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  • 1
    Electronic Resource
    Electronic Resource
    Katalysierte Dimerisierung von 1,2-Bis(dimethylamino)-1,2-dibora-4-cyclohexen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 45-47 
    Details
    ISSN: 0009-2940
    Keywords: Diboration / Cage compound ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Catalyzed Dimerisation of 1,2-Bis(dimethylamino)-1,2-dibora-4-cyclohexene1,2-Bis(dimethylamino)-1,2-dibora-4-cyclohexene (1) dimerizes under the catalytic action of Et2O-BF3 to form the cage compound 3,7,9,11-tetrakis(dimethylamino)-3,7,9,11-tetraboratricyclo[4.2.2.22.5] dodecane (2). The crystals of 2 are triclinic, and the molecule exhibits crystallographic centrosymmetry.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230109
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  • 2
    Electronic Resource
    Electronic Resource
    Neue Cyclooctatetraen-Komplexe des Niobs(1) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2663-2666 
    Details
    ISSN: 0009-2940
    Keywords: Niobium complexes ; Methylcyclopentadienyl derivatives ; Cyclooctatetraene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Cyclooctatetraene Complexes of Niobium[1]The (butadiene)niobium complexes Cp′Nb(C4H6)2 and Cp′Nb(C4H6)(PMe3)2 (Cp′=C5H4Me) react with cyclooctatetraene (COT) to give Cp′Nb(C4H6)(COT) (2), Cp′Nb(COT)2 (3), and Cp′Nb(PMe3)2(COT) (5) with fluxional COT ligands. The structure of 3 exhibits a prone-η3- and a supine-η4-COT ligand which interchange their role at elevated temperature. That of 5 shows a supine η3-COT ligand.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241205
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesen neuer bororganischer Ringe mit zwei Bor-Atomen durch Borylierung des Trimethylenmethan-Dianions (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 23-29 
    Details
    ISSN: 0009-2940
    Keywords: Diboracycloalkanes ; Diboracycloalkenes ; Trimethylenemethane, borylation of the dianion of ; Allylboranes, B - C bond length ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses of New Organoboron Rings with two Boron Atoms by Borylation of the Trimethylenemethane DianionBorylation of Li2[C(CH2)3] (1) provides a versatile starting point for the synthesis of 5-, 6-, 7-, and 8-membered ring systems with two boron atoms and leads to 1,5-bis(dialkylamino)-3,7-dimethylene-1,5-diboracyclooctanes 2a, b (a: R=Et; b: R=iPr), 1,3-bis(dialkylamino)-5-methylene-1,3-diboracyclohexanes 8a, b, 1,3-bis(diethylamino)-5-methyl-1,3-dibora-4-cyclo-hexene (10), and 1,4-bis(dialkylamino)-6-methylene-1,4-dibora-2-cycloheptenes 11a, b. The compounds 2b, 8b, and the 2,3-biboratafulvene derivative [Li(TMEDA)]2[CH2C(CHB)2-(NiPr2)2] are characterized by X-ray diffraction analysis. It is shown that for trigonal boron B - C(allyl) bond distances (typically 160 ± 1 pm) are significantly larger than B - C(alkyl) distances (typically 158 + 1 pm).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250105
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  • 4
    Electronic Resource
    Electronic Resource
    Elektronenüberschuß-Komplexe von Cobalt und Nickel mit Cyclobutadien-Liganden: Synthese, Cyclovoltammetrie und Reaktivität (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1589-1595 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron-Excess Complexes of Cobalt and Nickel with Cyclobutadiene Ligands: Syntheses, Cyclovoltammetry, and Reactivity[1]A cyclovoltammetric investigation of tetraphenylcyclobutadiene complexes [ML(C4Ph4)]+ [1: ML = NiCp; 2a: ML = Co(C6H6); 2b: ML = Co(mesitylene)] reveals a reversible reduction to paramagnetic complexes 1 and 2a,b with a 19-electron count, and a subsequent irreversible reduction to anions 1- and 2a,b- with a 20-electron shell. Preparative reduction by one equivalent of CpFe(HMB) (HMB = C6Me6) produces the novel 19-electron complexes 1 and 2b. Complex 1 can also be obtained by treatment of 1 · Br with one equivalent of CoCp2 at room temperature while reduction at -20°C with two equivalents of CoCp2 affords a novel C-C-linked adduct CpNi[μ,η3:η4-(C4Ph4-C5H5)]CoCp (5). Above -10°C a slow equilibrium between 5 and its components 1 and CoCp2 is observed with ΔH = 15 kJ/mol for the dissociation process. With an excess of the stronger reductant sodium amalgam the cations 1+ and 2a+ are reduced to give cyclobutenyl complexes ML(η3-1,2,3,endo-4-C4HPh4) [6: ML = NiCp; 7: ML = Co(C6H6)]. 1 reacts with p-nitrobenzyl bromide to give 1 Br and a p-nitrobenzyl addition product CpNi[η3-exo-4-(p-O2NC6H4CH2)-1,2,3,endo-4-C4Ph4] (11) while 2b reacts with MeI to give 2b · I and two isomeric methyl addition products (η5-1,3,5,exo-6-C6H3Me4)Co(C4Ph4)] (12) and (mes)Co(η3-exo-4-Me-1,2,3,endo-4-C4Ph4) (13). Sodium-amalgam reduction of the tetramethylcyclobutadiene cations [(arene)Co(C4Me4)]+ (4a: arene = C6H6; 4b: arene = mesitylene) affords diamagnetic dinuclear compounds of type 8-10 with C-C linkages between C4Me4/C4Me4, arene/C4Me4, and arene/arene rings, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250713
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  • 5
    Electronic Resource
    Electronic Resource
    Derivate des Borols, XVIII. Tricarbonyl[η5-(1-phenylborol)]eisen: Zur Reaktivität der koordinierten Liganden (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1801-1805 
    Details
    ISSN: 0009-2940
    Keywords: (Borole)carbonyliron derivatives, electrophilic substitution, nucleophilic addition, reduction ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatives of Borole, XVIII. - Tricarbonyl[η5-(1-phenylborole)]iron: Reactivity of the Coordinated LigandsThe borole complex (C4H4BPh)Fe(CO)3 (1) undergoes Friedel-Crafts acetylation (MeCOCl/AlCl3) at the meta-position of the phenyl substituent while the derivatives (C4H4BPh)Fe(CO)2L (3, a: L = NMe3′ b: L = PMe3) are acetylated at the 2-position of the borole ring. Organolithium reagents (LiMe, LiBu) add to 1 at the boron atom below - 50°C while nucleophilic attack at the carbonyl C atom takes place at higher temperature with formation of acyl anions [(C4H4BPh)Fe(CO)2(COR)]- (6a,b-). The Fischer carbene complex (C4H4BPh)Fe(CO)2[C(OMe)Me] (7) is obtained from 6a-/[Me3O]BF4. Complex 1 reacts with LiN(SiMe3)2 to give [(C4H4BPh)Fe(CO)2(CN)]- (8-) and with 5 M NaOH/C6H6/NBu4HSO4 to produce the hydride NBu4-[(C4H4BPh)FeH(CO)2] (NBu4 · 9). A highly reactive dianion [(C4H4BPh)Fe(CO)2]2- (102-) is obtained by deprotonation of 9- or by reduction of 1 or 3a in THF at -70°C. Treatment of 102- with Ph3SnCl gives [(C4H4BPh)Fe(CO)2(SnPh3)]- (11-) which is isolated as NEt4 · 11. Slow reduction of 3a with sodium amalgam in THF at -30°C produces doubly CO-bridged cis-[{(C4H4BPh)Fe(CO)2}2]2- (122-) which is protonated to the μ2-hydrido anion [μ-H-{(C4H4BPh)Fe(CO)2}2]- (13-).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250804
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  • 6
    Electronic Resource
    Electronic Resource
    Reaktionen von 1-Phenyl-3-borolenen mit Aldehyden, Ketonen und Ketenen: Synthese von 1,2-Oxaborolan-Derivaten, 2,3-anti-1,3-Diolen und ungesättigten β1-Hydroxyalkylketonen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 297-304 
    Details
    ISSN: 0009-2940
    Keywords: Diastereoselective synthesis ; Homoallylic alcohols ; 1,3-Diols, homoallylic ; β1-Hydroxyalkyl ketones ; 2,5-Dihydro-1H1-boroles ; 1,2-Oxaborolanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Phenyl-3-borolenes CH2CR1=CR1CH2BPh) (1a: R1=H; b: R1=Me) react with aldehydes R2CHO to give cis-1,2-oxaborolanes CH2CR1[CR1(=CH2)]CR2R3OBPh (2, R2 = e.g. Me, Ph, CH=CH2, tBu, CCl3, R3 = H). Yields are nearly quantitative. Stereoselectivities usually are 100% (but only 95% for R2=CH=CH2, 97% for R2=Me). Oxidation with NaOH/H2O2 in THF affords homoallylic anti-1,3-diols HOCR2R31-CR1[CR1(=CH2)]CH2OH (3). An X-ray diffraction analysis of 3a (R2=p1-tolyl) proves the assigned stereochemistries. Ketones R2R3CO react analogously. Ketenes R2CCO form 5-alkylidene-4-vinyl-1,2-oxaborolanes (4), which tend to undergo double-bond migration. Oxidation produces two types of β1-hydroxylalkyl ketones R22CHCOC[(E)=CHMe]CH2OH (5) and R22CHCOCMe[CMe=CH2]CH2OH (6).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260205
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  • 7
    Electronic Resource
    Electronic Resource
    2-Boraindane und 2-(Dialkylamino)1-2-benzoborol-Dianionen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1397-1402 
    Details
    ISSN: 0009-2940
    Keywords: 2-Boraindanes ; 2-Benzoboroles, 1,3-dihydro- ; 2-Benzoborole-1,3-diides, 1,3-dihydro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Boraindanes and 2-(Dialkylamino)1-2-benzoborole Dianionsortho1-Xylene reacts with the Lochmann-Schlosser base to produce a mixture of the potassium derivatives K2[1,2-C6H4(CH2)2] (2) and K[2-MeC6H4CH2] (3). Condensation of 1 + 2 with BCl2(NR2) (R=Me, Et, iPr) affords 2-(dialkylamino)1-2-boraindanes (1a-c) (50%). Treatment of 1a, b with LiTMP/TMEDA in THF yields dilithio derivatives [Li(tmeda)]2[C6H4(CH)2BNR2] (8a, b) (40%) which show tripledecked structures consisting of an aromatic 10′-electron 2-benzoborole dianion and two [Li-(tmeda)]+ units facially bound to the borole ring. 1a reacts with HCl/Et2O/hexane to give C6H4(CH2)2BCl · OEt2 (1d · OEt2) (76%) which decomposes in vacuo to give the chloro derivative 1d. The methyl derivative C6H4(CH2)2BMe (1e) is obtained from 1a by treatment with LiMe/Et2O at -78°C and subsequently with HCl/Et2O at -78°C (41%). 1a, b react with MeOH at -78°C to give solid adducts C6H4(CH2)2BOMe · NHR2 (12a, b) while 1c affords C6H4(CH2)2BOMe (1f). Subsequent ring-opening produces 2-MeC6H4CH2B(OMe)2 (13). With the exception of 1b the 2-boraindanes 1 are crystalline solids. The silylation of the 2-benzoborole dianions and various (2-methylbenzyl)borane derivatives is also described.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260618
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  • 8
    Electronic Resource
    Electronic Resource
    Derivate des Borols, XVII {η5-[1-(Diisopropylamino)borol]}metall-Komplexe: Synthesen, Protonierung, interne Rotation (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 25-29 
    Details
    ISSN: 0009-2940
    Keywords: Borole complexes ; {η5-[1-(Diisopropylamino)borole]}metal complexes, internal rotation of, protonation of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatives of Borole, XVII1). - {η5-[1-(Diisopropylamino)borole]}metal Complexes: Syntheses, Protonation, Internal RotationNew complexes M(CO)4L (M = Cr, W), cis-M(CO)2L2 [M = Mo, W (not isolated)], and (COD)NiL have been prepared from the Diels-Alder dimer L2, where L is 1-(diisopropylamino)borole, C4H4BNiPr2. Complexes of L can be protonated at the nitrogen atom to give stable salts such as [Cr(CO)4(LH)]BF4, [Fe(CO)3(LH)]BF4, [(C6Me6)Ru(LH)]BF4, and [CpCo(LH)]BF4; B  -  N bond dissociation is not observed. Barriers to internal rotation have been determined by variable temperature NMR spectroscopy for Cr(CO)4L, (COD)NiL, and NiL2. Three processes have been identified: rotation of the NiPr2 group around the B  -  N bond, gear-mesh rotation of the isopropyl groups around the C  -  N bonds, and rotation of L with respect to the counter ligands.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240105
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  • 9
    Electronic Resource
    Electronic Resource
    (Butadien)(cyclopentadienyl)niob-Komplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 975-980 
    Details
    ISSN: 0009-2940
    Keywords: Niobium complexes ; Cyclopentadienyl derivatives ; Butadiene derivatives ; Acetylene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Butadiene)(cyclopentadienyl)niobium ComplexesThe known bis(butadiene)(cyclopentadienyl)niobium complex (C5H4R)Nb(C4H6)2 (1, R=H) exists in solution as a 1 : 1 mixture of a bis(cis-butadiene) isomer 1a and a (cis-butadiene)(trans-butadiene) isomer 1b. In solution the barrier to isomerisation is 80 ± 2 kJ/mol. New derivatives 2 (R=Me) and 3 (R=SiMe3) of 1 are described. One of the butadiene ligands in 1 - 3 is readily substituted with CO, CNtBu, P(OMe)3, and PMe3. CpNb(PMe3)2(C4H6) (7) reacts with disubstituted acetylenes to form acetylene complexes CpNb(PMe3)(C4H6)(RC=CR') (8: R, R'=Ph, 9: R=Me, R'=Ph, and 10: R=Ph, R'=SiMe3), The structure of 9 resembles that of bent metallocene derivatives with the acetylene acting as a 2-e ligand.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240502
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of the New α-Aminosilanolate [LiOSiMe2(NMe2)]6 (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1619-1620 
    Details
    ISSN: 0009-2940
    Keywords: Silanolate ; Aminosilanolate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithium (dimethylamino)dimethylsilanolate (1) is obtained from trimeric dimethylsiloxane and lithium dimethylamide in quantitative yield. In the crystal 1 is a hexamer [LiOSiMe2(NMe2)]6 with crystallograpic C3i (S6, 3) symmetry. The molecule of 1 consists of a hexagonal prismatic (LiO)6 core and an N,O-chelating anion.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270912
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