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1Author    M. =. Cr, Mo, W., Norbert Kuhn, Martin Göhner, Manfred SteimannRequires cookie*
 Title    Über Komplexe des Typs {(PhC=C)3P}3M(CO)3 (M = Cr, Mo, W) On Complexes of the Type {(PhC=C)3P}3M(CO)3 (  
 Abstract    The tris(alkinyl)phosphine complexes {(PhC=C)3P}3M(CO)3, M = Cr (3a), Mo (3b), W (3c), are obtained from P(C=CPh)3 and (C6H 15N3)M(CO)3 (C6H 15N3 = 1,3,5-trimethyl-1,3,5-triazacyclohexane) as stable yellow solids in good yields. While IR data indicate significant acceptor properties of the phosphane ligands, the X-ray structure analysis of 3c also allows the discussion of weak donor interactions. 
  Reference    (Z. Naturforsch. 56b, 95—99 [2001]; eingegangen am 22. September 2000) 
  Published    2001 
  Keywords    Chromium, Molybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0095.pdf 
 Identifier    ZNB-2001-56b-0095 
 Volume    56 
2Author    Ceyhan Kayran, Pazilaiti RouziRequires cookie*
 Title    Thermal Catalytic Hydrosilylation of Conjugated Dienes with Triethylsilane in the Presence of Tricarbonyl(o-xylene)Metal (Metal = Cr, Mo, W) Complexes  
 Abstract    The thermal catalytic hydrosilylation of 1,3-butadiene (1), rra«5-2-methyl-l,3-pentadiene 
  Reference    Z. Naturforsch. 56b, 1138—1142 (2001); received July 2 2001 
  Published    2001 
  Keywords    Hydrosilylation, Tungsten, Carbonyl 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1138.pdf 
 Identifier    ZNB-2001-56b-1138 
 Volume    56 
3Author    HerbertW. Roesky, Michael Zimmer, Regine Herbst, GeorgeM. Sheldrick, Prof Heinz, G. WagnerRequires cookie*
 Title    N,N'-Bis(diphenyIphosphino)-S,S-dimethylsulfodiimin — ein Ligand für cyclische Übergangsmetallkomplexe N,N'-Bis(diphenylphosphino)-S,S-dimethylsulfodiimine — a Ligand for Cyclic Transition Metal Complexes  
 Abstract    Me 2 SN 2 P 2 Ph 4 M(CO) 4 complexes (1) (M: la Cr, lb Mo, lc W) have been synthesized from Me 2 S(NPPh 2) 2 and C 7 H s M(CO) 4 . la—lc are stable at room temperature, lb crystallizes in the space group P2,2,2 with cell constants a = 2486.3(2); b = 1488.8(1); c = 882.0(1) pm. 
  Reference    Z. Naturforsch. 43b, 933—936 (1988); eingegangen am 26. Februar 1988 
  Published    1988 
  Keywords    Crystal Structure, Chromium, Molybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-0933.pdf 
 Identifier    ZNB-1988-43b-0933 
 Volume    43 
4Author    Holger Szillat, Hanskarl Müller-BuschbaumRequires cookie*
 Title    Synthesis and Crystal Structure of Cuq^sH oj 25w 2o 8  
 Abstract    Single crystals of Cu(l.2sHO|.2sW20 8 were prepared by recrystallization from melts and investigated by X-ray diffractometer technique. Cuo^sHoj 25W 2Os crystallizes with m ono­ clinic symmetry, space group C2/c, o -19.123, b -5.613, c = 11.479 Ä , ß = 111.44°. Z = 8. It represents a new structure type characterized by W40 18 groups and Cu+/H o3+ at one point position in statistical distribution. Cu+/H o3+ show an octahedral coordination. A nother point position is occupied by Ho3+ with C. N. = 7. 
  Reference    Z. Naturforsch. 49b, 1145—1149 (1994); eingegangen am 25. März 1994 
  Published    1994 
  Keywords    Crystal Structure Copper Holmium, Tungsten, Oxide 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1145.pdf 
 Identifier    ZNB-1994-49b-1145 
 Volume    49 
5Author    T. Gressling, Hk Müller-BuschbaumRequires cookie*
 Title    Zur Kristallstruktur von Ce2(W 0 4)3 On the Crystal Structure of Ce2(W 0 4)3  
 Abstract    Single crystals of Ce2(W 0 4)3 have been prepared by crystallisation from molten mixtures of W 0 3 and C e 0 2. The compound shows m onoclinic symmetry, a = 7.813(4), b = 11.720(2), c = 11.586(3), ß = 109.36(3)°, Z = 4, and is isotypic to Eu2(W 0 4)3, but shows large differences of the atomic coordinates especially of oxygen. The crystal structure of Ce2(W 0 4)3 is charac­ terized by W (1)0 4 tetrahedra, square W (2)0 5 pyramids and a distorted capped trigonal prism of oxygen around cerium. The decrease o f the oxidation states of C e4+ or W6+ was proved by thermogravimetric and magnetic measurements as well as by calculations of the Coulomb terms of lattice energy. 
  Reference    Z. Naturforsch. 50b, 1513—1516 (1995); eingegangen am 25. Mai 1995 
  Published    1995 
  Keywords    Cerium, Tungsten, Oxygen, Crystal Structure 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-1513.pdf 
 Identifier    ZNB-1995-50b-1513 
 Volume    50 
6Author    A.B M Sham, Rahm An, H. Boiler, K. O. KleppRequires cookie*
 Title    Synthesis and Spectroscopic Investigations of New Linear Heterobimetallic Clusters [Me4N]3[(TOS3 )2Ag] (T = Mo, W). Crystal Structure of [Me4N]3[(MoOS3 )2 Ag]  
 Abstract    Red-brown crystals of a new bis(thiomolybdate) complex [Me4N]3[(MoOS3)2Ag] were formed at room temperature through the reaction of a solution of [Me4N]2[MoOS3] in MeCN with solid AgCN. They are monoclinic, space group P2i/c with unit cell parameters a = 16.662(9), b = 9.464(3), c = 17.890(8) A, /3 = 101.87(2)°, Z = 4. The crystal structure was determined from single crystal diffractometer data (MoKa-radiation) and refined to R = 0.044 (3614 reflections, 236 variable parameters). The structure is characterized by trinuclear complex anions, [(MoOS3)2Ag]3~. According to Weissenberg investigations the homologous tungsten compound is isostructural. The infrared spectrum of the molybdenum complex (KBr powder) shows absorption bands at 884 (vs) and 871 (w) cm-1 (terminal i/(Mo-0)), 483 (vs) cm-1 (terminal i/(Mo-S)), 451 (vs), and 435 (w) cm-1 (bridging i/(Mo-S)). The tungsten complex showed bands at 901 (vs) cm-1 (terminal ^(W-O)), 478 (vs) cm-1 (terminal u(W-S)), and 435 (vs) cm-1 (bridging ^(W-S)). The anionic mass spectra shows molecular ion peaks at m/z 524 and 700 for [(MoOS3)2Ag]_ and [(WOS3)2Ag]~, respectively, as well as peaks for other fragments. 
  Reference    Z. Naturforsch. 55b, 238—242 (2000); received Oktober 10 1999 
  Published    2000 
  Keywords    IR Data, Chalcogenides, Molybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0238.pdf 
 Identifier    ZNB-2000-55b-0238 
 Volume    55 
7Author    Requires cookie*
 Title    Reaktionen von Metallcarbonylen mit Diazirin1  
 Abstract    W o l f g a n g B e c k u n d W o l f g a n g D a n z e r Pentamethylendiazirine (N = N) has been found in metal carbonyl compounds as a monodentate two electron ligand (7t-CH3C5H 4Mn(CO)2 N = N , (OC)sW N = N) or as a 
  Reference    (Z. Naturforsch. 30b, 716—719 [1975]; eingegangen am 2. Juni 1975) 
  Published    1975 
  Keywords    Diazirine Carbonyl Complexes, Manganese, Iron, Molybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0716.pdf 
 Identifier    ZNB-1975-30b-0716 
 Volume    30 
8Author    Herbert Binder, Dieter SellmannRequires cookie*
 Title    Röntgen-photoelektronenspektroskopische Untersuchungen an Pentacarbonyl- Chrom-und -Wolfram-Komplexen mit Stickstoffliganden c X-ray Photoelectron Studies of Pentacarbonyl Chromium and Tungsten Complexes with Nitrogen Ligands  
 Abstract    The ionization energies of some chromium and tungsten pentacarbonyl complexes of the type [M(CO)5] xL (L = N2H2, N2H4, NH3; x = 1 or 2 for N2H4 or a; = 1 for N2H2) are reported. The results are discussed in terms of the effects of tr-donor and 7r-acceptor bonds on XPS data. Satellite lines, which can be explained in terms of a shake-up process, give information about the nature of the metal-ligand bond. These shake-up processes are, to a large extent, specific to the atoms of the acceptor groups. The spectroscopic and chemical importance of multi-peak structures of XPS bands is emphasised. 
  Reference    Z. Naturforsch. 33b, 173—179 (1978); eingegangen am 21. Dezember 1977 
  Published    1978 
  Keywords    X-ray, PE Spectra, Monosubstituted Pentacarbonyls, Chromium, Tungsten 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0173.pdf 
 Identifier    ZNB-1978-33b-0173 
 Volume    33 
9Author    ErnstOtto Fischer, FranzJ. GammelRequires cookie*
 Title    Übergangsmetall-Carbin-Komplexe, L [1] Darstellung und nukleophile Substitution von Tetracarbonyl(organylcarbin)tetrafluoroborato-metall-Komplexen Transition Metal Carbyne Complexes, L [1] Preparation and Nucleophilic Substitution of Tetracarbonyl(organylcarbyne)tetrafluoroborato Metal Complexes  
 Abstract    Pentacarbonyl[methoxy(organyl)carbene]chromium complexes react in boron tri-fluoride dimethyletherate in the presence of BF3 to form tetracarbonyl(organylcarbyne)-tetrafluoroborato complexes of chromium. In the analogous tungsten complex BF4(CO)4WCC6Hs the BF4--ligand is displaced by nucleophilic reagents. With As(C6H5)3 and <-C4H9NC the cationic derivatives [As(C6H5)3(CO)4WCC6H5][BF4] as well as [<-C4H9NC(CO)4WCC6H5][BF4] are obtained. Die Umsetzung von Pentacarbonyl[alkoxy(orga-nyl)carben]-Komplexen mit Bortrihalogeniden BX3 in Pentan bei tiefen Temperaturen führt für X = Cl, Br, I zu den in großer Vielfalt dargestellten trans-Halogeno(tetracarbonyl)carbin-Komplexen desTyps 
  Reference    Z. Naturforsch. 34b, 1183—1185 (1979); eingegangen am 21. Mai 1979 
  Published    1979 
  Keywords    Tetracarbonyl(organylcarbyne)tetrafluoroborato Complexes, Chromium, Tungsten, Nucleophdic Substitution 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-1183.pdf 
 Identifier    ZNB-1979-34b-1183 
 Volume    34 
10Author    Anke Brauel, Dieter RehderRequires cookie*
 Title    Ein neuer Weg zur Darstellung der Nitrosylkomplexe CpM(CO) 2 NO (M = Cr/Mo/(W)) durch NO/CO-Austausch zwischen [Co(NO) 2 Hal] 2 und Carbonyl-cyclopentadienylkomplexen* A Novel Route to the Nitrosyl Complexes CpM(CO) 2 NO (M = Cr/Mo/(W)) by NO/CO Exchange between [Co(NO) 2 Hal] 2 and Carbonyl-cyclopentadienyl Complexes  
 Abstract    The title compounds have been prepared by NO transfer from [Co(NO)iHal] 2 (Hal = Cl, Br, I) to [CpM(CO) 3 ] 2 , CpM(H)(CO) 3 and [CpM(CO) 3 ]" (M = Cr, Mo, W; Cp = ?7 5 -C 5 H 5). In the case of the neutral complexes, the reactions need initiation and support by light; the anionic complexes are nitrosylated in a dark reaction. The highest yields (60%) are obtained from the reactions between [Co(NO) 2 Br] 2 and [CpM(CO) 3 ] 2 (M = Cr, Mo). 
  Reference    Z. Naturforsch. 42b, 605—609 (1987); eingegangen am 26. November 1986/7. Januar 1987 
  Published    1987 
  Keywords    Nitrosyltransfer, Carbonyl-Nitrosyl Complexes, Chromium, Molybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-0605.pdf 
 Identifier    ZNB-1987-42b-0605 
 Volume    42 
11Author    Regine Herbst, KatteshV. Katti, HerbertW. Roesky, GeorgeM. SheldrickRequires cookie*
 Title    Synthese und Struktur des ersten Cyclophosphazens mit einer M etall—Metall-Bindung im Ringgerüst Synthesis and Structure o f the First Cyclophosphazene Containing a Metal —Metal Bond within the Ring Skeleton  
 Abstract    The reaction of [H2NPPh2NPPh2N H 2]Cl (1) with WClft (2) proceeds with formation of NPPh2NPPh2NWCl3 (3) and HCl,N6P4Ph8W 2 (4). 3 is the main product of this reaction. 4 was characterized by an X-ray structure determination. 4 contains a seven and a six-membered phos-phorus-nitrogen ring with a W —W bond of 269.2 pm. 
  Reference    Z. Naturforsch. 42b, 1387 (1987); eingegangen am 22. Juni/6. August 1987 
  Published    1987 
  Keywords    Tungsten, 6;r-Systems, X-Ray, Phosphorus-Nitrogen Compound 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-1387.pdf 
 Identifier    ZNB-1987-42b-1387 
 Volume    42 
12Author    K. Endrich, P. Alburquerque, R. P. Korswagen, M. L. ZieglerRequires cookie*
 Title    Über die Reaktionen von Phosphoryliden mit homodinuklearen Organometallverbindungen des Molybdän und Wolfram On the Reaction of Phosphorylides with Homodinuclear Organometallic Compounds of Molybdenum and Tungsten  
 Abstract    We report first the complete study of the reactions of [CpMo(CO) 2 ]^ (Mo=Mo) (1, Cp = ?7 5 -C,H s) with salt-free phosphorus ylides Ph,P=CHR (2, Ph = QH,; R = H (2a), CH, (2b), C,H 7 (2c), C 6 H s (2d)) and with the Nal-adducts of the ylides Ph,P=CMe, (Me = CH,), PhMe 2 P=CH 2 and (PhO) 3 P=CH 2 . With 2, products of the type Cp(CO) 2 LMo-MoL(CO) 2 Cp (7, L = ylide) were obtained, and the salt adducts gave addition compounds of the type Cp(CO) 2 LMo-MoL(CO) 2 Cp-2NaI (12, L = ylide). These very reactive products represent novel bisphosphonioalkyl complexes, and were characterized by IR, mass and 'H NMR spec-trometry. The reaction of 1 with hexaphenylcarbodiphosphorane, C(PPh,) 2 , leads to a novel double addition product, Cp 2 Mo 2 (CO) 4 [C(PPh,) 2 ] 2 (14). Some reactions of compounds 7, 12 and 14 were also studied; 7d (L = CHPh —PPh,) reacts with NaNH 2 yielding ammonia and the disodium salt of the novel dianionic complex [CpMo(CO) 2 (CPh-PPh,)]^ 2 ~ (15); 7a (L = CH 2 —PPh,) reacts with CH,I forming CpMo(CO),CH, and traces of CpM~o(CO) 2 (PPh,)I; all compounds of types 7,12 and 14 react with adsorbents (Silica-gel, A1 2 0,, etc.); thus chromatogra-phy is impossible, even under strict protection from air and humidity. A study of the processes occurring during chromatography under various conditions and the resulting products are also reported and discussed. [CpW(CO),] 2 (18) reacts with 2 a forming also a bisphosphonioalkyl complex [CpW(CO) 2 L] 2 (L = CH 2 =PPh 3); in this case, the ylide substitutes two carbonyl groups in 18. The compounds [Cp*M(CO) 2 ] 2 (M^M) (Cp* = C 5 Me 5 ; M = Cr, W) apparently do not react with phosphorous ylides; the corresponding Mo compound, [Cp*Mo(CO) 2 ] 2 , does react, but only the new mono-nuclear complex Cp*Mo(CO) 2 (PPh,)Cl (22) could be isolated. 
  Reference    Z. Naturforsch. 43b, 1293—1306 (1988); eingegangen am 29. März/16. Juni 1988 
  Published    1988 
  Keywords    Phosphorylides, Homodinuclear Organometallic Compounds, Molybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-1293.pdf 
 Identifier    ZNB-1988-43b-1293 
 Volume    43 
13Author    Dieter Sellmann+, W. Olfgang Kern, Adelgunde Holzmeier, Georg Pöhlmann, M. Atthias, MollRequires cookie*
 Title    Übergangsmetallkomplexe mit Schwefelliganden, LXVI  
 Abstract    Substitutions-und Additionsreaktionen an Molybdän-und Wolfram-Schwefel-Zentren von |M (Cl)(NO)('S4)], M = Mo, W, mit Thiolaten SR" (R = Me, 'Pr, w Bu, Ph) und PM e3 ('S4'2-= l,2-Bis(2-mercaptophenylthio)ethan(2-)) Transition M etal Complexes with Sulfur Ligands, LXVI* Substitution and A ddition Reactions at M olybdenum and Tungsten Sulfur Centres of [M(Cl)(NO)('S4')], M = M o, W, with Thiolates SR " (R = Me, 'Pr, "Bu, Ph) and PM e3('S4'2~ = l,2-Bis(2-mercaptophenylthio)ethane(2-)) Since substrate addition and elim ination reactions are essential reactions o f metal sulfur centres in oxidoreductases, we investigated the substitution o f chloride in [Mo(C1)(NO)('S4')](1) ('S4'2-= l,2-Bis(2-m ercaptophenylthio)ethane(2-)) [4] and in the anal­ ogous tungsten complex [W (Cl)(NO)('S4')](2). The chloride ligands in 1 and 2 can easily be substituted by thiolates to give [M (SR)(NO)('S4')] (M = M o, R = Me 3a, 'Pr 3b, "Bu 3c, Ph 3d; M = W, R = Me 4 a , Ph 4b). For these substitution reactions an associative mechanism is suggested. The SR~ ligands act probably as o-n four electron donor ligands to give metal centres with an 18 electron configuration as also found in the amido complexes [M o(N R 2)(NO)('S4')] [4]. 1 and 2 react with PM e3 to yield the adducts [M(PMe3)(Cl)(NO)('S4')] (M = Mo 5, W 6), w hose N M R spectra indicate the formation o f two stereoisomers in a ratio o f about 2:3. 
  Reference    Z. Naturforsch. 46b, 1349—1356 (1991); eingegangen am 28. Januar 1991 
  Published    1991 
  Keywords    Sulfur Complexes, Synthesis, Reactions, Stereochemistry, M olybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-1349.pdf 
 Identifier    ZNB-1991-46b-1349 
 Volume    46 
14Author    Dieter Sellmann+, Bernd Seubert, W. Olfgang Kern, Falk Knoch, M. Atthias, MollRequires cookie*
 Title    Übergangsmetallkomplexe mit Schwefelliganden, LXIX* and X-Ray Structure Analyses  
 Abstract    Chrom-und Wolfram-Nitrosyl-Komplexe mit schwefeldominierten Koordinationssphären: IC r(N O)XS4')]v (x = 1, y = 2; x = 2, y = 1), (NR4)2[W (NO)2(S 2)2] (R = M e, /i-Bu), [W(L)(NO)('S4)] (L = NO , N P M e3, NPEt3) und [//-0 { W (N 0)(S4)} 2] ('S2'2" = l,2-Benzoldithiolat(2-); 'S4'2-= l,2-Bis(2-mercaptophenylthio)ethan(2-)); Synthesen, Eigenschaften und Röntgenstrukturanalysen Transition M etal Complexes with Sulfur Ligands, LXIX* Chromium and Tungsten Nitrosyl Complexes with Sulfur Dom inated C oordination Spheres: [C r(N O)/S 4')]v(* = \ , y = 2 \x = 2 , y = 1), (N R 4)2[W(NO)2('S2')2] (R = Me, «-Bu), [W(L)(NO)('S4')] (L = NO, N PM e3, N P E t3) and [//-0{W (N 0)('s7)}2] ('S2'2-= 1.2-B enzenedithiolate(2-);'S4'2-= 1.2-Bis(2-mercaptophenylthio)ethane(2-)); Syntheses, Properties In order to study the properties o f sulfur coordinated metal centres, the chromium and tung­ sten complexes [Cr(NO)(//-'S4% (4), (N R 4),[W (N O)2('S 0 2] (1) (R = Me (la), «-Bu (lb)), [W (NO)2('S4')] (2), [^ -0 {W (N 0)('S 4')}2] (3) and [W (N PR 3)(N O)('S4')] (5) (R = Me (5a), Et (5b)) were synthesized ('S2'2 = 1,2-benzenedithiolate(2—) ; 'S4'2 = 1,2-bis(2-mercaptophenyl-th io)ethane(2-)). la and lb result from the reductive nitrosylation o f Li2[W('S2')3] which was prepared by reduction o f [W('S2')3] with rc-BuLi. la was also obtained from [W (NO)2(Cl)2]", 'S2'2-and N M e4+. Alkylation o f la or lb by 1.2-dibromoethane yields 2, whose X-ray structure 
  Reference    Z. Naturforsch. 46b, 1435—5 (1991); eingegangen am 8. A pril/ 8. Juli 1991 
  Published    1991 
  Keywords    Chromium, Tungsten, Nitrosyl Complexes, Sulfur Ligands, X-Ray 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-1435.pdf 
 Identifier    ZNB-1991-46b-1435 
 Volume    46 
15Author    Saim Özkar, Zahide ÖzerRequires cookie*
 Title    3C NMR Spectroscopic Study of Pentacarbonylacetonitrilemetal(O) Complexes of the Group 6 B Elements  
 Abstract    The com plexes M (CO)5(C H 3C N) (M: Cr, M o, W) were obtained from the substitution o f TH F in M (C O)5(TH F) which has been generated by photolysis o f M(CO)6 in T H F and characterized by using IR , 'H N M R and l3C N M R spectrosco­ pies. The acetonitrile ligand is found to be N -bonded to the M (CO)5-moiety with a local C4v-symmetry. The effect o f the acetonitrile ligand on the metal-carbonyl bonding was discussed in terms o f l3C N M R chemical shifts. 
  Reference    Z. Naturforsch. 48b, 1431 (1993); received M ay 17 1993 
  Published    1993 
  Keywords    Chromium, M olybdenum, Tungsten, Carbonyl, Acetonitrile 
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 TEI-XML for    default:Reihe_B/48/ZNB-1993-48b-1431_n.pdf 
 Identifier    ZNB-1993-48b-1431_n 
 Volume    48 
16Author    İzzetA. Mour, Saim Ozkar, CorneliusG. KreiterRequires cookie*
 Title    Synthesis and Spectroscopic Studies of Pentacarbonylfumaronitrile-chromium(O), -molybdenum(O), and -tungsten(O)  
 Abstract    Photolysis of hexacarbonyl-chromium(O), -molybdenum(O), and -tungsten(O) in presence of fumaronitrile yields at room tem perature pentacarbonyl-fumaronitrile-chromium(O) (1), -molybdenum(O) (2), and -tungsten(O) (3). The complexes were purified by crystallization and characterized by IR and 13C-NM R spectroscopy. The fumaronitrile ligand is bonded to the M (CO)5 moiety by one nitrile nitrogen atom rather than by the carbon-carbon double bond. In toluene 2 dissociates into fumaronitrile and pentacarbonyl-molybdenum(O), which is stabi­ lized by the solvent. Fumaronitrile and solvated pentacarbonyl-molybdenum(O) exist in solu­ tion together with 2 in an equilibrium which lies in favour of the former species. 
  Reference    Z. Naturforsch. 49b, 1059—1062 (1994); eingegangen am 13. April 1994 
  Published    1994 
  Keywords    Chromium, Molybdenum, Tungsten, Carbonyl, Fumaronitrile Complexes 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1059.pdf 
 Identifier    ZNB-1994-49b-1059 
 Volume    49 
17Author    Thomas Schmidt, Stephan Neis, Richard GoddardRequires cookie*
 Title    Synthesis, Structure, and Properties of Homoleptic l-Oxa-l,3-diene Molybdenum and Tungsten Complexes  
 Abstract    Homoleptic tris(l-oxa-l,3-diene)m olybdenum and tungsten complexes are formed as yel­ low, crystalline compounds in 54-80% isolated yield on treatm ent of the corresponding /3-unsubstituted a,/3-unsaturated ketones with W (CO)3(CH 3CH 2CN)3 or (y6-C6H 6)M o(CO)3 in refluxing hexane. Reaction of these oxadienes with (^6-C6H 5CH3)2Mo in tetrahydrofuran or /7-hexane provides a new high yield route to homoleptic molybdenum complexes that are otherwise difficult to prepare. X-ray crystal structure analyses of two air-stable, isomeric tungsten complexes reveal a significant contribution of a cr2,?/2-bonding mode in the coordi­ nated oxadiene moieties. U nder reaction conditions that allow the platinum catalyzed hydro­ genation of phenyl substituents in these ligands, the coordinated oxadiene fragments are inert, thus demonstrating an unprecedented chemoselectivity in the hydrogenation of aryl-substituted enones. On the other hand, the complexes are labile enough to catalyze the cyclotrimerization of alkynes such as methyl propiolate. 
  Reference    Z. Naturforsch. 50b, 315—325 (1995); received September 7 1994 
  Published    1995 
  Keywords    Oxadiene Complex, Molybdenum, Tungsten, X-Ray, Selective Hydrogenation 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-0315.pdf 
 Identifier    ZNB-1995-50b-0315 
 Volume    50 
18Author    KatrinA. Köhler, H. Lexander Steiner, W. Erbert, RoeskyRequires cookie*
 Title    Die Kristallstrukturen von (j75-C5Me5)MoMe4 und (j75-C5Me5)WMe4 The Crystal Structures of (?75-C5Me5)M oMe4 and (^5-C5Me5)W M e4  
 Abstract    The crystal structures of (/75-C5Me5)MoMe4 1 and (j/5-C5Me5)WMe4 2 are reported. 1 and 2 crystallize in the orthorhom bic space group Pbcm with the lattice param eters a = 681.4(2) pm, b = 1538.6(6) pm, c = 1402.4(6) pm with 4 units per cell (1), and a = 684.99(6) pm, b = 1547.3(2) pm, c = 1405.5(2) pm with 4 units per cell (2). Both compounds are monomeric and have a square-pyramidal geometry. 
  Reference    Z. Naturforsch. 50b, 1207—1209 (1995); eingegangen am 20. Januar 1995 
  Published    1995 
  Keywords    Molybdenum, Tungsten, Alkyl Complexes, Crystal Structures 
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 Identifier    ZNB-1995-50b-1207 
 Volume    50 
19Author    C. Ogric, W. Schütt, T. Lehotkay, E. Herdtweck, F. R. KreißlRequires cookie*
 Title    Umwandlung von ?72-Thiocarbenkomplexen des Molybdäns und Wolframs in Metalla-thia-cyclopropan-Systeme Conversion of ?/2-Thiocarbene Complexes of M olybdenum and Tungsten to Metalla-thio-cyclopropane Systems  
 Abstract    Cationic ^2-thiocarbene complexes of molybdenum and tungsten [Cp(CO)2M =C(R)S-Me][BF4] (M = Mo, W; R = Ph, Tol; L = CO, PM e3) react with the germylene G e{N('Bu)CH 2CH2N('Bu)}, the plumbylene Pb{N(SiM e3)2}2, or with sodium azide and sodium thiosulfate to give neutral metalla-thia-cyclopropane com plexes C p(CO)2-M -C(R)(SM e)SM e. Instead of the expected cycloaddition or substitution reactions the formal addition of thiomethanolat at the carbene carbon atom is observed. On treating the corre­ sponding trimethylphosphine substituted /;2-thiocarbene com plex of molybdenum [Cp(CO)(PM e3)M o=C(Tol)SM e][BF4] with diethylamine or N,N,N',N'-tetramethylguanidine a cationic molybda-thia-cyclopropane system is formed. The products have been characteri­ zed by 'H, 13C, 31P NMR, IR and mass spectra. The crystal structure of 5a has been determin­ ed; space group with a = 1340,4(2), b -1097,7(1), c = 1101,8(5) pm and Z = 4. 
  Reference    Z. Naturforsch. 50b, 1839—1844 (1995); eingegangen am 11. Mai 1995 
  Published    1995 
  Keywords    ?72-Thiocarbene Complexes, Molybdenum, Tungsten, Carbon Sulfur Coupling 
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 Identifier    ZNB-1995-50b-1839 
 Volume    50 
20Author    Ating Giirkan, AhmetM. Yilmaz, Saim Önal, ÖzkarRequires cookie*
 Title    Electrochemical Study of Tricarbonyl(y;6-cyclooctatetraene)metal(0) Complexes of the Group 6 Elements  
 Abstract    Tricarbonyl(?76-cyclooctatetraene)metal(0) complexes of the group 6 elements were prepared by using the procedures described in the literature with some minor modifications and identi­ fied by IR and NMR spectroscopy. Their electrochemical behavior was studied by using cyclic voltammetry in dichloromethane solution containing 0.1 M tetrabutylammonium tetrafiuorob-orate as supporting electrolyte. Their oxidation and reduction potentials were measured and discussed in terms of the frontier energy levels in connection with the UV-Visible electronic ab­ sorption spectral data. In order to elucidate the mechanism of electrooxidation of the complexes, constant potential electrolysis was performed for one representative example, tricarbonyl(^6-cyclooctatetraene)chromium(O). The IR monitoring of the reaction showed that it is gradually converted to hexacarbonylchromium(O) upon electrolysis at constant potential. 
  Reference    Z. Naturforsch. 53b, 875—880 (1998); received March 9 1998 
  Published    1998 
  Keywords    Carbonyl, Chromium, Molybdenum, Tungsten, Cyclic Voltammetry 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0875.pdf 
 Identifier    ZNB-1998-53b-0875 
 Volume    53 
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