| | 41 | Author
| Jörn Müller, Ke Qiao, Regina Schubert, M. Atthias Tschampel | Requires cookie* | | | Title
| ;r-01efin-Iridium-Komplexe, XVIII [1] Reaktionen von Bis[cycloocta-l,5-dien-//-chloro-iridium] mit w-Propyllithium in Gegenwart von Alkinen yr-Olefin Iridium Complexes, XVIII [1] Reactions of Bis[cycloocta-l,5-diene-/z-chloro-iridium] with n -Propyllithium in the Presence of Alkynes  | | | | Abstract
| The reaction of [(cod)IrCl]2 (cod = //4-cycloocta-l,5-diene) with n-C3H7Li gives non-isola-ble (cod)IrH species by /3-elimination of (cod)Ir-n-C3H7 intermediates; the stable final prod ucts of further reactions with RC = CR highly depend on the nature of the substituents R. With R = Me the 6-endo-H-hexamethylcyclohexadienyl complex 1 is obtained together with the iridacyclopentadienyl compound 2 and known }[(cod)IrH]4C3H4} (3). In case of R = Et steric effects cause transfer of the hydridic hydrogen to the cod ligand, and the hexaethyl-benzene species 4 is isolated which was characterized by crystal structure analysis. The reac tion system with tolane again yields a 6-enJo-H-cyclohexadienyl complex (5). In all cases free substituted benzenes are formed as cyclotrimerization products of the alkynes. | | | |
Reference
| Z. Naturforsch. 48b, 1558—1564 (1993); eingegangen am 15. Juli 1993 | | | |
Published
| 1993 | | | |
Keywords
| Substituted Benzene, Cyclohexadienyl and Iridacyclopentadienyl Complexes, Synthesis, NMR Spectra, Crystal Structure | | | |
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| default:Reihe_B/48/ZNB-1993-48b-1558.pdf | | | | Identifier
| ZNB-1993-48b-1558 | | | | Volume
| 48 | |
| 42 | Author
| Wolfgang Jeitschko, Jörg Wallinda, MartinV. Dewalsky, Ulrich Wortmann | Requires cookie* | | | Title
| Preparation, Properties, and Structure of the Polyphosphides VM4P16, NbNi4P16, and WNi4P16 | | | | Abstract
| The title compounds were prepared by reacting powders of the binary transition metal alloys with phosphorus in a tin melt. They crystallize with a monoclinic structure of space group C 2/c, which was determined from single-crystal X-ray data; VNi4P16: a = 1956.0(3), b = 565.9(1), c = 1106.6(2) pm, ß = 100.99(1)°, R -0.020 for 1904 structure factors and 97 variable parameters; NbNi4P16: a = 1973.0(3), b = 571.2(3), c = 1117.2(2) pm, ß = 100.74(1)°, R = 0.023 for 2431 F-values and 97 variables; WNi4P16: a = 1964.2(3), b = 568.3(2), c = 1109.3(2) pm,/? = 101.04(2)°, R = 0.031 for 371 F-values and 43 variables. The T atoms (T = V, Nb, W) have eight P neighbors, which form a slightly distorted square antiprism, and the Ni atoms have appro ximately octahedral P coordination. The P atoms form novel P8 units, which consist of 6 -mem-bered rings with a P2 side chain. Chemical bonding is discussed on the basis of classical two-electron bonds. A comparison of the interatomic distances suggests that the Fermi level cuts through a band formed by antibonding nickel-phosphorus states. A band structure is propos ed, which also rationalizes the metallic conductivity and the Pauli paramagnetism of the com pounds. | | | |
Reference
| Z. Naturforsch. 48b, 1774—1780 (1993); received July 291993 | | | |
Published
| 1993 | | | |
Keywords
| Crystal Structure, Magnetic Properties, Electrical Conductivity, Chemical Bonding, Transition Metal Polyphosphides | | | |
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| 48 | |
| 43 | Author
| Magdolna Hargittai, Gabor Jancsó | Requires cookie* | | | Title
| Correlation of Crystal Structure and Vapor Composition of Metal Dihalides | | | | Abstract
| The presence of dimers in the vapor of metal dihalides, as seen in electron diffraction experiments, is found to be correlated with the crystal structure of the halide and with the difference in the heat of vaporization between monomers and dimers. If the dimeric molecule cannot be recognized as a unit in the crystal, dimers are not detected in the vapor. If dimeric molecules are discernible in the crystal, they will be observed in the vapor if their heat of vaporization is not greater than that of the monomer by more than 10kcal/mol. | | | |
Reference
| Z. Naturforsch. 48a, 1000—1004 (1993); received July 20 1993 | | | |
Published
| 1993 | | | |
Keywords
| Crystal structure, Vapor composition, Metal dihalides, Correlation of structure and vapor composition, Gas-phase electron diffraction | | | |
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| 48 | |
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