*Fe(η4-P5PH2)]− als das Hauptprodukt ergibt, mit {[Cp*Fe(η4-P5)]2PH}2− als Nebenprodukt. Die berechneten Energieprofile der Reaktionen liefern eine Erklärung für die Bildung der unterschiedlichen Produkte.
    Angewandte Chemie 07/2014; 126(29).
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    ABSTRACT: Eine neue einstufige und selektive Synthese für den ersten Schritt der Aktivierung von weißem Phosphor wurde unter Verwendung organischer Radikale entwickelt. Die Reaktion von NaCpR mit P4 in Gegenwart von CuX oder FeBr3 führt zur direkten Bildung der organisch substituierten P4-Butterfly-Verbindungen CpR2P4 (CpR: CpBIG=C5(4-nBuC6H4)5 (1 a), Cp′′′=C5H2tBu3 (1 b), Cp*=C5Me5 (1 c) und Cp4iPr=C5HiPr4 (1 d)). Die Reaktion verläuft über die Aktivierung von P4 mittels CpR-Radikalen, die durch Übergangsmetallen erzeugt wurden. Die neu gebildeten organischen P4-Derivate wurden durch NMR-Spektroskopie und Röntgenstrukturanalyse umfangreich charakterisiert.
    Angewandte Chemie 07/2014; 126(29).
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    ABSTRACT: Die selektive Bildung der zweikernigen Butterflykomplexe [{Cp′′′Fe(CO)2}2(μ,η1:1-E4)] (E=P (1 a), As (1 b)) und [{Cp*Cr(CO)3}2(μ,η1:1-E4)] (E=P (2 a), As (2 b)) als neue Vertreter dieser seltenen Verbindungsklasse wurde durch die Reaktion von E4 mit den entsprechenden dimeren Carbonylkomplexen gefunden. Die Komplexe 1 a und 2 b repräsentieren die ersten As4-Butterflyverbindungen in einer verbrückenden Koordinationsform. Überdies werden erste Studien zur Reaktivität von 1 und 2 b präsentiert, die die Bildung der präzedenzlosen As8-Cuneankomplexe [{Cp′′′Fe(CO)2}2{Cp′′′Fe(CO)}2(μ4,η1:1:2:2-As8)] (3 b) und [{Cp*Cr(CO)3}4(μ4,η1:1:1:1-As8)] (4) zeigen. Die Verbindungen sind vollständig durch NMR- und IR-Spektroskopie sowie durch Röntgenstrukturanalyse charakterisiert. Zusätzlich geben DFT-Rechnungen Einsicht in den Umwandlungsweg von der E4-Butterflystruktur zum entsprechenden Strukturmotiv des Cuneans.
    Angewandte Chemie 07/2014;
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    ABSTRACT: Unprecedented functionalized products with an η(4) -P5 ring are obtained by the reaction of [Cp*Fe(η(5) -P5 )] (1; Cp*=η(5) -C5 Me5 ) with different nucleophiles. With LiCH2 SiMe3 and LiNMe2 , the monoanionic products [Cp*Fe(η(4) -P5 CH2 SiMe3 )](-) and [Cp*Fe(η(4) -P5 NMe2 )](-) , respectively, are formed. The reaction of 1 with NaNH2 leads to the formation of the trianionic compound [{Cp*Fe(η(4) -P5 )}2 N](3-) , whereas the reaction with LiPH2 yields [Cp*Fe(η(4) -P5 PH2 )](-) as the main product, with {[Cp*Fe(η(4) -P5 )]2 PH}(2-) as a byproduct. The calculated energy profile of the reactions provides a rationale for the formation of the different products.
    Angewandte Chemie International Edition in English 06/2014; · 13.45 Impact Factor
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    ABSTRACT: A new and selective one-step synthesis was developed for the first activation stage of white phosphorus by organic radicals. The reactions of NaCp(R) with P4 in the presence of CuX or FeBr3 leads to the clean formation of organic substituted P4 butterfly compounds Cp(R) 2 P4 (Cp(R) : Cp(BIG) =C5 (4-nBuC6 H4 )5 (1 a), Cp'''=C5 H2 tBu3 (1 b), Cp*=C5 Me5 (1 c) und Cp(4iPr) =C5 HiPr4 (1 d)). The reaction proceeds via the activation of P4 by Cp(R) radicals mediated by transition metals. The newly formed organic derivatives of P4 have been comprehensively characterized by NMR spectroscopy and X-ray crystallography.
    Angewandte Chemie International Edition in English 05/2014; · 13.45 Impact Factor
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    ABSTRACT: Invited for the cover of this issue is the group of Manfred Scheer at the University of Regensburg. The cover image shows organometallic and inorganic building blocks being combined to form unprecedented new species.
    Berichte der deutschen chemischen Gesellschaft 04/2014; 2014(10). · 2.94 Impact Factor
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    ABSTRACT: By using [(Cp″′Co)2tol] (Cp″′ = η5-C5H2tBu3, tol = toluene), a new synthesis of the 1,3-diphosphete complexes [Cp″′Co(η4-P2C2tBu2)] (1a) and [Cp″′Co(η4-P2C2iPr2)] (1b) was found, and their reactions with the Lewis acids W(CO)4 and CuI halides were investigated. The reaction of 1b with W(CO)4(nbd) (nbd = norbornadiene) leads to the complex [(Cp″′Co)(μ,η4:1-{PCiPr}2)]2W(CO)4 (2) with the two diphosphete complexes 1b coordinated trans to a central W(CO)4 moiety. The reactions of 1a with CuI halides result in different products depending on the stoichiometry. In a 1:1 ratio, the dimeric compounds 3a–c [(Cp″′Co)(μ,η4:1-{PCtBu}2)Cu(μ-X)]2 (3a: X = Cl; 3b: X = Br, 3c: X = I) were isolated, whereas an excess of CuX gave the two-dimensional polymers [({Cp″′Co}{μ3,η4:1:1-(PCtBu)2})2(Cu{μ3-X})4]n (6a: X = Cl, 6b: X = Br, 6c: X = I). From the reaction of 1a and 1b with CuBr and CuI in a 1:2 or 2:3 ratio, the one-dimensional polymers [({Cp″′Co}{μ3,η4:1:1-(PCR)2})({Cp″′Co}{μ,η4:1-(PCR)2})(Cu{μ3-X})4]n (4a: X = Br, R = iPr, 4b: X = I, R = iPr, 4c: X = I, R = tBu) are formed. From the reaction of 1a with CuI, a second product, [({Cp″′Co}{μ3,η4:1:1-(PCtBu)2})(Cu{μ3-I})4(MeCN)2]n (5), was isolated by using CH3CN for crystallization. The products were comprehensively characterized by spectroscopic methods, X-ray crystallography, and 31P magic angle spinning (MAS) NMR spectroscopy.
    Berichte der deutschen chemischen Gesellschaft 04/2014; 2014(10). · 2.94 Impact Factor
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    ABSTRACT: Chromium(II) chloride reacts with lithium pentamethylcyclopentadienide (LiCp*, Cp* = C5Me5) and LiE(SiMe3)2 (E = P or As) to give the heterocubane chromium phosphide [(η5-Cp*Cr)(μ3-P)]4 (1) or the chromium arsenide cage [(η5-Cp*Cr)3(μ3-As)2] (2), respectively. The crystal and molecular structures of both compounds have been determined by X-ray crystallography. The reactions represent unusual oxidative additions of pnictogen atoms to chromium(II), which in the case of 1 results in the formation of the unusual chromium(IV) formal oxidation state, and in the case of 2 provides access to chromium(III). Compound 1 is also a rare example of a transition metal μ3-phosphide-ligated cubane. Magnetic susceptibility and magnetization measurements, with support from DFT calculations, indicate S = 2 and S = 9/2 ground states for 1 and 2, respectively, which can be rationalized by considering the electronic structure in terms of chromium-chromium bonding.
    Chemical Science 03/2014; · 8.31 Impact Factor
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    ABSTRACT: Reaction of [U(TrenTIPS)(THF)][BPh4] (1; TrenTIPS=N{CH2CH2NSi(iPr)3}3) with NaPH2 afforded the novel f-block terminal parent phosphide complex [U(TrenTIPS)(PH2)] (2; U–P=2.883(2) Å). Treatment of 2 with one equivalent of KCH2C6H5 and two equivalents of benzo-15-crown-5 ether (B15C5) afforded the unprecedented metal-stabilized terminal parent phosphinidene complex [U(TrenTIPS)(PH)][K(B15C5)2] (4; UP=2.613(2) Å). DFT calculations reveal a polarized-covalent UP bond with a Mayer bond order of 1.92.
    Angewandte Chemie 03/2014;
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    ABSTRACT: Whilst catena-phosphorus cations have been intensively studied in the last years, mixed Group 13/15 element cationic chains have not yet been reported. Reaction of the pnictogenboranes H2 EBH2 ⋅NMe3 (E=P, As) with monohalideboranes lead to the cationic chain compounds [Me3 N⋅BH2 EH2 BH2 ⋅NMe3 ][X] (E=P, As; X=AlCl4 , I) and [Me3 N⋅BH2 PH2 BH2 PH2 BH2 ⋅NMe3 ][X] (X=I, VCl4 (thf)2 ), respectively. All of the compounds have been characterized by X-ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations elucidate the reaction pathway, the high thermodynamic stability, the charge distribution within the chain and confirm the observed solid-state structures.
    Angewandte Chemie International Edition 03/2014; · 11.34 Impact Factor
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    ABSTRACT: Während catena-Phosphorkationen innerhalb der letzten Jahre intensiv untersucht wurden, gab es über gemischte kationische Ketten aus Gruppe-13- und Gruppe-15-Elementen bislang keine Berichte. Die Umsetzung der Pnictogenborane H2EBH2⋅NMe3 (E=P, As) mit Monohalogenboranen führt zu den kationischen Kettenverbindungen [Me3N⋅BH2EH2BH2⋅NMe3][X] (E=P, As; X=AlCl4, I) und [Me3N⋅BH2PH2BH2PH2BH2⋅NMe3][X] (X=I, VCl4(thf)2). Alle Verbindungen wurden durch Röntgenstrukturanalyse, NMR-Spektroskopie, IR-Spektroskopie und Massenspektrometrie charakterisiert. DFT-Rechnungen erklären den Reaktionsverlauf, die hohe thermodynamische Stabilität und die Ladungsverteilung innerhalb der Kette und bestätigen die beobachteten Festkörperstrukturen.
    Angewandte Chemie 03/2014;
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    ABSTRACT: Reactions of the sandwich complexes [Cp*Fe(η(5) -E5 )] (Cp*=η(5) -C5 Me5 ; E=P (1), As (2)) with the monovalent Group 13 metals Tl(+) , In(+) , and Ga(+) containing the weakly coordinating anion [TEF] ([TEF]=[Al{OC(CF3 )3 }4 ](-) ) are described. Here, the one-dimensional coordination polymers [M(μ,η(5) :η(1) -E5 FeCp*)3 ]n [TEF]n (E=P, M=Tl (3 a), In (3 b), Ga (3 c); E=As, M=Tl (4 a), In (4 b)) are obtained as sole products in good yields. All products were analyzed by single-crystal X-ray diffraction, revealing a similar assembly of the products with η(5) -bound E5 ligands and very weak σ-interactions between one P or As atom of the ring to the neighbored Group 13 metal cation. By exchanging the [TEF] anion of 4 a for the larger [FAl] anion ([FAl]=[FAl{OC6 F10 (C6 F5 )}3 ](-) ), the coordination compound [Tl{(η(5) -As5 )FeCp*}3 ][FAl] (5) without any σ-interactions of the As5 -ring is obtained. All products are readily soluble in CH2 Cl2 and exhibit a dynamic coordination behavior in solution, which is supported by NMR spectroscopy and ESI-MS spectrometry as well as by osmometric molecular-weight determination. For a better understanding of the proceeding equilibrium DFT calculations of the cationic complexes were performed for the gas phase and in solution. Furthermore, the (31) P{(1) H} magic-angle spinning (MAS) NMR spectra of 3 a-c are presented and the first crystal structure of the starting material 2 was determined.
    Chemistry 02/2014; · 5.93 Impact Factor
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    ABSTRACT: Die Reaktion eines P4-Butterfly-Komplexes mit gelbem Arsen ergibt die größten bisher synthetisierten gemischten PnAsm-Ligandkomplexe. [{Cp′′′Fe(CO)2}2(μ,η1:1-P4)] reagiert mit As4 zu [{Cp′′′Fe}2(μ,η4:4-PnAs4−n)] und [Cp′′′Fe(η5-PnAs5−n)]. Massenspektrometrie liefert zusammen mit NMR-Spektroskopie und Röntgenstrukturanalyse eindeutige Belege für die Anordnung der E-Positionen in den cyclo-E5- und E4-Einheiten der Produkte. Weiterhin stimmen die Ergebnisse der DFT-Rechnungen gut mit den experimentellen Befunden überein. Bei der Koordination des E4-Komplexes [{Cp′′′Fe}2(μ,η4:4-PnAs4−n)] mit CuCl erfolgt eine Umlagerung der E-Positionen zugunsten einer bevorzugten Phosphorkoordination zu den Kupferatomen in der resultierenden 1D-polymeren Kette.
    Angewandte Chemie 01/2014; 126(1).
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    ABSTRACT: A number of stannylene complexes with different M: Sn ratios were obtained using various metals and substituents at the tin atom. The structures of the complexes were examined. A reaction of CpMn(CO)2THF with (Ph4As)+(SnCl3)− gave the ionic complex [Ph4As]+[CpMn(CO)2SnCl3]− (I). The action of C6F5MgBr on the complex C5H5Mn(CO)(NO)SnCl3 produced C5H5Mn(CO)(NO)Sn(C6F5)3 (II). Replacement of the Cl ions in the complex [CpFe(CO)2]2SnCl2 by phenylacetylenide groups gave rise to the neutral complex [CpFe(CO)2]2Sn(C≡CPh)2 (III). A reaction of (Dppm)PtCl2 (Dppm is 1,1-bis(diphenylphosphino)methane) with SnCl2 · 2H2O in the presence of diglyme yielded the ionic complex [η3-CH3O(CH2)2O(CH2)2OCH3)SnCl]+[(η 2-Dppm)Pt(SnCl3)3]− (IV). Transmetalation in a reaction of [(Dppe)2CoCl][SnCl3] · PhBr (Dppe is 1,2-bis(diphenylphosphino)ethane) with (Dcpd)PtCl2 (Dcpd is dicyclopentadiene) in the presence of SnCl2 afforded the ionic complex [Pt(Dppe)2]3[Pt(SnCl3)5]2 (V). Structures I–V were identified by X-ray diffraction. In these structures, the formally single bonds between the atoms of transition metals M (Mn, Fe, and Pt) and Main Group heavy elements (Sn and P) having vacant d orbitals are appreciably shortened. The M-Sn bond length in complexes II and III are virtually independent of the substituents at the tin atom and the Pt-Sn bond length in complexes IV and V is virtually independent of the Pt: Sn ratio.
    Russian Journal of Coordination Chemistry 01/2014; 40(3). · 0.63 Impact Factor
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    ABSTRACT: The structure of a gallium tribromide complex with 2-aminomethylpyridine (amPy) (1: 1) has been established by single-crystal X-ray diffraction for the first time. The complex has been shown to have the ionic structure [GaBr2amPy2]+[GaBr4]− in the condensed phase. The qualitative composition of the vapor over the complex has been determined by mass spectrometry within a temperature range of 80–250°C. The elimination of hydrogen bromide and 2-aminomethylpyridine proceed at 80–180°C to enrich the condensed phase with gallium tribromide. GaBr2(amPy-H), GaBr3amPy, GaBr(amPy-2H), and Ga2Br5(amPy-H) are the major gallium-containing vapor species at 250°C.
    Russian Journal of Inorganic Chemistry 01/2014; 59(3). · 0.42 Impact Factor
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    ABSTRACT: The reduction of [(Cp‴Co)2(μ,η(2:2)-P2)2] (Cp‴ = 1,2,4-tBu3C5H2) with the samarocenes, [(C5Me4R)2Sm(THF)n] (R = Me or n-propyl), gives [(Cp‴Co)2P4Sm(C5Me4R)2]. This is the first example of an intramolecular P-P coupling in a polyphosphide complex upon reduction of the transition metal. The formation of the P-P bond is not a result of the direct reduction of the phosphorus atoms but is induced by a rearrangement of the positive charges between the metal atoms.
    Inorganic Chemistry 12/2013; · 4.59 Impact Factor
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    ABSTRACT: The reaction of a P4 butterfly complex with yellow arsenic yields the largest mixed Pn Asm ligand complexes synthesized to date. [{Cp'''Fe(CO)2 }2 (μ,η(1:1) -P4 )] reacts with As4 to yield [{Cp'''Fe}2 (μ,η(4:4) -Pn As4-n )] and [Cp'''Fe(η(5) -Pn As5-n )]. Mass spectrometry together with NMR spectroscopy and X-ray crystallography give clear evidence about the arrangement of the E positions within the cyclo-E5 and E4 moieties of the products. Moreover, the results of DFT calculations agree well with the experimental determined outcomes. By coordinating the E4 complex [{Cp'''Fe}2 (μ,η(4:4) -Pn As4-n )] with CuCl, a rearrangement of the E positions occurs in favor with a preferred phosphorus coordination towards copper atoms in the resulting 1D polymeric chain.
    Angewandte Chemie International Edition 11/2013; · 11.34 Impact Factor
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    ABSTRACT: Phase-pure FeP nanoparticles (NPs) have been synthesized through low temperature thermolysis of the single source precursor [(CO)4Fe(PH3)]. Examination of the mechanism demonstrates the central role of the labile CO ligands and the weak P-H bonds to yield stoichiometry controlled FeP materials.
    Chemical Communications 11/2013; · 6.38 Impact Factor

Publication Stats

803 Citations
1,172.67 Total Impact Points

Institutions

  • 2005–2014
    • Universität Regensburg
      • Institute of Inorganic Chemistry
      Ratisbon, Bavaria, Germany
  • 2011–2013
    • Saint Petersburg State University
      • Faculty of Chemistry
      Sankt-Peterburg, St.-Petersburg, Russia
    • The University of Manchester
      • School of Chemistry
      Manchester, ENG, United Kingdom
    • Novosibirsk State University
      Novo-Nikolaevsk, Novosibirsk, Russia
    • Institute of General and Inorganic Chemistry
      Kievo, Kyiv City, Ukraine
  • 1997–2013
    • Karlsruhe Institute of Technology
      • Institut für Anorganische Chemie
      Eggenstein-Leopoldshafen, Baden-Wuerttemberg, Germany
  • 2010
    • Russian Academy of Sciences
      • Kurnakov Institute of General and Inorganic Chemistry
      Moskva, Moscow, Russia
  • 2008
    • The Ohio State University
      • Department of Chemistry and Biochemistry
      Columbus, OH, United States
  • 2003–2008
    • Nanjing University
      • • State Key Laboratory of Coordination Chemistry
      • • Department of Chemical Engineering
      Nanjing, Jiangsu Sheng, China
  • 1993
    • Indiana University Bloomington
      Bloomington, Indiana, United States
  • 1991–1993
    • Universitätsklinikum Halle (Saale)
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 1988–1993
    • Martin Luther University of Halle-Wittenberg
      • Institute of Chemistry
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 1991–1992
    • Technische Universität Braunschweig
      • Institute of Inorganic and Analytical Chemistry
      Braunschweig, Lower Saxony, Germany