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1983 (1)
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1978 (1)
1Author    JaapN. Louwen, RonaldR. Andréa, DerkJ. Stufkens, Ad OskamRequires cookie*
 Title    He(I) and He(II) Photoelectron Spectra of M[Co(CO)4]2 and M[Mn(CO)5]2 Complexes (M = Zn, Cd, and Hg)  
 Abstract    The He(I) and He(II) photoelectron spectra of M[Co(CO)4]2 and M[Mn(CO)ö]2 complexes (M = Zn, Cd, Hg) are reported. Bands attributable to metal-metal bonds, metal d-levels and CO orbitals are assigned in agreement with a semi-ionic model, i.e. M 2+ and [M'(CO)"] -. Relativistic effects prove to be important in assigning these ultraviolet photoelectron spectra. 
  Reference    Z. Naturforsch. 37b, 711—717 (1982); received January 26 1982 
  Published    1982 
  Keywords    Carbonyl Complexes, Metal-Metal Bonds, Mercury, Relativistic Effect 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-0711.pdf 
 Identifier    ZNB-1982-37b-0711 
 Volume    37 
2Author    Egbert Keller, Heinrich VahrenkampRequires cookie*
 Title    Stereochemie der Metall-Metall-Bindung: Darstellung und Struktur von Co2(CO)4C5H5P(CH3)2  
 Abstract    The title complex 4 was prepared from 7?-C3H5Co(CO)3 and »/-C5H5(CO)Co-P(CH3)2H. It completes the series of PR2-and AsR2-bridged homodinuclear complexes C^CO^CsHs-As(CH3)2, Mn2(CO)6C5H5As(CH3)2, and Fe2(CO)5C5H5P(CH3)2. Its crystal structure ana-lysis reveals the systematic variation of the ligand distribution along the series which depends only on the number of ligands present and not on given coordination geometries. The metal-metal bond length in 4 is mainly determined by the stereochemical require-ments of the bridging phosphido ligand. 
  Reference    Z. Naturforsch. 33b, 537—541 (1978); eingegangen am 27. Februar 1978 
  Published    1978 
  Keywords    Dinuclear Complexes, Metal-Metal Bonds, Stereochemistry 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0537.pdf 
 Identifier    ZNB-1978-33b-0537 
 Volume    33 
3Author    Ute Honrath, Heimich VahrenkampRequires cookie*
 Title    zur Natur einfach arsenverbrückter Metall-Metall-Bindungen Electrochemical and Electron Spectroscopic Measurements on the Nature of Singly Arsenic Bridged Metal-Metal Bonds  
 Abstract    For a series of singly arsenic bridged dinuclear metal carbonyl complexes with metal-metal bonds electronic spectra and dc-voltammograms in 1,2-dichloroethane were recorded. There is a reasonable correlation between the a ->cr* transitions and the first reduction potentials which can both be taken as measures of the relative strength of the metal-metal bonds. The a ^ a* excitation energy and the negative reduction potential increase (a) with increasing atomic weight of the connected metal atoms, (b) with in-creasing number of CO groups present, (c) with decreasing intramolecular steric hindrance. Steric and electronic factors cannot be cleanly separated. There seems to be no correlation with metal-metal bond lengths. Terminal phosphine ligands decrease all redox potentials but hardly change the electronic absorptions. Die Stärke von Metall-Metall-Bindungen ist sehr schwierig zu bestimmen. Da thermochemische Methoden nur in besonders einfachen Fällen heran-gezogen werden können [1], bedient man sich meist indirekter Messungen [2]. Von den dazu verwend-baren Verfahren haben in jüngster Zeit zwei an Be-deutung gewonnen. Dies ist einmal die Elektro-chemie [3], deren Bedeutung darauf beruht, daß in mehrkernigen metallorganischen Komplexen die HOMOs und LUMOs die Metall-Metall-Wechsel-wirkungen betreffen [2, 4, 5]. Das andere ist die Elektronenspektroskopie, seit entdeckt wurde, daß mit der Metall-Metall-Bindung ein <x->cx*-Übergang im nahen UV verknüpft ist [6], und daß dessen Energie sich mit der Metall-Metall-Bindungsstärke verknüpfen läßt [7]. Wir haben eine Serie einfach phosphor-bzw. arsen-verbrückter Metallcarbonyl-Zweikernkomplexe ge-wonnen, die sich vorteilhaft auf die Eigenschaften von Metall-Metall-Bindungen untersuchen lassen. Denn die Brückenfunktion bewirkt, daß nach einer Spaltung der Metall-Metall-Bindung die beiden Organometall-Einheiten zusammen in einem Kom-plex verbleiben. Nach einer ausführlichen chemi-schen [8] und kristallographischen [9] Bearbeitung dieser Verbindungen erschien es daher auch lohnend, sie weiter physikalisch zu charakterisieren. Wir * Sonderdruckanforderungen an Prof. Dr. H. Vahren-kamp. 0340-5087/79/0900-1190/5 01.00/0 wählten dazu die elektrochemischen und elektronen-spektroskopischen Messungen, einerseits wegen ihrer erwähnten Vorteile, andererseits weil wir bei einer Untersuchung sehr einfacher Zweikernkomplexe [10] die gute Vergleichbarkeit der jeweiligen Meßergeb-nisse festgestellt hatten. Messungen Es wurden von den unsubstituierten arsenver-brückten Metallcarbonyl-Zweikernkomplexen mit Metall-Metall-Bindungen die bekannten Vertreter 1-5 und dazu vier ausgewählte phosphinsubstitu-ierte Derivate 6 vermessen. Die elektrochemischen Messungen geschahen mit Platin-Scheibenelektroden und Ag/AgCl/Cl --Bezugs-elektrode. Als Lösungsmittel diente 1.2-Dichlor-ethan, das die gleichen Vorzüge hat wie Methylen-Me2 As / \ (C0)5Cr M 1 Me2 As / \ (C0)< Fe M Me2 As /\ ICOLCW M Me2 As / \ Cp(C0)Co M Me2 As / \ Cp(C0)2Mn M Me2 As / \ L-(CO),Fe Mn(C0),-L l-5:M = Cr(CO)2Cp: a Mo(CO)2Cp: b W(CO)2Cp: c Mn(CO)4 Re(CO)4 Co(CO)3 6: L/L'=CO/PMe3: a PMe3/CO: b 
  Reference    Z. Naturforsch. 34b, 1190—1194 (1979); eingegangen am 5. Juni 1979 
  Published    1979 
  Keywords    Electrochemistry, Electron Spectroscopy, Metal-Metal Bonds 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-1190.pdf 
 Identifier    ZNB-1979-34b-1190 
 Volume    34 
4Author    Olli Orama, Ulrich Schubert, FritzRoland Kreißl, ErnstOtto FischerRequires cookie*
 Title    Übergangsmetall-Carbin-Komplexe, LVI [1] Umsetzung eines kationischen Carbin-Komplexes mit einem Carbonylmetallat. Der Phenylketenyl-Rest als Briickenhgand Transition Metal Carbyne Complexes, LVI [1] Reaction of a Cationic Carbyne Complex with a Carbonylmetalate. The Phenylketenyl Group as a Bridging Ligand  
 Abstract    By reaction of [(jr^HsHCOfeMnEEC-CeHslBCLi with NaRe(CO)5 a new type of complex is obtained. It crystallizes in the monoclinic space group P 2i/c, Z = 4, a — 1115(1), b= 1464(1), c= 1657(2) pm, ß= 136.79(8)°. Structure determination reveals a binuclear complex, the Mn-Re bond (281.7(3) pm) of which is bridged by the a-carbon atom of a phenylketenyl group (Mn-C 221(3), Re-C 224(3) pm) and semi-bridged by a CO group (Mn-C 187(4), Re-C 254(4), Mn-C-0 160(3)°). 
  Reference    (Z. Naturforsch. 35b, 82—85 [1980]; eingegangen am 2. Oktober 1979) 
  Published    1980 
  Keywords    Carbyne Complex, X-ray, Metal-Metal Bond 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0082.pdf 
 Identifier    ZNB-1980-35b-0082 
 Volume    35 
5Author    A. Müller, S. Pohl, M. Dartmann, J. P. Cohen, J. M. Bennett, R. M. KirchnerRequires cookie*
 Title    Crystal Structure of (NH4)2[Mo3S(S2)6] Containing the Novel Isolated Cluster [MO3S13] 2  
 Abstract    The novel tri-nuclear metal-sulfur cluster [Mo3S(S2)6] 2 ~ can be obtained as its am-monium salt by the reaction of a Mo iv containing aqueous solutions with polysulfide. Its crystal and molecular structure has been determined by a single crystal X-ray study. The crystals are monoclinic (space group Cm, with a = 11.577(6) A, b = 16.448(7) Ä, c = 5.716(2) Ä, ß = 117.30(3)°, V = 967.2 A 3 , Z = 2, dexpti. = 2.54(2) g/cm 3 , dcai = 2.54 g/cm 3). The structure consists of isolated [Mo3S(S2)6] 2_ units, with three Mo atoms at the vertices of a triangle. There are bridging as well as terminal S2 2 ~-ligands lying above and below the Mo3-plane (bond distances: Mo-Mo = 2.722 A, Mo-S(terminal) = 2.435, Mo-S(bridging) = 2.452, Mo3-S = 2.353(4) A and S-S = 2.04 A (mean values)). Transition metal sulfur clusters are model com-pounds of bioinorganic interest [1, 2]. Isolated binary sulfur clusters were unknown until recently, though several halogen cluster compounds were reported. We were able to isolate the novel com-pound (NH4)2[Mo3S(S2)6] containing bridging as well as terminal S2 2_ -ligands in the molybdenum-sulfur-cluster anion [2]. In this paper the crystal structure of the compound is reported. Experimental 
  Reference    Z. Naturforsch. 34b, 434—436 (1979); received August 28/November 10 1978 
  Published    1979 
  Keywords    Crystal Structure, Molybdenum, Sulfur, Cluster, Metal-Metal Bond, Disulfide Diatomic Ligands 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0434.pdf 
 Identifier    ZNB-1979-34b-0434 
 Volume    34 
6Author    JaapN. Louwen, RonaldR. Andréa, DerkJ. Stufkens, Ad OskamRequires cookie*
 Title    He(I) and He(II) Photoelectron Spectra of Some L3MCo(CO)4 Complexes (M = Si, Ge, Sn, Pb and L = Cl, Br and CH3)  
 Abstract    The He(I) and He(II) photoelectron spectra of L3MCo(CO)4 complexes (M = Si, Ge, Sn, and Pb and L = Cl, Brand CH3) are reported. Bands attributable to the metal-cobalt bond, cobalt 3d and CO orbitals are assigned in agreement with a qualitative MO model. Rela-tivistic effects and He(I)/He(II) intensity ratios prove to be important in assigning these ultraviolet photoelectron spectra. 
  Reference    Z. Naturforsch. 38b, 194—202 (1983); received October 3 1982 
  Published    1983 
  Keywords    Metal-Metal Bond, UPS, Cobalt Complexes, Relativistic Effects, Ionization Potentials 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0194.pdf 
 Identifier    ZNB-1983-38b-0194 
 Volume    38