55,881 research outputs found
Ferrocenyl-functionalised terpyridines and their transition-metal complexes: Syntheses, structures and spectroscopic and electrochemical properties
No full textSiemeling U, Vor der Brüggen J, Vorfeld U, et al. Ferrocenyl-functionalised terpyridines and their transition-metal complexes: Syntheses, structures and spectroscopic and electrochemical properties. Chemistry. 2003;9(12):2819-2833
DIELS-ALDER REACTIONS OF A DOUBLE-LAYERED, CYCLOPHANOID CYCLOPENTADIENONE - A NOVEL-APPROACH TO [N,N]PARACYCLOPHANES
No full textJutzi P, SIEMELING U. DIELS-ALDER REACTIONS OF A DOUBLE-LAYERED, CYCLOPHANOID CYCLOPENTADIENONE - A NOVEL-APPROACH TO [N,N]PARACYCLOPHANES. CHEMISCHE BERICHTE. 1989;122(5):993-995
[3]Ferrocenophanes with a tetramethyldisiloxane bridge: synthesis and molecular structure
No full textSiemeling U, Krallmann R, Jutzi P, Neumann B, Stammler H-G. [3]Ferrocenophanes with a tetramethyldisiloxane bridge: synthesis and molecular structure. Monatshefte für Chemie. 1994;125(5):579-586.6,6,8,8-Tetramethyl-7-oxa-6,8-disila[3]-ferrocenophan 2 entsteht aus dem Di(alkoxysilyl)ferrocen (H4C5SiMe2OR)2Fe (R=CH2CH2OCH2CH2OCH2CH2OMe) durch Hydrolyse und anschließende intramolekulare Disiloxan-Bildung. 2,2',3,3',4,4',5,5',6,6,8,8-Dodecamethyl-7-oxa-6,8-disila[3]ferrocenophan 3 wurde durch Luftoxidation von 2,2',3,3',4,4',5,5',6,6,7,7-Dodecamethyl-6,7-disila[2]ferrocenophan erhalten. Die Kristallstrukturen beider Verbindungen wurden durch Einkristall-Röntgenstrukturanalyse bestimmt (2:a=8.5330(10), b=15.610(3), c=18.774(5)Å, [alpha]=70.68(2), [beta]=77.94(2), [gamma]=75.150(10)°, V=2259.8(8)Å3, Z=6, Raumgruppe P1, R=0.045, Rw =0.044; 3:a=12.388(3), b=9.924(3), c=19.136(10)Å, [beta]=105.11(3)°, V=2271.2(15)Å3, Z=4, Raumgruppe P21/c, R=0.076, Rw =0.060). Wegen der Flexibilität der Disiloxan-Brücke sind 2 und 3 ungespannte Moleküle
BINUCLEAR TRANSITION-METAL COMPLEXES OF CYCLOPHANOID CYCLOPENTADIENONE AND CYCLOPENTADIENYL LIGANDS
No full textJutzi P, SIEMELING U, Müller A, Bögge H. BINUCLEAR TRANSITION-METAL COMPLEXES OF CYCLOPHANOID CYCLOPENTADIENONE AND CYCLOPENTADIENYL LIGANDS. ORGANOMETALLICS. 1989;8(7):1744-1750
CYCLOPENTADIENYL COMPOUNDS WITH NITROGEN DONORS IN THE SIDE-CHAIN
No full textJutzi P, SIEMELING U. CYCLOPENTADIENYL COMPOUNDS WITH NITROGEN DONORS IN THE SIDE-CHAIN. JOURNAL OF ORGANOMETALLIC CHEMISTRY. 1995;500(1-2):175-185.The coordination chemistry of cyclopentadienyl ligands bearing either a dimethylaminoethyl side-chain or a pendant pyridyl group is described. The influence of these N donor functionalities on the structure and the physical as well. as chemical properties of relevant metal complexes is discussed. In several cases, a relatively weak intramolecular coordination of the pendant amine is found; the hemilabile coordination profile of the N functionalised cyclopentadienyl ligands towards d-block elements may prove useful for the development of single-component catalysts
Benefits of the chelate effect: Preparation of an unsymmetrical ansa-bis(imido)molybdenum complex containing a seven-membered chelate ring
No full textSiemeling U, Turk T, Schoeller W, Redshaw C, Gibson VC. Benefits of the chelate effect: Preparation of an unsymmetrical ansa-bis(imido)molybdenum complex containing a seven-membered chelate ring. INORGANIC CHEMISTRY. 1998;37(18):4738-4739
Crystal Structure of Isopropyllithium
No full textSiemeling U, Redecker T, Neumann B, Stammler H-G. Crystal Structure of Isopropyllithium. Journal of the American Chemical Society. 1994;116(12):5507-5508
TRINUCLEAR HOMOMETALLIC AND HETEROMETALLIC COMPLEXES OF A DOUBLY BRIDGED CYCLOPENTADIENYL LIGAND
No full textSIEMELING U, Jutzi P. TRINUCLEAR HOMOMETALLIC AND HETEROMETALLIC COMPLEXES OF A DOUBLY BRIDGED CYCLOPENTADIENYL LIGAND. CHEMISCHE BERICHTE-RECUEIL. 1992;125(1):31-35.Metal complexes that are derived from the doubly bridged cyclopentadiene system 2,2,8,8-tetramethyl-2,8-disilatricyclo-[7.3.0.0(3,7)]dodeca-3,5,9,11-tet raene (LH2) are investigated. The dilithio salt of this compound (LLi2) reacts with (Me3Si)3-C5H2FeCl to give, amongst other products, the trinuclear ferrocene [(Me3Si)3C5H2FeL]2Fe (2). A starting material well suited for the selective preparation of similar trinuclear complexes is the mononuclear ferrocene (HL2)Fe (3) which is formed by reaction of HLLi with iron(II) chloride. Reaction of dilithiiated 3 with trimethyltin chloride yields (Me3SnL)2Fe (4). Cocomplexation of dilithiated 3 and Cp*Li(Cp* = C5Me5) with iron(II) chloride leads to the trinuclear ferrocene (Cp*FeL)2Fe (5). By reaction of 3 with octacarbonyldicobalt the heterometallic complex [(CO)2CoL]2Fe (6) is obtained, which yields [(CO)I2CoL]2Fe (7) by oxidative decarbonylation with iodine. The stereochemistry of the complexes presented is discussed. The trinuclear complexes 2, 5, 6, and 7 are model systems for organometallic polymers with spatially directed structures, whose stability even in mixed-valence states is evidenced by the mass spectra of these complexes
Terpyridines functionalised with ferrocenyl groups of different redox potential
No full text2,2′:6′,2′′-Terpyridines bearing a substituent × in the 4′-position [3a: × = Fc–C≡C–p-C6H4; 3b: × = Fc#–C≡C–p-C6H4; Fc = (C5H5)Fe(C5H4), Fc# = (C5Me4H)Fe(C5Me4)] were prepared by Pd0-catalysed cross-coupling reactions. 3b was characterised by X-ray structure analysis. [(3a)RuCl2(DMSO)] (4a) and [(3b)RuCl2(DMSO)] (4b) were obtained by reaction of [RuCl2(DMSO)4] with 1 equivalent of 3a and 3b, respectively, while the analogous reaction with 2 equivalents afforded [(3a)2Ru][PF6]2 (5a) and [(3b)2Ru][PF6]2 (5b), respectively, after precipitation with aqueous [NH4][PF6]. Similarly, [(3a)Ru(tpy)][PF6]2 (6) was isolated from the reaction of 4a with 2,2′:6′,2′′-terpyridine (tpy). Compounds 3 and 5 were investigated by cyclic voltammetry, which revealed that the introduction of eight methyl groups leads to the expected cathodic shift of the E0′ values of ca. 0.44 V for the ferrocenyl-centered redox processes
METAL-METAL INTERACTIONS IN COMPLEXES WITH A DOUBLE DIMETHYLSILANDIYL-BRIDGED DICYCLOPENTADIENYL LIGAND
No full textSIEMELING U, Jutzi P, BILL E, TRAUTWEIN AX. METAL-METAL INTERACTIONS IN COMPLEXES WITH A DOUBLE DIMETHYLSILANDIYL-BRIDGED DICYCLOPENTADIENYL LIGAND. JOURNAL OF ORGANOMETALLIC CHEMISTRY. 1993;463(1-2):151-154.The metal-metal interaction in the mixed-valence ferrocenium salt [trans-Cp*FeLFeCp*]+PF6- ([5(+)]PF6-) (Cp* = C(5)Me(5), L = [C(5)H(3)SiMe(2)](2)) was investigated by cyclic voltammetry, electron spectroscopy, EPR and temperature dependent Mossbauer spectroscopy. The compound is best described as a valence-localised system (class I according to Robin and Day)
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