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Berichte der deutschen chemischen Gesellschaft 05/2010; 2010(19):2911 - 2918. · 2.94 Impact Factor
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ABSTRACT: Colliding double deckers: Addition of zinc to a reaction mixture of [{Cp*RuCl}(4)]/pentamethyl-2,3-dihydro-1,3-diborole (C(3)B(2)Me(5)H) in THF leads to three known double- and triple-decker complexes of [C(3)B(2)Me(5)](-), and unexpectedly to the slipped triple-decker (see picture) with two fused diborole rings. The endo C--H bonds of two MeC--H groups donate two additional electrons to achieve the stable 34 VE configuration.
Angewandte Chemie International Edition 02/2009; 48(8):1429-31. · 13.45 Impact Factor
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Berichte der deutschen chemischen Gesellschaft 06/2008; 2008(21):3320 - 3329. · 2.94 Impact Factor
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ABSTRACT: The syntheses of diboryl porphyrin complexes [(BX2)2(ttp)] (ttp: dianion of tetra-p-tolylporphyrin) and the B-B single-bond diboranyl complexes [(BX)2(ttp)] (X=F, Cl, Br, I) are given. The former are prepared from the reactions of BX3 (X=F, Cl) with [Li2(ttp)] and the latter from B(2)Cl(4) (X=Cl), the reaction of SbF3 with [(BCl)2(ttp)] (for X=F), and, in the cases of X=Br or I, in a remarkable reductive coupling reaction resulting directly from the reaction of BBr3 or BI3 with [Li2(ttp)]. Density functional theory (DFT) calculations on the thermochemical parameters for the reductive coupling reactions (and those calculated for related dipyrromethene complexes) indicate that a combination of the reducing ability of bromide and iodide ions combined with the constrained environment of the porphyrin ligand contribute to the driving force. The reductive coupling is also observed in the reaction of [(BCl2)2(ttp)] with nBuLi to give [(BnBu)2(ttp)], which was characterised crystallographically. The reaction of [(BCl)2(ttp)] with catechol gives a boron catecholato porphyrin complex, [B2(O(2)C(6)H(4))(ttp)]. Chloride abstraction from [(BCl)2(ttp)] gives the planar dication [B2(ttp)]2+, whereas chemical reduction of [(BCl)2(ttp)] by using magnesium anthracenide gives a neutral complex, [B(2)(ttp)], in which the TTP ligand has been reduced by two electrons to give an unusual example of an isophlorin complex. The cationic and neutral complexes [B2(ttp)]2+ and [B2(ttp)] were characterised through a combination of spectroscopic data that is supported by DFT calculations on the porphine analogues.
Chemistry 02/2007; 13(21):5982-93. · 5.93 Impact Factor
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ABSTRACT: Bis(aren)eisen 1a – e (Aren = p-Xylol, Toluol, Benzol, Benzotrifluorid, 1,4-Difluorbenzol) reagieren im Temperaturbereich von – 100 bis −60°C mit 3,4-Diethyl-2,5-dihydro-2,5-di-methyl-1,2,5-thiadiborol (Thiadiborolen, 2) zu reaktiven Zwischenverbindungen, die durch Zersetzung bei −30°C (η6-Aren)(η5-thiadiborolen)eisen 3a – e ergeben. Alternativ gelingt die Synthese über Aren-bis(ethen)eisen 4a, c (Aren = p-Xylol, Benzol), welche bei tiefen Temperaturen aus 1a, c und Ethen darstellbar sind. Reaktionen, spektroskopische Daten und die Kristallstruktur von (η6-Benzol)(η5-thiadiborolen)eisen (3c) werden mitgeteilt.Reactive π-Complexes of the Group VIII Transition Metals, I. (η6-Arene)(η5-2,5-dihydro-1,2,5-thiadiborol)iron: Syntheses from Bis(arene)iron and Arene-bis(ethene)ironBis(arene)iron 1a – e, (arene = p-xylene, benzene, benzotrifluoride, 1,4-difluorobenzene) react in the temperature range of −100 to −60°C with 3,4-diethyl-2,5-dihydro-2,5-dimethyl-1,2,5-thiadiborole (thiadiborolene, 2) to form reactive intermediates which decompose at −30°C and (η6-arene)(η5-thiadiborolene)iron 3a – e are obtained. Alternatively, the synthesis is achieved via arene-bis(ethene)iron 4a,c (arene = p-xylene, benzene), which is formed from 1a,c and ethene at low temperature. Reactions, spectroscopic data, and the crystal structure of (η6-benzene)(η5-thiadiborolene)iron (3c) are reported.
Berichte der deutschen chemischen Gesellschaft 01/2006; 119(3):971 - 979. · 2.94 Impact Factor
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ABSTRACT: Die 1,2,3,6-Tetrahydro-1,2,3,6-diphosphadiborin-Derivate 3a und 3b entstehen durch Cyclokondensation aus 1,2-Bis[chlor(dialkylamino)boryl]ethenen 2 und 1,2-Dikalium-1,2-di-tert-butyldiphosphandiid. Die Temperaturabhngigkeit der 1H-NMR-Spektren von 3b dokumentiert wie bei 2,5-Dihydro-1H-1,2,5-phosphadiborol-Derivaten 1 eine erniedrigte Phosphor-Inversionsbarriere. Die Röntgenstrukturanalyse von 3b zeigt, daß der C2B2P2-Sechsring im Kristall nicht eben ist und daß die P-Atome pyramidal koordiniert sind. Versuche zur Substitution der Dialkylaminogruppen an den Boratomen von 3a und 3b mit HCl·Et2O oder tBuLi führen zur Spaltung der BP-Bindungen. Die Umsetzung von 3a bzw. 3b mit Cr(CO)3(MeCN)3 ergibt keine Tricarbonylchrom-Komplexe, sondern die Tetracarbonylchrom-Komplexe 6a bzw. 6b, in denen die Liganden 3a und 3b pentahapto gebunden sind.Synthesis, Structure, and Reactions of 1,2,3,6-Tetrahydro-1,2,3,6-diphosphadiborine DerivativesThe 1,2,3,6-tetrahydro-1,2,3,6-diphosphadiborine derivatives 3a and 3b are obtained by cyclocondensation of 1,2-bis[chloro(dialkylamino)boryl]ethenes 2 and 1,2-dipotassium 1,2-di-tert-butyldiphosphanediide. As in the case of 2,5-dihydro-1H-1,2,5-phosphadiborole derivatives 1 the temperature-dependent 1H-NMR spectra of 3b exhibit a lowered barrier of inversion at phosphorus. The X-ray structure analysis of 3b shows, that the six-membered C2B2P2 ring is nonplanar and the P atoms are coordinated pyramidally. Attempts to substitute the dialkylamino groups at the boron atoms of 3a and 3b with HCl·Et2O or tBuLi lead to cleavage of the BP bonds. Reaction between 3a or 3b and Cr(CO)3(MeCN)3 does not result in the formation of tricarbonylchromium complexes but of tetracarbonylchromium complexes 6a and 6b with pentahapto-bonded ligands 3a and 3b.
Berichte der deutschen chemischen Gesellschaft 01/2006; 122(3):467 - 472. · 2.94 Impact Factor
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ABSTRACT: New Routes to Bis[(cyclopentadienyl)cobalt]-μ-(η5-2,3-dihydro-1,3-diborolyl) Triple-Decker Complexes by Hydrogen Shift Reactions in Derivatives of 4,5-Diisopropylidene-1,3-diborolane, 2,4,5-Triisopropylidene-1,3-diborolane, and Benzo-1,3-diborafulveneThe 31 VE dicobalt triple-decker complexes 6, 7a, 7b, c, 8a, b, and 9a, b with bridging 2,3-dihydro-1,3-diborolyl ligands are prepared. The reaction of the 1,3-diborole 1 with [(C5Me5)-Co(C2H4)2] leads to the sandwich complex 5, which is treated with [(C5H5)Co(C2H4)2] to yield unsymmetrical 6. The 4,5-diisopropylidenetrimethyl-1,3-diborolane 3 undergoes a metal-induced 1,5-hydrogen shift and reacts with [(C5H5)Co(C2H4)2] to form the triple-decker 7a. The reaction of the 2,4,5-triisopropylidene-1,3-diborolane 4 with [(C5H5)Co(C2H4)2] leads to a mixture of the triple-deckers 7b/c, formed by intermolecular hydrogen shift. The benzo-1,3-diborafulvene derivatives 2b and 2c also react with [(C5H5)Co(C2H4)2] to give the triple-decker 8b and a mixture of 9a, b. In addition, the trinuclear complex 8c is obtained in low yield. The new paramagnetic triple-decker complexes have been analyzed by NMR and ESR spectroscopic measurements as well as by electochemistry. The constitutions of 7b/c, 8b, 8c, and 9a/b have been confirmed by X-ray structure analyses. The complexes are iso-structural, the Co—Co distances range from 3.277(1) (7b/c) to 3.316(1) Å for 8c.
Berichte der deutschen chemischen Gesellschaft 01/2006; 126(10):2197 - 2203. · 2.94 Impact Factor
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ABSTRACT: 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.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.
Berichte der deutschen chemischen Gesellschaft 01/2006; 118(2):729 - 740. · 2.94 Impact Factor
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Angewandte Chemie 01/2006; 100(3):410 - 411.
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Angewandte Chemie 01/2006; 96(12):994 - 995.
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Angewandte Chemie 01/2006; 106(2):215 - 217.
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Berichte der deutschen chemischen Gesellschaft 12/2005; 2006(3):566 - 572. · 2.94 Impact Factor
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Berichte der deutschen chemischen Gesellschaft 08/2005; 2005(20):4086 - 4089. · 2.94 Impact Factor
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Angewandte Chemie International Edition 02/2005; 44(4):632-4. · 13.45 Impact Factor
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Berichte der deutschen chemischen Gesellschaft 05/2004; 2004(13):2635 - 2645. · 2.94 Impact Factor
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Berichte der deutschen chemischen Gesellschaft 04/2004; 2004(12):2425 - 2433. · 2.94 Impact Factor
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ABSTRACT: In the title compound, 1,1,6a,7,9a,10-hexachloro-2,3,5,6,8,9,11,12-octa-p-tolyl-1,6a,9a,12a-tetraborata-3a,4a,7,10-tetrabora-4a(1),6b,9b,12b-tetraoxonia-4-oxatetracyclopenta[1,2-a:2,1,5-de:1,2-g:1,2-i]naphthalene dichloromethane pentasolvate, C(64)H(56)B(8)Cl(6)O(5).5CH(2)Cl(2), two condensed oxadiborole rings are attached to two further oxadiborole rings in a type of donor-acceptor bonding, thus forming a ten-membered alternating (B-O)(5) naphthalene-like arrangement as the central building block.
Acta Crystallographica Section C Crystal Structure Communications 06/2003; 59(Pt 5):o257-8. · 0.52 Impact Factor
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ABSTRACT: The treatment of 3,3-dimethyl-1-butynyllithium with boron trichloride followed by double hydroboration with HBCl2 afforded 1,1,1-tris(dichloroboryl)-3,3-dimethylbutane (1a), characterized as its catechol derivative 1b. Analogously, three isomers (3a, 4a, and 5a) were obtained with trimethylsilylacetylide and identified as catechol derivatives 3b, 4b, and 5b. On heating, 1a formed 2,3,4-trichloro-1,5-dicarba-closo-pentaborane(5) (6a) with elimination of boron trichloride. Compound 6a reacted with methyllithium and trimethylaluminium, and also with pentamethylsilazane and acetylides, to give the corresponding carborane derivatives 6c, 6d, 6e, and 6f. The compositions of the products followed from analytical data and X-ray structure analyses of 1b, 4b, 5b, 6a, and 6f. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
Berichte der deutschen chemischen Gesellschaft 05/2002; 2002(6):1293 - 1300. · 2.94 Impact Factor
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Angewandte Chemie International Edition 05/2002; 41(9):1529-32. · 13.45 Impact Factor
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04/2002;
