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  • Carbene complexes  (7)
  • Wiley-Blackwell  (7)
  • American Geophysical Union (AGU)
  • 1
    Electronic Resource
    Electronic Resource
    Heterobimetallic Complexes with a Propynylidene C3-Bridge: General Synthetic Routes to Bimetallic Ethynylcarbene Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 479-488 
    Details
    ISSN: 0009-2940
    Keywords: Heterobimetallic complexes ; Carbene complexes ; Alkynes ; Coupling reaction ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sequential reaction of the dimethylamino(trimethylsilylethylnyl)carbene complexes [(CO)5M'=C(NMe2)C≡CSiMe3] [M' = W (1a)] with KF/THFMeOH, nBuLi and transition metal halides, [XMLn], affords heterobimetallic propynyliden complexes of the type [(CO)5M'=C(N-Me2)C≡CMLn] [MLn = Ni(PPh3) Cp (4a, b). Ni(PMe2Ph)2- {Mes) (Mes=2,4,6-C6H2Me3) (5a), Rh(CO)(PPh3)2 (6a), Fe(CO)2Cp (7a,b)]. In contrast, reaction of 1a with MeLi · LiBr and [IFe(CO)2Cp] yields the novel N-metallated complex [(CO)5W=C{N(ME)Fe(CO)2Cp}C≡CSiMe3] (8a). The complexes [(CO)5M'=C(NMe2)C≡CMLn=Fe(CO)2Cp (7a, b), Ru(CO)2Cp (10a,b), Ru(CO)(PPh3)Cp (11a), Mn(CO)5 (12a), Re(CO)5 (13a)] are accessible by Pd-catalyzed coupling of the C-stannylated carbene complexes [(CO)5M'=C-(NMe2)C≡CSnBu3] (9a, b) with [XMLn]. The related monomethylaminocarbene complexes [(CO)5M'=C(NHMe)C≡ CSnBu3] (16a, b), obtained by stannylation of [(C))5M'=C(NHMe)C=CH] (15a, B) with Bu3SnNEt2, react with [IFe(CO)2Cp] to give the bimetallic complexes [(CO)5M'=C(NHMe)C≡CFe(CO)2Cp] (17a, b). The complexes 4a, 5a, 7a and 10a were characterized by X-ray structural analysis. The spectroscopic and structural data suggest that the two metal centers in 4-7, 10-13, and 17 interact only weakly.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300407
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  • 2
    Electronic Resource
    Electronic Resource
    Verknüpfung von Cyanamiden mit einem Carbinliganden - Bildung von η2-(C,N)-Imidazolium- und Ansa-Carben-KomplexenHerrn Prof. Dr. Ernst Otto Fischer zum 75. Geburtstag gewidmet. (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2373-2378 
    Details
    ISSN: 0009-2940
    Keywords: Imidazolium manganese complexes ; Carbene complexes ; Cyclization ; Carbyne manganese complexes, cationic ; Cyanamides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coupling of Cyanamides with a Carbyne Ligand - Formation of η2-(C,N)-Imidazolium Complexes and Ansa-Carbene ComplexesHerrn Prof. Dr. Ernst Otto Fischer zum 75. Geburtstag gewidmet.Dicarbonyl(cyclopentadienyl)(phenylcarbyne)manganese complexes [Cp(CO)2Mn≡CPh]+X- (1-X) (X = BF4, BCl4) react with dimethyl- (2a), diethyl- (2b), and diisopropylcyanamide (2c) in five-fold excess by a head-to-tail cyclization of two cyanamides with the carbyne ligand to give η2-(C,N)-imidazolium complexes (3a-c-X). As byproducts ansa-amino(alkylide-neamino)carbene complexes (4a-c) are formed in which a N=C(Ph) group bridges the carbene carbon and the Cp ring. With increasing excess of the cyanamide the product ratio 3-X: 4 increases. Among the products of the reaction of 1-X with the cyanamides N≡CNR2 [NR2 = N(iBu)2, N(Bzl)2, N(Me)Ph] no imidazolium complexes 3-X are detected, only ansa-carbene complexes 4 are isolated. PMe3/H2O or pyridine/H2O displaces the heterocyclic ligand from 3a-BF4. The structure of 3a-BF4 is established by an X-ray analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931261104
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  • 3
    Electronic Resource
    Electronic Resource
    Carbohydratocarbene Complexes of Manganese and RheniumDedicated to Prof. Hans H. Brintzinger on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 373-378 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Carbyne complexes ; Carbohydrates ; Diastereoselective addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic carbyne complexes [Cp(CO)2M≡CR]+ [BX4]- [M = Mn, X = F: R = Ph (1), Tol (2); M = Re, X = 3,5-C6H2(CF3)2: R = Ph (3)] add the anion of monodeprotonated protected mannofuranose (4a), glucofuranose (4b), and fructopyranose (4c) to the carbyne carbon atom to form the carbohydratocarbene complexes 5a-c, 6a, b, and 7a. With 5b, 5c, and 6b the addition proceeds with retention of configuration at the anomeric center. Due to inversion of configuration in the deprotonation step the complexes 5a, 6a, and 7a are obtained as β-glycosides. The carbene ligand is oxidatively cleaved from the metal by trimethylamine N-oxide or air. Cleavage of the C(carbene)—O bond with reformation of the cation of the carbyne complex 2 is achieved by reaction of 6a with BCl3. Photolysis of [Cp(CO)2Mn=C(Ph)OEt] in the presence of L affords the carbene complexes [Cp(CO)(L)Mn=C(Ph)OEt] [L = P(OMe)3 (11), P(Tol)3 (12)]. Ethoxide abstraction from 11 and 12 by BF3 gives the chiral cationic carbyne complexes [Cp(CO)(L)Mn=CPh]+[EF4]- (13, 14) which add 4a to form the corresponding mannofura-nosylcarbene complexes (15, 16). When 0.5 equivalents of 4a are employed in the reaction with 13, 14 the ratio of diastereomers is 3:2, both for 15 and 16. Complex 11 was characterized by an X-ray structural analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280409
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  • 4
    Electronic Resource
    Electronic Resource
    Synthetic Routes to Transition-Metal-Substituted Pentadiynylidene Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1063-1067 
    Details
    ISSN: 0009-2940
    Keywords: Heterobimetallic complex ; Carbene complexes ; Bridging ligands ; Coupling reaction ; Alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sequential reaction of the dimethylamino(ethynyl)carbene complex [(CO)5 W=C(NMe2)C≡CH] (1) with nBuLi, CuI and BrC≡CSiMe3 affords the dimethylamino(trimethylsilylbutadiynyl)carbene [(CO)5W=C(NMe2)C≡C—C≡C—SiMe3] (2). Desilylation of 2 with KF/THF/MeOH gives [(CO)5W=C(NMe2)C≡C—C≡CH] (3). The C-stannylated carbene complex [(CO)5W=C(NMe2)C≡C—C≡CSnBu3] (4) is obtained by deprotonation of 3 with nBuLi and subsequent reaction with Bu3SnCl. Pd-catalyzed coupling of complex 4 with [ClRu(CO),Cp] affords the heterobimetallic pentadiynylidene complex [(CO)5W=C(NMe,)C≡C—C≡CRu-(CO)2Cp] (5) The analogous Fe derivative [(CO),W=C(NMe,)C≡C—C≡CFe(CO)2Cp] (6) is obtained by sequential reaction of 3 with nBuLi and [IFe(CO)2Cp] Similarly, treatment of 3 first with nBuLi and then with half an equivalent of HgCl2 affords the novel C4HgC4-bridged biscarbene complex [(CO)3W=C(NMe2)C≡C—C≡CHgC≡C—C≡CC(NMe2)=W(CO)5]( 7 ) All new compounds are stable at room temperature. Spectroscopic data suggest weak interaction of the metal centers in 5 - 7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300807
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  • 5
    Electronic Resource
    Electronic Resource
    Diastereoselective Substitution of PR3 for CO in Carbohydrato- and Menthyloxycarbene Complexes of Manganese - Synthesis of Chiral-at-metal Carbene and Carbyne Complexes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 385-390 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Carbyne complexes ; Carbohydrates ; Diastereoselective substitution ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The substitution of PR3 (R = C6H4CH3-p, C6H4Cl-p, C6H11,OCH3) for a CO ligand in chiral carbohydratocarbene complexes [(η5-C5H5)(CO)2Mn=C(OR*)Ph] [OR* = α- (1α) and β-mannofuranosyl (1β), (-)-menthyloxy (9)] proceeds diastereoselectively. The diastereoselectivity depends on PR3 and on the OR* substituent and ranges from 12% de (R = OCH3) to 80% (R = C6H4CH3-p). In contrast, the reaction of 1β with P(OPh)3 is non-selective. The diastereoselectivity generally increases with increasing nucleophilicity of PR3 and decreases in the series 1β 〉 1α 〉 9. The highest diastereoselectivity was observed in the reaction of 1β with P(C6H4CH3-p)3. Predominantly, the isomer with the (S) configuration at the metal [(S Mn)-2β] was formed which could be separated from the diastereomeric mixture by chromatography and be obtained in a pure form. Subsequent reaction of (SMn)-2β with BF3 afforded the carbyne-manganese complex (SMn)-[(η5-C5H5){P(C6H4CH3-p)3}(CO)Mn≡CPh]BF4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290404
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  • 6
    Electronic Resource
    Electronic Resource
    Polynuclear Complexes with Propynylidene C3-Bridges: General Synthetic Route to Bis-, Tris-, and Tetrakis(ethynylcarbene) Complexes (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 191-202 
    Details
    ISSN: 1434-1948
    Keywords: Polynuclear complexes ; Carbene complexes ; Bridging ligands ; Alkynyl complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The sequential reaction of two equivalents of the dimethylamino(ethynyl)carbene complexes [(CO)5M=C(NMe2)C≡CH] [M = W (1a), Cr (1b)] with two equivalents of nBuLi and one equivalent of a transition metal dichloride, [Cl2M′(Ln)], affords trinuclear biscarbene complexes of the type [(CO)5M=C(NMe2)C≡C-M′(Ln)-C≡CC(NMe)2=M(CO)5] [M′(Ln) = Ni(PEt3)2 (2a, b), Pd(PEt3)2 (3a, b), Pt(PEt3)2 (4a, b), Fe(dmpe)2 (6a), Hg (8a), Ti(η5-C5H5)2 (9a, b)] [dmpe = 1,2-bis(dimethylphosphino)ethane]. Treatment of 1a with equimolar amounts of first nBuLi and then [Cl2M′(Ln)] results in the formation of the monosubstitution products [(CO)5W=C(NMe2)C≡CM′(Ln)] [M′(Ln) = trans-Pd(PEt3)2Cl (5a), trans-Fe(dmpe)2Cl (7a)]. Additionally, the synthesis of the heterobimetallicethynylcarbene complex [(CO)5W=C(NMe2)C≡CPd(PEt3)2C≡CH] (10a), starting from 1a and [ClPd(PEt3)2C≡CH], is described. When three equivalents of 1a are treated, first with three equivalents of nBuLi and then with one equivalent of the trihalides PCl3 or BBr3, the novel tris(ethynylcarbene) complexes [{(CO)5W=C(NMe2)C≡C}3E] [E = B (11a), P (12a)] are obtained. The reaction of four equivalents of 1a,b with four equivalents of nBuLi, followed by addition of one equivalent of a group 14 tetrachloride [M′Cl4], yields the novel tetrakis(ethynylcarbene) complexes [{(CO)5M=C(NMe2)C≡C}4M′] [M′ = Si (13a, b), Ge (14a), Sn (15a, b)]. The complexes 8a, 9a, 12a, and 15a were characterized by X-ray structural analyses. All spectroscopic and structural data suggest that the carbene fragments and the central transition metal or heteroatom in these new bis-, tris-, and tetrakis(ethynylcarbene) complexes interact only weakly.
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  • 7
    Electronic Resource
    Electronic Resource
    Diastereoselective Substitution of PR3 for CO in Carbene(dicarbonyl)cyclopentadienyl Complexes of Manganese - Synthesis of (SMn)- and (RMn)-[Cp(CO)(PR3)Mn=C(OR*)R′] Complexes (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 339-347 
    Details
    ISSN: 1434-1948
    Keywords: Carbene complexes ; Carbyne complexes ; Asymmetric synthesis ; Carbohydrates ; Chiral auxiliaries ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral carbene complexes [Cp(CO)2Mn=C(OR*)Ph] (4a-e) were prepared by reaction of [Cp(CO)2Mn=C(OAc)Ph] (2) with HOR* [HOR* = 1,2:3,4-di-O-isopropylidene-D-galactopyranose (3a), 2,3,4,6-tetra-O-acetyl-D-galactopyranose (3b), 2,3,4,6-tetra-O-acetyl-D-glucopyranose (3c), (S)- (3d) and (R)-1,2-O-isopropylideneglycerol (3e)]. The replacement of a CO ligand with PTol3 in 4a-e proceeded diastereoselectively to give [Cp(CO)(PTol3)Mn=C(OR*)Ph] (5a-e). The diastereoselectivity increased in the order a, b, c, d: de = 8% (5a), 33% (5b), 70% (5c), 〉 96% (5d). For (R)-5d the isomer with the (S) configuration at manganese (SMn) was formed predominantly. For (S)-5d, only (RMn,S)-5d was detected (de 〉 96%). Photolysis of (R)-4d in the presence of phosphites or phosphanes afforded (SMn)-[Cp(CO)(PR3)Mn=C(OR*)Ph] [PR3 = P(OPh)3 (8), P(OMe)3 (9), P(OMe)2Ph (10), P(OMe)Ph2 (11), PPh3 (12), P(C6H4Cl-p)3 (13)] with a de 〉 96%. Photolysis of (S)-4d in the presence of P(OMe)3 gave (RMn,S)-9. Complex (R)-14 [related to (R)-4d] was obtained from [Cp(CO)2Mn=C(OAc)Tol-p] and 3d. Replacement of CO by PR3 in (R)-14 gave (SMn,R)-[Cp(CO)(PR3)Mn=C(OR*)Tol-p] [R = Tol-p (15), OMe (16), C6H4Cl-p (17)] with a de 〉 96%. In solution, the PTol3-substituted complex 5d is configurationally stable whereas the P(OMe)3 complex 9 epimerizes slowly at room temperature in CH2Cl2, Et2O, and THF within about one week.
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