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  • 1
    Electronic Resource
    Electronic Resource
    Synthese und Struktur Platin-haltiger Tripeldecker- und Tetradecker-Komplexe (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 729-740 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Platinum-Containing Triple-Decker and Tetra-Decker ComplexesStacking of the acceptor sandwich bis(η5-2,3-dihydro-1H-1,3-diborolyl)platinum 1 (≙ (C2B2C)2Pt) with (C5H5)M fragments leads to the unsymmetrical triple-decker complexes (η5-C5H5)M-μ-(η5-C2B2C)Pt(η5-C2B2C) 2 (M = Co) and 3 (M = Ni) as well as to the symmetrical tetra-decker complexes [(η5-C5H5)M-μ-(η5-C2B2C)]2Pt 4 (M = Fe) and 5 (M = Ni). In these reactions 1 and (C5H5)Fe(C8H12) yield the tetra-decker 4, whereas with (C5H5)Co(C2H4)2 only the triple-decker 2 is formed. With [(C5H5)Ni(CO)]2 both the triple-decker 3 and the tetra-decker 5 are obtained. NMR studies on the diamagnetic complexes 2 (30 valence electrons), 4 (42 VE), and 5 (46 VE) indicate high-symmetrical conformations, or free rotation of the ligands. 2 and 3 crystallize isotypic; the X-ray structure analyses exhibit the triple-decker arrangement with antiperiplanar conformation of the heterocycles. 3 in comparison with 2 is elongated along the molecular axis. The tetra-deckers 4 and 5 also crystallize isotypic; for the first time a synclinale conformation of the bridging ligands is found.
    Notes: Aufstockung des Akzeptor-Sandwichs Bis(η5-2,3-dihydro-1H-1,3-diborolyl)platin 1 (≙ (C2B2C)2Pt) mit (C5H5)M-Fragmenten führt zu den unsymmetrischen Tripeldecker-Komplexen (η5-C5H5)M-μ(η5-C2B2C)Pt(η5-C2B2C) 2 (M = Co) und 3 (M = Ni) sowie zu den symmetrischen Tetradecker-Komplexen [(η5-C5H5)M-μ-(η5-C2B2C)]2Pt 4 (M = Fe) und 5 (M = Ni). Dabei ergibt die Reaktion von 1 mit (C5H5Fe(C8H12) den Tetradecker 4, während mit (C5H5)Co(C2H4)2 nur der Tripeldecker 2 entsteht. Mit [(C5H5)Ni(CO)]2 werden der Tripeldecker 3 und der Tetradecker 5 gebildet. NMR-Untersuchungen an den diamagnetischen Komplexen 2 (30 Valenzelektronen), 4 (42 VE) und 5 (46 VE) sprechen für hochsymmetrische Konformationen oder freie Rotation der Liganden. 2 und 3 kristallisieren isotyp; die Röntgenstrukturanalysen zeigen die Tripeldeckeranordnung mit antiperiplanarer Konformation der Heterocyclen. 3 ist im Vergleich zu 2 entlang der Molekülachse aufgeweitet. Die Tetradecker 4 und 5 kristallisieren ebenfalls isotyp, es wird erstmals eine synclinale Konformation der Brückenliganden gefunden.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180232
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  • 2
    Electronic Resource
    Electronic Resource
    Diborylethylen-Verbindungen als Liganden in Metallkomplexen, XIX. Neue Koordinationsvarianten des 2,3-Dihydro-1 H-1,3-diborols und 2,3-Dihydro-1 H-1,3-diborolyls in Platinkomplexen (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 2103-2108 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diborylethene Compounds as Ligands in Metal Complexes, XIX. - New Coordination Patterns of 2,3-Dihydro-1 H-1,3-diboroles and 2,3-Dihydro-1 H-1,3-diborolyls in Platinum ComplexesBis(cyclooctadiene)platinum reacts with the 2,3-dihydro-1 H-1,3-diborole derivative 1a to yield the isomeric 16-VE complexes 2a and 3a; with 1b and 1c the 30-VE triple-decker 4b and 4c are formed. 2a is the first complex with 1a as two-electron donor. The X-ray structure analyses of 2a, 3a, and 4c reveal nonplanar heterocycles.
    Notes: Bis(cyclooctadien)platin reagiert mit dem 2,3-Dihydro-1 H-1,3-diborol-Derivat 1a zu den isomeren 16-VE-Komplexen 2a und 3a; mit 1b und 1c entstehen die 30-VE-Tripeldecker 4b und 4c. 2a ist der erste Komplex mit 1a als Zweielektronendonor. Die Röntgenstrukturanalysen von 2a, 3a und 4c ergeben nichtebene Borheterocyclen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881211205
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  • 3
    Electronic Resource
    Electronic Resource
    C-H Bond Activation of Simple Alkenes with (C5H5)CO Fragments: Preparation, Molecular Structure, and Dynamical Behaviour of Tri- and Tetranuclear Cyclopentadienylcobalt Cluster complexes with μ-Cycloalkyne Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 593-603 
    Details
    ISSN: 0009-2940
    Keywords: C-H activation ; Alkyne complexes ; Cyclopentadienyl cobalt ; Fluxionality ; Hydrido complexes ; Clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vicinal C-H bonds of the cycloalkenes CnH2n (n = 5-8) were activated upon treatment under mild conditions with reactive sources of the (C5H5)CO fragment. With [C5H5)CO(C2H4)2] (2a), the trinuclear cluster complexes [H2((C5H5)CO)3(μ3-C2(CH2)n-2)] (5a: n = 5; 5c: n = 5d: n = 8) were formed. Using the more reactive [(C5H5)2Co]/K, 5a-5dwere obtained, along with small amounts of the tetranuclear [{(C5H5)CO}4r{μ4-C2(CH2)n-2}] (8a-c: n = 5-7). X-ray structure analyses of 5c, d and 8b, c were performed. A μ-‖ (orμ3-η1:η2:η1) coordination of the cycloalkyne ligands was found in the trinuclear cluster complexes. The tetranuclear 8b, c had the cycloalkynes quadruply bridging (μ4-η1:η2:η2:η1_ a butterfly arrangement of the metal atoms. The acetylenic carbon-carbon bonds are considerably lengthened upon coordination [1.392(4), 1.398(3) å in 5c d; 1.464(8), 1.499(5) Å in 8b, c]. Three dynamic processes - alkyne “walk” on top of the CO3 triangle, μ2-hydride migration, and μ2/μ3-hydride exchange - are operational in the trinuclear 5a-d. Dynamic NMR data for 5a are consistent with a “windshield-wiper” mechanism for the alkyne migration. Hydride exchange is associated with a higher energy barrier, and is probably and independent dynamic process.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300510
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  • 4
    Electronic Resource
    Electronic Resource
    Metallorganische Clusterkomplexe mit flächenüberbrückenden Aren-Liganden, 5[1a]. C-H-Aktivierung und Bildung eines μ3-Aren-Komplexes: Konkurrenzreaktionen beim Aufbau von (CpCo)3-Clusterkomplexen mit Vinylbenzolen als Liganden (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1615-1618 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopentadienylcobalt ; Alkyne cluster ; Arene cluster ; Bond activation, C-H ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Clusters with Face-Capping Arene Ligands, 5[1a].-C-H Activation and Formation of a μ3-Arene Complex: Competing Reactions During Assembly of (CpCo)3 Cluster Complexes with Vinylbenzenes as LigandsA number of ring-substituted styrenes R(C6H4)C2H3 (R=CH3, F) reacts with [CpCo(C2H4)2] (1) to give both the cluster complexes [(CpCo)3{μ3-η2:η2:η2-(C6H4R)C2H3}] [2a (R=p-CH3), 2c (R=m-F), 2d (R=p-F)} with Co3 face-capping arenes and [(μ2-H)(μ3-H)(CpCo)3{μ3-1-s̰:2-s̰:η2-HCC(C6H4R)}] [7a (R=p-CH3), 7b (R=o-F), 7c (R=m-F), 7d (R=p-F)] with Co3 face capping alkynes derived from dehydrogenation of the vinyl group. The X-ray structure analysis of 7a confirms the 1-s̰:2-s̰:η2 coordination of the bridging alkyne ligand. In solution the complexes 7 are fluxional and exhibit migration of the alkyne and hydride ligands on the Co3 cluster.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260718
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  • 5
    Electronic Resource
    Electronic Resource
    (C5H5)Co-Induced Head-Head Coupling of Dimethylfulvene: Formation, Molecular Structure and Electrochemistry of (1,1,2,2-Tetramethyl-1,2-ethanediyl)bis(cobaltocene)Dedicated to Professor Peter Paetzold on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 317-320 
    Details
    ISSN: 0009-2940
    Keywords: Fulvene ; Cobaltocene ; (Cyclopentadienyl)cobalt ; Mixed valence complexes ; Electrochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Head-head coupling of a dimethylfulvene ligand occures in the reaction of 6,6-dimethylpentafulvene (1a) with [(C5H5)Co(C2H4)2] (7) to give (1,1,2,2-tetramethyl-1,2-ethanediyl)bis(cobaltocene) (8a). In contrast, the mononuclear η4-fulvene complexes 3b, c are obtained from 6-ethyl-6-methyl-(1b) and 6,6-diethylfulvene (1c) and 7. The crystal structures of 8a and the corresponding bis(ferrocene) 9a have been determined. The electrochemical behaviour of 8a and 9a shows 8a+, 8a-, and 9a+ to be localised mixed-valence species. Molecular mechanics calculations have been performed on the title complex and related derivatives.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280317
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  • 6
    Electronic Resource
    Electronic Resource
    Komplexe mit einem pentakoordinierten Kohlenstoffatom, IV. Tricarbonyl(η5-2,3-dihydro-1H-1,3-diborol)eisen und Bis[(tricarbonyleisen)-μ-(η5-2,3-dihydro-1H-1,3-diborol-2-yl)]eisen-Komplexe (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1511-1514 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes with a Pentacoordinated Carbon Atom, IV. -Tricarbonyl (η5-2,3-dihydro-1 H-1,3-diborole)iron and Bis[(tricarbonyliron)-μ(η5-2,3-dihydro-1H-1,3-diborol-2-yl)]iron ComplexesTricarbonylbis(cis-cyclooctene)iron reacts with the 2,3-dihydro-1H-1,3-diborole derivative 1a to yield the complex 3a, whereas with 1b the paramagnetic tetradecker complex 4b is formed. 4a is obtained from the iron sandwich 5a and Fe(CO)5. Spectroscopic data of 3a are in agreement with a pentacoordination at C-2. The X-ray structure analysis of 4b reveals a trans arrangement of the bridging ligands.
    Notes: Tricarbonylbis(cis-cycloocten)eisen reagiert mit dem 2,3-Dihydro-1H-1,3-diborol-Derivat 1a zu dem Komplex 3a, während mit 1b der paramagnetische Tetradecker-Komplex 4b entsteht. 4a wird aus dem Eisensandwich 5a und Fe(CO)5 erhalten. Spektroskopische Daten von 3a sind in Einklang mit einer Pentakoordination an C-2. Die Röntgenstrukturanalyse von 4b ergibt eine trans-Anordnung der Brückenliganden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200908
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  • 7
    Electronic Resource
    Electronic Resource
    A Novel Type of Resonance-Stabilised Dicobalt Complex with a Cyclopentadienylidene Bridge - Synthesis, Structure and Electronic Properties of [(C5R5)Co(μ-C5H4)Co(L)(C5R5)'] (L = C2H4, CO, CNtBu, PR3, P(OMe)3; R = H, Me) (1996)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 1453-1465 
    Details
    ISSN: 0947-6539
    Keywords: carbenes ; CH activation ; dinuclear complexes ; sandwich complexes ; spin equilibria ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dinuclear μ-cyclopentadienylidene complexes [(C5R5)Co(μ-C5H4)-Co(C2H4)(C5R'5)] (5) [5aa (R = R' = H), 5ab (R = H, R' = Me), 5ac (R = H, R'5 = H4Me), 5ba (R = Me, R' = H), 5bb (R = R' = Me) and 5da (R5 = Me4Et, R' = H)] were synthesised from [(C5R5)Co(η4-C5H6)] (4) [4a (R = H), 4b (R = Me), 4d (R5 = Me4Et)] and [(C5R'5)Co(C2H4)2] (1) [1a (R' = H), 1b (R' = Me) and 1c (R'5 = H4Me)]. In these reactions, both CH bonds of the methylene group of coordinated cyclopentadiene are activated under mild conditions. Substitution of the ethylene ligand in 5 by L leads to the carbonyl, isocyanide, phosphine, and phosphite derivatives [(C5R5)Co(μ-C5H4)Co(L)-(C5R'5)] [6aa, 6ab, 6ba, 6bb (L = CO), 7aa (L = tBuNC), 8aa, 8ab (L = PMe3), 9aa (L = PMe2Ph), 10aa (L = PMePh2) and 11aa (L = P(OMe)3)]. The crystal structures of 5aa, 5ab, 5ba, 6aa and 8aa have been determined. The experimental geometry is rationalised in terms of two limiting structures with μ-η4:η1 and μ-η5:η1 coordination of the bridging cyclopentadienylidene ligand. On the basis of the 18 valence electron rule, zwitterionic character is assigned to latter. This structure is preferred when L is an acceptor ligand, as in 6. In solution, 5-11 are fluxional with rapid rotation about the very short cobalt-carbene C bond. In addition the hindered rotation of the ethylene ligand in 5ab was studied by DNMR spectroscopy. In solution, a singlet-triplet equilibrium was established by variable-temperature NMR spectroscopy for 8aa. The temperature-dependent 1H NMR line shifts were analysed by means of an isotropic shift model to give 24≤ΔH° ≤ 32 kJ mol-1 and 45≤ΔS° ≤74 J mol-1 K-1 with the triplet state being preferred by entropy at higher temperatures.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19960021119
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  • 8
    Electronic Resource
    Electronic Resource
    Reductive Degradation of Tetracobalt Cluster Complexes with a Facial C8H8 Ligand - Synthesis of [Co3(CO)3(μ3-CO)3(μ3-C8H8)]- and [Ru(C5Me5)Co3(CO)3(μ3-CO)3(μ3-C8H8)] (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 783-788 
    Details
    ISSN: 1434-1948
    Keywords: Carbocycles ; Clusters ; Cobalt ; Electrochemistry ; Facial ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical reduction of the cluster complexes [Co4(CO)3(μ3-CO)3(μ3-C8H8)L2] 3 (L2 = C8H8), 4 (L = CO), 5 (L2 = C6H8) and 6 (L2 = 6,6-Ph2C6H4) gives the trinuclear anion [Co3(CO)3(μ2-CO)3(μ3-C8H8)]- (7) in high yield. It is proposed that formation of 7 occurs via degradation of the radical anions [3]- - [6]-, which can be generated reversibly via cyclic voltammetry. The anion 7 is stabilised by the facial C8H8 ligand and does not degrade further. Reaction of 7 with [(C5Me5)Ru(NCMe)3][BF4] results in the formation of [Ru(C5Me5)Co3(CO)3(μ3-CO)3(μ3-C8H8)] (8). The crystal structures of [NEt4]+-7, [(C5H5)2Co]+-7, and 8 were determined. In 7 and 8, the cyclooctatetraene ligand is coordinated to the Co3 face of the cluster in the facial mode.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Electron-poor 2,3-Dihydro-1,3-Diborolyl Complexes of Iron and Ruthenium: Synthesis, Reactivity, and Crystal and Electronic Structures of an Iron Sandwich ComplexDedicated to Professor Herbert Schumann on the occasion of his 60th birthday (1996)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 487-494 
    Details
    ISSN: 0947-6539
    Keywords: boron compounds ; diboroles ; Group 8 complexes ; sandwich complexes ; semi-empirical calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition product of sodium hydride and the 2,3-dihydro-1,3-diborole (CiPr)2(BEt)2CHMe (3c) reacted with [{(C5Me5)FeCl}x] to produce the green sandwich complex [(C5Me5)Fe{n5-(CiPr)2(BEt)2CMe}] (2 c), which formally contains 16 valence electrons (VE). Complex 2c has unexpected structural properties in the solid state: the 1,3-diborolyl ring is extremely folded (41°), and the Fe-C2 distance is short (1.90 Å). Analogously, violet Ru complexes 4a,c,d were obtained from 3a,c, NaH or tBuLi, and [{(C5Me5)RuCl}4]. With the less bulky heterocycles 3 b,e the new 30 VE triple-decker complexes [(C5Me5)Ru{μ,n5-(CR1)2(BR2)2CMe}RuH(C5Me5)] (5b,e) were formed, which contain a Ru-H bond. Cyclic voltammetric studies revealed the existence of stable anions 2c- and 4d- formed by reversible one-electron reduction at -1.26 and -1.40 V, respectively (vs. SCE). The red-brown anions were further characterized by ESR spectroscopy following stepwise reduction of the neutral species with potassium in THF. Addition of CO to 4a and 4d led to formation of the monocarbonyl complexes [(C5Me5)Ru(CO){n5-(CR1)2-(BR2)2CMe}] (6a,d), and 6d was characterized by X-ray structure analysis. The heterocycle in 6d is less folded (19°) than in 2 c. Its CO ligand causes a 28.5° tilt of the cyclic ligands. Reaction of CO with 2 c yielded a red product of unknown structure. The electronic structure of 2 was studied by EH-MO theory, which revealed a unique bonding in the sandwich. The s̰ electron density of the B-C bonds participates in the bonding to the iron atom; this demonstrates that the number of bonding electrons is the same as in ferrocene. Thus, the complexes 2 actually have 18 VE.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19960020506
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  • 10
    Electronic Resource
    Electronic Resource
    Borylmetallkomplexe, Borankomplexe und katalytische (Hydro)borierung (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 109 (1997), S. 2547-2550 
    Details
    ISSN: 0044-8249
    Keywords: Bor ; Homogene Katalyse ; Hydroborierungen ; Übergangsmetalle ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19971092206
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